-Libpng 1.5.2 - March 31, 2011
+Libpng 1.5.9 - February 18, 2012
This is a public release of libpng, intended for use in production codes.
Source files with LF line endings (for Unix/Linux) and with a
"configure" script
- libpng-1.5.2.tar.xz (LZMA-compressed, recommended)
- libpng-1.5.2.tar.gz
- libpng-1.5.2.tar.bz2
+ libpng-1.5.9.tar.xz (LZMA-compressed, recommended)
+ libpng-1.5.9.tar.gz
+ libpng-1.5.9.tar.bz2
Source files with CRLF line endings (for Windows), without the
"configure" script
- lpng152.7z (LZMA-compressed, recommended)
- lpng152.zip
+ lpng159.7z (LZMA-compressed, recommended)
+ lpng159.zip
Other information:
- libpng-1.5.2-README.txt
- libpng-1.5.2-LICENSE.txt
-
-Changes since the last public release (1.5.2):
-
- More -Wshadow fixes for older gcc compilers. Older gcc versions apparently
- check formal parameters names in function declarations (as well as
- definitions) to see if they match a name in the global namespace.
- Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
- old VisualC++ preprocessor.
- Turned on interlace handling in png_read_png().
- Fixed gcc pendantic warnings.
- Handle longjmp in Cygwin.
- Fixed png_get_current_row_number() in the interlaced case.
- Cleaned up ALPHA flags and transformations.
- Implemented expansion to 16 bits.
- Fixed mistake in the descriptions of user read_transform and write_transform
- function prototypes in the manual. The row_info struct is png_row_infop.
- Corrected png_get_current_row_number documentation
- Fixed the read/write row callback documentation.
- This documents the current behavior, where the callback is called after
- every row with information pertaining to the next row.
- Fixed scripts/makefile.vcwin32
- Updated contrib/pngsuite/README to add the word "modify".
- Define PNG_ALLOCATED and other attributes to blank when _MSC_VER<1300.
- ifdef out mask arrays in pngread.c when interlacing is not supported.
- Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
- and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
- from the makefiles.
- Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
- to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
- Don't include standard header files in png.h while building the symbol table,
- to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
+ libpng-1.5.9-README.txt
+ libpng-1.5.9-LICENSE.txt
+
+Changes since the last public release (1.5.8):
+
+ Rebuilt configure scripts in the tar distributions.
+ Removed two unused definitions from scripts/pnglibconf.h.prebuilt
+ Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
+ Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
+ Fixed CVE-2011-3026 buffer overrun bug. Deal more correctly with the test
+ on iCCP chunk length. Also removed spurious casts that may hide problems
+ on 16-bit systems.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe) or to glennrp at users.sourceforge.net
+to subscribe)
+or to glennrp at users.sourceforge.net
Glenn R-P
#if 0
-libpng_changes(){ /*
CHANGES - changes for libpng
Version 0.2
fixed some bugs in writer
interfaced with zlib 0.5
added K&R support
- added check for 64 KB blocks for 16 bit machines
+ added check for 64 KB blocks for 16-bit machines
Version 0.4
cleaned up code and commented code
Version 0.85 [December, 1995]
added more medium model code (almost everything's a far)
added i/o, error, and memory callback functions
- fixed some bugs (16 bit, 4 bit interlaced, etc.)
+ fixed some bugs (16-bit, 4-bit interlaced, etc.)
added first run progressive reader (barely tested)
Version 0.86 [January, 1996]
Fixed serious bug with < 8bpp images introduced in 0.95
Fixed 256-color transparency bug (Greg Roelofs)
Fixed up documentation (Greg Roelofs, Laszlo Nyul)
- Fixed "error" in pngconf.h for Linux setjmp() behaviour
+ Fixed "error" in pngconf.h for Linux setjmp() behavior
Fixed DOS medium model support (Tim Wegner)
Fixed png_check_keyword() for case with error in static string text
Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
Minor corrections in libpng.txt
Added simple sRGB support (Glenn R-P)
- Easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+ Easier conditional compiling, e.g.,
+ define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
all configurable options can be selected from command-line instead
of having to edit pngconf.h (Glenn R-P)
Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
Added more conditions for png_do_background, to avoid changing
black pixels to background when a background is supplied and
no pixels are transparent
- Repaired PNG_NO_STDIO behaviour
- Tested NODIV support and made it default behaviour (Greg Roelofs)
+ Repaired PNG_NO_STDIO behavior
+ Tested NODIV support and made it default behavior (Greg Roelofs)
Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
Regularized version numbering scheme and bumped shared-library major
- version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
+ version number to 2 to avoid problems with libpng 0.89 apps
+ (Greg Roelofs)
Version 0.98 [January, 1998]
Cleaned up some typos in libpng.txt and in code documentation
Removed AC_FUNC_MALLOC from configure.ac
Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
Change "logical" to "bitwise" throughout documentation.
- Detect and fix attempt to write wrong iCCP profile length.
+ Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
Version 1.0.21, 1.2.13 [November 14, 2006]
Fix potential buffer overflow in sPLT chunk handler.
Version 1.4.0beta73 [August 1, 2009]
Reject attempt to write iCCP chunk with negative embedded profile length
- (JD Chen)
+ (JD Chen) (CVE-2009-5063).
Version 1.4.0beta74 [August 8, 2009]
Changed png_ptr and info_ptr member "trans" to "trans_alpha".
PNG_INTERLACE transform and to get the number of rows in the current
pass.
A new test program, pngvalid.c, validates the gamma code.
- Errors in the 16 bit gamma correction (overflows) have been corrected.
+ Errors in the 16-bit gamma correction (overflows) have been corrected.
cHRM chunk testing is done consistently (previously the floating point
API bypassed it, because the test really didn't work on FP, now the test
is performed on the actual values to be stored in the PNG file so it
in version 1.5.0beta36 but is not noted in the CHANGES. Similarly,
it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
- internally happens to call it with one.
- Fixed a failure to handle palette mapped images correctly.
+ internally happens to call it with one, and fixed a failure to handle
+ palette mapped images correctly. This fixes CVE-2690.
Version 1.5.1beta02 [January 14, 2011]
Fixed a bug in handling of interlaced images (bero at arklinux.org).
pngvalid contains tests of transforms, which tests are currently disabled
because they are incompletely tested. gray_to_rgb was failing to expand
the bit depth for smaller bit depth images; this seems to be a long
- standing error and resulted, apparently, in invalid output. The
- documentation did not accurately describe what libpng really does when
- converting RGB to gray.
+ standing error and resulted, apparently, in invalid output
+ (CVE-2011-0408, CERT VU#643140). The documentation did not accurately
+ describe what libpng really does when converting RGB to gray.
Version 1.5.1beta10 [January 27, 2010]
Fixed incorrect examples of callback prototypes in the manual, that were
Version 1.5.1beta11 [January 28, 2011]
Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
Corrected local variable type in new API png_process_data_skip()
- The type was self-evidently incorrect but only causes problems on 64 bit
+ The type was self-evidently incorrect but only causes problems on 64-bit
architectures.
Added transform tests to pngvalid and simplified the arguments.
to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
Version 1.5.2 [March 31, 2011]
+ No changes.
+
+Version 1.5.3beta01 [April 1, 2011]
+ Re-initialize the zlib compressor before compressing non-IDAT chunks.
+ Added API functions (png_set_text_compression_level() and four others) to
+ set parameters for zlib compression of non-IDAT chunks.
+
+Version 1.5.3beta02 [April 3, 2011]
+ Updated scripts/symbols.def with new API functions.
+ Only compile the new zlib re-initializing code when text or iCCP is
+ supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
+ Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
+ Optimize the zlib CMF byte in non-IDAT compressed chunks
+
+Version 1.5.3beta03 [April 16, 2011]
+ Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
+ snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
+ than __STDC__ (John Bowler).
+ Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
+ the compiler that a user supplied callback (the error handler) does not
+ return, yet there is no guarantee in practice that the application code
+ will correctly implement the error handler because the compiler only
+ issues a warning if there is a mistake (John Bowler).
+ Removed the no-longer-used PNG_DEPSTRUCT macro.
+ Updated the zlib version to 1.2.5 in the VStudio project.
+ Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
+ pngwutil.c (John Bowler).
+ Fixed bug with stripping the filler or alpha channel when writing, that
+ was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+ Updated pngtest.png with the new zlib CMF optimization.
+ Cleaned up conditional compilation code and of background/gamma handling
+ Internal changes only except a new option to avoid compiling the
+ png_build_grayscale_palette API (which is not used at all internally.)
+ The main change is to move the transform tests (READ_TRANSFORMS,
+ WRITE_TRANSFORMS) up one level to the caller of the APIs. This avoids
+ calls to spurious functions if all transforms are disabled and slightly
+ simplifies those functions. Pngvalid modified to handle this.
+ A minor change is to stop the strip_16 and expand_16 interfaces from
+ disabling each other; this allows the future alpha premultiplication
+ code to use 16-bit intermediate values while still producing 8-bit output.
+ png_do_background and png_do_gamma have been simplified to take a single
+ pointer to the png_struct rather than pointers to every item required
+ from the png_struct. This makes no practical difference to the internal
+ code.
+ A serious bug in the pngvalid internal routine 'standard_display_init' has
+ been fixed - this failed to initialize the red channel and accidentally
+ initialized the alpha channel twice.
+ Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+ avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+ Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+ correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+ pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+ Removed png_snprintf and added formatted warning messages. This change adds
+ internal APIs to allow png_warning messages to have parameters without
+ requiring the host OS to implement snprintf. As a side effect the
+ dependency of the tIME-supporting RFC1132 code on stdio is removed and
+ PNG_NO_WARNINGS does actually work now.
+ Pass "" instead of '\0' to png_default_error() in png_err(). This mistake
+ was introduced in libpng-1.2.20beta01. This fixes CVE-2011-2691.
+ Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+ optimization configureable.
+ IDAT compression failed if preceded by a compressed text chunk (bug
+ introduced in libpng-1.5.3beta01-02). This was because the attempt to
+ reset the zlib stream in png_write_IDAT happened after the first IDAT
+ chunk had been deflated - much too late. In this change internal
+ functions were added to claim/release the z_stream and, hopefully, make
+ the code more robust. Also deflateEnd checking is added - previously
+ libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+ Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+ Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+ Added expand_16 support to the high level interface.
+ Added named value and 'flag' gamma support to png_set_gamma. Made a minor
+ change from the previous (unreleased) ABI/API to hide the exact value used
+ for Macs - it's not a good idea to embed this in the ABI!
+ Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+ from pngpriv.h to png.h because they must be visible to applications
+ that call png_set_unknown_chunks().
+ Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+ before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+ Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+ Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+ The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+ parameters are supplied by the caller), while in the absence of cHRM
+ sRGB/Rec 709 values are still used. This introduced a divide-by-zero
+ bug in png_handle_cHRM().
+ The bKGD chunk no longer overwrites the background value set by
+ png_set_background(), allowing the latter to be used before the file
+ header is read. It never performed any useful function to override
+ the default anyway.
+ Added memory overwrite and palette image checks to pngvalid.c
+ Previously palette image code was poorly checked. Since the transformation
+ code has a special palette path in most cases this was a severe weakness.
+ Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+ expanding an indexed image, always expand to RGBA if transparency is
+ present.
+
+Version 1.5.3beta09 [May 17, 2011]
+ Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+ back where it was. The change doesn't work because it requires 16-bit
+ gamma tables when the code only generates 8-bit ones. This fails
+ silently; the libpng code just doesn't do any gamma correction. Moving
+ the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+ these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+ png_set_background() and png_expand_16() did not work together correctly.
+ This problem is present in 1.5.2; if png_set_background is called with
+ need_expand false and the matching 16 bit color libpng erroneously just
+ treats it as an 8-bit color because of where png_do_expand_16 is in the
+ transform list. This simple fix reduces the supplied colour to 8-bits,
+ so it gets smashed, but this is better than the current behavior.
+ Added tests for expand16, more fixes for palette image tests to pngvalid.
+ Corrects the code for palette image tests and disables attempts to
+ validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+ No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+ Fixed uninitialized memory read in png_format_buffer() (Bug report by
+ Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+ Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
+ Added sCAL to pngtest.png
+ Revised documentation about png_set_user_limits() to say that it also affects
+ png writing.
+ Revised handling of png_set_user_limits() so that it can increase the
+ limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+ reduce it.
+ Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+ wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+ wrong in 128 out of 65536 cases. Getting the right answer all the time
+ without division is easy.
+ Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+ Added projects/owatcom, an IDE project for OpenWatcom to replace
+ scripts/makefile.watcom. This project works with OpenWatcom 1.9. The
+ IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+ The project is configurable, unlike the Visual Studio project, so long
+ as the developer has an awk.
+ Changed png_set_gAMA to limit the gamma value range so that the inverse
+ of the stored value cannot overflow the fixed point representation,
+ and changed other things OpenWatcom warns about.
+ Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+ pngvalid to build when ALPHA_MODE is not supported, which is required if
+ it is to build on libpng 1.4.
+ Removed string/memory macros that are no longer used and are not
+ necessarily fully supportable, particularly png_strncpy and png_snprintf.
+ Added log option to pngvalid.c and attempted to improve gamma messages.
+
+Version 1.5.3 [omitted]
+ People found the presence of a beta release following an rc release
+ to be confusing; therefore we bump the version to libpng-1.5.4beta01
+ and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+ Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+ to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+ Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+ outside of an unknown-chunk block in png.h because they are also
+ needed for other uses.
+
+Version 1.5.4beta02 [June 14, 2011]
+ Fixed and clarified LEGACY 16-to-8 scaling code.
+ Added png_set_chop_16() API, to match inaccurate results from previous
+ libpng versions.
+ Removed the ACCURATE and LEGACY options (they are no longer useable)
+ Use the old scaling method for background if png_set_chop_16() was
+ called.
+ Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
+
+Version 1.5.4beta03 [June 15, 2011]
+ Fixed a problem in png_do_expand_palette() exposed by optimization in
+ 1.5.3beta06
+ Also removed a spurious and confusing "trans" member ("trans") from png_info.
+ The palette expand optimization prevented expansion to an intermediate RGBA
+ form if tRNS was present but alpha was marked to be stripped; this exposed
+ a check for tRNS in png_do_expand_palette() which is inconsistent with the
+ code elsewhere in libpng.
+ Correction to the expand_16 code; removed extra instance of
+ png_set_scale_16_to_8 from pngpriv.h
+
+Version 1.5.4beta04 [June 16, 2011]
+ Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
+ Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
+ Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again. If this is
+ not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
+ Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
+
+Version 1.5.4beta05 [June 16, 2011]
+ Renamed png_set_strip_16() to png_set_scale_16() and renamed
+ png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
+ behavior changes between libpng14 and libpng15.
+
+Version 1.5.4beta06 [June 18, 2011]
+ Fixed new bug that was causing both strip_16 and scale_16 to be applied.
+
+Version 1.5.4beta07 [June 19, 2011]
+ Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
+ The ACCURATE scale macro is no longer defined in 1.5 - call the
+ png_scale_16_to_8 API. Made sure that PNG_READ_16_TO_8 is still defined
+ if the png_strip_16_to_8 API is present. png_check_fp_number now
+ maintains some state so that positive, negative and zero values are
+ identified. sCAL uses these to be strictly spec conformant.
+
+Version 1.5.4beta08 [June 23, 2011]
+ Fixed pngvalid if ACCURATE_SCALE is defined.
+ Updated scripts/pnglibconf.h.prebuilt.
+
+Version 1.5.4rc01 [June 30, 2011]
+ Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
+
+Version 1.5.4 [July 7, 2011]
+ No changes.
+
+Version 1.5.5beta01 [July 13, 2011]
+ Fixed some typos and made other minor changes in the manual.
+ Updated contrib/pngminus/makefile.std (Samuli Souminen)
+
+Version 1.5.5beta02 [July 14, 2011]
+ Revised Makefile.am and Makefile.in to look in the right directory for
+ pnglibconf.h.prebuilt
+
+Version 1.5.5beta03 [July 27, 2011]
+ Enabled compilation with g++ compiler. This compiler does not recognize
+ the file extension, so it always compiles with C++ rules. Made minor
+ changes to pngrutil.c to cast results where C++ expects it but C does not.
+ Minor editing of libpng.3 and libpng-manual.txt.
+
+Version 1.5.5beta04 [July 29, 2011]
+ Revised CMakeLists.txt (Clifford Yapp)
+ Updated commentary about the png_rgb_to_gray() default coefficients
+ in the manual and in pngrtran.c
+
+Version 1.5.5beta05 [August 17, 2011]
+ Prevent unexpected API exports from non-libpng DLLs on Windows. The "_DLL"
+ is removed from the test of whether a DLL is being built (this erroneously
+ caused the libpng APIs to be marked as DLL exports in static builds under
+ Microsoft Visual Studio). Almost all of the libpng building configuration
+ is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
+ pngconf.h, though, so that it is colocated with the import definition (it
+ is no longer used anywhere in the installed headers). The VStudio project
+ definitions have been cleaned up: "_USRDLL" has been removed from the
+ static library builds (this was incorrect), and PNG_USE_DLL has been added
+ to pngvalid to test the functionality (pngtest does not supply it,
+ deliberately). The spurious "_EXPORTS" has been removed from the
+ libpng build (all these errors were a result of copy/paste between project
+ configurations.)
+ Added new types and internal functions for CIE RGB end point handling to
+ pngpriv.h (functions yet to be implemented).
+
+Version 1.5.5beta06 [August 26, 2011]
+ Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
+ (Clifford Yap)
+ Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
+ The rgb_to_gray code had errors when combined with gamma correction.
+ Some pixels were treated as true grey when they weren't and such pixels
+ and true grey ones were not gamma corrected (the original value of the
+ red component was used instead). APIs to get and set cHRM using color
+ space end points have been added and the rgb_to_gray code that defaults
+ based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
+ VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
+ A considerable number of tests has been added to pngvalid for the
+ rgb_to_gray transform.
+ Arithmetic errors in rgb_to_gray whereby the calculated gray value was
+ truncated to the bit depth rather than rounded have been fixed except in
+ the 8-bit non-gamma-corrected case (where consistency seems more important
+ than correctness.) The code still has considerable inaccuracies in the
+ 8-bit case because 8-bit linear arithmetic is used.
+
+Version 1.5.5beta07 [September 7, 2011]
+ Added "$(ARCH)" option to makefile.darwin
+ Added SunOS support to configure.ac and Makefile.am
+ Changed png_chunk_benign_error() to png_warning() in png.c, in
+ png_XYZ_from_xy_checked().
+
+Version 1.5.5beta08 [September 10, 2011]
+ Fixed 64-bit compilation errors (gcc). The errors fixed relate
+ to conditions where types that are 32 bits in the GCC 32-bit
+ world (uLong and png_size_t) become 64 bits in the 64-bit
+ world. This produces potential truncation errors which the
+ compiler correctly flags.
+ Relocated new HAVE_SOLARIS_LD definition in configure.ac
+ Constant changes for 64-bit compatibility (removal of L suffixes). The
+ 16-bit cases still use "L" as we don't have a 16-bit test system.
+
+Version 1.5.5rc01 [September 15, 2011]
+ Removed "L" suffixes in pngpriv.h
+
+Version 1.5.5 [September 22, 2011]
+ No changes.
+
+Version 1.5.6beta01 [September 22, 2011]
+ Fixed some 64-bit type conversion warnings in pngrtran.c
+ Moved row_info from png_struct to a local variable.
+ The various interlace mask arrays have been made into arrays of
+ bytes and made PNG_CONST and static (previously some arrays were
+ marked PNG_CONST and some weren't).
+ Additional checks have been added to the transform code to validate the
+ pixel depths after the transforms on both read and write.
+ Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
+ Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
+ This removes the need to allocate temporary strings for chunk names on
+ the stack in the read/write code. Unknown chunk handling still uses the
+ string form because this is exposed in the API.
+
+Version 1.5.6beta02 [September 26, 2011]
+ Added a note in the manual the png_read_update_info() must be called only
+ once with a particular info_ptr.
+ Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
+
+Version 1.5.6beta03 [September 28, 2011]
+ Revised test-pngtest.sh to report FAIL when pngtest fails.
+ Added "--strict" option to pngtest, to report FAIL when the failure is
+ only because the resulting valid files are different.
+ Revised CMakeLists.txt to work with mingw and removed some material from
+ CMakeLists.txt that is no longer useful in libpng-1.5.
+
+Version 1.5.6beta04 [October 5, 2011]
+ Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
+
+Version 1.5.6beta05 [October 12, 2011]
+ Speed up png_combine_row() for interlaced images. This reduces the generality
+ of the code, allowing it to be optimized for Adam7 interlace. The masks
+ passed to png_combine_row() are now generated internally, avoiding
+ some code duplication and localizing the interlace handling somewhat.
+ Align png_struct::row_buf - previously it was always unaligned, caused by
+ a bug in the code that attempted to align it; the code needs to subtract
+ one from the pointer to take account of the filter byte prepended to
+ each row.
+ Optimized png_combine_row() when rows are aligned. This gains a small
+ percentage for 16-bit and 32-bit pixels in the typical case where the
+ output row buffers are appropriately aligned. The optimization was not
+ previously possible because the png_struct buffer was always misaligned.
+ Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
+
+Version 1.5.6beta06 [October 17, 2011]
+ Removed two redundant tests for unitialized row.
+ Fixed a relatively harmless memory overwrite in compressed text writing
+ with a 1 byte zlib buffer.
+ Add ability to call png_read_update_info multiple times to pngvalid.c.
+ Fixes for multiple calls to png_read_update_info. These fixes attend to
+ most of the errors revealed in pngvalid, however doing the gamma work
+ twice results in inaccuracies that can't be easily fixed. There is now
+ a warning in the code if this is going to happen.
+ Turned on multiple png_read_update_info in pngvalid transform tests.
+ Prevent libpng from overwriting unused bits at the end of the image when
+ it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
+ overwrite the partial byte at the end of each row if the row width was not
+ an exact multiple of 8 bits and the image is not interlaced.
+
+Version 1.5.6beta07 [October 21, 2011]
+ Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
+ (Mans Rullgard).
+
+Version 1.5.6rc01 [October 26, 2011]
+ Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
+
+Version 1.5.6rc02 [October 27, 2011]
+ Added LSR() macro to defend against buggy compilers that evaluate non-taken
+ code branches and complain about out-of-range shifts.
+
+Version 1.5.6rc03 [October 28, 2011]
+ Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
+ Fixed compiler warnings with Intel and MSYS compilers. The logical shift
+ fix for Microsoft Visual C is required by other compilers, so this
+ enables that fix for all compilers when using compile-time constants.
+ Under MSYS 'byte' is a name declared in a system header file, so we
+ changed the name of a local variable to avoid the warnings that result.
+ Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
+
+Version 1.5.6 [November 3, 2011]
+ No changes.
+
+Version 1.5.7beta01 [November 4, 2011]
+ Added support for ARM processor (Mans Rullgard)
+ Fixed bug in pngvalid on early allocation failure; fixed type cast in
+ pngmem.c; pngvalid would attempt to call png_error() if the allocation
+ of a png_struct or png_info failed. This would probably have led to a
+ crash. The pngmem.c implementation of png_malloc() included a cast
+ to png_size_t which would fail on large allocations on 16-bit systems.
+ Fix for the preprocessor of the Intel C compiler. The preprocessor
+ splits adjacent @ signs with a space; this changes the concatentation
+ token from @-@-@ to PNG_JOIN; that should work with all compiler
+ preprocessors.
+ Paeth filter speed improvements from work by Siarhei Siamashka. This
+ changes the 'Paeth' reconstruction function to improve the GCC code
+ generation on x86. The changes are only part of the suggested ones;
+ just the changes that definitely improve speed and remain simple.
+ The changes also slightly increase the clarity of the code.
+
+Version 1.5.7beta02 [November 11, 2011]
+ Check compression_type parameter in png_get_iCCP and remove spurious
+ casts. The compression_type parameter is always assigned to, so must
+ be non-NULL. The cast of the profile length potentially truncated the
+ value unnecessarily on a 16-bit int system, so the cast of the (byte)
+ compression type to (int) is specified by ANSI-C anyway.
+ Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
+ the sBIT fields in the test pixel as 0, which resulted in a floating
+ point division by zero which was irrelevant but causes systems where
+ FP exceptions cause a crash. Added code to pngvalid to turn on FP
+ exceptions if the appropriate glibc support is there to ensure this is
+ tested in the future.
+ Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
+ new PNG_JOIN macro.
+ Added versioning to pnglibconf.h comments.
+ Simplified read/write API initial version; basic read/write tested on
+ a variety of images, limited documentation (in the header file.)
+ Installed more accurate linear to sRGB conversion tables. The slightly
+ modified tables reduce the number of 16-bit values that
+ convert to an off-by-one 8-bit value. The "makesRGB.c" code that was used
+ to generate the tables is now in a contrib/sRGBtables sub-directory.
+
+Version 1.5.7beta03 [November 17, 2011]
+ Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
+ Added run-time detection of NEON support.
+ Added contrib/libtests; includes simplified API test and timing test and
+ a color conversion utility for rapid checking of failed 'pngstest' results.
+ Multiple transform bug fixes plus a work-round for double gamma correction.
+ libpng does not support more than one transform that requires linear data
+ at once - if this is tried typically the results is double gamma
+ correction. Since the simplified APIs can need rgb to gray combined with
+ a compose operation it is necessary to do one of these outside the main
+ libpng transform code. This check-in also contains fixes to various bugs
+ in the simplified APIs themselves and to some bugs in compose and rgb to
+ gray (on palette) itself.
+ Fixes for C++ compilation using g++ When libpng source is compiled
+ using g++. The compiler imposes C++ rules on the C source; thus it
+ is desireable to make the source work with either C or C++ rules
+ without throwing away useful error information. This change adds
+ png_voidcast to allow C semantic (void*) cases or the corresponding
+ C++ static_cast operation, as appropriate.
+ Added --noexecstack to assembler file compilation. GCC does not set
+ this on assembler compilation, even though it does on C compilation.
+ This creates security issues if assembler code is enabled; the
+ work-around is to set it by default in the flags for $(CCAS)
+ Work around compilers that don't support declaration of const data. Some
+ compilers fault 'extern const' data declarations (because the data is
+ not initialized); this turns on const-ness only for compilers where
+ this is known to work.
+
+Version 1.5.7beta04 [November 17, 2011]
+ Since the gcc driver does not recognize the --noexecstack flag, we must
+ use the -Wa prefix to have it passed through to the assembler.
+ Also removed a duplicate setting of this flag.
+ Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
+
+Version 1.5.7beta05 [November 25, 2011]
+ Removed "zTXt" from warning in generic chunk decompression function.
+ Validate time settings passed to pngset() and png_convert_to_rfc1123()
+ (Frank Busse).
+ Added MINGW support to CMakeLists.txt
+ Reject invalid compression flag or method when reading the iTXt chunk.
+ Backed out 'simplified' API changes. The API seems too complex and there
+ is a lack of consensus or enthusiasm for the proposals. The API also
+ reveals significant bugs inside libpng (double gamma correction and the
+ known bug of being unable to retrieve a corrected palette). It seems
+ better to wait until the bugs, at least, are corrected.
+ Moved pngvalid.c into contrib/libtests
+ Rebuilt Makefile.in, configure, etc., with autoconf-2.68
+
+Version 1.5.7rc01 [December 1, 2011]
+ Replaced an "#if" with "#ifdef" in pngrtran.c
+ Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
+
+Version 1.5.7rc02 [December 5, 2011]
+ Revised project files and contrib/pngvalid/pngvalid.c to account for
+ the relocation of pngvalid into contrib/libtests.
+ Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
+ as in libpng-1.5.4.
+ Put CRLF line endings in the owatcom project files.
+
+Version 1.5.7rc03 [December 7, 2011]
+ Updated CMakeLists.txt to account for the relocation of pngvalid.c
+
+Version 1.5.7 [December 15, 2011]
+ Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
+ reported by earlier versions.
+
+Version 1.5.8beta01 [January 15, 2011]
+ Removed '#include config.h"' from contrib/libtests/pngvalid.c. It's not
+ needed and causes trouble for VPATH building.
+ Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
+ location in configure.ac (Gilles Espinasse).
+ Fix bug in pngerror.c: some long warnings were being improperly truncated
+ (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
+
+Version 1.5.8rc01 [January 21, 2012]
+ No changes.
+
+Version 1.5.8rc02 [January 25, 2012]
+ Fixed Min/GW uninstall to remove libpng.dll.a
+ Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt
+
+Version 1.5.8 [February 1, 2012]
+ No changes.
+
+Version 1.5.9beta01 [February 3, 2012]
+ Rebuilt configure scripts in the tar distributions.
+
+Version 1.5.9beta02 [February 16, 2012]
+ Removed two unused definitions from scripts/pnglibconf.h.prebuilt
+ Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
+ Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
+
+Version 1.5.9rc01 [February 17, 2012]
+ Fixed CVE-2011-3026 buffer overrun bug. Deal more correctly with the test
+ on iCCP chunk length. Also removed spurious casts that may hide problems
+ on 16-bit systems.
+
+Version 1.5.9 [February 18, 2012]
+ No changes.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
or to glennrp at users.sourceforge.net
Glenn R-P
-*/ }
#endif
This code is released under the libpng license.
-libpng versions 1.2.6, August 15, 2004, through 1.5.2, March 31, 2011, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.9, February 18, 2012, are
Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.2.5
with the following individual added to the list of Contributing Authors
Glenn Randers-Pehrson
glennrp at users.sourceforge.net
-March 31, 2011
+February 18, 2012
-README for libpng version 1.5.2 - March 31, 2011 (shared library 15.0)
+README for libpng version 1.5.9 - February 18, 2012 (shared library 15.0)
See the note about version numbers near the top of png.h
See INSTALL for instructions on how to install libpng.
read mail addressed to the png-implement list, however.
Please do not send general questions about PNG. Send them to
-the (png-list at ccrc.wustl.edu, subscription required, write to
-majordomo at ccrc.wustl.edu with "subscribe png-list" in your message).
-On the other hand,
-please do not send libpng questions to that address, send them to me
-or to the png-implement list. I'll
-get them in the end anyway. If you have a question about something
+png-mng-misc at lists.sf.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
+subscribe). If you have a question about something
in the PNG specification that is related to using libpng, send it
to me. Send me any questions that start with "I was using libpng,
and ...". If in doubt, send questions to me. I'll bounce them
to others, if necessary.
Please do not send suggestions on how to change PNG. We have
-been discussing PNG for nine years now, and it is official and
+been discussing PNG for sixteen years now, and it is official and
finished. If you have suggestions for libpng, however, I'll
gladly listen. Even if your suggestion is not used immediately,
it may be used later.
+++ /dev/null
-libpng.txt - A description on how to use and modify libpng
-
- libpng version 1.4.4 - September 23, 2010
- Updated and distributed by Glenn Randers-Pehrson
- <glennrp at users.sourceforge.net>
- Copyright (c) 1998-2010 Glenn Randers-Pehrson
-
- This document is released under the libpng license.
- For conditions of distribution and use, see the disclaimer
- and license in png.h
-
- Based on:
-
- libpng versions 0.97, January 1998, through 1.4.4 - September 23, 2010
- Updated and distributed by Glenn Randers-Pehrson
- Copyright (c) 1998-2010 Glenn Randers-Pehrson
-
- libpng 1.0 beta 6 version 0.96 May 28, 1997
- Updated and distributed by Andreas Dilger
- Copyright (c) 1996, 1997 Andreas Dilger
-
- libpng 1.0 beta 2 - version 0.88 January 26, 1996
- For conditions of distribution and use, see copyright
- notice in png.h. Copyright (c) 1995, 1996 Guy Eric
- Schalnat, Group 42, Inc.
-
- Updated/rewritten per request in the libpng FAQ
- Copyright (c) 1995, 1996 Frank J. T. Wojcik
- December 18, 1995 & January 20, 1996
-
-I. Introduction
-
-This file describes how to use and modify the PNG reference library
-(known as libpng) for your own use. There are five sections to this
-file: introduction, structures, reading, writing, and modification and
-configuration notes for various special platforms. In addition to this
-file, example.c is a good starting point for using the library, as
-it is heavily commented and should include everything most people
-will need. We assume that libpng is already installed; see the
-INSTALL file for instructions on how to install libpng.
-
-For examples of libpng usage, see the files "example.c", "pngtest.c",
-and the files in the "contrib" directory, all of which are included in
-the libpng distribution.
-
-Libpng was written as a companion to the PNG specification, as a way
-of reducing the amount of time and effort it takes to support the PNG
-file format in application programs.
-
-The PNG specification (second edition), November 2003, is available as
-a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
-<http://www.w3.org/TR/2003/REC-PNG-20031110/
-The W3C and ISO documents have identical technical content.
-
-The PNG-1.2 specification is available at
-<http://www.libpng.org/pub/png/documents/>. It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
-
-The PNG-1.0 specification is available
-as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
-W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
-
-Some additional chunks are described in the special-purpose public chunks
-documents at <http://www.libpng.org/pub/png/documents/>.
-
-Other information
-about PNG, and the latest version of libpng, can be found at the PNG home
-page, <http://www.libpng.org/pub/png/>.
-
-Most users will not have to modify the library significantly; advanced
-users may want to modify it more. All attempts were made to make it as
-complete as possible, while keeping the code easy to understand.
-Currently, this library only supports C. Support for other languages
-is being considered.
-
-Libpng has been designed to handle multiple sessions at one time,
-to be easily modifiable, to be portable to the vast majority of
-machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
-to use. The ultimate goal of libpng is to promote the acceptance of
-the PNG file format in whatever way possible. While there is still
-work to be done (see the TODO file), libpng should cover the
-majority of the needs of its users.
-
-Libpng uses zlib for its compression and decompression of PNG files.
-Further information about zlib, and the latest version of zlib, can
-be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
-The zlib compression utility is a general purpose utility that is
-useful for more than PNG files, and can be used without libpng.
-See the documentation delivered with zlib for more details.
-You can usually find the source files for the zlib utility wherever you
-find the libpng source files.
-
-Libpng is thread safe, provided the threads are using different
-instances of the structures. Each thread should have its own
-png_struct and png_info instances, and thus its own image.
-Libpng does not protect itself against two threads using the
-same instance of a structure.
-
-II. Structures
-
-There are two main structures that are important to libpng, png_struct
-and png_info. The first, png_struct, is an internal structure that
-will not, for the most part, be used by a user except as the first
-variable passed to every libpng function call.
-
-The png_info structure is designed to provide information about the
-PNG file. At one time, the fields of png_info were intended to be
-directly accessible to the user. However, this tended to cause problems
-with applications using dynamically loaded libraries, and as a result
-a set of interface functions for png_info (the png_get_*() and png_set_*()
-functions) was developed. The fields of png_info are still available for
-older applications, but it is suggested that applications use the new
-interfaces if at all possible.
-
-Applications that do make direct access to the members of png_struct (except
-for png_ptr->jmpbuf) must be recompiled whenever the library is updated,
-and applications that make direct access to the members of png_info must
-be recompiled if they were compiled or loaded with libpng version 1.0.6,
-in which the members were in a different order. In version 1.0.7, the
-members of the png_info structure reverted to the old order, as they were
-in versions 0.97c through 1.0.5. Starting with version 2.0.0, both
-structures are going to be hidden, and the contents of the structures will
-only be accessible through the png_get/png_set functions.
-
-The png.h header file is an invaluable reference for programming with libpng.
-And while I'm on the topic, make sure you include the libpng header file:
-
-#include <png.h>
-
-III. Reading
-
-We'll now walk you through the possible functions to call when reading
-in a PNG file sequentially, briefly explaining the syntax and purpose
-of each one. See example.c and png.h for more detail. While
-progressive reading is covered in the next section, you will still
-need some of the functions discussed in this section to read a PNG
-file.
-
-Setup
-
-You will want to do the I/O initialization(*) before you get into libpng,
-so if it doesn't work, you don't have much to undo. Of course, you
-will also want to insure that you are, in fact, dealing with a PNG
-file. Libpng provides a simple check to see if a file is a PNG file.
-To use it, pass in the first 1 to 8 bytes of the file to the function
-png_sig_cmp(), and it will return 0 (false) if the bytes match the
-corresponding bytes of the PNG signature, or nonzero (true) otherwise.
-Of course, the more bytes you pass in, the greater the accuracy of the
-prediction.
-
-If you are intending to keep the file pointer open for use in libpng,
-you must ensure you don't read more than 8 bytes from the beginning
-of the file, and you also have to make a call to png_set_sig_bytes_read()
-with the number of bytes you read from the beginning. Libpng will
-then only check the bytes (if any) that your program didn't read.
-
-(*): If you are not using the standard I/O functions, you will need
-to replace them with custom functions. See the discussion under
-Customizing libpng.
-
-
- FILE *fp = fopen(file_name, "rb");
- if (!fp)
- {
- return (ERROR);
- }
- fread(header, 1, number, fp);
- is_png = !png_sig_cmp(header, 0, number);
- if (!is_png)
- {
- return (NOT_PNG);
- }
-
-
-Next, png_struct and png_info need to be allocated and initialized. In
-order to ensure that the size of these structures is correct even with a
-dynamically linked libpng, there are functions to initialize and
-allocate the structures. We also pass the library version, optional
-pointers to error handling functions, and a pointer to a data struct for
-use by the error functions, if necessary (the pointer and functions can
-be NULL if the default error handlers are to be used). See the section
-on Changes to Libpng below regarding the old initialization functions.
-The structure allocation functions quietly return NULL if they fail to
-create the structure, so your application should check for that.
-
- png_structp png_ptr = png_create_read_struct
- (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
- user_error_fn, user_warning_fn);
- if (!png_ptr)
- return (ERROR);
-
- png_infop info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr)
- {
- png_destroy_read_struct(&png_ptr,
- (png_infopp)NULL, (png_infopp)NULL);
- return (ERROR);
- }
-
- png_infop end_info = png_create_info_struct(png_ptr);
- if (!end_info)
- {
- png_destroy_read_struct(&png_ptr, &info_ptr,
- (png_infopp)NULL);
- return (ERROR);
- }
-
-If you want to use your own memory allocation routines,
-define PNG_USER_MEM_SUPPORTED and use
-png_create_read_struct_2() instead of png_create_read_struct():
-
- png_structp png_ptr = png_create_read_struct_2
- (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
- user_error_fn, user_warning_fn, (png_voidp)
- user_mem_ptr, user_malloc_fn, user_free_fn);
-
-The error handling routines passed to png_create_read_struct()
-and the memory alloc/free routines passed to png_create_struct_2()
-are only necessary if you are not using the libpng supplied error
-handling and memory alloc/free functions.
-
-When libpng encounters an error, it expects to longjmp back
-to your routine. Therefore, you will need to call setjmp and pass
-your png_jmpbuf(png_ptr). If you read the file from different
-routines, you will need to update the jmpbuf field every time you enter
-a new routine that will call a png_*() function.
-
-See your documentation of setjmp/longjmp for your compiler for more
-information on setjmp/longjmp. See the discussion on libpng error
-handling in the Customizing Libpng section below for more information
-on the libpng error handling. If an error occurs, and libpng longjmp's
-back to your setjmp, you will want to call png_destroy_read_struct() to
-free any memory.
-
- if (setjmp(png_jmpbuf(png_ptr)))
- {
- png_destroy_read_struct(&png_ptr, &info_ptr,
- &end_info);
- fclose(fp);
- return (ERROR);
- }
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the input code. The default for libpng is to
-use the C function fread(). If you use this, you will need to pass a
-valid FILE * in the function png_init_io(). Be sure that the file is
-opened in binary mode. If you wish to handle reading data in another
-way, you need not call the png_init_io() function, but you must then
-implement the libpng I/O methods discussed in the Customizing Libpng
-section below.
-
- png_init_io(png_ptr, fp);
-
-If you had previously opened the file and read any of the signature from
-the beginning in order to see if this was a PNG file, you need to let
-libpng know that there are some bytes missing from the start of the file.
-
- png_set_sig_bytes(png_ptr, number);
-
-You can change the zlib compression buffer size to be used while
-reading compressed data with
-
- png_set_compression_buffer_size(png_ptr, buffer_size);
-
-where the default size is 8192 bytes. Note that the buffer size
-is changed immediately and the buffer is reallocated immediately,
-instead of setting a flag to be acted upon later.
-
-Setting up callback code
-
-You can set up a callback function to handle any unknown chunks in the
-input stream. You must supply the function
-
- read_chunk_callback(png_ptr ptr,
- png_unknown_chunkp chunk);
- {
- /* The unknown chunk structure contains your
- chunk data, along with similar data for any other
- unknown chunks: */
-
- png_byte name[5];
- png_byte *data;
- png_size_t size;
-
- /* Note that libpng has already taken care of
- the CRC handling */
-
- /* put your code here. Search for your chunk in the
- unknown chunk structure, process it, and return one
- of the following: */
-
- return (-n); /* chunk had an error */
- return (0); /* did not recognize */
- return (n); /* success */
- }
-
-(You can give your function another name that you like instead of
-"read_chunk_callback")
-
-To inform libpng about your function, use
-
- png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
- read_chunk_callback);
-
-This names not only the callback function, but also a user pointer that
-you can retrieve with
-
- png_get_user_chunk_ptr(png_ptr);
-
-If you call the png_set_read_user_chunk_fn() function, then all unknown
-chunks will be saved when read, in case your callback function will need
-one or more of them. This behavior can be changed with the
-png_set_keep_unknown_chunks() function, described below.
-
-At this point, you can set up a callback function that will be
-called after each row has been read, which you can use to control
-a progress meter or the like. It's demonstrated in pngtest.c.
-You must supply a function
-
- void read_row_callback(png_ptr ptr, png_uint_32 row,
- int pass);
- {
- /* put your code here */
- }
-
-(You can give it another name that you like instead of "read_row_callback")
-
-To inform libpng about your function, use
-
- png_set_read_status_fn(png_ptr, read_row_callback);
-
-Unknown-chunk handling
-
-Now you get to set the way the library processes unknown chunks in the
-input PNG stream. Both known and unknown chunks will be read. Normal
-behavior is that known chunks will be parsed into information in
-various info_ptr members while unknown chunks will be discarded. This
-behavior can be wasteful if your application will never use some known
-chunk types. To change this, you can call:
-
- png_set_keep_unknown_chunks(png_ptr, keep,
- chunk_list, num_chunks);
- keep - 0: default unknown chunk handling
- 1: ignore; do not keep
- 2: keep only if safe-to-copy
- 3: keep even if unsafe-to-copy
- You can use these definitions:
- PNG_HANDLE_CHUNK_AS_DEFAULT 0
- PNG_HANDLE_CHUNK_NEVER 1
- PNG_HANDLE_CHUNK_IF_SAFE 2
- PNG_HANDLE_CHUNK_ALWAYS 3
- chunk_list - list of chunks affected (a byte string,
- five bytes per chunk, NULL or '\0' if
- num_chunks is 0)
- num_chunks - number of chunks affected; if 0, all
- unknown chunks are affected. If nonzero,
- only the chunks in the list are affected
-
-Unknown chunks declared in this way will be saved as raw data onto a
-list of png_unknown_chunk structures. If a chunk that is normally
-known to libpng is named in the list, it will be handled as unknown,
-according to the "keep" directive. If a chunk is named in successive
-instances of png_set_keep_unknown_chunks(), the final instance will
-take precedence. The IHDR and IEND chunks should not be named in
-chunk_list; if they are, libpng will process them normally anyway.
-
-Here is an example of the usage of png_set_keep_unknown_chunks(),
-where the private "vpAg" chunk will later be processed by a user chunk
-callback function:
-
- png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'};
-
- #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
- png_byte unused_chunks[]=
- {
- 104, 73, 83, 84, (png_byte) '\0', /* hIST */
- 105, 84, 88, 116, (png_byte) '\0', /* iTXt */
- 112, 67, 65, 76, (png_byte) '\0', /* pCAL */
- 115, 67, 65, 76, (png_byte) '\0', /* sCAL */
- 115, 80, 76, 84, (png_byte) '\0', /* sPLT */
- 116, 73, 77, 69, (png_byte) '\0', /* tIME */
- };
- #endif
-
- ...
-
- #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
- /* ignore all unknown chunks: */
- png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
- /* except for vpAg: */
- png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
- /* also ignore unused known chunks: */
- png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
- (int)sizeof(unused_chunks)/5);
- #endif
-
-User limits
-
-The PNG specification allows the width and height of an image to be as
-large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
-Since very few applications really need to process such large images,
-we have imposed an arbitrary 1-million limit on rows and columns.
-Larger images will be rejected immediately with a png_error() call. If
-you wish to override this limit, you can use
-
- png_set_user_limits(png_ptr, width_max, height_max);
-
-to set your own limits, or use width_max = height_max = 0x7fffffffL
-to allow all valid dimensions (libpng may reject some very large images
-anyway because of potential buffer overflow conditions).
-
-You should put this statement after you create the PNG structure and
-before calling png_read_info(), png_read_png(), or png_process_data().
-If you need to retrieve the limits that are being applied, use
-
- width_max = png_get_user_width_max(png_ptr);
- height_max = png_get_user_height_max(png_ptr);
-
-The PNG specification sets no limit on the number of ancillary chunks
-allowed in a PNG datastream. You can impose a limit on the total number
-of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
-
- png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
-
-where 0x7fffffffL means unlimited. You can retrieve this limit with
-
- chunk_cache_max = png_get_chunk_cache_max(png_ptr);
-
-This limit also applies to the number of buffers that can be allocated
-by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks.
-
-You can also set a limit on the amount of memory that a compressed chunk
-other than IDAT can occupy, with
-
- png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
-
-and you can retrieve the limit with
-
- chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
-
-Any chunks that would cause either of these limits to be exceeded will
-be ignored.
-
-The high-level read interface
-
-At this point there are two ways to proceed; through the high-level
-read interface, or through a sequence of low-level read operations.
-You can use the high-level interface if (a) you are willing to read
-the entire image into memory, and (b) the input transformations
-you want to do are limited to the following set:
-
- PNG_TRANSFORM_IDENTITY No transformation
- PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to
- 8 bits
- PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
- PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
- samples to bytes
- PNG_TRANSFORM_PACKSWAP Change order of packed
- pixels to LSB first
- PNG_TRANSFORM_EXPAND Perform set_expand()
- PNG_TRANSFORM_INVERT_MONO Invert monochrome images
- PNG_TRANSFORM_SHIFT Normalize pixels to the
- sBIT depth
- PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
- to BGRA
- PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
- to AG
- PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
- to transparency
- PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
- PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples
- to RGB (or GA to RGBA)
-
-(This excludes setting a background color, doing gamma transformation,
-quantizing, and setting filler.) If this is the case, simply do this:
-
- png_read_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some
-set of transformation flags. This call is equivalent to png_read_info(),
-followed the set of transformations indicated by the transform mask,
-then png_read_image(), and finally png_read_end().
-
-(The final parameter of this call is not yet used. Someday it might point
-to transformation parameters required by some future input transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_read_png().
-
-After you have called png_read_png(), you can retrieve the image data
-with
-
- row_pointers = png_get_rows(png_ptr, info_ptr);
-
-where row_pointers is an array of pointers to the pixel data for each row:
-
- png_bytep row_pointers[height];
-
-If you know your image size and pixel size ahead of time, you can allocate
-row_pointers prior to calling png_read_png() with
-
- if (height > PNG_UINT_32_MAX/png_sizeof(png_byte))
- png_error (png_ptr,
- "Image is too tall to process in memory");
- if (width > PNG_UINT_32_MAX/pixel_size)
- png_error (png_ptr,
- "Image is too wide to process in memory");
- row_pointers = png_malloc(png_ptr,
- height*png_sizeof(png_bytep));
- for (int i=0; i<height, i++)
- row_pointers[i]=NULL; /* security precaution */
- for (int i=0; i<height, i++)
- row_pointers[i]=png_malloc(png_ptr,
- width*pixel_size);
- png_set_rows(png_ptr, info_ptr, &row_pointers);
-
-Alternatively you could allocate your image in one big block and define
-row_pointers[i] to point into the proper places in your block.
-
-If you use png_set_rows(), the application is responsible for freeing
-row_pointers (and row_pointers[i], if they were separately allocated).
-
-If you don't allocate row_pointers ahead of time, png_read_png() will
-do it, and it'll be free'ed when you call png_destroy_*().
-
-The low-level read interface
-
-If you are going the low-level route, you are now ready to read all
-the file information up to the actual image data. You do this with a
-call to png_read_info().
-
- png_read_info(png_ptr, info_ptr);
-
-This will process all chunks up to but not including the image data.
-
-Querying the info structure
-
-Functions are used to get the information from the info_ptr once it
-has been read. Note that these fields may not be completely filled
-in until png_read_end() has read the chunk data following the image.
-
- png_get_IHDR(png_ptr, info_ptr, &width, &height,
- &bit_depth, &color_type, &interlace_type,
- &compression_type, &filter_method);
-
- width - holds the width of the image
- in pixels (up to 2^31).
- height - holds the height of the image
- in pixels (up to 2^31).
- bit_depth - holds the bit depth of one of the
- image channels. (valid values are
- 1, 2, 4, 8, 16 and depend also on
- the color_type. See also
- significant bits (sBIT) below).
- color_type - describes which color/alpha channels
- are present.
- PNG_COLOR_TYPE_GRAY
- (bit depths 1, 2, 4, 8, 16)
- PNG_COLOR_TYPE_GRAY_ALPHA
- (bit depths 8, 16)
- PNG_COLOR_TYPE_PALETTE
- (bit depths 1, 2, 4, 8)
- PNG_COLOR_TYPE_RGB
- (bit_depths 8, 16)
- PNG_COLOR_TYPE_RGB_ALPHA
- (bit_depths 8, 16)
-
- PNG_COLOR_MASK_PALETTE
- PNG_COLOR_MASK_COLOR
- PNG_COLOR_MASK_ALPHA
-
- filter_method - (must be PNG_FILTER_TYPE_BASE
- for PNG 1.0, and can also be
- PNG_INTRAPIXEL_DIFFERENCING if
- the PNG datastream is embedded in
- a MNG-1.0 datastream)
- compression_type - (must be PNG_COMPRESSION_TYPE_BASE
- for PNG 1.0)
- interlace_type - (PNG_INTERLACE_NONE or
- PNG_INTERLACE_ADAM7)
-
- Any or all of interlace_type, compression_type, or
- filter_method can be NULL if you are
- not interested in their values.
-
- Note that png_get_IHDR() returns 32-bit data into
- the application's width and height variables.
- This is an unsafe situation if these are 16-bit
- variables. In such situations, the
- png_get_image_width() and png_get_image_height()
- functions described below are safer.
-
- width = png_get_image_width(png_ptr,
- info_ptr);
- height = png_get_image_height(png_ptr,
- info_ptr);
- bit_depth = png_get_bit_depth(png_ptr,
- info_ptr);
- color_type = png_get_color_type(png_ptr,
- info_ptr);
- filter_method = png_get_filter_type(png_ptr,
- info_ptr);
- compression_type = png_get_compression_type(png_ptr,
- info_ptr);
- interlace_type = png_get_interlace_type(png_ptr,
- info_ptr);
-
- channels = png_get_channels(png_ptr, info_ptr);
- channels - number of channels of info for the
- color type (valid values are 1 (GRAY,
- PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
- 4 (RGB_ALPHA or RGB + filler byte))
- rowbytes = png_get_rowbytes(png_ptr, info_ptr);
- rowbytes - number of bytes needed to hold a row
-
- signature = png_get_signature(png_ptr, info_ptr);
- signature - holds the signature read from the
- file (if any). The data is kept in
- the same offset it would be if the
- whole signature were read (i.e. if an
- application had already read in 4
- bytes of signature before starting
- libpng, the remaining 4 bytes would
- be in signature[4] through signature[7]
- (see png_set_sig_bytes())).
-
-These are also important, but their validity depends on whether the chunk
-has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
-png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
-data has been read, or zero if it is missing. The parameters to the
-png_get_<chunk> are set directly if they are simple data types, or a
-pointer into the info_ptr is returned for any complex types.
-
- png_get_PLTE(png_ptr, info_ptr, &palette,
- &num_palette);
- palette - the palette for the file
- (array of png_color)
- num_palette - number of entries in the palette
-
- png_get_gAMA(png_ptr, info_ptr, &gamma);
- gamma - the gamma the file is written
- at (PNG_INFO_gAMA)
-
- png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
- srgb_intent - the rendering intent (PNG_INFO_sRGB)
- The presence of the sRGB chunk
- means that the pixel data is in the
- sRGB color space. This chunk also
- implies specific values of gAMA and
- cHRM.
-
- png_get_iCCP(png_ptr, info_ptr, &name,
- &compression_type, &profile, &proflen);
- name - The profile name.
- compression - The compression type; always
- PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
- You may give NULL to this argument to
- ignore it.
- profile - International Color Consortium color
- profile data. May contain NULs.
- proflen - length of profile data in bytes.
-
- png_get_sBIT(png_ptr, info_ptr, &sig_bit);
- sig_bit - the number of significant bits for
- (PNG_INFO_sBIT) each of the gray,
- red, green, and blue channels,
- whichever are appropriate for the
- given color type (png_color_16)
-
- png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
- &num_trans, &trans_color);
- trans_alpha - array of alpha (transparency)
- entries for palette (PNG_INFO_tRNS)
- trans_color - graylevel or color sample values of
- the single transparent color for
- non-paletted images (PNG_INFO_tRNS)
- num_trans - number of transparent entries
- (PNG_INFO_tRNS)
-
- png_get_hIST(png_ptr, info_ptr, &hist);
- (PNG_INFO_hIST)
- hist - histogram of palette (array of
- png_uint_16)
-
- png_get_tIME(png_ptr, info_ptr, &mod_time);
- mod_time - time image was last modified
- (PNG_VALID_tIME)
-
- png_get_bKGD(png_ptr, info_ptr, &background);
- background - background color (PNG_VALID_bKGD)
- valid 16-bit red, green and blue
- values, regardless of color_type
-
- num_comments = png_get_text(png_ptr, info_ptr,
- &text_ptr, &num_text);
- num_comments - number of comments
- text_ptr - array of png_text holding image
- comments
- text_ptr[i].compression - type of compression used
- on "text" PNG_TEXT_COMPRESSION_NONE
- PNG_TEXT_COMPRESSION_zTXt
- PNG_ITXT_COMPRESSION_NONE
- PNG_ITXT_COMPRESSION_zTXt
- text_ptr[i].key - keyword for comment. Must contain
- 1-79 characters.
- text_ptr[i].text - text comments for current
- keyword. Can be empty.
- text_ptr[i].text_length - length of text string,
- after decompression, 0 for iTXt
- text_ptr[i].itxt_length - length of itxt string,
- after decompression, 0 for tEXt/zTXt
- text_ptr[i].lang - language of comment (empty
- string for unknown).
- text_ptr[i].lang_key - keyword in UTF-8
- (empty string for unknown).
- Note that the itxt_length, lang, and lang_key
- members of the text_ptr structure only exist
- when the library is built with iTXt chunk support.
-
- num_text - number of comments (same as
- num_comments; you can put NULL here
- to avoid the duplication)
- Note while png_set_text() will accept text, language,
- and translated keywords that can be NULL pointers, the
- structure returned by png_get_text will always contain
- regular zero-terminated C strings. They might be
- empty strings but they will never be NULL pointers.
-
- num_spalettes = png_get_sPLT(png_ptr, info_ptr,
- &palette_ptr);
- palette_ptr - array of palette structures holding
- contents of one or more sPLT chunks
- read.
- num_spalettes - number of sPLT chunks read.
-
- png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
- &unit_type);
- offset_x - positive offset from the left edge
- of the screen
- offset_y - positive offset from the top edge
- of the screen
- unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
- png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
- &unit_type);
- res_x - pixels/unit physical resolution in
- x direction
- res_y - pixels/unit physical resolution in
- x direction
- unit_type - PNG_RESOLUTION_UNKNOWN,
- PNG_RESOLUTION_METER
-
- png_get_sCAL(png_ptr, info_ptr, &unit, &width,
- &height)
- unit - physical scale units (an integer)
- width - width of a pixel in physical scale units
- height - height of a pixel in physical scale units
- (width and height are doubles)
-
- png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
- &height)
- unit - physical scale units (an integer)
- width - width of a pixel in physical scale units
- height - height of a pixel in physical scale units
- (width and height are strings like "2.54")
-
- num_unknown_chunks = png_get_unknown_chunks(png_ptr,
- info_ptr, &unknowns)
- unknowns - array of png_unknown_chunk
- structures holding unknown chunks
- unknowns[i].name - name of unknown chunk
- unknowns[i].data - data of unknown chunk
- unknowns[i].size - size of unknown chunk's data
- unknowns[i].location - position of chunk in file
-
- The value of "i" corresponds to the order in which the
- chunks were read from the PNG file or inserted with the
- png_set_unknown_chunks() function.
-
-The data from the pHYs chunk can be retrieved in several convenient
-forms:
-
- res_x = png_get_x_pixels_per_meter(png_ptr,
- info_ptr)
- res_y = png_get_y_pixels_per_meter(png_ptr,
- info_ptr)
- res_x_and_y = png_get_pixels_per_meter(png_ptr,
- info_ptr)
- res_x = png_get_x_pixels_per_inch(png_ptr,
- info_ptr)
- res_y = png_get_y_pixels_per_inch(png_ptr,
- info_ptr)
- res_x_and_y = png_get_pixels_per_inch(png_ptr,
- info_ptr)
- aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
- info_ptr)
-
- (Each of these returns 0 [signifying "unknown"] if
- the data is not present or if res_x is 0;
- res_x_and_y is 0 if res_x != res_y)
-
-The data from the oFFs chunk can be retrieved in several convenient
-forms:
-
- x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
- y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
- x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
- y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
-
- (Each of these returns 0 [signifying "unknown" if both
- x and y are 0] if the data is not present or if the
- chunk is present but the unit is the pixel)
-
-For more information, see the png_info definition in png.h and the
-PNG specification for chunk contents. Be careful with trusting
-rowbytes, as some of the transformations could increase the space
-needed to hold a row (expand, filler, gray_to_rgb, etc.).
-See png_read_update_info(), below.
-
-A quick word about text_ptr and num_text. PNG stores comments in
-keyword/text pairs, one pair per chunk, with no limit on the number
-of text chunks, and a 2^31 byte limit on their size. While there are
-suggested keywords, there is no requirement to restrict the use to these
-strings. It is strongly suggested that keywords and text be sensible
-to humans (that's the point), so don't use abbreviations. Non-printing
-symbols are not allowed. See the PNG specification for more details.
-There is also no requirement to have text after the keyword.
-
-Keywords should be limited to 79 Latin-1 characters without leading or
-trailing spaces, but non-consecutive spaces are allowed within the
-keyword. It is possible to have the same keyword any number of times.
-The text_ptr is an array of png_text structures, each holding a
-pointer to a language string, a pointer to a keyword and a pointer to
-a text string. The text string, language code, and translated
-keyword may be empty or NULL pointers. The keyword/text
-pairs are put into the array in the order that they are received.
-However, some or all of the text chunks may be after the image, so, to
-make sure you have read all the text chunks, don't mess with these
-until after you read the stuff after the image. This will be
-mentioned again below in the discussion that goes with png_read_end().
-
-Input transformations
-
-After you've read the header information, you can set up the library
-to handle any special transformations of the image data. The various
-ways to transform the data will be described in the order that they
-should occur. This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths. Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data. For example, don't swap red and blue on grayscale data.
-
-The colors used for the background and transparency values should be
-supplied in the same format/depth as the current image data. They
-are stored in the same format/depth as the image data in a bKGD or tRNS
-chunk, so this is what libpng expects for this data. The colors are
-transformed to keep in sync with the image data when an application
-calls the png_read_update_info() routine (see below).
-
-Data will be decoded into the supplied row buffers packed into bytes
-unless the library has been told to transform it into another format.
-For example, 4 bit/pixel paletted or grayscale data will be returned
-2 pixels/byte with the leftmost pixel in the high-order bits of the
-byte, unless png_set_packing() is called. 8-bit RGB data will be stored
-in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
-is called to insert filler bytes, either before or after each RGB triplet.
-16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
-byte of the color value first, unless png_set_strip_16() is called to
-transform it to regular RGB RGB triplets, or png_set_filler() or
-png_set_add alpha() is called to insert filler bytes, either before or
-after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
-be modified with
-png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
-
-The following code transforms grayscale images of less than 8 to 8 bits,
-changes paletted images to RGB, and adds a full alpha channel if there is
-transparency information in a tRNS chunk. This is most useful on
-grayscale images with bit depths of 2 or 4 or if there is a multiple-image
-viewing application that wishes to treat all images in the same way.
-
- if (color_type == PNG_COLOR_TYPE_PALETTE)
- png_set_palette_to_rgb(png_ptr);
-
- if (color_type == PNG_COLOR_TYPE_GRAY &&
- bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
-
- if (png_get_valid(png_ptr, info_ptr,
- PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
-
-These three functions are actually aliases for png_set_expand(), added
-in libpng version 1.0.4, with the function names expanded to improve code
-readability. In some future version they may actually do different
-things.
-
-As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
-added. It expands the sample depth without changing tRNS to alpha.
-
-As of libpng version 1.4.4, not all possible expansions are supported.
-
-In the following table, the 01 means grayscale with depth<8, 31 means
-indexed with depth<8, other numerals represent the color type, "T" means
-the tRNS chunk is present, A means an alpha channel is present, and O
-means tRNS or alpha is present but all pixels in the image are opaque.
-
- FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O
- TO
- 01 -
- 31 -
- 0 1 -
- 0T -
- 0O -
- 2 GX -
- 2T -
- 2O -
- 3 1 -
- 3T -
- 3O -
- 4A T -
- 4O -
- 6A GX TX TX -
- 6O GX TX -
-
-Within the matrix,
- "-" means the transformation is not supported.
- "X" means the transformation is obtained by png_set_expand().
- "1" means the transformation is obtained by
- png_set_expand_gray_1_2_4_to_8
- "G" means the transformation is obtained by
- png_set_gray_to_rgb().
- "P" means the transformation is obtained by
- png_set_expand_palette_to_rgb().
- "T" means the transformation is obtained by
- png_set_tRNS_to_alpha().
-
-PNG can have files with 16 bits per channel. If you only can handle
-8 bits per channel, this will strip the pixels down to 8 bit.
-
- if (bit_depth == 16)
- png_set_strip_16(png_ptr);
-
-If, for some reason, you don't need the alpha channel on an image,
-and you want to remove it rather than combining it with the background
-(but the image author certainly had in mind that you *would* combine
-it with the background, so that's what you should probably do):
-
- if (color_type & PNG_COLOR_MASK_ALPHA)
- png_set_strip_alpha(png_ptr);
-
-In PNG files, the alpha channel in an image
-is the level of opacity. If you need the alpha channel in an image to
-be the level of transparency instead of opacity, you can invert the
-alpha channel (or the tRNS chunk data) after it's read, so that 0 is
-fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
-images) is fully transparent, with
-
- png_set_invert_alpha(png_ptr);
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit
-files. This code expands to 1 pixel per byte without changing the
-values of the pixels:
-
- if (bit_depth < 8)
- png_set_packing(png_ptr);
-
-PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels
-stored in a PNG image have been "scaled" or "shifted" up to the next
-higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
-to 8 bits/sample in the range [0, 255]). However, it is also possible
-to convert the PNG pixel data back to the original bit depth of the
-image. This call reduces the pixels back down to the original bit depth:
-
- png_color_8p sig_bit;
-
- if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
- png_set_shift(png_ptr, sig_bit);
-
-PNG files store 3-color pixels in red, green, blue order. This code
-changes the storage of the pixels to blue, green, red:
-
- if (color_type == PNG_COLOR_TYPE_RGB ||
- color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- png_set_bgr(png_ptr);
-
-PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
-into 4 or 8 bytes for windowing systems that need them in this format:
-
- if (color_type == PNG_COLOR_TYPE_RGB)
- png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
-
-where "filler" is the 8 or 16-bit number to fill with, and the location is
-either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
-you want the filler before the RGB or after. This transformation
-does not affect images that already have full alpha channels. To add an
-opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
-will generate RGBA pixels.
-
-Note that png_set_filler() does not change the color type. If you want
-to do that, you can add a true alpha channel with
-
- if (color_type == PNG_COLOR_TYPE_RGB ||
- color_type == PNG_COLOR_TYPE_GRAY)
- png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
-
-where "filler" contains the alpha value to assign to each pixel.
-This function was added in libpng-1.2.7.
-
-If you are reading an image with an alpha channel, and you need the
-data as ARGB instead of the normal PNG format RGBA:
-
- if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- png_set_swap_alpha(png_ptr);
-
-For some uses, you may want a grayscale image to be represented as
-RGB. This code will do that conversion:
-
- if (color_type == PNG_COLOR_TYPE_GRAY ||
- color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- png_set_gray_to_rgb(png_ptr);
-
-Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
-with alpha.
-
- if (color_type == PNG_COLOR_TYPE_RGB ||
- color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- png_set_rgb_to_gray_fixed(png_ptr, error_action,
- int red_weight, int green_weight);
-
- error_action = 1: silently do the conversion
- error_action = 2: issue a warning if the original
- image has any pixel where
- red != green or red != blue
- error_action = 3: issue an error and abort the
- conversion if the original
- image has any pixel where
- red != green or red != blue
-
- red_weight: weight of red component times 100000
- green_weight: weight of green component times 100000
- If either weight is negative, default
- weights (21268, 71514) are used.
-
-If you have set error_action = 1 or 2, you can
-later check whether the image really was gray, after processing
-the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
-It will return a png_byte that is zero if the image was gray or
-1 if there were any non-gray pixels. bKGD and sBIT data
-will be silently converted to grayscale, using the green channel
-data, regardless of the error_action setting.
-
-With red_weight+green_weight<=100000,
-the normalized graylevel is computed:
-
- int rw = red_weight * 65536;
- int gw = green_weight * 65536;
- int bw = 65536 - (rw + gw);
- gray = (rw*red + gw*green + bw*blue)/65536;
-
-The default values approximate those recommended in the Charles
-Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
-Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
-
- Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
-
-Libpng approximates this with
-
- Y = 0.21268 * R + 0.7151 * G + 0.07217 * B
-
-which can be expressed with integers as
-
- Y = (6969 * R + 23434 * G + 2365 * B)/32768
-
-The calculation is done in a linear colorspace, if the image gamma
-is known.
-
-If you have a grayscale and you are using png_set_expand_depth(),
-png_set_expand(), or png_set_gray_to_rgb to change to truecolor or to
-a higher bit-depth, you must either supply the background color as a gray
-value at the original file bit-depth (need_expand = 1) or else supply the
-background color as an RGB triplet at the final, expanded bit depth
-(need_expand = 0). Similarly, if you are reading a paletted image, you
-must either supply the background color as a palette index (need_expand = 1)
-or as an RGB triplet that may or may not be in the palette (need_expand = 0).
-
- png_color_16 my_background;
- png_color_16p image_background;
-
- if (png_get_bKGD(png_ptr, info_ptr, &image_background))
- png_set_background(png_ptr, image_background,
- PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
- else
- png_set_background(png_ptr, &my_background,
- PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
-
-The png_set_background() function tells libpng to composite images
-with alpha or simple transparency against the supplied background
-color. If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
-you may use this color, or supply another color more suitable for
-the current display (e.g., the background color from a web page). You
-need to tell libpng whether the color is in the gamma space of the
-display (PNG_BACKGROUND_GAMMA_SCREEN for colors you supply), the file
-(PNG_BACKGROUND_GAMMA_FILE for colors from the bKGD chunk), or one
-that is neither of these gammas (PNG_BACKGROUND_GAMMA_UNIQUE - I don't
-know why anyone would use this, but it's here).
-
-To properly display PNG images on any kind of system, the application needs
-to know what the display gamma is. Ideally, the user will know this, and
-the application will allow them to set it. One method of allowing the user
-to set the display gamma separately for each system is to check for a
-SCREEN_GAMMA or DISPLAY_GAMMA environment variable, which will hopefully be
-correctly set.
-
-Note that display_gamma is the overall gamma correction required to produce
-pleasing results, which depends on the lighting conditions in the surrounding
-environment. In a dim or brightly lit room, no compensation other than
-the physical gamma exponent of the monitor is needed, while in a dark room
-a slightly smaller exponent is better.
-
- double gamma, screen_gamma;
-
- if (/* We have a user-defined screen
- gamma value */)
- {
- screen_gamma = user_defined_screen_gamma;
- }
- /* One way that applications can share the same
- screen gamma value */
- else if ((gamma_str = getenv("SCREEN_GAMMA"))
- != NULL)
- {
- screen_gamma = (double)atof(gamma_str);
- }
- /* If we don't have another value */
- else
- {
- screen_gamma = 2.2; /* A good guess for a
- PC monitor in a bright office or a dim room */
- screen_gamma = 2.0; /* A good guess for a
- PC monitor in a dark room */
- screen_gamma = 1.7 or 1.0; /* A good
- guess for Mac systems */
- }
-
-The png_set_gamma() function handles gamma transformations of the data.
-Pass both the file gamma and the current screen_gamma. If the file does
-not have a gamma value, you can pass one anyway if you have an idea what
-it is (usually 0.45455 is a good guess for GIF images on PCs). Note
-that file gammas are inverted from screen gammas. See the discussions
-on gamma in the PNG specification for an excellent description of what
-gamma is, and why all applications should support it. It is strongly
-recommended that PNG viewers support gamma correction.
-
- if (png_get_gAMA(png_ptr, info_ptr, &gamma))
- png_set_gamma(png_ptr, screen_gamma, gamma);
- else
- png_set_gamma(png_ptr, screen_gamma, 0.45455);
-
-If you need to reduce an RGB file to a paletted file, or if a paletted
-file has more entries then will fit on your screen, png_set_quantize()
-will do that. Note that this is a simple match dither that merely
-finds the closest color available. This should work fairly well with
-optimized palettes, and fairly badly with linear color cubes. If you
-pass a palette that is larger then maximum_colors, the file will
-reduce the number of colors in the palette so it will fit into
-maximum_colors. If there is a histogram, it will use it to make
-more intelligent choices when reducing the palette. If there is no
-histogram, it may not do as good a job.
-
- if (color_type & PNG_COLOR_MASK_COLOR)
- {
- if (png_get_valid(png_ptr, info_ptr,
- PNG_INFO_PLTE))
- {
- png_uint_16p histogram = NULL;
-
- png_get_hIST(png_ptr, info_ptr,
- &histogram);
- png_set_quantize(png_ptr, palette, num_palette,
- max_screen_colors, histogram, 1);
- }
- else
- {
- png_color std_color_cube[MAX_SCREEN_COLORS] =
- { ... colors ... };
-
- png_set_quantize(png_ptr, std_color_cube,
- MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
- NULL,0);
- }
- }
-
-PNG files describe monochrome as black being zero and white being one.
-The following code will reverse this (make black be one and white be
-zero):
-
- if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
- png_set_invert_mono(png_ptr);
-
-This function can also be used to invert grayscale and gray-alpha images:
-
- if (color_type == PNG_COLOR_TYPE_GRAY ||
- color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- png_set_invert_mono(png_ptr);
-
-PNG files store 16 bit pixels in network byte order (big-endian,
-ie. most significant bits first). This code changes the storage to the
-other way (little-endian, i.e. least significant bits first, the
-way PCs store them):
-
- if (bit_depth == 16)
- png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
- if (bit_depth < 8)
- png_set_packswap(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs. This is done by setting a callback
-with
-
- png_set_read_user_transform_fn(png_ptr,
- read_transform_fn);
-
-You must supply the function
-
- void read_transform_fn(png_ptr ptr, row_info_ptr
- row_info, png_bytep data)
-
-See pngtest.c for a working example. Your function will be called
-after all of the other transformations have been processed.
-
-You can also set up a pointer to a user structure for use by your
-callback function, and you can inform libpng that your transform
-function will change the number of channels or bit depth with the
-function
-
- png_set_user_transform_info(png_ptr, user_ptr,
- user_depth, user_channels);
-
-The user's application, not libpng, is responsible for allocating and
-freeing any memory required for the user structure.
-
-You can retrieve the pointer via the function
-png_get_user_transform_ptr(). For example:
-
- voidp read_user_transform_ptr =
- png_get_user_transform_ptr(png_ptr);
-
-The last thing to handle is interlacing; this is covered in detail below,
-but you must call the function here if you want libpng to handle expansion
-of the interlaced image.
-
- number_of_passes = png_set_interlace_handling(png_ptr);
-
-After setting the transformations, libpng can update your png_info
-structure to reflect any transformations you've requested with this
-call. This is most useful to update the info structure's rowbytes
-field so you can use it to allocate your image memory. This function
-will also update your palette with the correct screen_gamma and
-background if these have been given with the calls above.
-
- png_read_update_info(png_ptr, info_ptr);
-
-After you call png_read_update_info(), you can allocate any
-memory you need to hold the image. The row data is simply
-raw byte data for all forms of images. As the actual allocation
-varies among applications, no example will be given. If you
-are allocating one large chunk, you will need to build an
-array of pointers to each row, as it will be needed for some
-of the functions below.
-
-Reading image data
-
-After you've allocated memory, you can read the image data.
-The simplest way to do this is in one function call. If you are
-allocating enough memory to hold the whole image, you can just
-call png_read_image() and libpng will read in all the image data
-and put it in the memory area supplied. You will need to pass in
-an array of pointers to each row.
-
-This function automatically handles interlacing, so you don't need
-to call png_set_interlace_handling() or call this function multiple
-times, or any of that other stuff necessary with png_read_rows().
-
- png_read_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
- png_bytep row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to read in the whole image at once, you can
-use png_read_rows() instead. If there is no interlacing (check
-interlace_type == PNG_INTERLACE_NONE), this is simple:
-
- png_read_rows(png_ptr, row_pointers, NULL,
- number_of_rows);
-
-where row_pointers is the same as in the png_read_image() call.
-
-If you are doing this just one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
- png_bytep row_pointer = row;
- png_read_row(png_ptr, row_pointer, NULL);
-
-If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
-get somewhat harder. The only current (PNG Specification version 1.2)
-interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7)
-is a somewhat complicated 2D interlace scheme, known as Adam7, that
-breaks down an image into seven smaller images of varying size, based
-on an 8x8 grid.
-
-libpng can fill out those images or it can give them to you "as is".
-If you want them filled out, there are two ways to do that. The one
-mentioned in the PNG specification is to expand each pixel to cover
-those pixels that have not been read yet (the "rectangle" method).
-This results in a blocky image for the first pass, which gradually
-smooths out as more pixels are read. The other method is the "sparkle"
-method, where pixels are drawn only in their final locations, with the
-rest of the image remaining whatever colors they were initialized to
-before the start of the read. The first method usually looks better,
-but tends to be slower, as there are more pixels to put in the rows.
-
-If you don't want libpng to handle the interlacing details, just call
-png_read_rows() seven times to read in all seven images. Each of the
-images is a valid image by itself, or they can all be combined on an
-8x8 grid to form a single image (although if you intend to combine them
-you would be far better off using the libpng interlace handling).
-
-The first pass will return an image 1/8 as wide as the entire image
-(every 8th column starting in column 0) and 1/8 as high as the original
-(every 8th row starting in row 0), the second will be 1/8 as wide
-(starting in column 4) and 1/8 as high (also starting in row 0). The
-third pass will be 1/4 as wide (every 4th pixel starting in column 0) and
-1/8 as high (every 8th row starting in row 4), and the fourth pass will
-be 1/4 as wide and 1/4 as high (every 4th column starting in column 2,
-and every 4th row starting in row 0). The fifth pass will return an
-image 1/2 as wide, and 1/4 as high (starting at column 0 and row 2),
-while the sixth pass will be 1/2 as wide and 1/2 as high as the original
-(starting in column 1 and row 0). The seventh and final pass will be as
-wide as the original, and 1/2 as high, containing all of the odd
-numbered scanlines. Phew!
-
-If you want libpng to expand the images, call this before calling
-png_start_read_image() or png_read_update_info():
-
- if (interlace_type == PNG_INTERLACE_ADAM7)
- number_of_passes
- = png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed. Currently, this
-is seven, but may change if another interlace type is added.
-This function can be called even if the file is not interlaced,
-where it will return one pass.
-
-If you are not going to display the image after each pass, but are
-going to wait until the entire image is read in, use the sparkle
-effect. This effect is faster and the end result of either method
-is exactly the same. If you are planning on displaying the image
-after each pass, the "rectangle" effect is generally considered the
-better looking one.
-
-If you only want the "sparkle" effect, just call png_read_rows() as
-normal, with the third parameter NULL. Make sure you make pass over
-the image number_of_passes times, and you don't change the data in the
-rows between calls. You can change the locations of the data, just
-not the data. Each pass only writes the pixels appropriate for that
-pass, and assumes the data from previous passes is still valid.
-
- png_read_rows(png_ptr, row_pointers, NULL,
- number_of_rows);
-
-If you only want the first effect (the rectangles), do the same as
-before except pass the row buffer in the third parameter, and leave
-the second parameter NULL.
-
- png_read_rows(png_ptr, NULL, row_pointers,
- number_of_rows);
-
-Finishing a sequential read
-
-After you are finished reading the image through the
-low-level interface, you can finish reading the file. If you are
-interested in comments or time, which may be stored either before or
-after the image data, you should pass the separate png_info struct if
-you want to keep the comments from before and after the image
-separate. If you are not interested, you can pass NULL.
-
- png_read_end(png_ptr, end_info);
-
-When you are done, you can free all memory allocated by libpng like this:
-
- png_destroy_read_struct(&png_ptr, &info_ptr,
- &end_info);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
- png_free_data(png_ptr, info_ptr, mask, seq)
- mask - identifies data to be freed, a mask
- containing the bitwise OR of one or
- more of
- PNG_FREE_PLTE, PNG_FREE_TRNS,
- PNG_FREE_HIST, PNG_FREE_ICCP,
- PNG_FREE_PCAL, PNG_FREE_ROWS,
- PNG_FREE_SCAL, PNG_FREE_SPLT,
- PNG_FREE_TEXT, PNG_FREE_UNKN,
- or simply PNG_FREE_ALL
- seq - sequence number of item to be freed
- (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user and not by libpng, and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-The default behavior is only to free data that was allocated internally
-by libpng. This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
- png_data_freer(png_ptr, info_ptr, freer, mask)
- mask - which data elements are affected
- same choices as in png_free_data()
- freer - one of
- PNG_DESTROY_WILL_FREE_DATA
- PNG_SET_WILL_FREE_DATA
- PNG_USER_WILL_FREE_DATA
-
-This function only affects data that has already been allocated.
-You can call this function after reading the PNG data but before calling
-any png_set_*() functions, to control whether the user or the png_set_*()
-function is responsible for freeing any existing data that might be present,
-and again after the png_set_*() functions to control whether the user
-or png_destroy_*() is supposed to free the data. When the user assumes
-responsibility for libpng-allocated data, the application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated your row_pointers in a single block, as suggested above in
-the description of the high level read interface, you must not transfer
-responsibility for freeing it to the png_set_rows or png_read_destroy function,
-because they would also try to free the individual row_pointers[i].
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key. Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-
-The png_free_data() function will turn off the "valid" flag for anything
-it frees. If you need to turn the flag off for a chunk that was freed by
-your application instead of by libpng, you can use
-
- png_set_invalid(png_ptr, info_ptr, mask);
- mask - identifies the chunks to be made invalid,
- containing the bitwise OR of one or
- more of
- PNG_INFO_gAMA, PNG_INFO_sBIT,
- PNG_INFO_cHRM, PNG_INFO_PLTE,
- PNG_INFO_tRNS, PNG_INFO_bKGD,
- PNG_INFO_hIST, PNG_INFO_pHYs,
- PNG_INFO_oFFs, PNG_INFO_tIME,
- PNG_INFO_pCAL, PNG_INFO_sRGB,
- PNG_INFO_iCCP, PNG_INFO_sPLT,
- PNG_INFO_sCAL, PNG_INFO_IDAT
-
-For a more compact example of reading a PNG image, see the file example.c.
-
-Reading PNG files progressively
-
-The progressive reader is slightly different then the non-progressive
-reader. Instead of calling png_read_info(), png_read_rows(), and
-png_read_end(), you make one call to png_process_data(), which calls
-callbacks when it has the info, a row, or the end of the image. You
-set up these callbacks with png_set_progressive_read_fn(). You don't
-have to worry about the input/output functions of libpng, as you are
-giving the library the data directly in png_process_data(). I will
-assume that you have read the section on reading PNG files above,
-so I will only highlight the differences (although I will show
-all of the code).
-
-png_structp png_ptr;
-png_infop info_ptr;
-
- /* An example code fragment of how you would
- initialize the progressive reader in your
- application. */
- int
- initialize_png_reader()
- {
- png_ptr = png_create_read_struct
- (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
- user_error_fn, user_warning_fn);
- if (!png_ptr)
- return (ERROR);
- info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr)
- {
- png_destroy_read_struct(&png_ptr, (png_infopp)NULL,
- (png_infopp)NULL);
- return (ERROR);
- }
-
- if (setjmp(png_jmpbuf(png_ptr)))
- {
- png_destroy_read_struct(&png_ptr, &info_ptr,
- (png_infopp)NULL);
- return (ERROR);
- }
-
- /* This one's new. You can provide functions
- to be called when the header info is valid,
- when each row is completed, and when the image
- is finished. If you aren't using all functions,
- you can specify NULL parameters. Even when all
- three functions are NULL, you need to call
- png_set_progressive_read_fn(). You can use
- any struct as the user_ptr (cast to a void pointer
- for the function call), and retrieve the pointer
- from inside the callbacks using the function
-
- png_get_progressive_ptr(png_ptr);
-
- which will return a void pointer, which you have
- to cast appropriately.
- */
- png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
- info_callback, row_callback, end_callback);
-
- return 0;
- }
-
- /* A code fragment that you call as you receive blocks
- of data */
- int
- process_data(png_bytep buffer, png_uint_32 length)
- {
- if (setjmp(png_jmpbuf(png_ptr)))
- {
- png_destroy_read_struct(&png_ptr, &info_ptr,
- (png_infopp)NULL);
- return (ERROR);
- }
-
- /* This one's new also. Simply give it a chunk
- of data from the file stream (in order, of
- course). On machines with segmented memory
- models machines, don't give it any more than
- 64K. The library seems to run fine with sizes
- of 4K. Although you can give it much less if
- necessary (I assume you can give it chunks of
- 1 byte, I haven't tried less then 256 bytes
- yet). When this function returns, you may
- want to display any rows that were generated
- in the row callback if you don't already do
- so there.
- */
- png_process_data(png_ptr, info_ptr, buffer, length);
- return 0;
- }
-
- /* This function is called (as set by
- png_set_progressive_read_fn() above) when enough data
- has been supplied so all of the header has been
- read.
- */
- void
- info_callback(png_structp png_ptr, png_infop info)
- {
- /* Do any setup here, including setting any of
- the transformations mentioned in the Reading
- PNG files section. For now, you _must_ call
- either png_start_read_image() or
- png_read_update_info() after all the
- transformations are set (even if you don't set
- any). You may start getting rows before
- png_process_data() returns, so this is your
- last chance to prepare for that.
- */
- }
-
- /* This function is called when each row of image
- data is complete */
- void
- row_callback(png_structp png_ptr, png_bytep new_row,
- png_uint_32 row_num, int pass)
- {
- /* If the image is interlaced, and you turned
- on the interlace handler, this function will
- be called for every row in every pass. Some
- of these rows will not be changed from the
- previous pass. When the row is not changed,
- the new_row variable will be NULL. The rows
- and passes are called in order, so you don't
- really need the row_num and pass, but I'm
- supplying them because it may make your life
- easier.
-
- For the non-NULL rows of interlaced images,
- you must call png_progressive_combine_row()
- passing in the row and the old row. You can
- call this function for NULL rows (it will just
- return) and for non-interlaced images (it just
- does the memcpy for you) if it will make the
- code easier. Thus, you can just do this for
- all cases:
- */
-
- png_progressive_combine_row(png_ptr, old_row,
- new_row);
-
- /* where old_row is what was displayed for
- previously for the row. Note that the first
- pass (pass == 0, really) will completely cover
- the old row, so the rows do not have to be
- initialized. After the first pass (and only
- for interlaced images), you will have to pass
- the current row, and the function will combine
- the old row and the new row.
- */
- }
-
- void
- end_callback(png_structp png_ptr, png_infop info)
- {
- /* This function is called after the whole image
- has been read, including any chunks after the
- image (up to and including the IEND). You
- will usually have the same info chunk as you
- had in the header, although some data may have
- been added to the comments and time fields.
-
- Most people won't do much here, perhaps setting
- a flag that marks the image as finished.
- */
- }
-
-
-
-IV. Writing
-
-Much of this is very similar to reading. However, everything of
-importance is repeated here, so you won't have to constantly look
-back up in the reading section to understand writing.
-
-Setup
-
-You will want to do the I/O initialization before you get into libpng,
-so if it doesn't work, you don't have anything to undo. If you are not
-using the standard I/O functions, you will need to replace them with
-custom writing functions. See the discussion under Customizing libpng.
-
- FILE *fp = fopen(file_name, "wb");
- if (!fp)
- {
- return (ERROR);
- }
-
-Next, png_struct and png_info need to be allocated and initialized.
-As these can be both relatively large, you may not want to store these
-on the stack, unless you have stack space to spare. Of course, you
-will want to check if they return NULL. If you are also reading,
-you won't want to name your read structure and your write structure
-both "png_ptr"; you can call them anything you like, such as
-"read_ptr" and "write_ptr". Look at pngtest.c, for example.
-
- png_structp png_ptr = png_create_write_struct
- (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
- user_error_fn, user_warning_fn);
- if (!png_ptr)
- return (ERROR);
-
- png_infop info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr)
- {
- png_destroy_write_struct(&png_ptr,
- (png_infopp)NULL);
- return (ERROR);
- }
-
-If you want to use your own memory allocation routines,
-define PNG_USER_MEM_SUPPORTED and use
-png_create_write_struct_2() instead of png_create_write_struct():
-
- png_structp png_ptr = png_create_write_struct_2
- (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
- user_error_fn, user_warning_fn, (png_voidp)
- user_mem_ptr, user_malloc_fn, user_free_fn);
-
-After you have these structures, you will need to set up the
-error handling. When libpng encounters an error, it expects to
-longjmp() back to your routine. Therefore, you will need to call
-setjmp() and pass the png_jmpbuf(png_ptr). If you
-write the file from different routines, you will need to update
-the png_jmpbuf(png_ptr) every time you enter a new routine that will
-call a png_*() function. See your documentation of setjmp/longjmp
-for your compiler for more information on setjmp/longjmp. See
-the discussion on libpng error handling in the Customizing Libpng
-section below for more information on the libpng error handling.
-
- if (setjmp(png_jmpbuf(png_ptr)))
- {
- png_destroy_write_struct(&png_ptr, &info_ptr);
- fclose(fp);
- return (ERROR);
- }
- ...
- return;
-
-If you would rather avoid the complexity of setjmp/longjmp issues,
-you can compile libpng with PNG_NO_SETJMP, in which case
-errors will result in a call to PNG_ABORT() which defaults to abort().
-
-You can #define PNG_ABORT() to a function that does something
-more useful than abort(), as long as your function does not
-return.
-
-Now you need to set up the output code. The default for libpng is to
-use the C function fwrite(). If you use this, you will need to pass a
-valid FILE * in the function png_init_io(). Be sure that the file is
-opened in binary mode. Again, if you wish to handle writing data in
-another way, see the discussion on libpng I/O handling in the Customizing
-Libpng section below.
-
- png_init_io(png_ptr, fp);
-
-If you are embedding your PNG into a datastream such as MNG, and don't
-want libpng to write the 8-byte signature, or if you have already
-written the signature in your application, use
-
- png_set_sig_bytes(png_ptr, 8);
-
-to inform libpng that it should not write a signature.
-
-Write callbacks
-
-At this point, you can set up a callback function that will be
-called after each row has been written, which you can use to control
-a progress meter or the like. It's demonstrated in pngtest.c.
-You must supply a function
-
- void write_row_callback(png_ptr, png_uint_32 row,
- int pass);
- {
- /* put your code here */
- }
-
-(You can give it another name that you like instead of "write_row_callback")
-
-To inform libpng about your function, use
-
- png_set_write_status_fn(png_ptr, write_row_callback);
-
-You now have the option of modifying how the compression library will
-run. The following functions are mainly for testing, but may be useful
-in some cases, like if you need to write PNG files extremely fast and
-are willing to give up some compression, or if you want to get the
-maximum possible compression at the expense of slower writing. If you
-have no special needs in this area, let the library do what it wants by
-not calling this function at all, as it has been tuned to deliver a good
-speed/compression ratio. The second parameter to png_set_filter() is
-the filter method, for which the only valid values are 0 (as of the
-July 1999 PNG specification, version 1.2) or 64 (if you are writing
-a PNG datastream that is to be embedded in a MNG datastream). The third
-parameter is a flag that indicates which filter type(s) are to be tested
-for each scanline. See the PNG specification for details on the specific
-filter types.
-
-
- /* turn on or off filtering, and/or choose
- specific filters. You can use either a single
- PNG_FILTER_VALUE_NAME or the bitwise OR of one
- or more PNG_FILTER_NAME masks. */
- png_set_filter(png_ptr, 0,
- PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
- PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
- PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
- PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
- PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
- PNG_ALL_FILTERS);
-
-If an application
-wants to start and stop using particular filters during compression,
-it should start out with all of the filters (to ensure that the previous
-row of pixels will be stored in case it's needed later), and then add
-and remove them after the start of compression.
-
-If you are writing a PNG datastream that is to be embedded in a MNG
-datastream, the second parameter can be either 0 or 64.
-
-The png_set_compression_*() functions interface to the zlib compression
-library, and should mostly be ignored unless you really know what you are
-doing. The only generally useful call is png_set_compression_level()
-which changes how much time zlib spends on trying to compress the image
-data. See the Compression Library (zlib.h and algorithm.txt, distributed
-with zlib) for details on the compression levels.
-
- /* set the zlib compression level */
- png_set_compression_level(png_ptr,
- Z_BEST_COMPRESSION);
-
- /* set other zlib parameters */
- png_set_compression_mem_level(png_ptr, 8);
- png_set_compression_strategy(png_ptr,
- Z_DEFAULT_STRATEGY);
- png_set_compression_window_bits(png_ptr, 15);
- png_set_compression_method(png_ptr, 8);
- png_set_compression_buffer_size(png_ptr, 8192)
-
-extern PNG_EXPORT(void,png_set_zbuf_size)
-
-Setting the contents of info for output
-
-You now need to fill in the png_info structure with all the data you
-wish to write before the actual image. Note that the only thing you
-are allowed to write after the image is the text chunks and the time
-chunk (as of PNG Specification 1.2, anyway). See png_write_end() and
-the latest PNG specification for more information on that. If you
-wish to write them before the image, fill them in now, and flag that
-data as being valid. If you want to wait until after the data, don't
-fill them until png_write_end(). For all the fields in png_info and
-their data types, see png.h. For explanations of what the fields
-contain, see the PNG specification.
-
-Some of the more important parts of the png_info are:
-
- png_set_IHDR(png_ptr, info_ptr, width, height,
- bit_depth, color_type, interlace_type,
- compression_type, filter_method)
- width - holds the width of the image
- in pixels (up to 2^31).
- height - holds the height of the image
- in pixels (up to 2^31).
- bit_depth - holds the bit depth of one of the
- image channels.
- (valid values are 1, 2, 4, 8, 16
- and depend also on the
- color_type. See also significant
- bits (sBIT) below).
- color_type - describes which color/alpha
- channels are present.
- PNG_COLOR_TYPE_GRAY
- (bit depths 1, 2, 4, 8, 16)
- PNG_COLOR_TYPE_GRAY_ALPHA
- (bit depths 8, 16)
- PNG_COLOR_TYPE_PALETTE
- (bit depths 1, 2, 4, 8)
- PNG_COLOR_TYPE_RGB
- (bit_depths 8, 16)
- PNG_COLOR_TYPE_RGB_ALPHA
- (bit_depths 8, 16)
-
- PNG_COLOR_MASK_PALETTE
- PNG_COLOR_MASK_COLOR
- PNG_COLOR_MASK_ALPHA
-
- interlace_type - PNG_INTERLACE_NONE or
- PNG_INTERLACE_ADAM7
- compression_type - (must be
- PNG_COMPRESSION_TYPE_DEFAULT)
- filter_method - (must be PNG_FILTER_TYPE_DEFAULT
- or, if you are writing a PNG to
- be embedded in a MNG datastream,
- can also be
- PNG_INTRAPIXEL_DIFFERENCING)
-
-If you call png_set_IHDR(), the call must appear before any of the
-other png_set_*() functions, because they might require access to some of
-the IHDR settings. The remaining png_set_*() functions can be called
-in any order.
-
-If you wish, you can reset the compression_type, interlace_type, or
-filter_method later by calling png_set_IHDR() again; if you do this, the
-width, height, bit_depth, and color_type must be the same in each call.
-
- png_set_PLTE(png_ptr, info_ptr, palette,
- num_palette);
- palette - the palette for the file
- (array of png_color)
- num_palette - number of entries in the palette
-
- png_set_gAMA(png_ptr, info_ptr, gamma);
- gamma - the gamma the image was created
- at (PNG_INFO_gAMA)
-
- png_set_sRGB(png_ptr, info_ptr, srgb_intent);
- srgb_intent - the rendering intent
- (PNG_INFO_sRGB) The presence of
- the sRGB chunk means that the pixel
- data is in the sRGB color space.
- This chunk also implies specific
- values of gAMA and cHRM. Rendering
- intent is the CSS-1 property that
- has been defined by the International
- Color Consortium
- (http://www.color.org).
- It can be one of
- PNG_sRGB_INTENT_SATURATION,
- PNG_sRGB_INTENT_PERCEPTUAL,
- PNG_sRGB_INTENT_ABSOLUTE, or
- PNG_sRGB_INTENT_RELATIVE.
-
-
- png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
- srgb_intent);
- srgb_intent - the rendering intent
- (PNG_INFO_sRGB) The presence of the
- sRGB chunk means that the pixel
- data is in the sRGB color space.
- This function also causes gAMA and
- cHRM chunks with the specific values
- that are consistent with sRGB to be
- written.
-
- png_set_iCCP(png_ptr, info_ptr, name, compression_type,
- profile, proflen);
- name - The profile name.
- compression - The compression type; always
- PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
- You may give NULL to this argument to
- ignore it.
- profile - International Color Consortium color
- profile data. May contain NULs.
- proflen - length of profile data in bytes.
-
- png_set_sBIT(png_ptr, info_ptr, sig_bit);
- sig_bit - the number of significant bits for
- (PNG_INFO_sBIT) each of the gray, red,
- green, and blue channels, whichever are
- appropriate for the given color type
- (png_color_16)
-
- png_set_tRNS(png_ptr, info_ptr, trans_alpha,
- num_trans, trans_color);
- trans_alpha - array of alpha (transparency)
- entries for palette (PNG_INFO_tRNS)
- trans_color - graylevel or color sample values
- (in order red, green, blue) of the
- single transparent color for
- non-paletted images (PNG_INFO_tRNS)
- num_trans - number of transparent entries
- (PNG_INFO_tRNS)
-
- png_set_hIST(png_ptr, info_ptr, hist);
- (PNG_INFO_hIST)
- hist - histogram of palette (array of
- png_uint_16)
-
- png_set_tIME(png_ptr, info_ptr, mod_time);
- mod_time - time image was last modified
- (PNG_VALID_tIME)
-
- png_set_bKGD(png_ptr, info_ptr, background);
- background - background color (PNG_VALID_bKGD)
-
- png_set_text(png_ptr, info_ptr, text_ptr, num_text);
- text_ptr - array of png_text holding image
- comments
- text_ptr[i].compression - type of compression used
- on "text" PNG_TEXT_COMPRESSION_NONE
- PNG_TEXT_COMPRESSION_zTXt
- PNG_ITXT_COMPRESSION_NONE
- PNG_ITXT_COMPRESSION_zTXt
- text_ptr[i].key - keyword for comment. Must contain
- 1-79 characters.
- text_ptr[i].text - text comments for current
- keyword. Can be NULL or empty.
- text_ptr[i].text_length - length of text string,
- after decompression, 0 for iTXt
- text_ptr[i].itxt_length - length of itxt string,
- after decompression, 0 for tEXt/zTXt
- text_ptr[i].lang - language of comment (NULL or
- empty for unknown).
- text_ptr[i].translated_keyword - keyword in UTF-8 (NULL
- or empty for unknown).
- Note that the itxt_length, lang, and lang_key
- members of the text_ptr structure only exist
- when the library is built with iTXt chunk support.
-
- num_text - number of comments
-
- png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
- num_spalettes);
- palette_ptr - array of png_sPLT_struct structures
- to be added to the list of palettes
- in the info structure.
- num_spalettes - number of palette structures to be
- added.
-
- png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
- unit_type);
- offset_x - positive offset from the left
- edge of the screen
- offset_y - positive offset from the top
- edge of the screen
- unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
-
- png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
- unit_type);
- res_x - pixels/unit physical resolution
- in x direction
- res_y - pixels/unit physical resolution
- in y direction
- unit_type - PNG_RESOLUTION_UNKNOWN,
- PNG_RESOLUTION_METER
-
- png_set_sCAL(png_ptr, info_ptr, unit, width, height)
- unit - physical scale units (an integer)
- width - width of a pixel in physical scale units
- height - height of a pixel in physical scale units
- (width and height are doubles)
-
- png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
- unit - physical scale units (an integer)
- width - width of a pixel in physical scale units
- height - height of a pixel in physical scale units
- (width and height are strings like "2.54")
-
- png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
- num_unknowns)
- unknowns - array of png_unknown_chunk
- structures holding unknown chunks
- unknowns[i].name - name of unknown chunk
- unknowns[i].data - data of unknown chunk
- unknowns[i].size - size of unknown chunk's data
- unknowns[i].location - position to write chunk in file
- 0: do not write chunk
- PNG_HAVE_IHDR: before PLTE
- PNG_HAVE_PLTE: before IDAT
- PNG_AFTER_IDAT: after IDAT
-
-The "location" member is set automatically according to
-what part of the output file has already been written.
-You can change its value after calling png_set_unknown_chunks()
-as demonstrated in pngtest.c. Within each of the "locations",
-the chunks are sequenced according to their position in the
-structure (that is, the value of "i", which is the order in which
-the chunk was either read from the input file or defined with
-png_set_unknown_chunks).
-
-A quick word about text and num_text. text is an array of png_text
-structures. num_text is the number of valid structures in the array.
-Each png_text structure holds a language code, a keyword, a text value,
-and a compression type.
-
-The compression types have the same valid numbers as the compression
-types of the image data. Currently, the only valid number is zero.
-However, you can store text either compressed or uncompressed, unlike
-images, which always have to be compressed. So if you don't want the
-text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
-Because tEXt and zTXt chunks don't have a language field, if you
-specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
-any language code or translated keyword will not be written out.
-
-Until text gets around 1000 bytes, it is not worth compressing it.
-After the text has been written out to the file, the compression type
-is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
-so that it isn't written out again at the end (in case you are calling
-png_write_end() with the same struct.
-
-The keywords that are given in the PNG Specification are:
-
- Title Short (one line) title or
- caption for image
- Author Name of image's creator
- Description Description of image (possibly long)
- Copyright Copyright notice
- Creation Time Time of original image creation
- (usually RFC 1123 format, see below)
- Software Software used to create the image
- Disclaimer Legal disclaimer
- Warning Warning of nature of content
- Source Device used to create the image
- Comment Miscellaneous comment; conversion
- from other image format
-
-The keyword-text pairs work like this. Keywords should be short
-simple descriptions of what the comment is about. Some typical
-keywords are found in the PNG specification, as is some recommendations
-on keywords. You can repeat keywords in a file. You can even write
-some text before the image and some after. For example, you may want
-to put a description of the image before the image, but leave the
-disclaimer until after, so viewers working over modem connections
-don't have to wait for the disclaimer to go over the modem before
-they start seeing the image. Finally, keywords should be full
-words, not abbreviations. Keywords and text are in the ISO 8859-1
-(Latin-1) character set (a superset of regular ASCII) and can not
-contain NUL characters, and should not contain control or other
-unprintable characters. To make the comments widely readable, stick
-with basic ASCII, and avoid machine specific character set extensions
-like the IBM-PC character set. The keyword must be present, but
-you can leave off the text string on non-compressed pairs.
-Compressed pairs must have a text string, as only the text string
-is compressed anyway, so the compression would be meaningless.
-
-PNG supports modification time via the png_time structure. Two
-conversion routines are provided, png_convert_from_time_t() for
-time_t and png_convert_from_struct_tm() for struct tm. The
-time_t routine uses gmtime(). You don't have to use either of
-these, but if you wish to fill in the png_time structure directly,
-you should provide the time in universal time (GMT) if possible
-instead of your local time. Note that the year number is the full
-year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
-that months start with 1.
-
-If you want to store the time of the original image creation, you should
-use a plain tEXt chunk with the "Creation Time" keyword. This is
-necessary because the "creation time" of a PNG image is somewhat vague,
-depending on whether you mean the PNG file, the time the image was
-created in a non-PNG format, a still photo from which the image was
-scanned, or possibly the subject matter itself. In order to facilitate
-machine-readable dates, it is recommended that the "Creation Time"
-tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
-although this isn't a requirement. Unlike the tIME chunk, the
-"Creation Time" tEXt chunk is not expected to be automatically changed
-by the software. To facilitate the use of RFC 1123 dates, a function
-png_convert_to_rfc1123(png_timep) is provided to convert from PNG
-time to an RFC 1123 format string.
-
-Writing unknown chunks
-
-You can use the png_set_unknown_chunks function to queue up chunks
-for writing. You give it a chunk name, raw data, and a size; that's
-all there is to it. The chunks will be written by the next following
-png_write_info_before_PLTE, png_write_info, or png_write_end function.
-Any chunks previously read into the info structure's unknown-chunk
-list will also be written out in a sequence that satisfies the PNG
-specification's ordering rules.
-
-The high-level write interface
-
-At this point there are two ways to proceed; through the high-level
-write interface, or through a sequence of low-level write operations.
-You can use the high-level interface if your image data is present
-in the info structure. All defined output
-transformations are permitted, enabled by the following masks.
-
- PNG_TRANSFORM_IDENTITY No transformation
- PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
- PNG_TRANSFORM_PACKSWAP Change order of packed
- pixels to LSB first
- PNG_TRANSFORM_INVERT_MONO Invert monochrome images
- PNG_TRANSFORM_SHIFT Normalize pixels to the
- sBIT depth
- PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
- to BGRA
- PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
- to AG
- PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
- to transparency
- PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
- PNG_TRANSFORM_STRIP_FILLER Strip out filler
- bytes (deprecated).
- PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
- filler bytes
- PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing
- filler bytes
-
-If you have valid image data in the info structure (you can use
-png_set_rows() to put image data in the info structure), simply do this:
-
- png_write_png(png_ptr, info_ptr, png_transforms, NULL)
-
-where png_transforms is an integer containing the bitwise OR of some set of
-transformation flags. This call is equivalent to png_write_info(),
-followed the set of transformations indicated by the transform mask,
-then png_write_image(), and finally png_write_end().
-
-(The final parameter of this call is not yet used. Someday it might point
-to transformation parameters required by some future output transform.)
-
-You must use png_transforms and not call any png_set_transform() functions
-when you use png_write_png().
-
-The low-level write interface
-
-If you are going the low-level route instead, you are now ready to
-write all the file information up to the actual image data. You do
-this with a call to png_write_info().
-
- png_write_info(png_ptr, info_ptr);
-
-Note that there is one transformation you may need to do before
-png_write_info(). In PNG files, the alpha channel in an image is the
-level of opacity. If your data is supplied as a level of transparency,
-you can invert the alpha channel before you write it, so that 0 is
-fully transparent and 255 (in 8-bit or paletted images) or 65535
-(in 16-bit images) is fully opaque, with
-
- png_set_invert_alpha(png_ptr);
-
-This must appear before png_write_info() instead of later with the
-other transformations because in the case of paletted images the tRNS
-chunk data has to be inverted before the tRNS chunk is written. If
-your image is not a paletted image, the tRNS data (which in such cases
-represents a single color to be rendered as transparent) won't need to
-be changed, and you can safely do this transformation after your
-png_write_info() call.
-
-If you need to write a private chunk that you want to appear before
-the PLTE chunk when PLTE is present, you can write the PNG info in
-two steps, and insert code to write your own chunk between them:
-
- png_write_info_before_PLTE(png_ptr, info_ptr);
- png_set_unknown_chunks(png_ptr, info_ptr, ...);
- png_write_info(png_ptr, info_ptr);
-
-After you've written the file information, you can set up the library
-to handle any special transformations of the image data. The various
-ways to transform the data will be described in the order that they
-should occur. This is important, as some of these change the color
-type and/or bit depth of the data, and some others only work on
-certain color types and bit depths. Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data. For example, don't swap red and blue on grayscale data.
-
-PNG files store RGB pixels packed into 3 or 6 bytes. This code tells
-the library to strip input data that has 4 or 8 bytes per pixel down
-to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
-bytes per pixel).
-
- png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
-
-where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
-PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
-is stored XRGB or RGBX.
-
-PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
-they can, resulting in, for example, 8 pixels per byte for 1 bit files.
-If the data is supplied at 1 pixel per byte, use this code, which will
-correctly pack the pixels into a single byte:
-
- png_set_packing(png_ptr);
-
-PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your
-data is of another bit depth, you can write an sBIT chunk into the
-file so that decoders can recover the original data if desired.
-
- /* Set the true bit depth of the image data */
- if (color_type & PNG_COLOR_MASK_COLOR)
- {
- sig_bit.red = true_bit_depth;
- sig_bit.green = true_bit_depth;
- sig_bit.blue = true_bit_depth;
- }
- else
- {
- sig_bit.gray = true_bit_depth;
- }
- if (color_type & PNG_COLOR_MASK_ALPHA)
- {
- sig_bit.alpha = true_bit_depth;
- }
-
- png_set_sBIT(png_ptr, info_ptr, &sig_bit);
-
-If the data is stored in the row buffer in a bit depth other than
-one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
-this will scale the values to appear to be the correct bit depth as
-is required by PNG.
-
- png_set_shift(png_ptr, &sig_bit);
-
-PNG files store 16 bit pixels in network byte order (big-endian,
-ie. most significant bits first). This code would be used if they are
-supplied the other way (little-endian, i.e. least significant bits
-first, the way PCs store them):
-
- if (bit_depth > 8)
- png_set_swap(png_ptr);
-
-If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
-need to change the order the pixels are packed into bytes, you can use:
-
- if (bit_depth < 8)
- png_set_packswap(png_ptr);
-
-PNG files store 3 color pixels in red, green, blue order. This code
-would be used if they are supplied as blue, green, red:
-
- png_set_bgr(png_ptr);
-
-PNG files describe monochrome as black being zero and white being
-one. This code would be used if the pixels are supplied with this reversed
-(black being one and white being zero):
-
- png_set_invert_mono(png_ptr);
-
-Finally, you can write your own transformation function if none of
-the existing ones meets your needs. This is done by setting a callback
-with
-
- png_set_write_user_transform_fn(png_ptr,
- write_transform_fn);
-
-You must supply the function
-
- void write_transform_fn(png_ptr ptr, row_info_ptr
- row_info, png_bytep data)
-
-See pngtest.c for a working example. Your function will be called
-before any of the other transformations are processed.
-
-You can also set up a pointer to a user structure for use by your
-callback function.
-
- png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
-
-The user_channels and user_depth parameters of this function are ignored
-when writing; you can set them to zero as shown.
-
-You can retrieve the pointer via the function png_get_user_transform_ptr().
-For example:
-
- voidp write_user_transform_ptr =
- png_get_user_transform_ptr(png_ptr);
-
-It is possible to have libpng flush any pending output, either manually,
-or automatically after a certain number of lines have been written. To
-flush the output stream a single time call:
-
- png_write_flush(png_ptr);
-
-and to have libpng flush the output stream periodically after a certain
-number of scanlines have been written, call:
-
- png_set_flush(png_ptr, nrows);
-
-Note that the distance between rows is from the last time png_write_flush()
-was called, or the first row of the image if it has never been called.
-So if you write 50 lines, and then png_set_flush 25, it will flush the
-output on the next scanline, and every 25 lines thereafter, unless
-png_write_flush() is called before 25 more lines have been written.
-If nrows is too small (less than about 10 lines for a 640 pixel wide
-RGB image) the image compression may decrease noticeably (although this
-may be acceptable for real-time applications). Infrequent flushing will
-only degrade the compression performance by a few percent over images
-that do not use flushing.
-
-Writing the image data
-
-That's it for the transformations. Now you can write the image data.
-The simplest way to do this is in one function call. If you have the
-whole image in memory, you can just call png_write_image() and libpng
-will write the image. You will need to pass in an array of pointers to
-each row. This function automatically handles interlacing, so you don't
-need to call png_set_interlace_handling() or call this function multiple
-times, or any of that other stuff necessary with png_write_rows().
-
- png_write_image(png_ptr, row_pointers);
-
-where row_pointers is:
-
- png_byte *row_pointers[height];
-
-You can point to void or char or whatever you use for pixels.
-
-If you don't want to write the whole image at once, you can
-use png_write_rows() instead. If the file is not interlaced,
-this is simple:
-
- png_write_rows(png_ptr, row_pointers,
- number_of_rows);
-
-row_pointers is the same as in the png_write_image() call.
-
-If you are just writing one row at a time, you can do this with
-a single row_pointer instead of an array of row_pointers:
-
- png_bytep row_pointer = row;
-
- png_write_row(png_ptr, row_pointer);
-
-When the file is interlaced, things can get a good deal more complicated.
-The only currently (as of the PNG Specification version 1.2, dated July
-1999) defined interlacing scheme for PNG files is the "Adam7" interlace
-scheme, that breaks down an image into seven smaller images of varying
-size. libpng will build these images for you, or you can do them
-yourself. If you want to build them yourself, see the PNG specification
-for details of which pixels to write when.
-
-If you don't want libpng to handle the interlacing details, just
-use png_set_interlace_handling() and call png_write_rows() the
-correct number of times to write all seven sub-images.
-
-If you want libpng to build the sub-images, call this before you start
-writing any rows:
-
- number_of_passes =
- png_set_interlace_handling(png_ptr);
-
-This will return the number of passes needed. Currently, this is seven,
-but may change if another interlace type is added.
-
-Then write the complete image number_of_passes times.
-
- png_write_rows(png_ptr, row_pointers,
- number_of_rows);
-
-As some of these rows are not used, and thus return immediately, you may
-want to read about interlacing in the PNG specification, and only update
-the rows that are actually used.
-
-Finishing a sequential write
-
-After you are finished writing the image, you should finish writing
-the file. If you are interested in writing comments or time, you should
-pass an appropriately filled png_info pointer. If you are not interested,
-you can pass NULL.
-
- png_write_end(png_ptr, info_ptr);
-
-When you are done, you can free all memory used by libpng like this:
-
- png_destroy_write_struct(&png_ptr, &info_ptr);
-
-It is also possible to individually free the info_ptr members that
-point to libpng-allocated storage with the following function:
-
- png_free_data(png_ptr, info_ptr, mask, seq)
- mask - identifies data to be freed, a mask
- containing the bitwise OR of one or
- more of
- PNG_FREE_PLTE, PNG_FREE_TRNS,
- PNG_FREE_HIST, PNG_FREE_ICCP,
- PNG_FREE_PCAL, PNG_FREE_ROWS,
- PNG_FREE_SCAL, PNG_FREE_SPLT,
- PNG_FREE_TEXT, PNG_FREE_UNKN,
- or simply PNG_FREE_ALL
- seq - sequence number of item to be freed
- (-1 for all items)
-
-This function may be safely called when the relevant storage has
-already been freed, or has not yet been allocated, or was allocated
-by the user and not by libpng, and will in those cases do nothing.
-The "seq" parameter is ignored if only one item of the selected data
-type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
-are allowed for the data type identified in the mask, such as text or
-sPLT, only the n'th item in the structure is freed, where n is "seq".
-
-If you allocated data such as a palette that you passed in to libpng
-with png_set_*, you must not free it until just before the call to
-png_destroy_write_struct().
-
-The default behavior is only to free data that was allocated internally
-by libpng. This can be changed, so that libpng will not free the data,
-or so that it will free data that was allocated by the user with png_malloc()
-or png_zalloc() and passed in via a png_set_*() function, with
-
- png_data_freer(png_ptr, info_ptr, freer, mask)
- mask - which data elements are affected
- same choices as in png_free_data()
- freer - one of
- PNG_DESTROY_WILL_FREE_DATA
- PNG_SET_WILL_FREE_DATA
- PNG_USER_WILL_FREE_DATA
-
-For example, to transfer responsibility for some data from a read structure
-to a write structure, you could use
-
- png_data_freer(read_ptr, read_info_ptr,
- PNG_USER_WILL_FREE_DATA,
- PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
- png_data_freer(write_ptr, write_info_ptr,
- PNG_DESTROY_WILL_FREE_DATA,
- PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
-
-thereby briefly reassigning responsibility for freeing to the user but
-immediately afterwards reassigning it once more to the write_destroy
-function. Having done this, it would then be safe to destroy the read
-structure and continue to use the PLTE, tRNS, and hIST data in the write
-structure.
-
-This function only affects data that has already been allocated.
-You can call this function before calling after the png_set_*() functions
-to control whether the user or png_destroy_*() is supposed to free the data.
-When the user assumes responsibility for libpng-allocated data, the
-application must use
-png_free() to free it, and when the user transfers responsibility to libpng
-for data that the user has allocated, the user must have used png_malloc()
-or png_zalloc() to allocate it.
-
-If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
-separately, do not transfer responsibility for freeing text_ptr to libpng,
-because when libpng fills a png_text structure it combines these members with
-the key member, and png_free_data() will free only text_ptr.key. Similarly,
-if you transfer responsibility for free'ing text_ptr from libpng to your
-application, your application must not separately free those members.
-For a more compact example of writing a PNG image, see the file example.c.
-
-V. Modifying/Customizing libpng:
-
-There are two issues here. The first is changing how libpng does
-standard things like memory allocation, input/output, and error handling.
-The second deals with more complicated things like adding new chunks,
-adding new transformations, and generally changing how libpng works.
-Both of those are compile-time issues; that is, they are generally
-determined at the time the code is written, and there is rarely a need
-to provide the user with a means of changing them.
-
-Memory allocation, input/output, and error handling
-
-All of the memory allocation, input/output, and error handling in libpng
-goes through callbacks that are user-settable. The default routines are
-in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change
-these functions, call the appropriate png_set_*_fn() function.
-
-Memory allocation is done through the functions png_malloc(), png_calloc(),
-and png_free(). These currently just call the standard C functions.
-png_calloc() calls png_malloc() and then png_memset() to clear the newly
-allocated memory to zero. If your pointers can't access more then 64K
-at a time, you will want to set MAXSEG_64K in zlib.h. Since it is
-unlikely that the method of handling memory allocation on a platform
-will change between applications, these functions must be modified in
-the library at compile time. If you prefer to use a different method
-of allocating and freeing data, you can use png_create_read_struct_2() or
-png_create_write_struct_2() to register your own functions as described
-above. These functions also provide a void pointer that can be retrieved
-via
-
- mem_ptr=png_get_mem_ptr(png_ptr);
-
-Your replacement memory functions must have prototypes as follows:
-
- png_voidp malloc_fn(png_structp png_ptr,
- png_alloc_size_t size);
- void free_fn(png_structp png_ptr, png_voidp ptr);
-
-Your malloc_fn() must return NULL in case of failure. The png_malloc()
-function will normally call png_error() if it receives a NULL from the
-system memory allocator or from your replacement malloc_fn().
-
-Your free_fn() will never be called with a NULL ptr, since libpng's
-png_free() checks for NULL before calling free_fn().
-
-Input/Output in libpng is done through png_read() and png_write(),
-which currently just call fread() and fwrite(). The FILE * is stored in
-png_struct and is initialized via png_init_io(). If you wish to change
-the method of I/O, the library supplies callbacks that you can set
-through the function png_set_read_fn() and png_set_write_fn() at run
-time, instead of calling the png_init_io() function. These functions
-also provide a void pointer that can be retrieved via the function
-png_get_io_ptr(). For example:
-
- png_set_read_fn(png_structp read_ptr,
- voidp read_io_ptr, png_rw_ptr read_data_fn)
-
- png_set_write_fn(png_structp write_ptr,
- voidp write_io_ptr, png_rw_ptr write_data_fn,
- png_flush_ptr output_flush_fn);
-
- voidp read_io_ptr = png_get_io_ptr(read_ptr);
- voidp write_io_ptr = png_get_io_ptr(write_ptr);
-
-The replacement I/O functions must have prototypes as follows:
-
- void user_read_data(png_structp png_ptr,
- png_bytep data, png_size_t length);
- void user_write_data(png_structp png_ptr,
- png_bytep data, png_size_t length);
- void user_flush_data(png_structp png_ptr);
-
-The user_read_data() function is responsible for detecting and
-handling end-of-data errors.
-
-Supplying NULL for the read, write, or flush functions sets them back
-to using the default C stream functions, which expect the io_ptr to
-point to a standard *FILE structure. It is probably a mistake
-to use NULL for one of write_data_fn and output_flush_fn but not both
-of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
-It is an error to read from a write stream, and vice versa.
-
-Error handling in libpng is done through png_error() and png_warning().
-Errors handled through png_error() are fatal, meaning that png_error()
-should never return to its caller. Currently, this is handled via
-setjmp() and longjmp() (unless you have compiled libpng with
-PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
-but you could change this to do things like exit() if you should wish,
-as long as your function does not return.
-
-On non-fatal errors, png_warning() is called
-to print a warning message, and then control returns to the calling code.
-By default png_error() and png_warning() print a message on stderr via
-fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
-(because you don't want the messages) or PNG_NO_STDIO defined (because
-fprintf() isn't available). If you wish to change the behavior of the error
-functions, you will need to set up your own message callbacks. These
-functions are normally supplied at the time that the png_struct is created.
-It is also possible to redirect errors and warnings to your own replacement
-functions after png_create_*_struct() has been called by calling:
-
- png_set_error_fn(png_structp png_ptr,
- png_voidp error_ptr, png_error_ptr error_fn,
- png_error_ptr warning_fn);
-
- png_voidp error_ptr = png_get_error_ptr(png_ptr);
-
-If NULL is supplied for either error_fn or warning_fn, then the libpng
-default function will be used, calling fprintf() and/or longjmp() if a
-problem is encountered. The replacement error functions should have
-parameters as follows:
-
- void user_error_fn(png_structp png_ptr,
- png_const_charp error_msg);
- void user_warning_fn(png_structp png_ptr,
- png_const_charp warning_msg);
-
-The motivation behind using setjmp() and longjmp() is the C++ throw and
-catch exception handling methods. This makes the code much easier to write,
-as there is no need to check every return code of every function call.
-However, there are some uncertainties about the status of local variables
-after a longjmp, so the user may want to be careful about doing anything
-after setjmp returns non-zero besides returning itself. Consult your
-compiler documentation for more details. For an alternative approach, you
-may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net).
-
-Custom chunks
-
-If you need to read or write custom chunks, you may need to get deeper
-into the libpng code. The library now has mechanisms for storing
-and writing chunks of unknown type; you can even declare callbacks
-for custom chunks. However, this may not be good enough if the
-library code itself needs to know about interactions between your
-chunk and existing `intrinsic' chunks.
-
-If you need to write a new intrinsic chunk, first read the PNG
-specification. Acquire a first level of understanding of how it works.
-Pay particular attention to the sections that describe chunk names,
-and look at how other chunks were designed, so you can do things
-similarly. Second, check out the sections of libpng that read and
-write chunks. Try to find a chunk that is similar to yours and use
-it as a template. More details can be found in the comments inside
-the code. It is best to handle unknown chunks in a generic method,
-via callback functions, instead of by modifying libpng functions.
-
-If you wish to write your own transformation for the data, look through
-the part of the code that does the transformations, and check out some of
-the simpler ones to get an idea of how they work. Try to find a similar
-transformation to the one you want to add and copy off of it. More details
-can be found in the comments inside the code itself.
-
-Configuring for 16 bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time. Even if you can, the memory
-won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call. See zlib.h or zconf.h in the zlib library for more information.
-
-Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set. Everything in the library (except for zlib's structure) is
-expecting far data. You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful). Make
-note that the rows of data are defined as png_bytepp, which is an
-unsigned char far * far *.
-
-Configuring for gui/windowing platforms:
-
-You will need to write new error and warning functions that use the GUI
-interface, as described previously, and set them to be the error and
-warning functions at the time that png_create_*_struct() is called,
-in order to have them available during the structure initialization.
-They can be changed later via png_set_error_fn(). On some compilers,
-you may also have to change the memory allocators (png_malloc, etc.).
-
-Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h. If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-in turn includes pngconf.h.
-
-Configuring zlib:
-
-There are special functions to configure the compression. Perhaps the
-most useful one changes the compression level, which currently uses
-input compression values in the range 0 - 9. The library normally
-uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests
-have shown that for a large majority of images, compression values in
-the range 3-6 compress nearly as well as higher levels, and do so much
-faster. For online applications it may be desirable to have maximum speed
-(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also
-specify no compression (Z_NO_COMPRESSION = 0), but this would create
-files larger than just storing the raw bitmap. You can specify the
-compression level by calling:
-
- png_set_compression_level(png_ptr, level);
-
-Another useful one is to reduce the memory level used by the library.
-The memory level defaults to 8, but it can be lowered if you are
-short on memory (running DOS, for example, where you only have 640K).
-Note that the memory level does have an effect on compression; among
-other things, lower levels will result in sections of incompressible
-data being emitted in smaller stored blocks, with a correspondingly
-larger relative overhead of up to 15% in the worst case.
-
- png_set_compression_mem_level(png_ptr, level);
-
-The other functions are for configuring zlib. They are not recommended
-for normal use and may result in writing an invalid PNG file. See
-zlib.h for more information on what these mean.
-
- png_set_compression_strategy(png_ptr,
- strategy);
- png_set_compression_window_bits(png_ptr,
- window_bits);
- png_set_compression_method(png_ptr, method);
- png_set_compression_buffer_size(png_ptr, size);
-
-Controlling row filtering
-
-If you want to control whether libpng uses filtering or not, which
-filters are used, and how it goes about picking row filters, you
-can call one of these functions. The selection and configuration
-of row filters can have a significant impact on the size and
-encoding speed and a somewhat lesser impact on the decoding speed
-of an image. Filtering is enabled by default for RGB and grayscale
-images (with and without alpha), but not for paletted images nor
-for any images with bit depths less than 8 bits/pixel.
-
-The 'method' parameter sets the main filtering method, which is
-currently only '0' in the PNG 1.2 specification. The 'filters'
-parameter sets which filter(s), if any, should be used for each
-scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
-to turn filtering on and off, respectively.
-
-Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
-PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
-ORed together with '|' to specify one or more filters to use.
-These filters are described in more detail in the PNG specification.
-If you intend to change the filter type during the course of writing
-the image, you should start with flags set for all of the filters
-you intend to use so that libpng can initialize its internal
-structures appropriately for all of the filter types. (Note that this
-means the first row must always be adaptively filtered, because libpng
-currently does not allocate the filter buffers until png_write_row()
-is called for the first time.)
-
- filters = PNG_FILTER_NONE | PNG_FILTER_SUB
- PNG_FILTER_UP | PNG_FILTER_AVG |
- PNG_FILTER_PAETH | PNG_ALL_FILTERS;
-
- png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
- filters);
- The second parameter can also be
- PNG_INTRAPIXEL_DIFFERENCING if you are
- writing a PNG to be embedded in a MNG
- datastream. This parameter must be the
- same as the value of filter_method used
- in png_set_IHDR().
-
-It is also possible to influence how libpng chooses from among the
-available filters. This is done in one or both of two ways - by
-telling it how important it is to keep the same filter for successive
-rows, and by telling it the relative computational costs of the filters.
-
- double weights[3] = {1.5, 1.3, 1.1},
- costs[PNG_FILTER_VALUE_LAST] =
- {1.0, 1.3, 1.3, 1.5, 1.7};
-
- png_set_filter_heuristics(png_ptr,
- PNG_FILTER_HEURISTIC_WEIGHTED, 3,
- weights, costs);
-
-The weights are multiplying factors that indicate to libpng that the
-row filter should be the same for successive rows unless another row filter
-is that many times better than the previous filter. In the above example,
-if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
-"sum of absolute differences" 1.5 x 1.3 times higher than other filters
-and still be chosen, while the NONE filter could have a sum 1.1 times
-higher than other filters and still be chosen. Unspecified weights are
-taken to be 1.0, and the specified weights should probably be declining
-like those above in order to emphasize recent filters over older filters.
-
-The filter costs specify for each filter type a relative decoding cost
-to be considered when selecting row filters. This means that filters
-with higher costs are less likely to be chosen over filters with lower
-costs, unless their "sum of absolute differences" is that much smaller.
-The costs do not necessarily reflect the exact computational speeds of
-the various filters, since this would unduly influence the final image
-size.
-
-Note that the numbers above were invented purely for this example and
-are given only to help explain the function usage. Little testing has
-been done to find optimum values for either the costs or the weights.
-
-Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled. All the defines end in _SUPPORTED. If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four,
-along with directives to turn on any of the capabilities that you do
-want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra
-transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks. If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs. However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with pngr and all the writing files start with
-pngw. The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
-Requesting debug printout
-
-The macro definition PNG_DEBUG can be used to request debugging
-printout. Set it to an integer value in the range 0 to 3. Higher
-numbers result in increasing amounts of debugging information. The
-information is printed to the "stderr" file, unless another file
-name is specified in the PNG_DEBUG_FILE macro definition.
-
-When PNG_DEBUG > 0, the following functions (macros) become available:
-
- png_debug(level, message)
- png_debug1(level, message, p1)
- png_debug2(level, message, p1, p2)
-
-in which "level" is compared to PNG_DEBUG to decide whether to print
-the message, "message" is the formatted string to be printed,
-and p1 and p2 are parameters that are to be embedded in the string
-according to printf-style formatting directives. For example,
-
- png_debug1(2, "foo=%d\n", foo);
-
-is expanded to
-
- if(PNG_DEBUG > 2)
- fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
-
-When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
-can still use PNG_DEBUG to control your own debugging:
-
- #ifdef PNG_DEBUG
- fprintf(stderr, ...
- #endif
-
-When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
-having level = 0 will be printed. There aren't any such statements in
-this version of libpng, but if you insert some they will be printed.
-
-VI. MNG support
-
-The MNG specification (available at http://www.libpng.org/pub/mng) allows
-certain extensions to PNG for PNG images that are embedded in MNG datastreams.
-Libpng can support some of these extensions. To enable them, use the
-png_permit_mng_features() function:
-
- feature_set = png_permit_mng_features(png_ptr, mask)
- mask is a png_uint_32 containing the bitwise OR of the
- features you want to enable. These include
- PNG_FLAG_MNG_EMPTY_PLTE
- PNG_FLAG_MNG_FILTER_64
- PNG_ALL_MNG_FEATURES
- feature_set is a png_uint_32 that is the bitwise AND of
- your mask with the set of MNG features that is
- supported by the version of libpng that you are using.
-
-It is an error to use this function when reading or writing a standalone
-PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped
-in a MNG datastream. As a minimum, it must have the MNG 8-byte signature
-and the MHDR and MEND chunks. Libpng does not provide support for these
-or any other MNG chunks; your application must provide its own support for
-them. You may wish to consider using libmng (available at
-http://www.libmng.com) instead.
-
-VII. Changes to Libpng from version 0.88
-
-It should be noted that versions of libpng later than 0.96 are not
-distributed by the original libpng author, Guy Schalnat, nor by
-Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
-distributed versions 0.89 through 0.96, but rather by another member
-of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are
-still alive and well, but they have moved on to other things.
-
-The old libpng functions png_read_init(), png_write_init(),
-png_info_init(), png_read_destroy(), and png_write_destroy() have been
-moved to PNG_INTERNAL in version 0.95 to discourage their use. These
-functions will be removed from libpng version 2.0.0.
-
-The preferred method of creating and initializing the libpng structures is
-via the png_create_read_struct(), png_create_write_struct(), and
-png_create_info_struct() because they isolate the size of the structures
-from the application, allow version error checking, and also allow the
-use of custom error handling routines during the initialization, which
-the old functions do not. The functions png_read_destroy() and
-png_write_destroy() do not actually free the memory that libpng
-allocated for these structs, but just reset the data structures, so they
-can be used instead of png_destroy_read_struct() and
-png_destroy_write_struct() if you feel there is too much system overhead
-allocating and freeing the png_struct for each image read.
-
-Setting the error callbacks via png_set_message_fn() before
-png_read_init() as was suggested in libpng-0.88 is no longer supported
-because this caused applications that do not use custom error functions
-to fail if the png_ptr was not initialized to zero. It is still possible
-to set the error callbacks AFTER png_read_init(), or to change them with
-png_set_error_fn(), which is essentially the same function, but with a new
-name to force compilation errors with applications that try to use the old
-method.
-
-Starting with version 1.0.7, you can find out which version of the library
-you are using at run-time:
-
- png_uint_32 libpng_vn = png_access_version_number();
-
-The number libpng_vn is constructed from the major version, minor
-version with leading zero, and release number with leading zero,
-(e.g., libpng_vn for version 1.0.7 is 10007).
-
-You can also check which version of png.h you used when compiling your
-application:
-
- png_uint_32 application_vn = PNG_LIBPNG_VER;
-
-VIII. Changes to Libpng from version 1.0.x to 1.2.x
-
-Support for user memory management was enabled by default. To
-accomplish this, the functions png_create_read_struct_2(),
-png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
-png_malloc_default(), and png_free_default() were added.
-
-Support for the iTXt chunk has been enabled by default as of
-version 1.2.41.
-
-Support for certain MNG features was enabled.
-
-Support for numbered error messages was added. However, we never got
-around to actually numbering the error messages. The function
-png_set_strip_error_numbers() was added (Note: the prototype for this
-function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
-builds of libpng-1.2.15. It was restored in libpng-1.2.36).
-
-The png_malloc_warn() function was added at libpng-1.2.3. This issues
-a png_warning and returns NULL instead of aborting when it fails to
-acquire the requested memory allocation.
-
-Support for setting user limits on image width and height was enabled
-by default. The functions png_set_user_limits(), png_get_user_width_max(),
-and png_get_user_height_max() were added at libpng-1.2.6.
-
-The png_set_add_alpha() function was added at libpng-1.2.7.
-
-The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
-Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
-tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
-deprecated.
-
-A number of macro definitions in support of runtime selection of
-assembler code features (especially Intel MMX code support) were
-added at libpng-1.2.0:
-
- PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
- PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
- PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
- PNG_ASM_FLAG_MMX_READ_INTERLACE
- PNG_ASM_FLAG_MMX_READ_FILTER_SUB
- PNG_ASM_FLAG_MMX_READ_FILTER_UP
- PNG_ASM_FLAG_MMX_READ_FILTER_AVG
- PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
- PNG_ASM_FLAGS_INITIALIZED
- PNG_MMX_READ_FLAGS
- PNG_MMX_FLAGS
- PNG_MMX_WRITE_FLAGS
- PNG_MMX_FLAGS
-
-We added the following functions in support of runtime
-selection of assembler code features:
-
- png_get_mmx_flagmask()
- png_set_mmx_thresholds()
- png_get_asm_flags()
- png_get_mmx_bitdepth_threshold()
- png_get_mmx_rowbytes_threshold()
- png_set_asm_flags()
-
-We replaced all of these functions with simple stubs in libpng-1.2.20,
-when the Intel assembler code was removed due to a licensing issue.
-
-These macros are deprecated:
-
- PNG_READ_TRANSFORMS_NOT_SUPPORTED
- PNG_PROGRESSIVE_READ_NOT_SUPPORTED
- PNG_NO_SEQUENTIAL_READ_SUPPORTED
- PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
- PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
- PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
-
-They have been replaced, respectively, by:
-
- PNG_NO_READ_TRANSFORMS
- PNG_NO_PROGRESSIVE_READ
- PNG_NO_SEQUENTIAL_READ
- PNG_NO_WRITE_TRANSFORMS
- PNG_NO_READ_ANCILLARY_CHUNKS
- PNG_NO_WRITE_ANCILLARY_CHUNKS
-
-PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been
-deprecated since libpng-1.0.16 and libpng-1.2.6.
-
-The function
- png_check_sig(sig, num)
-was replaced with
- !png_sig_cmp(sig, 0, num)
-It has been deprecated since libpng-0.90.
-
-The function
- png_set_gray_1_2_4_to_8()
-which also expands tRNS to alpha was replaced with
- png_set_expand_gray_1_2_4_to_8()
-which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
-
-IX. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
-
-Private libpng prototypes and macro definitions were moved from
-png.h and pngconf.h into a new pngpriv.h header file.
-
-Functions png_set_benign_errors(), png_benign_error(), and
-png_chunk_benign_error() were added.
-
-Support for setting the maximum amount of memory that the application
-will allocate for reading chunks was added, as a security measure.
-The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
-were added to the library.
-
-We implemented support for I/O states by adding png_ptr member io_state
-and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
-
-We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
-input transforms.
-
-Checking for and reporting of errors in the IHDR chunk is more thorough.
-
-Support for global arrays was removed, to improve thread safety.
-
-Some obsolete/deprecated macros and functions have been removed.
-
-Typecasted NULL definitions such as
- #define png_voidp_NULL (png_voidp)NULL
-were eliminated. If you used these in your application, just use
-NULL instead.
-
-The png_struct and info_struct members "trans" and "trans_values" were
-changed to "trans_alpha" and "trans_color", respectively.
-
-The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
-were removed.
-
-The PNG_1_0_X and PNG_1_2_X macros were eliminated.
-
-The PNG_LEGACY_SUPPORTED macro was eliminated.
-
-Many WIN32_WCE #ifdefs were removed.
-
-The functions png_read_init(info_ptr), png_write_init(info_ptr),
-png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
-have been removed. They have been deprecated since libpng-0.95.
-
-The png_permit_empty_plte() was removed. It has been deprecated
-since libpng-1.0.9. Use png_permit_mng_features() instead.
-
-We removed the obsolete stub functions png_get_mmx_flagmask(),
-png_set_mmx_thresholds(), png_get_asm_flags(),
-png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
-png_set_asm_flags(), and png_mmx_supported()
-
-We removed the obsolete png_check_sig(), png_memcpy_check(), and
-png_memset_check() functions. Instead use !png_sig_cmp(), png_memcpy(),
-and png_memset(), respectively.
-
-The function png_set_gray_1_2_4_to_8() was removed. It has been
-deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
-png_set_expand_gray_1_2_4_to_8() because the former function also
-expanded palette images.
-
-We changed the prototype for png_malloc() from
- png_malloc(png_structp png_ptr, png_uint_32 size)
-to
- png_malloc(png_structp png_ptr, png_alloc_size_t size)
-
-This also applies to the prototype for the user replacement malloc_fn().
-
-The png_calloc() function was added and is used in place of
-of "png_malloc(); png_memset();" except in the case in png_read_png()
-where the array consists of pointers; in this case a "for" loop is used
-after the png_malloc() to set the pointers to NULL, to give robust.
-behavior in case the application runs out of memory part-way through
-the process.
-
-We changed the prototypes of png_get_compression_buffer_size() and
-png_set_compression_buffer_size() to work with png_size_t instead of
-png_uint_32.
-
-Support for numbered error messages was removed by default, since we
-never got around to actually numbering the error messages. The function
-png_set_strip_error_numbers() was removed from the library by default.
-
-The png_zalloc() and png_zfree() functions are no longer exported.
-The png_zalloc() function no longer zeroes out the memory that it
-allocates.
-
-Support for dithering was disabled by default in libpng-1.4.0, because
-been well tested and doesn't actually "dither". The code was not
-removed, however, and could be enabled by building libpng with
-PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support
-was reenabled, but the function was renamed png_set_quantize() to
-reflect more accurately what it actually does. At the same time,
-the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
-PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
-
-We removed the trailing '.' from the warning and error messages.
-
-X. Detecting libpng
-
-The png_get_io_ptr() function has been present since libpng-0.88, has never
-changed, and is unaffected by conditional compilation macros. It is the
-best choice for use in configure scripts for detecting the presence of any
-libpng version since 0.88. In an autoconf "configure.in" you could use
-
- AC_CHECK_LIB(png, png_get_io_ptr, ...
-
-XI. Source code repository
-
-Since about February 2009, version 1.2.34, libpng has been under "git" source
-control. The git repository was built from old libpng-x.y.z.tar.gz files
-going back to version 0.70. You can access the git repository (read only)
-at
-
- git://libpng.git.sourceforge.net/gitroot/libpng
-
-or you can browse it via "gitweb" at
-
- http://libpng.git.sourceforge.net/git/gitweb.cgi?p=libpng
-
-Patches can be sent to glennrp at users.sourceforge.net or to
-png-mng-implement at lists.sourceforge.net or you can upload them to
-the libpng bug tracker at
-
- http://libpng.sourceforge.net
-
-XII. Coding style
-
-Our coding style is similar to the "Allman" style, with curly
-braces on separate lines:
-
- if (condition)
- {
- action;
- }
-
- else if (another condition)
- {
- another action;
- }
-
-The braces can be omitted from simple one-line actions:
-
- if (condition)
- return (0);
-
-We use 3-space indentation, except for continued statements which
-are usually indented the same as the first line of the statement
-plus four more spaces.
-
-For macro definitions we use 2-space indentation, always leaving the "#"
-in the first column.
-
- #ifndef PNG_NO_FEATURE
- # ifndef PNG_FEATURE_SUPPORTED
- # define PNG_FEATURE_SUPPORTED
- # endif
- #endif
-
-Comments appear with the leading "/*" at the same indentation as
-the statement that follows the comment:
-
- /* Single-line comment */
- statement;
-
- /* This is a multiple-line
- * comment.
- */
- statement;
-
-Very short comments can be placed after the end of the statement
-to which they pertain:
-
- statement; /* comment */
-
-We don't use C++ style ("//") comments. We have, however,
-used them in the past in some now-abandoned MMX assembler
-code.
-
-Functions and their curly braces are not indented, and
-exported functions are marked with PNGAPI:
-
- /* This is a public function that is visible to
- * application programers. It does thus-and-so.
- */
- void PNGAPI
- png_exported_function(png_ptr, png_info, foo)
- {
- body;
- }
-
-The prototypes for all exported functions appear in png.h,
-above the comment that says
-
- /* Maintainer: Put new public prototypes here ... */
-
-We mark all non-exported functions with "/* PRIVATE */"":
-
- void /* PRIVATE */
- png_non_exported_function(png_ptr, png_info, foo)
- {
- body;
- }
-
-The prototypes for non-exported functions (except for those in
-pngtest) appear in
-pngpriv.h
-above the comment that says
-
- /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
-
-The names of all exported functions and variables begin
-with "png_", and all publicly visible C preprocessor
-macros begin with "PNG_".
-
-We put a space after each comma and after each semicolon
-in "for" statments, and we put spaces before and after each
-C binary operator and after "for" or "while", and before
-"?". We don't put a space between a typecast and the expression
-being cast, nor do we put one between a function name and the
-left parenthesis that follows it:
-
- for (i = 2; i > 0; --i)
- y[i] = a(x) + (int)b;
-
-We prefer #ifdef and #ifndef to #if defined() and if !defined()
-when there is only one macro being tested.
-
-We do not use the TAB character for indentation in the C sources.
-
-Lines do not exceed 80 characters.
-
-Other rules can be inferred by inspecting the libpng source.
-
-XIII. Y2K Compliance in libpng
-
-September 23, 2010
-
-Since the PNG Development group is an ad-hoc body, we can't make
-an official declaration.
-
-This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.4.4 are Y2K compliant. It is my belief that earlier
-versions were also Y2K compliant.
-
-Libpng only has three year fields. One is a 2-byte unsigned integer that
-will hold years up to 65535. The other two hold the date in text
-format, and will hold years up to 9999.
-
-The integer is
- "png_uint_16 year" in png_time_struct.
-
-The strings are
- "png_charp time_buffer" in png_struct and
- "near_time_buffer", which is a local character string in png.c.
-
-There are seven time-related functions:
-
- png_convert_to_rfc_1123() in png.c
- (formerly png_convert_to_rfc_1152() in error)
- png_convert_from_struct_tm() in pngwrite.c, called
- in pngwrite.c
- png_convert_from_time_t() in pngwrite.c
- png_get_tIME() in pngget.c
- png_handle_tIME() in pngrutil.c, called in pngread.c
- png_set_tIME() in pngset.c
- png_write_tIME() in pngwutil.c, called in pngwrite.c
-
-All appear to handle dates properly in a Y2K environment. The
-png_convert_from_time_t() function calls gmtime() to convert from system
-clock time, which returns (year - 1900), which we properly convert to
-the full 4-digit year. There is a possibility that applications using
-libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
-function, or that they are incorrectly passing only a 2-digit year
-instead of "year - 1900" into the png_convert_from_struct_tm() function,
-but this is not under our control. The libpng documentation has always
-stated that it works with 4-digit years, and the APIs have been
-documented as such.
-
-The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
-integer to hold the year, and can hold years as large as 65535.
-
-zlib, upon which libpng depends, is also Y2K compliant. It contains
-no date-related code.
-
-
- Glenn Randers-Pehrson
- libpng maintainer
- PNG Development Group
/* png.c - location for general purpose libpng functions
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
#include "pngpriv.h"
/* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_2 Your_png_h_is_not_version_1_5_2;
+typedef png_libpng_version_1_5_9 Your_png_h_is_not_version_1_5_9;
/* Tells libpng that we have already handled the first "num_bytes" bytes
* of the PNG file signature. If the PNG data is embedded into another
* can simply check the remaining bytes for extra assurance. Returns
* an integer less than, equal to, or greater than zero if sig is found,
* respectively, to be less than, to match, or be greater than the correct
- * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
*/
int PNGAPI
png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
void /* PRIVATE */
png_reset_crc(png_structp png_ptr)
{
- png_ptr->crc = crc32(0, Z_NULL, 0);
+ /* The cast is safe because the crc is a 32 bit value. */
+ png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
}
/* Calculate the CRC over a section of data. We can only pass as
{
int need_crc = 1;
- if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
+ if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
- else /* critical */
+ else /* critical */
{
if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
need_crc = 0;
}
- if (need_crc)
- png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
+ /* 'uLong' is defined as unsigned long, this means that on some systems it is
+ * a 64 bit value. crc32, however, returns 32 bits so the following cast is
+ * safe. 'uInt' may be no more than 16 bits, so it is necessary to perform a
+ * loop here.
+ */
+ if (need_crc && length > 0)
+ {
+ uLong crc = png_ptr->crc; /* Should never issue a warning */
+
+ do
+ {
+ uInt safeLength = (uInt)length;
+ if (safeLength == 0)
+ safeLength = (uInt)-1; /* evil, but safe */
+
+ crc = crc32(crc, ptr, safeLength);
+
+ /* The following should never issue compiler warnings, if they do the
+ * target system has characteristics that will probably violate other
+ * assumptions within the libpng code.
+ */
+ ptr += safeLength;
+ length -= safeLength;
+ }
+ while (length > 0);
+
+ /* And the following is always safe because the crc is only 32 bits. */
+ png_ptr->crc = (png_uint_32)crc;
+ }
+}
+
+/* Check a user supplied version number, called from both read and write
+ * functions that create a png_struct
+ */
+int
+png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver)
+{
+ if (user_png_ver)
+ {
+ int i = 0;
+
+ do
+ {
+ if (user_png_ver[i] != png_libpng_ver[i])
+ png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+ } while (png_libpng_ver[i++]);
+ }
+
+ else
+ png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+
+ if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
+ {
+ /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
+ * we must recompile any applications that use any older library version.
+ * For versions after libpng 1.0, we will be compatible, so we need
+ * only check the first digit.
+ */
+ if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
+ (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
+ (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
+ {
+#ifdef PNG_WARNINGS_SUPPORTED
+ size_t pos = 0;
+ char m[128];
+
+ pos = png_safecat(m, sizeof m, pos, "Application built with libpng-");
+ pos = png_safecat(m, sizeof m, pos, user_png_ver);
+ pos = png_safecat(m, sizeof m, pos, " but running with ");
+ pos = png_safecat(m, sizeof m, pos, png_libpng_ver);
+
+ png_warning(png_ptr, m);
+#endif
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ png_ptr->flags = 0;
+#endif
+
+ return 0;
+ }
+ }
+
+ /* Success return. */
+ return 1;
}
/* Allocate the memory for an info_struct for the application. We don't
/* Free any sCAL entry */
if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
{
-#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
png_free(png_ptr, info_ptr->scal_s_width);
png_free(png_ptr, info_ptr->scal_s_height);
info_ptr->scal_s_width = NULL;
info_ptr->scal_s_height = NULL;
-#endif
info_ptr->valid &= ~PNG_INFO_sCAL;
}
#endif
/* Initialize the default input/output functions for the PNG file. If you
* use your own read or write routines, you can call either png_set_read_fn()
* or png_set_write_fn() instead of png_init_io(). If you have defined
- * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
- * necessarily available.
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
+ * function of your own because "FILE *" isn't necessarily available.
*/
void PNGAPI
png_init_io(png_structp png_ptr, png_FILE_p fp)
if (png_ptr == NULL)
return (NULL);
- if (png_ptr->time_buffer == NULL)
+ if (ptime->year > 9999 /* RFC1123 limitation */ ||
+ ptime->month == 0 || ptime->month > 12 ||
+ ptime->day == 0 || ptime->day > 31 ||
+ ptime->hour > 23 || ptime->minute > 59 ||
+ ptime->second > 60)
{
- png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
- png_sizeof(char)));
+ png_warning(png_ptr, "Ignoring invalid time value");
+ return (NULL);
}
-# ifdef USE_FAR_KEYWORD
{
- char near_time_buf[29];
- png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",
- ptime->day % 32, short_months[(ptime->month - 1) % 12],
- ptime->year, ptime->hour % 24, ptime->minute % 60,
- ptime->second % 61);
- png_memcpy(png_ptr->time_buffer, near_time_buf,
- 29*png_sizeof(char));
+ size_t pos = 0;
+ char number_buf[5]; /* enough for a four-digit year */
+
+# define APPEND_STRING(string)\
+ pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\
+ pos, (string))
+# define APPEND_NUMBER(format, value)\
+ APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
+# define APPEND(ch)\
+ if (pos < (sizeof png_ptr->time_buffer)-1)\
+ png_ptr->time_buffer[pos++] = (ch)
+
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
+ APPEND(' ');
+ APPEND_STRING(short_months[(ptime->month - 1)]);
+ APPEND(' ');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
+ APPEND(' ');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
+ APPEND(':');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
+ APPEND(':');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
+ APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+
+# undef APPEND
+# undef APPEND_NUMBER
+# undef APPEND_STRING
}
-# else
- png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",
- ptime->day % 32, short_months[(ptime->month - 1) % 12],
- ptime->year, ptime->hour % 24, ptime->minute % 60,
- ptime->second % 61);
-# endif
+
return png_ptr->time_buffer;
}
# endif /* PNG_TIME_RFC1123_SUPPORTED */
#else
# ifdef __STDC__
return PNG_STRING_NEWLINE \
- "libpng version 1.5.2 - March 31, 2011" PNG_STRING_NEWLINE \
+ "libpng version 1.5.9 - February 18, 2012" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
PNG_STRING_NEWLINE;
# else
- return "libpng version 1.5.2 - March 31, 2011\
+ return "libpng version 1.5.9 - February 18, 2012\
Copyright (c) 1998-2011 Glenn Randers-Pehrson\
Copyright (c) 1996-1997 Andreas Dilger\
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
#endif
}
-#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-# ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
int PNGAPI
png_handle_as_unknown(png_structp png_ptr, png_const_bytep chunk_name)
{
/* Check chunk_name and return "keep" value if it's on the list, else 0 */
- int i;
- png_bytep p;
- if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)
- return 0;
+ png_const_bytep p, p_end;
- p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5;
- for (i = png_ptr->num_chunk_list; i; i--, p -= 5)
+ if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list <= 0)
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
+
+ p_end = png_ptr->chunk_list;
+ p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
+
+ /* The code is the fifth byte after each four byte string. Historically this
+ * code was always searched from the end of the list, so it should continue
+ * to do so in case there are duplicated entries.
+ */
+ do /* num_chunk_list > 0, so at least one */
+ {
+ p -= 5;
if (!png_memcmp(chunk_name, p, 4))
- return ((int)*(p + 4));
- return 0;
+ return p[4];
+ }
+ while (p > p_end);
+
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
}
-# endif
-#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
+
+int /* PRIVATE */
+png_chunk_unknown_handling(png_structp png_ptr, png_uint_32 chunk_name)
+{
+ png_byte chunk_string[5];
+
+ PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
+ return png_handle_as_unknown(png_ptr, chunk_string);
+}
+#endif
#ifdef PNG_READ_SUPPORTED
/* This function, added to libpng-1.0.6g, is untested. */
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-# ifdef PNG_SIZE_T
-/* Added at libpng version 1.2.6 */
- PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
-png_size_t PNGAPI
-png_convert_size(size_t size)
-{
- if (size > (png_size_t)-1)
- PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */
-
- return ((png_size_t)size);
-}
-# endif /* PNG_SIZE_T */
+/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
+ * at libpng 1.5.5!
+ */
/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
# ifdef PNG_CHECK_cHRM_SUPPORTED
if (png_ptr == NULL)
return 0;
+ /* (x,y,z) values are first limited to 0..100000 (PNG_FP_1), the white
+ * y must also be greater than 0. To test for the upper limit calculate
+ * (PNG_FP_1-y) - x must be <= to this for z to be >= 0 (and the expression
+ * cannot overflow.) At this point we know x and y are >= 0 and (x+y) is
+ * <= PNG_FP_1. The previous test on PNG_MAX_UINT_31 is removed because it
+ * pointless (and it produces compiler warnings!)
+ */
if (white_x < 0 || white_y <= 0 ||
red_x < 0 || red_y < 0 ||
green_x < 0 || green_y < 0 ||
"Ignoring attempt to set negative chromaticity value");
ret = 0;
}
- if (white_x > (png_fixed_point)PNG_UINT_31_MAX ||
- white_y > (png_fixed_point)PNG_UINT_31_MAX ||
- red_x > (png_fixed_point)PNG_UINT_31_MAX ||
- red_y > (png_fixed_point)PNG_UINT_31_MAX ||
- green_x > (png_fixed_point)PNG_UINT_31_MAX ||
- green_y > (png_fixed_point)PNG_UINT_31_MAX ||
- blue_x > (png_fixed_point)PNG_UINT_31_MAX ||
- blue_y > (png_fixed_point)PNG_UINT_31_MAX )
- {
- png_warning(png_ptr,
- "Ignoring attempt to set chromaticity value exceeding 21474.83");
- ret = 0;
- }
- if (white_x > 100000L - white_y)
+ /* And (x+y) must be <= PNG_FP_1 (so z is >= 0) */
+ if (white_x > PNG_FP_1 - white_y)
{
png_warning(png_ptr, "Invalid cHRM white point");
ret = 0;
}
- if (red_x > 100000L - red_y)
+ if (red_x > PNG_FP_1 - red_y)
{
png_warning(png_ptr, "Invalid cHRM red point");
ret = 0;
}
- if (green_x > 100000L - green_y)
+ if (green_x > PNG_FP_1 - green_y)
{
png_warning(png_ptr, "Invalid cHRM green point");
ret = 0;
}
- if (blue_x > 100000L - blue_y)
+ if (blue_x > PNG_FP_1 - blue_y)
{
png_warning(png_ptr, "Invalid cHRM blue point");
ret = 0;
}
# endif /* PNG_CHECK_cHRM_SUPPORTED */
+#ifdef PNG_cHRM_SUPPORTED
+/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
+ * cHRM, as opposed to using chromaticities. These internal APIs return
+ * non-zero on a parameter error. The X, Y and Z values are required to be
+ * positive and less than 1.0.
+ */
+int png_xy_from_XYZ(png_xy *xy, png_XYZ XYZ)
+{
+ png_int_32 d, dwhite, whiteX, whiteY;
+
+ d = XYZ.redX + XYZ.redY + XYZ.redZ;
+ if (!png_muldiv(&xy->redx, XYZ.redX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->redy, XYZ.redY, PNG_FP_1, d)) return 1;
+ dwhite = d;
+ whiteX = XYZ.redX;
+ whiteY = XYZ.redY;
+
+ d = XYZ.greenX + XYZ.greenY + XYZ.greenZ;
+ if (!png_muldiv(&xy->greenx, XYZ.greenX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->greeny, XYZ.greenY, PNG_FP_1, d)) return 1;
+ dwhite += d;
+ whiteX += XYZ.greenX;
+ whiteY += XYZ.greenY;
+
+ d = XYZ.blueX + XYZ.blueY + XYZ.blueZ;
+ if (!png_muldiv(&xy->bluex, XYZ.blueX, PNG_FP_1, d)) return 1;
+ if (!png_muldiv(&xy->bluey, XYZ.blueY, PNG_FP_1, d)) return 1;
+ dwhite += d;
+ whiteX += XYZ.blueX;
+ whiteY += XYZ.blueY;
+
+ /* The reference white is simply the same of the end-point (X,Y,Z) vectors,
+ * thus:
+ */
+ if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1;
+ if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1;
+
+ return 0;
+}
+
+int png_XYZ_from_xy(png_XYZ *XYZ, png_xy xy)
+{
+ png_fixed_point red_inverse, green_inverse, blue_scale;
+ png_fixed_point left, right, denominator;
+
+ /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
+ * have end points with 0 tristimulus values (these are impossible end
+ * points, but they are used to cover the possible colors.)
+ */
+ if (xy.redx < 0 || xy.redx > PNG_FP_1) return 1;
+ if (xy.redy < 0 || xy.redy > PNG_FP_1-xy.redx) return 1;
+ if (xy.greenx < 0 || xy.greenx > PNG_FP_1) return 1;
+ if (xy.greeny < 0 || xy.greeny > PNG_FP_1-xy.greenx) return 1;
+ if (xy.bluex < 0 || xy.bluex > PNG_FP_1) return 1;
+ if (xy.bluey < 0 || xy.bluey > PNG_FP_1-xy.bluex) return 1;
+ if (xy.whitex < 0 || xy.whitex > PNG_FP_1) return 1;
+ if (xy.whitey < 0 || xy.whitey > PNG_FP_1-xy.whitex) return 1;
+
+ /* The reverse calculation is more difficult because the original tristimulus
+ * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
+ * derived values were recorded in the cHRM chunk;
+ * (red,green,blue,white)x(x,y). This loses one degree of freedom and
+ * therefore an arbitrary ninth value has to be introduced to undo the
+ * original transformations.
+ *
+ * Think of the original end-points as points in (X,Y,Z) space. The
+ * chromaticity values (c) have the property:
+ *
+ * C
+ * c = ---------
+ * X + Y + Z
+ *
+ * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
+ * three chromaticity values (x,y,z) for each end-point obey the
+ * relationship:
+ *
+ * x + y + z = 1
+ *
+ * This describes the plane in (X,Y,Z) space that intersects each axis at the
+ * value 1.0; call this the chromaticity plane. Thus the chromaticity
+ * calculation has scaled each end-point so that it is on the x+y+z=1 plane
+ * and chromaticity is the intersection of the vector from the origin to the
+ * (X,Y,Z) value with the chromaticity plane.
+ *
+ * To fully invert the chromaticity calculation we would need the three
+ * end-point scale factors, (red-scale, green-scale, blue-scale), but these
+ * were not recorded. Instead we calculated the reference white (X,Y,Z) and
+ * recorded the chromaticity of this. The reference white (X,Y,Z) would have
+ * given all three of the scale factors since:
+ *
+ * color-C = color-c * color-scale
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * But cHRM records only white-x and white-y, so we have lost the white scale
+ * factor:
+ *
+ * white-C = white-c*white-scale
+ *
+ * To handle this the inverse transformation makes an arbitrary assumption
+ * about white-scale:
+ *
+ * Assume: white-Y = 1.0
+ * Hence: white-scale = 1/white-y
+ * Or: red-Y + green-Y + blue-Y = 1.0
+ *
+ * Notice the last statement of the assumption gives an equation in three of
+ * the nine values we want to calculate. 8 more equations come from the
+ * above routine as summarised at the top above (the chromaticity
+ * calculation):
+ *
+ * Given: color-x = color-X / (color-X + color-Y + color-Z)
+ * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
+ *
+ * This is 9 simultaneous equations in the 9 variables "color-C" and can be
+ * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
+ * determinants, however this is not as bad as it seems because only 28 of
+ * the total of 90 terms in the various matrices are non-zero. Nevertheless
+ * Cramer's rule is notoriously numerically unstable because the determinant
+ * calculation involves the difference of large, but similar, numbers. It is
+ * difficult to be sure that the calculation is stable for real world values
+ * and it is certain that it becomes unstable where the end points are close
+ * together.
+ *
+ * So this code uses the perhaps slighly less optimal but more understandable
+ * and totally obvious approach of calculating color-scale.
+ *
+ * This algorithm depends on the precision in white-scale and that is
+ * (1/white-y), so we can immediately see that as white-y approaches 0 the
+ * accuracy inherent in the cHRM chunk drops off substantially.
+ *
+ * libpng arithmetic: a simple invertion of the above equations
+ * ------------------------------------------------------------
+ *
+ * white_scale = 1/white-y
+ * white-X = white-x * white-scale
+ * white-Y = 1.0
+ * white-Z = (1 - white-x - white-y) * white_scale
+ *
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * This gives us three equations in (red-scale,green-scale,blue-scale) where
+ * all the coefficients are now known:
+ *
+ * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
+ * = white-x/white-y
+ * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
+ * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
+ * = (1 - white-x - white-y)/white-y
+ *
+ * In the last equation color-z is (1 - color-x - color-y) so we can add all
+ * three equations together to get an alternative third:
+ *
+ * red-scale + green-scale + blue-scale = 1/white-y = white-scale
+ *
+ * So now we have a Cramer's rule solution where the determinants are just
+ * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
+ * multiplication of three coefficients so we can't guarantee to avoid
+ * overflow in the libpng fixed point representation. Using Cramer's rule in
+ * floating point is probably a good choice here, but it's not an option for
+ * fixed point. Instead proceed to simplify the first two equations by
+ * eliminating what is likely to be the largest value, blue-scale:
+ *
+ * blue-scale = white-scale - red-scale - green-scale
+ *
+ * Hence:
+ *
+ * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
+ * (white-x - blue-x)*white-scale
+ *
+ * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
+ * 1 - blue-y*white-scale
+ *
+ * And now we can trivially solve for (red-scale,green-scale):
+ *
+ * green-scale =
+ * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
+ * -----------------------------------------------------------
+ * green-x - blue-x
+ *
+ * red-scale =
+ * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
+ * ---------------------------------------------------------
+ * red-y - blue-y
+ *
+ * Hence:
+ *
+ * red-scale =
+ * ( (green-x - blue-x) * (white-y - blue-y) -
+ * (green-y - blue-y) * (white-x - blue-x) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * green-scale =
+ * ( (red-y - blue-y) * (white-x - blue-x) -
+ * (red-x - blue-x) * (white-y - blue-y) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * Accuracy:
+ * The input values have 5 decimal digits of accuracy. The values are all in
+ * the range 0 < value < 1, so simple products are in the same range but may
+ * need up to 10 decimal digits to preserve the original precision and avoid
+ * underflow. Because we are using a 32-bit signed representation we cannot
+ * match this; the best is a little over 9 decimal digits, less than 10.
+ *
+ * The approach used here is to preserve the maximum precision within the
+ * signed representation. Because the red-scale calculation above uses the
+ * difference between two products of values that must be in the range -1..+1
+ * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
+ * factor is irrelevant in the calculation because it is applied to both
+ * numerator and denominator.
+ *
+ * Note that the values of the differences of the products of the
+ * chromaticities in the above equations tend to be small, for example for
+ * the sRGB chromaticities they are:
+ *
+ * red numerator: -0.04751
+ * green numerator: -0.08788
+ * denominator: -0.2241 (without white-y multiplication)
+ *
+ * The resultant Y coefficients from the chromaticities of some widely used
+ * color space definitions are (to 15 decimal places):
+ *
+ * sRGB
+ * 0.212639005871510 0.715168678767756 0.072192315360734
+ * Kodak ProPhoto
+ * 0.288071128229293 0.711843217810102 0.000085653960605
+ * Adobe RGB
+ * 0.297344975250536 0.627363566255466 0.075291458493998
+ * Adobe Wide Gamut RGB
+ * 0.258728243040113 0.724682314948566 0.016589442011321
+ */
+ /* By the argument, above overflow should be impossible here. The return
+ * value of 2 indicates an internal error to the caller.
+ */
+ if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.redy - xy.bluey, 7)) return 2;
+ if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.redx - xy.bluex, 7)) return 2;
+ denominator = left - right;
+
+ /* Now find the red numerator. */
+ if (!png_muldiv(&left, xy.greenx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
+ if (!png_muldiv(&right, xy.greeny-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
+
+ /* Overflow is possible here and it indicates an extreme set of PNG cHRM
+ * chunk values. This calculation actually returns the reciprocal of the
+ * scale value because this allows us to delay the multiplication of white-y
+ * into the denominator, which tends to produce a small number.
+ */
+ if (!png_muldiv(&red_inverse, xy.whitey, denominator, left-right) ||
+ red_inverse <= xy.whitey /* r+g+b scales = white scale */)
+ return 1;
+
+ /* Similarly for green_inverse: */
+ if (!png_muldiv(&left, xy.redy-xy.bluey, xy.whitex-xy.bluex, 7)) return 2;
+ if (!png_muldiv(&right, xy.redx-xy.bluex, xy.whitey-xy.bluey, 7)) return 2;
+ if (!png_muldiv(&green_inverse, xy.whitey, denominator, left-right) ||
+ green_inverse <= xy.whitey)
+ return 1;
+
+ /* And the blue scale, the checks above guarantee this can't overflow but it
+ * can still produce 0 for extreme cHRM values.
+ */
+ blue_scale = png_reciprocal(xy.whitey) - png_reciprocal(red_inverse) -
+ png_reciprocal(green_inverse);
+ if (blue_scale <= 0) return 1;
+
+
+ /* And fill in the png_XYZ: */
+ if (!png_muldiv(&XYZ->redX, xy.redx, PNG_FP_1, red_inverse)) return 1;
+ if (!png_muldiv(&XYZ->redY, xy.redy, PNG_FP_1, red_inverse)) return 1;
+ if (!png_muldiv(&XYZ->redZ, PNG_FP_1 - xy.redx - xy.redy, PNG_FP_1,
+ red_inverse))
+ return 1;
+
+ if (!png_muldiv(&XYZ->greenX, xy.greenx, PNG_FP_1, green_inverse)) return 1;
+ if (!png_muldiv(&XYZ->greenY, xy.greeny, PNG_FP_1, green_inverse)) return 1;
+ if (!png_muldiv(&XYZ->greenZ, PNG_FP_1 - xy.greenx - xy.greeny, PNG_FP_1,
+ green_inverse))
+ return 1;
+
+ if (!png_muldiv(&XYZ->blueX, xy.bluex, blue_scale, PNG_FP_1)) return 1;
+ if (!png_muldiv(&XYZ->blueY, xy.bluey, blue_scale, PNG_FP_1)) return 1;
+ if (!png_muldiv(&XYZ->blueZ, PNG_FP_1 - xy.bluex - xy.bluey, blue_scale,
+ PNG_FP_1))
+ return 1;
+
+ return 0; /*success*/
+}
+
+int png_XYZ_from_xy_checked(png_structp png_ptr, png_XYZ *XYZ, png_xy xy)
+{
+ switch (png_XYZ_from_xy(XYZ, xy))
+ {
+ case 0: /* success */
+ return 1;
+
+ case 1:
+ /* The chunk may be technically valid, but we got png_fixed_point
+ * overflow while trying to get XYZ values out of it. This is
+ * entirely benign - the cHRM chunk is pretty extreme.
+ */
+ png_warning(png_ptr,
+ "extreme cHRM chunk cannot be converted to tristimulus values");
+ break;
+
+ default:
+ /* libpng is broken; this should be a warning but if it happens we
+ * want error reports so for the moment it is an error.
+ */
+ png_error(png_ptr, "internal error in png_XYZ_from_xy");
+ break;
+ }
+
+ /* ERROR RETURN */
+ return 0;
+}
+#endif
+
void /* PRIVATE */
png_check_IHDR(png_structp png_ptr,
png_uint_32 width, png_uint_32 height, int bit_depth,
}
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
- if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX)
+ if (width > png_ptr->user_width_max)
# else
if (width > PNG_USER_WIDTH_MAX)
}
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
- if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)
+ if (height > png_ptr->user_height_max)
# else
if (height > PNG_USER_HEIGHT_MAX)
# endif
/* Check an ASCII formated floating point value, see the more detailed
* comments in pngpriv.h
*/
-/* The following is used internally to preserve the 'valid' flag */
+/* The following is used internally to preserve the sticky flags */
#define png_fp_add(state, flags) ((state) |= (flags))
-#define png_fp_set(state, value)\
- ((state) = (value) | ((state) & PNG_FP_WAS_VALID))
-
-/* Internal type codes: bits above the base state! */
-#define PNG_FP_SIGN 0 /* [+-] */
-#define PNG_FP_DOT 4 /* . */
-#define PNG_FP_DIGIT 8 /* [0123456789] */
-#define PNG_FP_E 12 /* [Ee] */
+#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
int /* PRIVATE */
png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
{
int type;
/* First find the type of the next character */
+ switch (string[i])
{
- char ch = string[i];
-
- if (ch >= 48 && ch <= 57)
- type = PNG_FP_DIGIT;
-
- else switch (ch)
- {
- case 43: case 45: type = PNG_FP_SIGN; break;
- case 46: type = PNG_FP_DOT; break;
- case 69: case 101: type = PNG_FP_E; break;
- default: goto PNG_FP_End;
- }
+ case 43: type = PNG_FP_SAW_SIGN; break;
+ case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
+ case 46: type = PNG_FP_SAW_DOT; break;
+ case 48: type = PNG_FP_SAW_DIGIT; break;
+ case 49: case 50: case 51: case 52:
+ case 53: case 54: case 55: case 56:
+ case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
+ case 69:
+ case 101: type = PNG_FP_SAW_E; break;
+ default: goto PNG_FP_End;
}
/* Now deal with this type according to the current
* state, the type is arranged to not overlap the
* bits of the PNG_FP_STATE.
*/
- switch ((state & PNG_FP_STATE) + type)
+ switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
{
- case PNG_FP_INTEGER + PNG_FP_SIGN:
+ case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
if (state & PNG_FP_SAW_ANY)
goto PNG_FP_End; /* not a part of the number */
- png_fp_add(state, PNG_FP_SAW_SIGN);
+ png_fp_add(state, type);
break;
- case PNG_FP_INTEGER + PNG_FP_DOT:
+ case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
/* Ok as trailer, ok as lead of fraction. */
if (state & PNG_FP_SAW_DOT) /* two dots */
goto PNG_FP_End;
else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */
- png_fp_add(state, PNG_FP_SAW_DOT);
+ png_fp_add(state, type);
else
- png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
+ png_fp_set(state, PNG_FP_FRACTION | type);
break;
- case PNG_FP_INTEGER + PNG_FP_DIGIT:
+ case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
if (state & PNG_FP_SAW_DOT) /* delayed fraction */
png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
- png_fp_add(state, PNG_FP_SAW_DIGIT + PNG_FP_WAS_VALID);
+ png_fp_add(state, type | PNG_FP_WAS_VALID);
break;
- case PNG_FP_INTEGER + PNG_FP_E:
+
+ case PNG_FP_INTEGER + PNG_FP_SAW_E:
if ((state & PNG_FP_SAW_DIGIT) == 0)
goto PNG_FP_End;
break;
- /* case PNG_FP_FRACTION + PNG_FP_SIGN:
- goto PNG_FP_End; ** no sign in exponent */
+ /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
+ goto PNG_FP_End; ** no sign in fraction */
- /* case PNG_FP_FRACTION + PNG_FP_DOT:
+ /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
goto PNG_FP_End; ** Because SAW_DOT is always set */
- case PNG_FP_FRACTION + PNG_FP_DIGIT:
- png_fp_add(state, PNG_FP_SAW_DIGIT + PNG_FP_WAS_VALID);
+ case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
+ png_fp_add(state, type | PNG_FP_WAS_VALID);
break;
- case PNG_FP_FRACTION + PNG_FP_E:
+ case PNG_FP_FRACTION + PNG_FP_SAW_E:
/* This is correct because the trailing '.' on an
* integer is handled above - so we can only get here
* with the sequence ".E" (with no preceding digits).
break;
- case PNG_FP_EXPONENT + PNG_FP_SIGN:
+ case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
if (state & PNG_FP_SAW_ANY)
goto PNG_FP_End; /* not a part of the number */
break;
- /* case PNG_FP_EXPONENT + PNG_FP_DOT:
+ /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
goto PNG_FP_End; */
- case PNG_FP_EXPONENT + PNG_FP_DIGIT:
- png_fp_add(state, PNG_FP_SAW_DIGIT + PNG_FP_WAS_VALID);
+ case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
+ png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
break;
- /* case PNG_FP_EXPONEXT + PNG_FP_E:
+ /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
goto PNG_FP_End; */
default: goto PNG_FP_End; /* I.e. break 2 */
int state=0;
png_size_t char_index=0;
- return png_check_fp_number(string, size, &state, &char_index) &&
- (char_index == size || string[char_index] == 0);
+ if (png_check_fp_number(string, size, &state, &char_index) &&
+ (char_index == size || string[char_index] == 0))
+ return state /* must be non-zero - see above */;
+
+ return 0; /* i.e. fail */
}
#endif /* pCAL or sCAL */
if (fp < 0)
{
fp = -fp;
- *ascii++ = 45; /* '-' PLUS 1 TOTAL 1*/
+ *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */
--size;
}
*/
size -= cdigits;
- *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision*/
- if (exp_b10 < 0)
+ *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
+
+ /* The following use of an unsigned temporary avoids ambiguities in
+ * the signed arithmetic on exp_b10 and permits GCC at least to do
+ * better optimization.
+ */
{
- *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
- exp_b10 = -exp_b10;
- }
+ unsigned int uexp_b10;
+
+ if (exp_b10 < 0)
+ {
+ *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
+ uexp_b10 = -exp_b10;
+ }
+
+ else
+ uexp_b10 = exp_b10;
- cdigits = 0;
+ cdigits = 0;
- while (exp_b10 > 0)
- {
- exponent[cdigits++] = (char)(48 + exp_b10 % 10);
- exp_b10 /= 10;
+ while (uexp_b10 > 0)
+ {
+ exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
+ uexp_b10 /= 10;
+ }
}
/* Need another size check here for the exponent digits, so
else
num = fp;
- if (num <= 0x80000000U) /* else overflowed */
+ if (num <= 0x80000000) /* else overflowed */
{
- unsigned int ndigits = 0, first = 16/*flag value*/;
+ unsigned int ndigits = 0, first = 16 /* flag value */;
char digits[10];
while (num)
r /= divisor;
r = floor(r+.5);
- /* A png_fixed_point is a 32 bit integer. */
+ /* A png_fixed_point is a 32-bit integer. */
if (r <= 2147483647. && r >= -2147483648.)
{
*res = (png_fixed_point)r;
if (s32 < D) /* else overflow */
{
- /* s32.s00 is now the 64 bit product, do a standard
+ /* s32.s00 is now the 64-bit product, do a standard
* division, we know that s32 < D, so the maximum
* required shift is 31.
*/
* 2010: moved from pngset.c) */
/*
* Multiply two 32-bit numbers, V1 and V2, using 32-bit
- * arithmetic, to produce a 64 bit result in the HI/LO words.
+ * arithmetic, to produce a 64-bit result in the HI/LO words.
*
* A B
* x C D
/* Fixed point gamma.
*
* To calculate gamma this code implements fast log() and exp() calls using only
- * fixed point arithmetic. This code has sufficient precision for either 8 or
- * 16 bit sample values.
+ * fixed point arithmetic. This code has sufficient precision for either 8-bit
+ * or 16-bit sample values.
*
* The tables used here were calculated using simple 'bc' programs, but C double
* precision floating point arithmetic would work fine. The programs are given
* at the head of each table.
*
- * 8 bit log table
+ * 8-bit log table
* This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
- * 255, so it's the base 2 logarithm of a normalized 8 bit floating point
- * mantissa. The numbers are 32 bit fractions.
+ * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ * mantissa. The numbers are 32-bit fractions.
*/
static png_uint_32
png_8bit_l2[128] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; }
-# endif
+# else
4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
24347096U, 0U
+# endif
+
#if 0
- /* The following are the values for 16 bit tables - these work fine for the 8
- * bit conversions but produce very slightly larger errors in the 16 bit log
- * (about 1.2 as opposed to 0.7 absolute error in the final value). To use
- * these all the shifts below must be adjusted appropriately.
+ /* The following are the values for 16-bit tables - these work fine for the
+ * 8-bit conversions but produce very slightly larger errors in the 16-bit
+ * log (about 1.2 as opposed to 0.7 absolute error in the final value). To
+ * use these all the shifts below must be adjusted appropriately.
*/
65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
#endif
};
-static png_int_32
+PNG_STATIC png_int_32
png_log8bit(unsigned int x)
{
unsigned int lg2 = 0;
return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
}
-/* The above gives exact (to 16 binary places) log2 values for 8 bit images,
- * for 16 bit images we use the most significant 8 bits of the 16 bit value to
+/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
+ * for 16-bit images we use the most significant 8 bits of the 16-bit value to
* get an approximation then multiply the approximation by a correction factor
* determined by the remaining up to 8 bits. This requires an additional step
- * in the 16 bit case.
+ * in the 16-bit case.
*
* We want log2(value/65535), we have log2(v'/255), where:
*
*
* So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
* to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
- * than 258. The final factor also needs to correct for the fact that our 8 bit
- * value is scaled by 255, whereas the 16 bit values must be scaled by 65535.
+ * than 258. The final factor also needs to correct for the fact that our 8-bit
+ * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
*
* This gives a final formula using a calculated value 'x' which is value/v' and
* scaling by 65536 to match the above table:
* Since these numbers are so close to '1' we can use simple linear
* interpolation between the two end values 256/257 (result -368.61) and 258/257
* (result 367.179). The values used below are scaled by a further 64 to give
- * 16 bit precision in the interpolation:
+ * 16-bit precision in the interpolation:
*
* Start (256): -23591
* Zero (257): 0
* End (258): 23499
*/
-static png_int_32
+PNG_STATIC png_int_32
png_log16bit(png_uint_32 x)
{
unsigned int lg2 = 0;
if ((x & 0x8000) == 0)
lg2 += 1, x <<= 1;
- /* Calculate the base logarithm from the top 8 bits as a 28 bit fractional
+ /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
* value.
*/
lg2 <<= 28;
return (png_int_32)((lg2 + 2048) >> 12);
}
-/* The 'exp()' case must invert the above, taking a 20 bit fixed point
- * logarithmic value and returning a 16 or 8 bit number as appropriate. In
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate. In
* each case only the low 16 bits are relevant - the fraction - since the
* integer bits (the top 4) simply determine a shift.
*
- * The worst case is the 16 bit distinction between 65535 and 65534, this
- * requires perhaps spurious accuracty in the decoding of the logarithm to
+ * The worst case is the 16-bit distinction between 65535 and 65534, this
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
* distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
* of getting this accuracy in practice.
*
* To deal with this the following exp() function works out the exponent of the
- * frational part of the logarithm by using an accurate 32 bit value from the
+ * frational part of the logarithm by using an accurate 32-bit value from the
* top four fractional bits then multiplying in the remaining bits.
*/
static png_uint_32
png_32bit_exp[16] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
-# endif
- /* NOTE: the first entry is deliberately set to the maximum 32 bit value. */
+# else
+ /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
2553802834U, 2445529972U, 2341847524U, 2242560872U
+# endif
};
/* Adjustment table; provided to explain the numbers in the code below. */
-#if PNG_DO_BC
+#ifdef PNG_DO_BC
for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
11 44937.64284865548751208448
10 45180.98734845585101160448
0 45425.85339951654943850496
#endif
-static png_uint_32
+PNG_STATIC png_uint_32
png_exp(png_fixed_point x)
{
if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
{
- /* Obtain a 4 bit approximation */
+ /* Obtain a 4-bit approximation */
png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
/* Incorporate the low 12 bits - these decrease the returned value by
return 0;
}
-static png_byte
+PNG_STATIC png_byte
png_exp8bit(png_fixed_point lg2)
{
- /* Get a 32 bit value: */
+ /* Get a 32-bit value: */
png_uint_32 x = png_exp(lg2);
- /* Convert the 32 bit value to 0..255 by multiplying by 256-1, note that the
+ /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
* second, rounding, step can't overflow because of the first, subtraction,
* step.
*/
return (png_byte)((x + 0x7fffffU) >> 24);
}
-static png_uint_16
+PNG_STATIC png_uint_16
png_exp16bit(png_fixed_point lg2)
{
- /* Get a 32 bit value: */
+ /* Get a 32-bit value: */
png_uint_32 x = png_exp(lg2);
- /* Convert the 32 bit value to 0..65535 by multiplying by 65536-1: */
+ /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
x -= x >> 16;
return (png_uint_16)((x + 32767U) >> 16);
}
}
/* This does the right thing based on the bit_depth field of the
- * png_struct, interpreting values as 8 or 16 bit. While the result
- * is nominally a 16 bit value if bit depth is 8 then the result is
- * 8 bit (as are the arguments.)
+ * png_struct, interpreting values as 8-bit or 16-bit. While the result
+ * is nominally a 16-bit value if bit depth is 8 then the result is
+ * 8-bit (as are the arguments.)
*/
png_uint_16 /* PRIVATE */
png_gamma_correct(png_structp png_ptr, unsigned int value,
gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
}
-/* Internal function to build a single 16 bit table - the table consists of
- * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
+/* Internal function to build a single 16-bit table - the table consists of
+ * 'num' 256-entry subtables, where 'num' is determined by 'shift' - the amount
* to shift the input values right (or 16-number_of_signifiant_bits).
*
* The caller is responsible for ensuring that the table gets cleaned up on
(png_uint_16p)png_malloc(png_ptr, 256 * png_sizeof(png_uint_16));
/* The 'threshold' test is repeated here because it can arise for one of
- * the 16 bit tables even if the others don't hit it.
+ * the 16-bit tables even if the others don't hit it.
*/
if (png_gamma_significant(gamma_val))
{
png_uint_16pp table = *ptable =
(png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
- /* 'num' is the number of tables and also the number of low bits of low
- * bits of the input 16 bit value used to select a table. Each table is
- * itself index by the high 8 bits of the value.
+ /* 'num' is the number of tables and also the number of low bits of the
+ * input 16-bit value used to select a table. Each table is itself indexed
+ * by the high 8 bits of the value.
*/
for (i = 0; i < num; i++)
table[i] = (png_uint_16p)png_malloc(png_ptr,
/* 'gamma_val' is set to the reciprocal of the value calculated above, so
* pow(out,g) is an *input* value. 'last' is the last input value set.
*
- * In the loop 'i' is used to find output values. Since the output is 8
- * bit there are only 256 possible values. The tables are set up to
+ * In the loop 'i' is used to find output values. Since the output is
+ * 8-bit there are only 256 possible values. The tables are set up to
* select the closest possible output value for each input by finding
* the input value at the boundary between each pair of output values
* and filling the table up to that boundary with the lower output
* value.
*
- * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9 bit
- * values the code below uses a 16 bit value in i; the values start at
+ * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
+ * values the code below uses a 16-bit value in i; the values start at
* 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
* entries are filled with 255). Start i at 128 and fill all 'last'
* table entries <= 'max'
*/
last = 0;
- for (i = 0; i < 255; ++i) /* 8 bit output value */
+ for (i = 0; i < 255; ++i) /* 8-bit output value */
{
/* Find the corresponding maximum input value */
- png_uint_16 out = (png_uint_16)(i * 257U); /* 16 bit output value */
+ png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
/* Find the boundary value in 16 bits: */
png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
}
}
-/* Build a single 8 bit table: same as the 16 bit case but much simpler (and
+/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
* typically much faster). Note that libpng currently does no sBIT processing
- * (apparently contrary to the spec) so a 256 entry table is always generated.
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
*/
static void
png_build_8bit_table(png_structp png_ptr, png_bytepp ptable,
table[i] = (png_byte)i;
}
+/* Used from png_read_destroy and below to release the memory used by the gamma
+ * tables.
+ */
+void /* PRIVATE */
+png_destroy_gamma_table(png_structp png_ptr)
+{
+ png_free(png_ptr, png_ptr->gamma_table);
+ png_ptr->gamma_table = NULL;
+
+ if (png_ptr->gamma_16_table != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_table[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_table);
+ png_ptr->gamma_16_table = NULL;
+ }
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ png_free(png_ptr, png_ptr->gamma_from_1);
+ png_ptr->gamma_from_1 = NULL;
+ png_free(png_ptr, png_ptr->gamma_to_1);
+ png_ptr->gamma_to_1 = NULL;
+
+ if (png_ptr->gamma_16_from_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_from_1);
+ png_ptr->gamma_16_from_1 = NULL;
+ }
+ if (png_ptr->gamma_16_to_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_to_1);
+ png_ptr->gamma_16_to_1 = NULL;
+ }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+}
+
/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
* tables, we don't make a full table if we are reducing to 8-bit in
* the future. Note also how the gamma_16 tables are segmented so that
{
png_debug(1, "in png_build_gamma_table");
+ /* Remove any existing table; this copes with multiple calls to
+ * png_read_update_info. The warning is because building the gamma tables
+ * multiple times is a performance hit - it's harmless but the ability to call
+ * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
+ * to warn if the app introduces such a hit.
+ */
+ if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
+ {
+ png_warning(png_ptr, "gamma table being rebuilt");
+ png_destroy_gamma_table(png_ptr);
+ }
+
if (bit_depth <= 8)
{
png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
png_ptr->screen_gamma) : PNG_FP_1);
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
- if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
+ if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
{
png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
png_reciprocal(png_ptr->gamma));
png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
png_ptr->gamma/* Probably doing rgb_to_gray */);
}
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
}
else
{
else
sig_bit = png_ptr->sig_bit.gray;
- /* 16 bit gamma code uses this equation:
+ /* 16-bit gamma code uses this equation:
*
* ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
*
* Where 'iv' is the input color value and 'ov' is the output value -
* pow(iv, gamma).
*
- * Thus the gamma table consists of up to 256 256 entry tables. The table
+ * Thus the gamma table consists of up to 256 256-entry tables. The table
* is selected by the (8-gamma_shift) most significant of the low 8 bits of
* the color value then indexed by the upper 8 bits:
*
*
* So the table 'n' corresponds to all those 'iv' of:
*
- * <all high 8 bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
+ * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
*
*/
if (sig_bit > 0 && sig_bit < 16U)
else
shift = 0; /* keep all 16 bits */
- if (png_ptr->transformations & PNG_16_TO_8)
+ if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
{
/* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
* the significant bits in the *input* when the output will
png_ptr->gamma_shift = shift;
#ifdef PNG_16BIT_SUPPORTED
- if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
+ /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
+ * PNG_COMPOSE). This effectively smashed the background calculation for
+ * 16-bit output because the 8-bit table assumes the result will be reduced
+ * to 8 bits.
+ */
+ if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
#endif
png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma,
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
- if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+ if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
{
png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
png_reciprocal(png_ptr->gamma));
png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
png_ptr->gamma/* Probably doing rgb_to_gray */);
}
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
}
}
#endif /* READ_GAMMA */
/* png.h - header file for PNG reference library
*
- * libpng version 1.5.2 - March 31, 2011
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * libpng version 1.5.9 - February 18, 2012
+ * Copyright (c) 1998-2012 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* Authors and maintainers:
* libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
* libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- * libpng versions 0.97, January 1998, through 1.5.2 - March 31, 2011: Glenn
+ * libpng versions 0.97, January 1998, through 1.5.9 - February 18, 2012: Glenn
* See also "Contributing Authors", below.
*
* Note about libpng version numbers:
* 1.5.2beta01-03 15 10502 15.so.15.2[.0]
* 1.5.2rc01-03 15 10502 15.so.15.2[.0]
* 1.5.2 15 10502 15.so.15.2[.0]
+ * 1.5.3beta01-10 15 10503 15.so.15.3[.0]
+ * 1.5.3rc01-02 15 10503 15.so.15.3[.0]
+ * 1.5.3beta11 15 10503 15.so.15.3[.0]
+ * 1.5.3 [omitted]
+ * 1.5.4beta01-08 15 10504 15.so.15.4[.0]
+ * 1.5.4rc01 15 10504 15.so.15.4[.0]
+ * 1.5.4 15 10504 15.so.15.4[.0]
+ * 1.5.5beta01-08 15 10505 15.so.15.5[.0]
+ * 1.5.5rc01 15 10505 15.so.15.5[.0]
+ * 1.5.5 15 10505 15.so.15.5[.0]
+ * 1.5.6beta01-07 15 10506 15.so.15.6[.0]
+ * 1.5.6rc01-03 15 10506 15.so.15.6[.0]
+ * 1.5.6 15 10506 15.so.15.6[.0]
+ * 1.5.7beta01-05 15 10507 15.so.15.7[.0]
+ * 1.5.7rc01-03 15 10507 15.so.15.7[.0]
+ * 1.5.7 15 10507 15.so.15.7[.0]
+ * 1.5.8beta01 15 10508 15.so.15.8[.0]
+ * 1.5.8rc01 15 10508 15.so.15.8[.0]
+ * 1.5.8 15 10508 15.so.15.8[.0]
+ * 1.5.9beta01-02 15 10509 15.so.15.9[.0]
+ * 1.5.9rc01 15 10509 15.so.15.9[.0]
+ * 1.5.9 15 10509 15.so.15.9[.0]
*
* Henceforth the source version will match the shared-library major
* and minor numbers; the shared-library major version number will be
*
* This code is released under the libpng license.
*
- * libpng versions 1.2.6, August 15, 2004, through 1.5.2, March 31, 2011, are
- * Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
+ * libpng versions 1.2.6, August 15, 2004, through 1.5.9, February 18, 2012, are
+ * Copyright (c) 2004, 2006-2012 Glenn Randers-Pehrson, and are
* distributed according to the same disclaimer and license as libpng-1.2.5
* with the following individual added to the list of Contributing Authors:
*
* Y2K compliance in libpng:
* =========================
*
- * March 31, 2011
+ * February 18, 2012
*
* Since the PNG Development group is an ad-hoc body, we can't make
* an official declaration.
*
* This is your unofficial assurance that libpng from version 0.71 and
- * upward through 1.5.2 are Y2K compliant. It is my belief that
+ * upward through 1.5.9 are Y2K compliant. It is my belief that
* earlier versions were also Y2K compliant.
*
- * Libpng only has three year fields. One is a 2-byte unsigned integer
- * that will hold years up to 65535. The other two hold the date in text
+ * Libpng only has two year fields. One is a 2-byte unsigned integer
+ * that will hold years up to 65535. The other holds the date in text
* format, and will hold years up to 9999.
*
* The integer is
* "png_uint_16 year" in png_time_struct.
*
- * The strings are
- * "png_charp time_buffer" in png_struct and
- * "near_time_buffer", which is a local character string in png.c.
+ * The string is
+ * "png_char time_buffer" in png_struct
*
* There are seven time-related functions:
* png.c: png_convert_to_rfc_1123() in png.c
* describes how to use libpng, and the file example.c summarizes it
* with some code on which to build. This file is useful for looking
* at the actual function definitions and structure components.
+ *
+ * If you just need to read a PNG file and don't want to read the documentation
+ * skip to the end of this file and read the section entitled 'simplified API'.
*/
/* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.5.2"
+#define PNG_LIBPNG_VER_STRING "1.5.9"
#define PNG_HEADER_VERSION_STRING \
- " libpng version 1.5.2 - March 31, 2011\n"
+ " libpng version 1.5.9 - February 18, 2012\n"
#define PNG_LIBPNG_VER_SONUM 15
#define PNG_LIBPNG_VER_DLLNUM 15
/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
#define PNG_LIBPNG_VER_MAJOR 1
#define PNG_LIBPNG_VER_MINOR 5
-#define PNG_LIBPNG_VER_RELEASE 2
+#define PNG_LIBPNG_VER_RELEASE 9
+
/* This should match the numeric part of the final component of
* PNG_LIBPNG_VER_STRING, omitting any leading zero:
*/
* version 1.0.0 was mis-numbered 100 instead of 10000). From
* version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
*/
-#define PNG_LIBPNG_VER 10502 /* 1.5.2 */
+#define PNG_LIBPNG_VER 10509 /* 1.5.9 */
/* Library configuration: these options cannot be changed after
* the library has been built.
/* This triggers a compiler error in png.c, if png.c and png.h
* do not agree upon the version number.
*/
-typedef char* png_libpng_version_1_5_2;
+typedef char* png_libpng_version_1_5_9;
/* Three color definitions. The order of the red, green, and blue, (and the
* exact size) is not important, although the size of the fields need to
#ifdef PNG_TEXT_SUPPORTED
/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
* and whether that contents is compressed or not. The "key" field
- * points to a regular zero-terminated C string. The "text", "lang", and
- * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
- * However, the * structure returned by png_get_text() will always contain
- * regular zero-terminated C strings (possibly empty), never NULL pointers,
- * so they can be safely used in printf() and other string-handling functions.
+ * points to a regular zero-terminated C string. The "text" fields can be a
+ * regular C string, an empty string, or a NULL pointer.
+ * However, the structure returned by png_get_text() will always contain
+ * the "text" field as a regular zero-terminated C string (possibly
+ * empty), never a NULL pointer, so it can be safely used in printf() and
+ * other string-handling functions. Note that the "itxt_length", "lang", and
+ * "lang_key" members of the structure only exist when the library is built
+ * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
+ * default without iTXt support. Also note that when iTXt *is* supported,
+ * the "lang" and "lang_key" fields contain NULL pointers when the
+ * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
+ * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
+ * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
+ * which is always 0 or 1, or its "compression method" which is always 0.
*/
typedef struct png_text_struct
{
/* libpng-using applications should NOT directly modify this byte. */
png_byte location; /* mode of operation at read time */
}
+
+
png_unknown_chunk;
typedef png_unknown_chunk FAR * png_unknown_chunkp;
typedef PNG_CONST png_unknown_chunk FAR * png_const_unknown_chunkp;
typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
#endif
+/* Values for the unknown chunk location byte */
+
+#define PNG_HAVE_IHDR 0x01
+#define PNG_HAVE_PLTE 0x02
+#define PNG_AFTER_IDAT 0x08
+
+/* The complete definition of png_info has, as of libpng-1.5.0,
+ * been moved into a separate header file that is not accessible to
+ * applications. Read libpng-manual.txt or libpng.3 for more info.
+ */
typedef struct png_info_def png_info;
typedef png_info FAR * png_infop;
typedef PNG_CONST png_info FAR * png_const_infop;
*/
#define PNG_FP_1 100000
#define PNG_FP_HALF 50000
+#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
+#define PNG_FP_MIN (-PNG_FP_MAX)
/* These describe the color_type field in png_info. */
/* color type masks */
#define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
#define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
#define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
-#define PNG_INFO_IDAT 0x8000L /* ESR, 1.0.6 */
+#define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
/* This is used for the transformation routines, as some of them
* change these values for the row. It also should enable using
typedef png_row_info FAR * png_row_infop;
typedef png_row_info FAR * FAR * png_row_infopp;
+/* The complete definition of png_struct has, as of libpng-1.5.0,
+ * been moved into a separate header file that is not accessible to
+ * applications. Read libpng-manual.txt or libpng.3 for more info.
+ */
+typedef struct png_struct_def png_struct;
+typedef PNG_CONST png_struct FAR * png_const_structp;
+typedef png_struct FAR * png_structp;
+
/* These are the function types for the I/O functions and for the functions
* that allow the user to override the default I/O functions with his or her
* own. The png_error_ptr type should match that of user-supplied warning
* modify the buffer it is passed. The 'read' function, on the other hand, is
* expected to return the read data in the buffer.
*/
-typedef struct png_struct_def png_struct;
-typedef PNG_CONST png_struct FAR * png_const_structp;
-typedef png_struct FAR * png_structp;
-
typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
#endif
#ifdef PNG_SETJMP_SUPPORTED
-/* This must match the function definition in <setjmp.h>, and the
- * application must include this before png.h to obtain the definition
- * of jmp_buf. The function is required to be PNG_NORETURN. (Note that
- * PNG_PTR_NORETURN is used here because current versions of the Microsoft
- * C compiler do not support the PNG_NORETURN attribute on a pointer.)
- *
- * If you get a type warning from the compiler when linking against this line
- * then your compiler has 'longjmp' that does not match the requirements of the
- * compiler that built libpng. You will have to write a wrapper function for
- * your compiler's longjmp and call png_set_longjmp_fn directly (not via the
- * png_jmpbuf macro.)
- *
- * If you get a warning here while building the library you will need to make
+/* This must match the function definition in <setjmp.h>, and the application
+ * must include this before png.h to obtain the definition of jmp_buf. The
+ * function is required to be PNG_NORETURN, but this is not checked. If the
+ * function does return the application will crash via an abort() or similar
+ * system level call.
+ *
+ * If you get a warning here while building the library you may need to make
* changes to ensure that pnglibconf.h records the calling convention used by
* your compiler. This may be very difficult - try using a different compiler
* to build the library!
*/
-typedef PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)),
- PNG_PTR_NORETURN);
+PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
#endif
/* Transform masks for the high-level interface */
#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
/* Added to libpng-1.4.0 */
#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
+/* Added to libpng-1.5.4 */
+#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
+#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
/* Flags for MNG supported features */
#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
#endif
#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16 bit channels, forces conversion of palette to RGB and expansion
+/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
* of a tRNS chunk if present.
*/
PNG_EXPORT(221, void, png_set_expand_16, (png_structp png_ptr));
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Reduce RGB to grayscale. */
+#define PNG_ERROR_ACTION_NONE 1
+#define PNG_ERROR_ACTION_WARN 2
+#define PNG_ERROR_ACTION_ERROR 3
+#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
+
PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structp png_ptr,
int error_action, double red, double green));
PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structp png_ptr,
png_ptr));
#endif
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
png_colorp palette));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* How the alpha channel is interpreted - this affects how the color channels of
+ * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
+ * file, is present.
+ *
+ * This has no effect on the way pixels are written into a PNG output
+ * datastream. The color samples in a PNG datastream are never premultiplied
+ * with the alpha samples.
+ *
+ * The default is to return data according to the PNG specification: the alpha
+ * channel is a linear measure of the contribution of the pixel to the
+ * corresponding composited pixel. The gamma encoded color channels must be
+ * scaled according to the contribution and to do this it is necessary to undo
+ * the encoding, scale the color values, perform the composition and reencode
+ * the values. This is the 'PNG' mode.
+ *
+ * The alternative is to 'associate' the alpha with the color information by
+ * storing color channel values that have been scaled by the alpha. The
+ * advantage is that the color channels can be resampled (the image can be
+ * scaled) in this form. The disadvantage is that normal practice is to store
+ * linear, not (gamma) encoded, values and this requires 16-bit channels for
+ * still images rather than the 8-bit channels that are just about sufficient if
+ * gamma encoding is used. In addition all non-transparent pixel values,
+ * including completely opaque ones, must be gamma encoded to produce the final
+ * image. This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
+ * latter being the two common names for associated alpha color channels.)
+ *
+ * Since it is not necessary to perform arithmetic on opaque color values so
+ * long as they are not to be resampled and are in the final color space it is
+ * possible to optimize the handling of alpha by storing the opaque pixels in
+ * the PNG format (adjusted for the output color space) while storing partially
+ * opaque pixels in the standard, linear, format. The accuracy required for
+ * standard alpha composition is relatively low, because the pixels are
+ * isolated, therefore typically the accuracy loss in storing 8-bit linear
+ * values is acceptable. (This is not true if the alpha channel is used to
+ * simulate transparency over large areas - use 16 bits or the PNG mode in
+ * this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is
+ * treated as opaque only if the alpha value is equal to the maximum value.
+ *
+ * The final choice is to gamma encode the alpha channel as well. This is
+ * broken because, in practice, no implementation that uses this choice
+ * correctly undoes the encoding before handling alpha composition. Use this
+ * choice only if other serious errors in the software or hardware you use
+ * mandate it; the typical serious error is for dark halos to appear around
+ * opaque areas of the composited PNG image because of arithmetic overflow.
+ *
+ * The API function png_set_alpha_mode specifies which of these choices to use
+ * with an enumerated 'mode' value and the gamma of the required output:
+ */
+#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
+#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
+#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
+#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
+
+PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structp png_ptr, int mode,
+ double output_gamma));
+PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structp png_ptr,
+ int mode, png_fixed_point output_gamma));
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* The output_gamma value is a screen gamma in libpng terminology: it expresses
+ * how to decode the output values, not how they are encoded. The values used
+ * correspond to the normal numbers used to describe the overall gamma of a
+ * computer display system; for example 2.2 for an sRGB conformant system. The
+ * values are scaled by 100000 in the _fixed version of the API (so 220000 for
+ * sRGB.)
+ *
+ * The inverse of the value is always used to provide a default for the PNG file
+ * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+ * to override the PNG gamma information.
+ *
+ * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+ * opaque pixels however pixels with lower alpha values are not encoded,
+ * regardless of the output gamma setting.
+ *
+ * When the standard Porter Duff handling is requested with mode 1 the output
+ * encoding is set to be linear and the output_gamma value is only relevant
+ * as a default for input data that has no gamma information. The linear output
+ * encoding will be overridden if png_set_gamma() is called - the results may be
+ * highly unexpected!
+ *
+ * The following numbers are derived from the sRGB standard and the research
+ * behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of
+ * 0.45455 (1/2.2) for PNG. The value implicitly includes any viewing
+ * correction required to take account of any differences in the color
+ * environment of the original scene and the intended display environment; the
+ * value expresses how to *decode* the image for display, not how the original
+ * data was *encoded*.
+ *
+ * sRGB provides a peg for the PNG standard by defining a viewing environment.
+ * sRGB itself, and earlier TV standards, actually use a more complex transform
+ * (a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is
+ * limited to simple power laws.) By saying that an image for direct display on
+ * an sRGB conformant system should be stored with a gAMA chunk value of 45455
+ * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+ * makes it possible to derive values for other display systems and
+ * environments.
+ *
+ * The Mac value is deduced from the sRGB based on an assumption that the actual
+ * extra viewing correction used in early Mac display systems was implemented as
+ * a power 1.45 lookup table.
+ *
+ * Any system where a programmable lookup table is used or where the behavior of
+ * the final display device characteristics can be changed requires system
+ * specific code to obtain the current characteristic. However this can be
+ * difficult and most PNG gamma correction only requires an approximate value.
+ *
+ * By default, if png_set_alpha_mode() is not called, libpng assumes that all
+ * values are unencoded, linear, values and that the output device also has a
+ * linear characteristic. This is only very rarely correct - it is invariably
+ * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+ * default if you don't know what the right answer is!
+ *
+ * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+ * 10.6) which used a correction table to implement a somewhat lower gamma on an
+ * otherwise sRGB system.
+ *
+ * Both these values are reserved (not simple gamma values) in order to allow
+ * more precise correction internally in the future.
+ *
+ * NOTE: the following values can be passed to either the fixed or floating
+ * point APIs, but the floating point API will also accept floating point
+ * values.
+ */
+#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
+#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
+#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
+#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
+#endif
+
+/* The following are examples of calls to png_set_alpha_mode to achieve the
+ * required overall gamma correction and, where necessary, alpha
+ * premultiplication.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * This is the default libpng handling of the alpha channel - it is not
+ * pre-multiplied into the color components. In addition the call states
+ * that the output is for a sRGB system and causes all PNG files without gAMA
+ * chunks to be assumed to be encoded using sRGB.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ * In this case the output is assumed to be something like an sRGB conformant
+ * display preceeded by a power-law lookup table of power 1.45. This is how
+ * early Mac systems behaved.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+ * This is the classic Jim Blinn approach and will work in academic
+ * environments where everything is done by the book. It has the shortcoming
+ * of assuming that input PNG data with no gamma information is linear - this
+ * is unlikely to be correct unless the PNG files where generated locally.
+ * Most of the time the output precision will be so low as to show
+ * significant banding in dark areas of the image.
+ *
+ * png_set_expand_16(pp);
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+ * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
+ * are assumed to have the sRGB encoding if not marked with a gamma value and
+ * the output is always 16 bits per component. This permits accurate scaling
+ * and processing of the data. If you know that your input PNG files were
+ * generated locally you might need to replace PNG_DEFAULT_sRGB with the
+ * correct value for your system.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+ * If you just need to composite the PNG image onto an existing background
+ * and if you control the code that does this you can use the optimization
+ * setting. In this case you just copy completely opaque pixels to the
+ * output. For pixels that are not completely transparent (you just skip
+ * those) you do the composition math using png_composite or png_composite_16
+ * below then encode the resultant 8-bit or 16-bit values to match the output
+ * encoding.
+ *
+ * Other cases
+ * If neither the PNG nor the standard linear encoding work for you because
+ * of the software or hardware you use then you have a big problem. The PNG
+ * case will probably result in halos around the image. The linear encoding
+ * will probably result in a washed out, too bright, image (it's actually too
+ * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
+ * substantially reduce the halos. Alternatively try:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+ * This option will also reduce the halos, but there will be slight dark
+ * halos round the opaque parts of the image where the background is light.
+ * In the OPTIMIZED mode the halos will be light halos where the background
+ * is dark. Take your pick - the halos are unavoidable unless you can get
+ * your hardware/software fixed! (The OPTIMIZED approach is slightly
+ * faster.)
+ *
+ * When the default gamma of PNG files doesn't match the output gamma.
+ * If you have PNG files with no gamma information png_set_alpha_mode allows
+ * you to provide a default gamma, but it also sets the ouput gamma to the
+ * matching value. If you know your PNG files have a gamma that doesn't
+ * match the output you can take advantage of the fact that
+ * png_set_alpha_mode always sets the output gamma but only sets the PNG
+ * default if it is not already set:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ * The first call sets both the default and the output gamma values, the
+ * second call overrides the output gamma without changing the default. This
+ * is easier than achieving the same effect with png_set_gamma. You must use
+ * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+ * fire if more than one call to png_set_alpha_mode and png_set_background is
+ * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+ * are ignored.
+ */
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
PNG_EXPORT(36, void, png_set_strip_alpha, (png_structp png_ptr));
#endif
#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* Handle alpha and tRNS by replacing with a background color. */
+/* Handle alpha and tRNS by replacing with a background color. Prior to
+ * libpng-1.5.4 this API must not be called before the PNG file header has been
+ * read. Doing so will result in unexpected behavior and possible warnings or
+ * errors if the PNG file contains a bKGD chunk.
+ */
PNG_FP_EXPORT(47, void, png_set_background, (png_structp png_ptr,
png_const_color_16p background_color, int background_gamma_code,
int need_expand, double background_gamma));
# define PNG_BACKGROUND_GAMMA_UNIQUE 3
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale a 16-bit depth file down to 8-bit, accurately. */
+PNG_EXPORT(229, void, png_set_scale_16, (png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
/* Strip the second byte of information from a 16-bit depth file. */
PNG_EXPORT(48, void, png_set_strip_16, (png_structp png_ptr));
#endif
*/
#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
-/* Handle gamma correction. Screen_gamma=(display_exponent) */
+/* Handle gamma correction. Screen_gamma=(display_exponent).
+ * NOTE: this API simply sets the screen and file gamma values. It will
+ * therefore override the value for gamma in a PNG file if it is called after
+ * the file header has been read - use with care - call before reading the PNG
+ * file for best results!
+ *
+ * These routines accept the same gamma values as png_set_alpha_mode (described
+ * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
+ * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
+ * is the inverse of a 'screen gamma' value.
+ */
PNG_FP_EXPORT(50, void, png_set_gamma,
(png_structp png_ptr, double screen_gamma,
- double default_file_gamma));
+ double override_file_gamma));
PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structp png_ptr,
- png_fixed_point screen_gamma, png_fixed_point default_file_gamma));
+ png_fixed_point screen_gamma, png_fixed_point override_file_gamma));
#endif
#ifdef PNG_WRITE_FLUSH_SUPPORTED
#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
+#ifdef PNG_WRITE_SUPPORTED
/* Set the library compression level. Currently, valid values range from
* 0 - 9, corresponding directly to the zlib compression levels 0 - 9
* (0 - no compression, 9 - "maximal" compression). Note that tests have
PNG_EXPORT(71, void, png_set_compression_strategy, (png_structp png_ptr,
int strategy));
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structp png_ptr,
int window_bits));
PNG_EXPORT(73, void, png_set_compression_method, (png_structp png_ptr,
int method));
+#endif
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+/* Also set zlib parameters for compressing non-IDAT chunks */
+PNG_EXPORT(222, void, png_set_text_compression_level,
+ (png_structp png_ptr, int level));
+
+PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structp png_ptr,
+ int mem_level));
+
+PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structp png_ptr,
+ int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(225, void, png_set_text_compression_window_bits, (png_structp
+ png_ptr, int window_bits));
+
+PNG_EXPORT(226, void, png_set_text_compression_method, (png_structp png_ptr,
+ int method));
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
/* These next functions are called for input/output, memory, and error
* handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
*/
PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structp));
+#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Function that combines rows. 'new_row' is a flag that should come from
* the callback and be non-NULL if anything needs to be done; the library
* stores its own version of the new data internally and ignores the passed
*/
PNG_EXPORT(93, void, png_progressive_combine_row, (png_structp png_ptr,
png_bytep old_row, png_const_bytep new_row));
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
PNG_EXPORTA(94, png_voidp, png_malloc,
PNG_EXPORTA(104, void, png_err, (png_structp png_ptr), PNG_NORETURN);
#endif
+#ifdef PNG_WARNINGS_SUPPORTED
/* Non-fatal error in libpng. Can continue, but may have a problem. */
PNG_EXPORT(105, void, png_warning, (png_structp png_ptr,
png_const_charp warning_message));
/* Non-fatal error in libpng, chunk name is prepended to message. */
PNG_EXPORT(106, void, png_chunk_warning, (png_structp png_ptr,
png_const_charp warning_message));
+#endif
#ifdef PNG_BENIGN_ERRORS_SUPPORTED
/* Benign error in libpng. Can continue, but may have a problem.
png_const_infop info_ptr, double *white_x, double *white_y, double *red_x,
double *red_y, double *green_x, double *green_y, double *blue_x,
double *blue_y));
+PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_structp png_ptr,
+ png_const_infop info_ptr, double *red_X, double *red_Y, double *red_Z,
+ double *green_X, double *green_Y, double *green_Z, double *blue_X,
+ double *blue_Y, double *blue_Z));
#ifdef PNG_FIXED_POINT_SUPPORTED /* Otherwise not implemented */
PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
(png_const_structp png_ptr,
png_fixed_point *int_green_y, png_fixed_point *int_blue_x,
png_fixed_point *int_blue_y));
#endif
+PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
+ (png_structp png_ptr, png_const_infop info_ptr,
+ png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+ png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+ png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+ png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+ png_fixed_point *int_blue_Z));
#endif
#ifdef PNG_cHRM_SUPPORTED
(png_structp png_ptr, png_infop info_ptr,
double white_x, double white_y, double red_x, double red_y, double green_x,
double green_y, double blue_x, double blue_y));
+PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_structp png_ptr,
+ png_infop info_ptr, double red_X, double red_Y, double red_Z,
+ double green_X, double green_Y, double green_Z, double blue_X,
+ double blue_Y, double blue_Z));
PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_structp png_ptr,
png_infop info_ptr, png_fixed_point int_white_x,
png_fixed_point int_white_y, png_fixed_point int_red_x,
png_fixed_point int_red_y, png_fixed_point int_green_x,
png_fixed_point int_green_y, png_fixed_point int_blue_x,
png_fixed_point int_blue_y));
+PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_structp png_ptr,
+ png_infop info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
+ png_fixed_point int_red_Z, png_fixed_point int_green_X,
+ png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+ png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+ png_fixed_point int_blue_Z));
#endif
#ifdef PNG_gAMA_SUPPORTED
/* Provide a list of chunks and how they are to be handled, if the built-in
handling or default unknown chunk handling is not desired. Any chunks not
listed will be handled in the default manner. The IHDR and IEND chunks
- must not be listed.
- keep = 0: follow default behaviour
- = 1: do not keep
- = 2: keep only if safe-to-copy
- = 3: keep even if unsafe-to-copy
+ must not be listed. Because this turns off the default handling for chunks
+ that would otherwise be recognized the behavior of libpng transformations may
+ well become incorrect!
+ keep = 0: PNG_HANDLE_CHUNK_AS_DEFAULT: follow default behavior
+ = 1: PNG_HANDLE_CHUNK_NEVER: do not keep
+ = 2: PNG_HANDLE_CHUNK_IF_SAFE: keep only if safe-to-copy
+ = 3: PNG_HANDLE_CHUNK_ALWAYS: keep even if unsafe-to-copy
*/
PNG_EXPORT(172, void, png_set_keep_unknown_chunks,
(png_structp png_ptr, int keep,
png_const_bytep chunk_list, int num_chunks));
+
+/* The handling code is returned; the result is therefore true (non-zero) if
+ * special handling is required, false for the default handling.
+ */
PNG_EXPORT(173, int, png_handle_as_unknown, (png_structp png_ptr,
png_const_bytep chunk_name));
#endif
* full, image which appears in a given pass. 'pass' is in the range 0
* to 6 and the result is in the range 0 to 7.
*/
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
+
+/* A macro to return the offset between pixels in the output row for a pair of
+ * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
+ * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
+ * COL_OFFSET is from one column to the next, within a row.
+ */
+#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
+#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
/* Two macros to help evaluate the number of rows or columns in each
* pass. This is expressed as a shift - effectively log2 of the number or
* the tile.
*/
#define PNG_PASS_MASK(pass,off) ( \
- ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
- ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+ ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
+ ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
{ png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
* (png_uint_16)(alpha) \
+ (png_uint_16)(bg)*(png_uint_16)(255 \
- - (png_uint_16)(alpha)) + (png_uint_16)128); \
+ - (png_uint_16)(alpha)) + 128); \
(composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
# define png_composite_16(composite, fg, alpha, bg) \
{ png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
* (png_uint_32)(alpha) \
- + (png_uint_32)(bg)*(png_uint_32)(65535L \
- - (png_uint_32)(alpha)) + (png_uint_32)32768L); \
+ + (png_uint_32)(bg)*(65535 \
+ - (png_uint_32)(alpha)) + 32768); \
(composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
#else /* Standard method using integer division */
# define png_composite(composite, fg, alpha, bg) \
(composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \
(png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
- (png_uint_16)127) / 255)
+ 127) / 255)
# define png_composite_16(composite, fg, alpha, bg) \
(composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
- (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) + \
- (png_uint_32)32767) / (png_uint_32)65535L)
+ (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
+ 32767) / 65535)
#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
* scripts/symbols.def as well.
*/
#ifdef PNG_EXPORT_LAST_ORDINAL
- PNG_EXPORT_LAST_ORDINAL(221);
+ PNG_EXPORT_LAST_ORDINAL(233);
#endif
#ifdef __cplusplus
/* pngconf.h - machine configurable file for libpng
*
- * libpng version 1.5.2 - March 31, 2011
+ * libpng version 1.5.9 - February 18, 2012
*
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2012 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* 'type', compiler specific.
*
* PNG_DLL_EXPORT Set to the magic to use during a libpng build to
- * make a symbol exported from the DLL.
+ * make a symbol exported from the DLL. Not used in the
+ * public header files; see pngpriv.h for how it is used
+ * in the libpng build.
*
* PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
* from a DLL - used to define PNG_IMPEXP when
# define PNGAPI PNGCAPI
#endif
-/* The default for PNG_IMPEXP depends on whether the library is
- * being built or used.
+/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
+ * then in an internal header file when building the library, otherwise (when
+ * using the library) it is set here.
*/
#ifndef PNG_IMPEXP
-# ifdef PNGLIB_BUILD
- /* Building the library */
-# if (defined(DLL_EXPORT)/*from libtool*/ ||\
- defined(_WINDLL) || defined(_DLL) || defined(__DLL__) ||\
- defined(_USRDLL) ||\
- defined(PNG_BUILD_DLL)) && defined(PNG_DLL_EXPORT)
- /* Building a DLL. */
-# define PNG_IMPEXP PNG_DLL_EXPORT
-# endif /* DLL */
-# else
- /* Using the library */
-# if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
- /* This forces use of a DLL, disallowing static linking */
-# define PNG_IMPEXP PNG_DLL_IMPORT
-# endif
+# if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
+ /* This forces use of a DLL, disallowing static linking */
+# define PNG_IMPEXP PNG_DLL_IMPORT
# endif
# ifndef PNG_IMPEXP
# ifndef PNG_NORETURN
# define PNG_NORETURN __attribute__((__noreturn__))
# endif
-# ifndef PNG_PTR_NORETURN
- /* It's not enough to have the compiler be the correct compiler at
- * this point - it's necessary for the library (which defines
- * the type of the library longjmp) to also be the GNU library.
- * This is because many systems use the GNU compiler with a
- * non-GNU libc implementation. Min/GW headers are also compatible
- * with GCC as well as uclibc, so it seems best to exclude known
- * problem libcs here rather than just including known libcs.
- *
- * NOTE: this relies on the only use of PNG_PTR_NORETURN being with
- * the system longjmp. If the same type is used elsewhere then this
- * will need to be changed.
- */
-# if !defined(__CYGWIN__)
-# define PNG_PTR_NORETURN __attribute__((__noreturn__))
-# endif
-# endif
# ifndef PNG_ALLOCATED
# define PNG_ALLOCATED __attribute__((__malloc__))
# endif
-
- /* This specifically protects structure members that should only be
- * accessed from within the library, therefore should be empty during
- * a library build.
- */
-# ifndef PNGLIB_BUILD
-# ifndef PNG_DEPRECATED
-# define PNG_DEPRECATED __attribute__((__deprecated__))
-# endif
-# ifndef PNG_DEPSTRUCT
-# define PNG_DEPSTRUCT __attribute__((__deprecated__))
-# endif
-# ifndef PNG_PRIVATE
-# if 0 /* Doesn't work so we use deprecated instead*/
-# define PNG_PRIVATE \
- __attribute__((warning("This function is not exported by libpng.")))
-# else
-# define PNG_PRIVATE \
- __attribute__((__deprecated__))
-# endif
+# ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED __attribute__((__deprecated__))
+# endif
+# ifndef PNG_PRIVATE
+# if 0 /* Doesn't work so we use deprecated instead*/
+# define PNG_PRIVATE \
+ __attribute__((warning("This function is not exported by libpng.")))
+# else
+# define PNG_PRIVATE \
+ __attribute__((__deprecated__))
# endif
-# endif /* PNGLIB_BUILD */
+# endif
# endif /* __GNUC__ */
# if defined(_MSC_VER) && (_MSC_VER >= 1300)
# define PNG_USE_RESULT /* not supported */
# endif
# ifndef PNG_NORETURN
-# define PNG_NORETURN __declspec(noreturn)
-# endif
-# ifndef PNG_PTR_NORETURN
-# define PNG_PTR_NORETURN /* not supported */
+# define PNG_NORETURN __declspec(noreturn)
# endif
# ifndef PNG_ALLOCATED
-# define PNG_ALLOCATED __declspec(restrict)
-# endif
-
- /* This specifically protects structure members that should only be
- * accessed from within the library, therefore should be empty during
- * a library build.
- */
-# ifndef PNGLIB_BUILD
-# ifndef PNG_DEPRECATED
-# define PNG_DEPRECATED __declspec(deprecated)
-# endif
-# ifndef PNG_DEPSTRUCT
-# define PNG_DEPSTRUCT __declspec(deprecated)
-# endif
-# ifndef PNG_PRIVATE
-# define PNG_PRIVATE __declspec(deprecated)
+# if (_MSC_VER >= 1400)
+# define PNG_ALLOCATED __declspec(restrict)
# endif
-# endif /* PNGLIB_BUILD */
+# endif
+# ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED __declspec(deprecated)
+# endif
+# ifndef PNG_PRIVATE
+# define PNG_PRIVATE __declspec(deprecated)
+# endif
# endif /* _MSC_VER */
#endif /* PNG_PEDANTIC_WARNINGS */
#ifndef PNG_NORETURN
# define PNG_NORETURN /* This function does not return */
#endif
-#ifndef PNG_PTR_NORETURN
-# define PNG_PTR_NORETURN /* This function does not return */
-#endif
#ifndef PNG_ALLOCATED
# define PNG_ALLOCATED /* The result of the function is new memory */
#endif
-#ifndef PNG_DEPSTRUCT
-# define PNG_DEPSTRUCT /* Access to this struct member is deprecated */
-#endif
#ifndef PNG_PRIVATE
# define PNG_PRIVATE /* This is a private libpng function */
#endif
/* pngerror.c - stub functions for i/o and memory allocation
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng 1.5.8 [February 1, 2011]
+ * Copyright (c) 1998-2012 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
PNG_FUNCTION(void,PNGAPI
png_err,(png_structp png_ptr),PNG_NORETURN)
{
+ /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
+ * erroneously as '\0', instead of the empty string "". This was
+ * apparently an error, introduced in libpng-1.2.20, and png_default_error
+ * will crash in this case.
+ */
if (png_ptr != NULL && png_ptr->error_fn != NULL)
- (*(png_ptr->error_fn))(png_ptr, '\0');
+ (*(png_ptr->error_fn))(png_ptr, "");
/* If the custom handler doesn't exist, or if it returns,
use the default handler, which will not return. */
- png_default_error(png_ptr, '\0');
+ png_default_error(png_ptr, "");
}
#endif /* PNG_ERROR_TEXT_SUPPORTED */
+/* Utility to safely appends strings to a buffer. This never errors out so
+ * error checking is not required in the caller.
+ */
+size_t
+png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+ png_const_charp string)
+{
+ if (buffer != NULL && pos < bufsize)
+ {
+ if (string != NULL)
+ while (*string != '\0' && pos < bufsize-1)
+ buffer[pos++] = *string++;
+
+ buffer[pos] = '\0';
+ }
+
+ return pos;
+}
+
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.
+ */
+png_charp
+png_format_number(png_const_charp start, png_charp end, int format,
+ png_alloc_size_t number)
+{
+ int count = 0; /* number of digits output */
+ int mincount = 1; /* minimum number required */
+ int output = 0; /* digit output (for the fixed point format) */
+
+ *--end = '\0';
+
+ /* This is written so that the loop always runs at least once, even with
+ * number zero.
+ */
+ while (end > start && (number != 0 || count < mincount))
+ {
+
+ static const char digits[] = "0123456789ABCDEF";
+
+ switch (format)
+ {
+ case PNG_NUMBER_FORMAT_fixed:
+ /* Needs five digits (the fraction) */
+ mincount = 5;
+ if (output || number % 10 != 0)
+ {
+ *--end = digits[number % 10];
+ output = 1;
+ }
+ number /= 10;
+ break;
+
+ case PNG_NUMBER_FORMAT_02u:
+ /* Expects at least 2 digits. */
+ mincount = 2;
+ /* fall through */
+
+ case PNG_NUMBER_FORMAT_u:
+ *--end = digits[number % 10];
+ number /= 10;
+ break;
+
+ case PNG_NUMBER_FORMAT_02x:
+ /* This format expects at least two digits */
+ mincount = 2;
+ /* fall through */
+
+ case PNG_NUMBER_FORMAT_x:
+ *--end = digits[number & 0xf];
+ number >>= 4;
+ break;
+
+ default: /* an error */
+ number = 0;
+ break;
+ }
+
+ /* Keep track of the number of digits added */
+ ++count;
+
+ /* Float a fixed number here: */
+ if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
+ {
+ /* End of the fraction, but maybe nothing was output? In that case
+ * drop the decimal point. If the number is a true zero handle that
+ * here.
+ */
+ if (output)
+ *--end = '.';
+ else if (number == 0) /* and !output */
+ *--end = '0';
+ }
+ }
+
+ return end;
+}
+#endif
+
#ifdef PNG_WARNINGS_SUPPORTED
/* This function is called whenever there is a non-fatal error. This function
* should not be changed. If there is a need to handle warnings differently,
else
png_default_warning(png_ptr, warning_message + offset);
}
+
+/* These functions support 'formatted' warning messages with up to
+ * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter
+ * is introduced by @<number>, where 'number' starts at 1. This follows the
+ * standard established by X/Open for internationalizable error messages.
+ */
+void
+png_warning_parameter(png_warning_parameters p, int number,
+ png_const_charp string)
+{
+ if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
+ (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
+}
+
+void
+png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
+ png_alloc_size_t value)
+{
+ char buffer[PNG_NUMBER_BUFFER_SIZE];
+ png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
+}
+
+void
+png_warning_parameter_signed(png_warning_parameters p, int number, int format,
+ png_int_32 value)
+{
+ png_alloc_size_t u;
+ png_charp str;
+ char buffer[PNG_NUMBER_BUFFER_SIZE];
+
+ /* Avoid overflow by doing the negate in a png_alloc_size_t: */
+ u = (png_alloc_size_t)value;
+ if (value < 0)
+ u = ~u + 1;
+
+ str = PNG_FORMAT_NUMBER(buffer, format, u);
+
+ if (value < 0 && str > buffer)
+ *--str = '-';
+
+ png_warning_parameter(p, number, str);
+}
+
+void
+png_formatted_warning(png_structp png_ptr, png_warning_parameters p,
+ png_const_charp message)
+{
+ /* The internal buffer is just 192 bytes - enough for all our messages,
+ * overflow doesn't happen because this code checks! If someone figures
+ * out how to send us a message longer than 192 bytes, all that will
+ * happen is that the message will be truncated appropriately.
+ */
+ size_t i = 0; /* Index in the msg[] buffer: */
+ char msg[192];
+
+ /* Each iteration through the following loop writes at most one character
+ * to msg[i++] then returns here to validate that there is still space for
+ * the trailing '\0'. It may (in the case of a parameter) read more than
+ * one character from message[]; it must check for '\0' and continue to the
+ * test if it finds the end of string.
+ */
+ while (i<(sizeof msg)-1 && *message != '\0')
+ {
+ /* '@' at end of string is now just printed (previously it was skipped);
+ * it is an error in the calling code to terminate the string with @.
+ */
+ if (p != NULL && *message == '@' && message[1] != '\0')
+ {
+ int parameter_char = *++message; /* Consume the '@' */
+ static const char valid_parameters[] = "123456789";
+ int parameter = 0;
+
+ /* Search for the parameter digit, the index in the string is the
+ * parameter to use.
+ */
+ while (valid_parameters[parameter] != parameter_char &&
+ valid_parameters[parameter] != '\0')
+ ++parameter;
+
+ /* If the parameter digit is out of range it will just get printed. */
+ if (parameter < PNG_WARNING_PARAMETER_COUNT)
+ {
+ /* Append this parameter */
+ png_const_charp parm = p[parameter];
+ png_const_charp pend = p[parameter] + (sizeof p[parameter]);
+
+ /* No need to copy the trailing '\0' here, but there is no guarantee
+ * that parm[] has been initialized, so there is no guarantee of a
+ * trailing '\0':
+ */
+ while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
+ msg[i++] = *parm++;
+
+ /* Consume the parameter digit too: */
+ ++message;
+ continue;
+ }
+
+ /* else not a parameter and there is a character after the @ sign; just
+ * copy that. This is known not to be '\0' because of the test above.
+ */
+ }
+
+ /* At this point *message can't be '\0', even in the bad parameter case
+ * above where there is a lone '@' at the end of the message string.
+ */
+ msg[i++] = *message++;
+ }
+
+ /* i is always less than (sizeof msg), so: */
+ msg[i] = '\0';
+
+ /* And this is the formatted message, it may be larger than
+ * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these are
+ * not (currently) formatted.
+ */
+ png_warning(png_ptr, msg);
+}
#endif /* PNG_WARNINGS_SUPPORTED */
#ifdef PNG_BENIGN_ERRORS_SUPPORTED
png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
error_message)
{
- int iout = 0, iin = 0;
+ png_uint_32 chunk_name = png_ptr->chunk_name;
+ int iout = 0, ishift = 24;
- while (iin < 4)
+ while (ishift >= 0)
{
- int c = png_ptr->chunk_name[iin++];
+ int c = (int)(chunk_name >> ishift) & 0xff;
+
+ ishift -= 8;
if (isnonalpha(c))
{
buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
else
{
- buffer[iout++] = (png_byte)c;
+ buffer[iout++] = (char)c;
}
}
else
{
+ int iin = 0;
+
buffer[iout++] = ':';
buffer[iout++] = ' ';
- png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
- buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
+
+ while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+ buffer[iout++] = error_message[iin++];
+
+ /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+ buffer[iout] = '\0';
}
}
#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
return NULL;
png_ptr->longjmp_fn = longjmp_fn;
- return &png_ptr->png_jmpbuf;
+ return &png_ptr->longjmp_buffer;
}
#endif
{
#ifdef PNG_CONSOLE_IO_SUPPORTED
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
- if (*error_message == PNG_LITERAL_SHARP)
+ /* Check on NULL only added in 1.5.4 */
+ if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
{
/* Strip "#nnnn " from beginning of error message. */
int offset;
else
#endif
{
- fprintf(stderr, "libpng error: %s", error_message);
+ fprintf(stderr, "libpng error: %s", error_message ? error_message :
+ "undefined");
fprintf(stderr, PNG_STRING_NEWLINE);
}
-#endif
-#ifndef PNG_CONSOLE_IO_SUPPORTED
+#else
PNG_UNUSED(error_message) /* Make compiler happy */
#endif
png_longjmp(png_ptr, 1);
{
# ifdef USE_FAR_KEYWORD
{
- jmp_buf png_jmpbuf;
- png_memcpy(png_jmpbuf, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
- png_ptr->longjmp_fn(png_jmpbuf, val);
+ jmp_buf tmp_jmpbuf;
+ png_memcpy(tmp_jmpbuf, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
+ png_ptr->longjmp_fn(tmp_jmpbuf, val);
}
# else
- png_ptr->longjmp_fn(png_ptr->png_jmpbuf, val);
+ png_ptr->longjmp_fn(png_ptr->longjmp_buffer, val);
# endif
}
#endif
/* This function is called when the application wants to use another method
* of handling errors and warnings. Note that the error function MUST NOT
* return to the calling routine or serious problems will occur. The return
- * method used in the default routine calls longjmp(png_ptr->png_jmpbuf, 1)
+ * method used in the default routine calls longjmp(png_ptr->longjmp_buffer, 1)
*/
void PNGAPI
png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
png_ptr->error_ptr = error_ptr;
png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
png_ptr->warning_fn = warning_fn;
+#else
+ PNG_UNUSED(warning_fn)
+#endif
}
/* pngget.c - retrieval of values from info struct
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
#endif
#ifdef PNG_cHRM_SUPPORTED
+/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the
+ * same time to correct the rgb grayscale coefficient defaults obtained from the
+ * cHRM chunk in 1.5.4
+ */
+png_uint_32 PNGFAPI
+png_get_cHRM_XYZ_fixed(png_structp png_ptr, png_const_infop info_ptr,
+ png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+ png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+ png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+ png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+ png_fixed_point *int_blue_Z)
+{
+ if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+ {
+ png_xy xy;
+ png_XYZ XYZ;
+
+ png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
+
+ xy.whitex = info_ptr->x_white;
+ xy.whitey = info_ptr->y_white;
+ xy.redx = info_ptr->x_red;
+ xy.redy = info_ptr->y_red;
+ xy.greenx = info_ptr->x_green;
+ xy.greeny = info_ptr->y_green;
+ xy.bluex = info_ptr->x_blue;
+ xy.bluey = info_ptr->y_blue;
+
+ /* The *_checked function handles error reporting, so just return 0 if
+ * there is a failure here.
+ */
+ if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
+ {
+ if (int_red_X != NULL)
+ *int_red_X = XYZ.redX;
+ if (int_red_Y != NULL)
+ *int_red_Y = XYZ.redY;
+ if (int_red_Z != NULL)
+ *int_red_Z = XYZ.redZ;
+ if (int_green_X != NULL)
+ *int_green_X = XYZ.greenX;
+ if (int_green_Y != NULL)
+ *int_green_Y = XYZ.greenY;
+ if (int_green_Z != NULL)
+ *int_green_Z = XYZ.greenZ;
+ if (int_blue_X != NULL)
+ *int_blue_X = XYZ.blueX;
+ if (int_blue_Y != NULL)
+ *int_blue_Y = XYZ.blueY;
+ if (int_blue_Z != NULL)
+ *int_blue_Z = XYZ.blueZ;
+
+ return (PNG_INFO_cHRM);
+ }
+ }
+
+ return (0);
+}
+
# ifdef PNG_FLOATING_POINT_SUPPORTED
png_uint_32 PNGAPI
png_get_cHRM(png_const_structp png_ptr, png_const_infop info_ptr,
return (0);
}
+
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ(png_structp png_ptr, png_const_infop info_ptr,
+ double *red_X, double *red_Y, double *red_Z, double *green_X,
+ double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
+ double *blue_Z)
+{
+ png_XYZ XYZ;
+
+ if (png_get_cHRM_XYZ_fixed(png_ptr, info_ptr,
+ &XYZ.redX, &XYZ.redY, &XYZ.redZ, &XYZ.greenX, &XYZ.greenY, &XYZ.greenZ,
+ &XYZ.blueX, &XYZ.blueY, &XYZ.blueZ) & PNG_INFO_cHRM)
+ {
+ if (red_X != NULL)
+ *red_X = png_float(png_ptr, XYZ.redX, "cHRM red X");
+ if (red_Y != NULL)
+ *red_Y = png_float(png_ptr, XYZ.redY, "cHRM red Y");
+ if (red_Z != NULL)
+ *red_Z = png_float(png_ptr, XYZ.redZ, "cHRM red Z");
+ if (green_X != NULL)
+ *green_X = png_float(png_ptr, XYZ.greenX, "cHRM green X");
+ if (green_Y != NULL)
+ *green_Y = png_float(png_ptr, XYZ.greenY, "cHRM green Y");
+ if (green_Z != NULL)
+ *green_Z = png_float(png_ptr, XYZ.greenZ, "cHRM green Z");
+ if (blue_X != NULL)
+ *blue_X = png_float(png_ptr, XYZ.blueX, "cHRM blue X");
+ if (blue_Y != NULL)
+ *blue_Y = png_float(png_ptr, XYZ.blueY, "cHRM blue Y");
+ if (blue_Z != NULL)
+ *blue_Z = png_float(png_ptr, XYZ.blueZ, "cHRM blue Z");
+ return (PNG_INFO_cHRM);
+ }
+
+ return (0);
+}
# endif
# ifdef PNG_FIXED_POINT_SUPPORTED
png_debug1(1, "in %s retrieval function", "iCCP");
if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
- && name != NULL && profile != NULL && proflen != NULL)
+ && name != NULL && compression_type != NULL && profile != NULL &&
+ proflen != NULL)
{
*name = info_ptr->iccp_name;
*profile = info_ptr->iccp_profile;
/* Compression_type is a dummy so the API won't have to change
* if we introduce multiple compression types later.
*/
- *proflen = (int)info_ptr->iccp_proflen;
- *compression_type = (int)info_ptr->iccp_compression;
+ *proflen = info_ptr->iccp_proflen;
+ *compression_type = info_ptr->iccp_compression;
return (PNG_INFO_iCCP);
}
{
if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
{
- png_debug1(1, "in %s retrieval function",
- (png_ptr->chunk_name[0] == '\0' ? "text" :
- (png_const_charp)png_ptr->chunk_name));
+ png_debug1(1, "in 0x%lx retrieval function",
+ (unsigned long)png_ptr->chunk_name);
if (text_ptr != NULL)
*text_ptr = info_ptr->text;
png_size_t PNGAPI
png_get_compression_buffer_size(png_const_structp png_ptr)
{
- return (png_ptr ? png_ptr->zbuf_size : 0L);
+ return (png_ptr ? png_ptr->zbuf_size : 0);
}
-
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
/* These functions were added to libpng 1.2.6 and were enabled
* by default in libpng-1.4.0 */
png_uint_32 PNGAPI
png_get_io_chunk_type (png_const_structp png_ptr)
{
- return ((png_ptr->chunk_name[0] << 24) +
- (png_ptr->chunk_name[1] << 16) +
- (png_ptr->chunk_name[2] << 8) +
- (png_ptr->chunk_name[3]));
+ return png_ptr->chunk_name;
}
png_const_bytep PNGAPI
png_get_io_chunk_name (png_structp png_ptr)
{
- return png_ptr->chunk_name;
+ PNG_CSTRING_FROM_CHUNK(png_ptr->io_chunk_string, png_ptr->chunk_name);
+ return png_ptr->io_chunk_string;
}
#endif /* ?PNG_IO_STATE_SUPPORTED */
* single color specified that should be treated as fully transparent.
* Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
*/
- png_bytep trans; /* alpha values for paletted image */
png_bytep trans_alpha; /* alpha values for paletted image */
png_color_16 trans_color; /* transparent color for non-palette image */
#endif
/* pnglibconf.h - library build configuration */
-/* libpng version 1.5.0 - last changed on February 11, 2011 */
+/* Libpng 1.5.9 - February 18, 2012 */
/* Copyright (c) 1998-2011 Glenn Randers-Pehrson */
/* pnglibconf.dfa with respect to the dependencies between the following */
/* symbols. It is much better to generate a new file using */
/* scripts/libpngconf.mak */
-
+
#ifndef PNGLCONF_H
#define PNGLCONF_H
/* settings */
#define PNG_sCAL_PRECISION 5
#define PNG_USER_CHUNK_CACHE_MAX 0
#define PNG_USER_CHUNK_MALLOC_MAX 0
-#define PNG_USER_HEIGHT_MAX 1000000L
-#define PNG_USER_WIDTH_MAX 1000000L
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
#define PNG_WEIGHT_SHIFT 8
#define PNG_ZBUF_SIZE 8192
/* end of settings */
#define PNG_ALIGN_MEMORY_SUPPORTED
#define PNG_BENIGN_ERRORS_SUPPORTED
#define PNG_bKGD_SUPPORTED
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
#define PNG_CHECK_cHRM_SUPPORTED
#define PNG_cHRM_SUPPORTED
#define PNG_CONSOLE_IO_SUPPORTED
#define PNG_CONVERT_tIME_SUPPORTED
#define PNG_EASY_ACCESS_SUPPORTED
+/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
#define PNG_ERROR_TEXT_SUPPORTED
#define PNG_FIXED_POINT_SUPPORTED
#define PNG_FLOATING_ARITHMETIC_SUPPORTED
#define PNG_POINTER_INDEXING_SUPPORTED
#define PNG_PROGRESSIVE_READ_SUPPORTED
#define PNG_READ_16BIT_SUPPORTED
-#define PNG_READ_16_TO_8_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
#define PNG_READ_BACKGROUND_SUPPORTED
#define PNG_READ_BGR_SUPPORTED
#define PNG_READ_bKGD_SUPPORTED
#define PNG_READ_cHRM_SUPPORTED
#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
+#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
#define PNG_READ_EXPAND_16_SUPPORTED
#define PNG_READ_EXPAND_SUPPORTED
#define PNG_READ_FILLER_SUPPORTED
#define PNG_READ_QUANTIZE_SUPPORTED
#define PNG_READ_RGB_TO_GRAY_SUPPORTED
#define PNG_READ_sBIT_SUPPORTED
+#define PNG_READ_SCALE_16_TO_8_SUPPORTED
#define PNG_READ_sCAL_SUPPORTED
#define PNG_READ_SHIFT_SUPPORTED
#define PNG_READ_sPLT_SUPPORTED
#define PNG_READ_sRGB_SUPPORTED
+#define PNG_READ_STRIP_16_TO_8_SUPPORTED
#define PNG_READ_STRIP_ALPHA_SUPPORTED
#define PNG_READ_SUPPORTED
#define PNG_READ_SWAP_ALPHA_SUPPORTED
#define PNG_WRITE_BGR_SUPPORTED
#define PNG_WRITE_bKGD_SUPPORTED
#define PNG_WRITE_cHRM_SUPPORTED
+#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
#define PNG_WRITE_FILLER_SUPPORTED
#define PNG_WRITE_FILTER_SUPPORTED
#define PNG_WRITE_FLUSH_SUPPORTED
#define PNG_WRITE_INVERT_SUPPORTED
#define PNG_WRITE_iTXt_SUPPORTED
#define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
#define PNG_WRITE_PACK_SUPPORTED
#define PNG_WRITE_PACKSWAP_SUPPORTED
#define PNG_WRITE_pCAL_SUPPORTED
#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
#define PNG_WRITE_zTXt_SUPPORTED
#define PNG_zTXt_SUPPORTED
-/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
-/*#undef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED*/
/* end of options */
#endif /* PNGLCONF_H */
/* pngmem.c - stub functions for memory allocation
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
if (malloc_fn != NULL)
{
png_struct dummy_struct;
- png_structp png_ptr = &dummy_struct;
- png_ptr->mem_ptr=mem_ptr;
- struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
+ memset(&dummy_struct, 0, sizeof dummy_struct);
+ dummy_struct.mem_ptr=mem_ptr;
+ struct_ptr = (*(malloc_fn))(&dummy_struct, (png_alloc_size_t)size);
}
else
if (free_fn != NULL)
{
png_struct dummy_struct;
- png_structp png_ptr = &dummy_struct;
- png_ptr->mem_ptr=mem_ptr;
- (*(free_fn))(png_ptr, struct_ptr);
+ memset(&dummy_struct, 0, sizeof dummy_struct);
+ dummy_struct.mem_ptr=mem_ptr;
+ (*(free_fn))(&dummy_struct, struct_ptr);
return;
}
# ifdef PNG_USER_MEM_SUPPORTED
if (png_ptr->malloc_fn != NULL)
- ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+ ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
else
ret = (png_malloc_default(png_ptr, size));
int num_blocks;
png_uint_32 total_size;
png_bytep table;
- int i;
+ int i, mem_level, window_bits;
png_byte huge * hptr;
+ int window_bits
if (ret != NULL)
{
ret = NULL;
}
- if (png_ptr->zlib_window_bits > 14)
- num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
+ window_bits =
+ png_ptr->zlib_window_bits >= png_ptr->zlib_text_window_bits ?
+ png_ptr->zlib_window_bits : png_ptr->zlib_text_window_bits;
+
+ if (window_bits > 14)
+ num_blocks = (int)(1 << (window_bits - 14));
else
num_blocks = 1;
- if (png_ptr->zlib_mem_level >= 7)
- num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
+ mem_level =
+ png_ptr->zlib_mem_level >= png_ptr->zlib_text_mem_level ?
+ png_ptr->zlib_mem_level : png_ptr->zlib_text_mem_level;
+
+ if (mem_level >= 7)
+ num_blocks += (int)(1 << (mem_level - 7));
else
num_blocks++;
{
# ifndef PNG_USER_MEM_SUPPORTED
if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
- png_error(png_ptr, "Out of Memory"); /* Note "o" and "M" */
+ png_error(png_ptr, "Out of Memory"); /* Note "O" and "M" */
else
png_warning(png_ptr, "Out of Memory");
/* pngpread.c - read a png file in push mode
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.9 [February 18, 2012]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
void /* PRIVATE */
png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
{
- PNG_IHDR;
- PNG_IDAT;
- PNG_IEND;
- PNG_PLTE;
-#ifdef PNG_READ_bKGD_SUPPORTED
- PNG_bKGD;
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
- PNG_cHRM;
-#endif
-#ifdef PNG_READ_gAMA_SUPPORTED
- PNG_gAMA;
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
- PNG_hIST;
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
- PNG_iCCP;
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
- PNG_iTXt;
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
- PNG_oFFs;
-#endif
-#ifdef PNG_READ_pCAL_SUPPORTED
- PNG_pCAL;
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
- PNG_pHYs;
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
- PNG_sBIT;
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
- PNG_sCAL;
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
- PNG_sRGB;
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
- PNG_sPLT;
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
- PNG_tEXt;
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
- PNG_tIME;
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
- PNG_tRNS;
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
- PNG_zTXt;
-#endif
+ png_uint_32 chunk_name;
/* First we make sure we have enough data for the 4 byte chunk name
* and the 4 byte chunk length before proceeding with decoding the
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
{
png_byte chunk_length[4];
+ png_byte chunk_tag[4];
if (png_ptr->buffer_size < 8)
{
png_push_fill_buffer(png_ptr, chunk_length, 4);
png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
png_reset_crc(png_ptr);
- png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
}
- if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ chunk_name = png_ptr->chunk_name;
+
+ if (chunk_name == png_IDAT)
+ {
+ /* This is here above the if/else case statement below because if the
+ * unknown handling marks 'IDAT' as unknown then the IDAT handling case is
+ * completely skipped.
+ *
+ * TODO: there must be a better way of doing this.
+ */
if (png_ptr->mode & PNG_AFTER_IDAT)
png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+ }
- if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
+ if (chunk_name == png_IHDR)
{
if (png_ptr->push_length != 13)
png_error(png_ptr, "Invalid IHDR length");
png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
}
- else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
+ else if (chunk_name == png_IEND)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
}
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
+ else if (png_chunk_unknown_handling(png_ptr, chunk_name))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
return;
}
- if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ if (chunk_name == png_IDAT)
png_ptr->mode |= PNG_HAVE_IDAT;
png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
- if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+ if (chunk_name == png_PLTE)
png_ptr->mode |= PNG_HAVE_PLTE;
- else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ else if (chunk_name == png_IDAT)
{
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
}
#endif
- else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+ else if (chunk_name == png_PLTE)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
}
- else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ else if (chunk_name == png_IDAT)
{
/* If we reach an IDAT chunk, this means we have read all of the
* header chunks, and we can start reading the image (or if this
}
#ifdef PNG_READ_gAMA_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
+ else if (png_ptr->chunk_name == png_gAMA)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
+ else if (png_ptr->chunk_name == png_sBIT)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
+ else if (png_ptr->chunk_name == png_cHRM)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
+ else if (chunk_name == png_sRGB)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
+ else if (png_ptr->chunk_name == png_iCCP)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
+ else if (chunk_name == png_sPLT)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
+ else if (chunk_name == png_tRNS)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_bKGD_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
+ else if (chunk_name == png_bKGD)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_hIST_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
+ else if (chunk_name == png_hIST)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
+ else if (chunk_name == png_pHYs)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
+ else if (chunk_name == png_oFFs)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
+ else if (chunk_name == png_pCAL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
+ else if (chunk_name == png_sCAL)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_tIME_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
+ else if (chunk_name == png_tIME)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
+ else if (chunk_name == png_tEXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
+ else if (chunk_name == png_zTXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
- else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
+ else if (chunk_name == png_iTXt)
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
old_buffer = png_ptr->save_buffer;
- png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
- (png_size_t)new_max);
+ png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max);
if (png_ptr->save_buffer == NULL)
{
void /* PRIVATE */
png_push_read_IDAT(png_structp png_ptr)
{
- PNG_IDAT;
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
{
png_byte chunk_length[4];
+ png_byte chunk_tag[4];
+ /* TODO: this code can be commoned up with the same code in push_read */
if (png_ptr->buffer_size < 8)
{
png_push_save_buffer(png_ptr);
png_push_fill_buffer(png_ptr, chunk_length, 4);
png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
png_reset_crc(png_ptr);
- png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
- if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ if (png_ptr->chunk_name != png_IDAT)
{
png_ptr->process_mode = PNG_READ_CHUNK_MODE;
png_ptr->idat_size = png_ptr->push_length;
}
+
if (png_ptr->idat_size && png_ptr->save_buffer_size)
{
png_size_t save_size = png_ptr->save_buffer_size;
void /* PRIVATE */
png_push_process_row(png_structp png_ptr)
{
- png_ptr->row_info.color_type = png_ptr->color_type;
- png_ptr->row_info.width = png_ptr->iwidth;
- png_ptr->row_info.channels = png_ptr->channels;
- png_ptr->row_info.bit_depth = png_ptr->bit_depth;
- png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
+ /* 1.5.6: row_info moved out of png_struct to a local here. */
+ png_row_info row_info;
- png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
- png_ptr->row_info.width);
+ row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+ row_info.color_type = png_ptr->color_type;
+ row_info.bit_depth = png_ptr->bit_depth;
+ row_info.channels = png_ptr->channels;
+ row_info.pixel_depth = png_ptr->pixel_depth;
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
- png_read_filter_row(png_ptr, &(png_ptr->row_info),
- png_ptr->row_buf + 1, png_ptr->prev_row + 1,
- (int)(png_ptr->row_buf[0]));
+ if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+ {
+ if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+ png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+ else
+ png_error(png_ptr, "bad adaptive filter value");
+ }
- png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
+ /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+ * 1.5.6, while the buffer really is this big in current versions of libpng
+ * it may not be in the future, so this was changed just to copy the
+ * interlaced row count:
+ */
+ png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
if (png_ptr->transformations)
- png_do_read_transformations(png_ptr);
+ png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+ /* The transformed pixel depth should match the depth now in row_info. */
+ if (png_ptr->transformed_pixel_depth == 0)
+ {
+ png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+ if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+ png_error(png_ptr, "progressive row overflow");
+ }
+
+ else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+ png_error(png_ptr, "internal progressive row size calculation error");
+
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Blow up interlaced rows to full size */
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
{
if (png_ptr->pass < 6)
-/* old interface (pre-1.0.9):
- png_do_read_interlace(&(png_ptr->row_info),
- png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
- */
- png_do_read_interlace(png_ptr);
+ png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+ png_ptr->transformations);
switch (png_ptr->pass)
{
void /* PRIVATE */
png_read_push_finish_row(png_structp png_ptr)
{
+#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
- PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+ static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
- PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+ static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
- PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/
+#endif
png_ptr->row_number++;
if (png_ptr->row_number < png_ptr->num_rows)
{
PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
png_error(png_ptr, "Out of place tEXt");
- /*NOT REACHED*/
+ /* NOT REACHED */
}
#ifdef PNG_MAX_MALLOC_64K
}
#endif
- png_ptr->current_text = (png_charp)png_malloc(png_ptr,
- (png_size_t)(length + 1));
+ png_ptr->current_text = (png_charp)png_malloc(png_ptr, length + 1);
png_ptr->current_text[length] = '\0';
png_ptr->current_text_ptr = png_ptr->current_text;
png_ptr->current_text_size = (png_size_t)length;
{
PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
png_error(png_ptr, "Out of place zTXt");
- /*NOT REACHED*/
+ /* NOT REACHED */
}
#ifdef PNG_MAX_MALLOC_64K
}
#endif
- png_ptr->current_text = (png_charp)png_malloc(png_ptr,
- (png_size_t)(length + 1));
+ png_ptr->current_text = (png_charp)png_malloc(png_ptr, length + 1);
png_ptr->current_text[length] = '\0';
png_ptr->current_text_ptr = png_ptr->current_text;
png_ptr->current_text_size = (png_size_t)length;
{
PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
png_error(png_ptr, "Out of place iTXt");
- /*NOT REACHED*/
+ /* NOT REACHED */
}
#ifdef PNG_MAX_MALLOC_64K
}
#endif
- png_ptr->current_text = (png_charp)png_malloc(png_ptr,
- (png_size_t)(length + 1));
+ png_ptr->current_text = (png_charp)png_malloc(png_ptr, length + 1);
png_ptr->current_text[length] = '\0';
png_ptr->current_text_ptr = png_ptr->current_text;
png_ptr->current_text_size = (png_size_t)length;
length)
{
png_uint_32 skip = 0;
+ png_uint_32 chunk_name = png_ptr->chunk_name;
- if (!(png_ptr->chunk_name[0] & 0x20))
+ if (PNG_CHUNK_CRITICAL(chunk_name))
{
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
- if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+ if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
&& png_ptr->read_user_chunk_fn == NULL
}
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+ /* TODO: the code below is apparently just using the
+ * png_struct::unknown_chunk member as a temporarily variable, it should be
+ * possible to eliminate both it and the temporary buffer.
+ */
if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
{
#ifdef PNG_MAX_MALLOC_64K
- if (length > (png_uint_32)65535L)
+ if (length > 65535)
{
png_warning(png_ptr, "unknown chunk too large to fit in memory");
- skip = length - (png_uint_32)65535L;
- length = (png_uint_32)65535L;
+ skip = length - 65535;
+ length = 65535;
}
#endif
- png_memcpy((png_charp)png_ptr->unknown_chunk.name,
- (png_charp)png_ptr->chunk_name,
- png_sizeof(png_ptr->unknown_chunk.name));
- png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1]
- = '\0';
+ /* This is just a record for the user; libpng doesn't use the character
+ * form of the name.
+ */
+ PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
- png_ptr->unknown_chunk.size = (png_size_t)length;
+ png_ptr->unknown_chunk.size = length;
if (length == 0)
png_ptr->unknown_chunk.data = NULL;
else
{
png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
- (png_size_t)length);
- png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+ png_ptr->unknown_chunk.size);
+ png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data,
+ png_ptr->unknown_chunk.size);
}
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
if (ret == 0)
{
- if (!(png_ptr->chunk_name[0] & 0x20))
- if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+ if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
+ if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS)
png_chunk_error(png_ptr, "unknown critical chunk");
png_set_unknown_chunks(png_ptr, info_ptr,
(int)png_ptr->pass);
}
+#ifdef PNG_READ_INTERLACING_SUPPORTED
void PNGAPI
png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
png_const_bytep new_row)
{
- PNG_CONST int FARDATA png_pass_dsp_mask[7] =
- {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
-
if (png_ptr == NULL)
return;
- if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
- png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
+ /* new_row is a flag here - if it is NULL then the app callback was called
+ * from an empty row (see the calls to png_struct::row_fn below), otherwise
+ * it must be png_ptr->row_buf+1
+ */
+ if (new_row != NULL)
+ png_combine_row(png_ptr, old_row, 1/*display*/);
}
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
void PNGAPI
png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
#ifndef PNGPRIV_H
#define PNGPRIV_H
+/* Feature Test Macros. The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both. On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+
/* This is required for the definition of abort(), used as a last ditch
* error handler when all else fails.
*/
#include <stdlib.h>
-#define PNGLIB_BUILD
+/* This is used to find 'offsetof', used below for alignment tests. */
+#include <stddef.h>
+
+#define PNGLIB_BUILD /*libpng is being built, not used*/
+
#ifdef PNG_USER_CONFIG
# include "pngusr.h"
/* These should have been defined in pngusr.h */
# define PNG_USER_DLLFNAME_POSTFIX "Cb"
# endif
#endif
+
+/* Is this a build of a DLL where compilation of the object modules requires
+ * different preprocessor settings to those required for a simple library? If
+ * so PNG_BUILD_DLL must be set.
+ *
+ * If libpng is used inside a DLL but that DLL does not export the libpng APIs
+ * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
+ * static library of libpng then link the DLL against that.
+ */
+#ifndef PNG_BUILD_DLL
+# ifdef DLL_EXPORT
+ /* This is set by libtool when files are compiled for a DLL; libtool
+ * always compiles twice, even on systems where it isn't necessary. Set
+ * PNG_BUILD_DLL in case it is necessary:
+ */
+# define PNG_BUILD_DLL
+# else
+# ifdef _WINDLL
+ /* This is set by the Microsoft Visual Studio IDE in projects that
+ * build a DLL. It can't easily be removed from those projects (it
+ * isn't visible in the Visual Studio UI) so it is a fairly reliable
+ * indication that PNG_IMPEXP needs to be set to the DLL export
+ * attributes.
+ */
+# define PNG_BUILD_DLL
+# else
+# ifdef __DLL__
+ /* This is set by the Borland C system when compiling for a DLL
+ * (as above.)
+ */
+# define PNG_BUILD_DLL
+# else
+ /* Add additional compiler cases here. */
+# endif
+# endif
+# endif
+#endif /* Setting PNG_BUILD_DLL if required */
+
+/* See pngconf.h for more details: the builder of the library may set this on
+ * the command line to the right thing for the specific compilation system or it
+ * may be automagically set above (at present we know of no system where it does
+ * need to be set on the command line.)
+ *
+ * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
+ * setting it to the "import" setting for a DLL build.
+ */
+#ifndef PNG_IMPEXP
+# ifdef PNG_BUILD_DLL
+# define PNG_IMPEXP PNG_DLL_EXPORT
+# else
+ /* Not building a DLL, or the DLL doesn't require specific export
+ * definitions.
+ */
+# define PNG_IMPEXP
+# endif
+#endif
+
+/* No warnings for private or deprecated functions in the build: */
+#ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED
+#endif
+#ifndef PNG_PRIVATE
+# define PNG_PRIVATE
+#endif
+
#include "png.h"
#include "pnginfo.h"
#include "pngstruct.h"
+/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
+#ifndef PNG_DLL_EXPORT
+# define PNG_DLL_EXPORT
+#endif
+
/* This is used for 16 bit gamma tables - only the top level pointers are const,
* this could be changed:
*/
# define PNG_ZBUF_SIZE 65536L
#endif
-/* If warnings or errors are turned off the code is disabled
- * or redirected here.
+/* PNG_STATIC is used to mark internal file scope functions if they need to be
+ * accessed for implementation tests (see the code in tests/?*).
*/
-#ifndef PNG_WARNINGS_SUPPORTED
-# define png_warning(s1,s2) ((void)0)
-# define png_chunk_warning(s1,s2) ((void)0)
+#ifndef PNG_STATIC
+# define PNG_STATIC static
+#endif
+
+/* C99 restrict is used where possible, to do this 'restrict' is defined as
+ * empty if we can't be sure it is supported. configure builds have already
+ * done this work.
+ */
+#ifdef PNG_CONFIGURE_LIBPNG
+# define PNG_RESTRICT restrict
+#else
+ /* Modern compilers support restrict, but assume not for anything not
+ * recognized here:
+ */
+# if defined __GNUC__ || defined _MSC_VER || defined __WATCOMC__
+# define PNG_RESTRICT restrict
+# else
+# define PNG_RESTRICT
+# endif
+#endif
+
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.4 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+# define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+# define png_warning(s1,s2) ((void)(s1))
+# define png_chunk_warning(s1,s2) ((void)(s1))
+# define png_warning_parameter(p,number,string) ((void)0)
+# define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+# define png_warning_parameter_signed(p,number,format,value) ((void)0)
+# define png_formatted_warning(pp,p,message) ((void)(pp))
+# define PNG_WARNING_PARAMETERS(p)
#endif
#ifndef PNG_ERROR_TEXT_SUPPORTED
# define png_error(s1,s2) png_err(s1)
# define png_fixed_error(s1,s2) png_err(s1)
#endif
+/* C allows up-casts from (void*) to any pointer and (const void*) to any
+ * pointer to a const object. C++ regards this as a type error and requires an
+ * explicit, static, cast and provides the static_cast<> rune to ensure that
+ * const is not cast away.
+ */
+#ifdef __cplusplus
+# define png_voidcast(type, value) static_cast<type>(value)
+#else
+# define png_voidcast(type, value) (value)
+#endif /* __cplusplus */
+
#ifndef PNG_EXTERN
/* The functions exported by PNG_EXTERN are internal functions, which
* aren't usually used outside the library (as far as I know), so it is
* debatable if they should be exported at all. In the future, when it
* is possible to have run-time registry of chunk-handling functions,
* some of these might be made available again.
-# define PNG_EXTERN extern
+ *
+ * 1.5.7: turned the use of 'extern' back on, since it is localized to pngpriv.h
+ * it should be safe now (it is unclear why it was turned off.)
*/
-# define PNG_EXTERN
+# define PNG_EXTERN extern
#endif
/* Some fixed point APIs are still required even if not exported because
# define NOCHECK 0
# define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
# define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
-# define png_strcpy _fstrcpy
-# define png_strncpy _fstrncpy /* Added to v 1.2.6 */
# define png_strlen _fstrlen
# define png_memcmp _fmemcmp /* SJT: added */
# define png_memcpy _fmemcpy
# define png_memset _fmemset
-# define png_sprintf sprintf
#else
# ifdef _WINDOWS_ /* Favor Windows over C runtime fns */
# define CVT_PTR(ptr) (ptr)
# define CVT_PTR_NOCHECK(ptr) (ptr)
-# define png_strcpy lstrcpyA
-# define png_strncpy lstrcpynA
# define png_strlen lstrlenA
# define png_memcmp memcmp
# define png_memcpy CopyMemory
# define png_memset memset
-# define png_sprintf wsprintfA
# else
# define CVT_PTR(ptr) (ptr)
# define CVT_PTR_NOCHECK(ptr) (ptr)
-# define png_strcpy strcpy
-# define png_strncpy strncpy /* Added to v 1.2.6 */
# define png_strlen strlen
# define png_memcmp memcmp /* SJT: added */
# define png_memcpy memcpy
# define png_memset memset
-# define png_sprintf sprintf
# endif
#endif
-/* End of memory model/platform independent support */
-#ifndef PNG_NO_SNPRINTF
-# ifdef _MSC_VER
-# define png_snprintf _snprintf /* Added to v 1.2.19 */
-# define png_snprintf2 _snprintf
-# define png_snprintf6 _snprintf
+/* These macros may need to be architecture dependent. */
+#define PNG_ALIGN_NONE 0 /* do not use data alignment */
+#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
+#ifdef offsetof
+# define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
+#else
+# define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
+#endif
+#define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */
+
+#ifndef PNG_ALIGN_TYPE
+ /* Default to using aligned access optimizations and requiring alignment to a
+ * multiple of the data type size. Override in a compiler specific fashion
+ * if necessary by inserting tests here:
+ */
+# define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
+#endif
+
+#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
+ /* This is used because in some compiler implementations non-aligned
+ * structure members are supported, so the offsetof approach below fails.
+ * Set PNG_ALIGN_TO_SIZE=0 for compiler combinations where unaligned access
+ * is good for performance. Do not do this unless you have tested the result
+ * and understand it.
+ */
+# define png_alignof(type) (sizeof (type))
+#else
+# if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
+# define png_alignof(type) offsetof(struct{char c; type t;}, t)
# else
-# define png_snprintf snprintf /* Added to v 1.2.19 */
-# define png_snprintf2 snprintf
-# define png_snprintf6 snprintf
+# if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
+# define png_alignof(type) (1)
+# endif
+ /* Else leave png_alignof undefined to prevent use thereof */
# endif
+#endif
+
+/* This implicitly assumes alignment is always to a power of 2. */
+#ifdef png_alignof
+# define png_isaligned(ptr, type)\
+ ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
#else
- /* You don't have or don't want to use snprintf(). Caution: Using
- * sprintf instead of snprintf exposes your application to accidental
- * or malevolent buffer overflows. If you don't have snprintf()
- * as a general rule you should provide one (you can get one from
- * Portable OpenSSH).
- */
-# define png_snprintf(s1,n,fmt,x1) png_sprintf(s1,fmt,x1)
-# define png_snprintf2(s1,n,fmt,x1,x2) png_sprintf(s1,fmt,x1,x2)
-# define png_snprintf6(s1,n,fmt,x1,x2,x3,x4,x5,x6) \
- png_sprintf(s1,fmt,x1,x2,x3,x4,x5,x6)
+# define png_isaligned(ptr, type) 0
#endif
+
+/* End of memory model/platform independent support */
/* End of 1.5.0beta36 move from pngconf.h */
/* CONSTANTS and UTILITY MACROS
*/
/* Various modes of operation. Note that after an init, mode is set to
- * zero automatically when the structure is created.
+ * zero automatically when the structure is created. Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
*/
-#define PNG_HAVE_IHDR 0x01
-#define PNG_HAVE_PLTE 0x02
+/* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */
+/* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */
#define PNG_HAVE_IDAT 0x04
-#define PNG_AFTER_IDAT 0x08 /* Have complete zlib datastream */
+/* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */
#define PNG_HAVE_IEND 0x10
#define PNG_HAVE_gAMA 0x20
#define PNG_HAVE_cHRM 0x40
#define PNG_SWAP_BYTES 0x0010
#define PNG_INVERT_MONO 0x0020
#define PNG_QUANTIZE 0x0040
-#define PNG_BACKGROUND 0x0080
+#define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */
#define PNG_BACKGROUND_EXPAND 0x0100
#define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */
-#define PNG_16_TO_8 0x0400
+#define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */
#define PNG_RGBA 0x0800
#define PNG_EXPAND 0x1000
#define PNG_GAMMA 0x2000
#define PNG_GRAY_TO_RGB 0x4000
-#define PNG_FILLER 0x8000L
-#define PNG_PACKSWAP 0x10000L
-#define PNG_SWAP_ALPHA 0x20000L
-#define PNG_STRIP_ALPHA 0x40000L
-#define PNG_INVERT_ALPHA 0x80000L
-#define PNG_USER_TRANSFORM 0x100000L
-#define PNG_RGB_TO_GRAY_ERR 0x200000L
-#define PNG_RGB_TO_GRAY_WARN 0x400000L
-#define PNG_RGB_TO_GRAY 0x600000L /* two bits, RGB_TO_GRAY_ERR|WARN */
- /* 0x800000L Unused */
-#define PNG_ADD_ALPHA 0x1000000L /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS 0x2000000L /* Added to libpng-1.2.9 */
- /* 0x4000000L unused */
- /* 0x8000000L unused */
- /* 0x10000000L unused */
- /* 0x20000000L unused */
- /* 0x40000000L unused */
-
+#define PNG_FILLER 0x8000
+#define PNG_PACKSWAP 0x10000
+#define PNG_SWAP_ALPHA 0x20000
+#define PNG_STRIP_ALPHA 0x40000
+#define PNG_INVERT_ALPHA 0x80000
+#define PNG_USER_TRANSFORM 0x100000
+#define PNG_RGB_TO_GRAY_ERR 0x200000
+#define PNG_RGB_TO_GRAY_WARN 0x400000
+#define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */
+ /* 0x8000000 unused */
+ /* 0x10000000 unused */
+ /* 0x20000000 unused */
+ /* 0x40000000 unused */
/* Flags for png_create_struct */
#define PNG_STRUCT_PNG 0x0001
#define PNG_STRUCT_INFO 0x0002
#define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200
#define PNG_FLAG_CRC_CRITICAL_USE 0x0400
#define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800
- /* 0x1000 unused */
- /* 0x2000 unused */
- /* 0x4000 unused */
-#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000L
-#define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000L
-#define PNG_FLAG_LIBRARY_MISMATCH 0x20000L
-#define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000L
-#define PNG_FLAG_STRIP_ERROR_TEXT 0x80000L
-#define PNG_FLAG_MALLOC_NULL_MEM_OK 0x100000L
- /* 0x200000L unused */
- /* 0x400000L unused */
-#define PNG_FLAG_BENIGN_ERRORS_WARN 0x800000L /* Added to libpng-1.4.0 */
- /* 0x1000000L unused */
- /* 0x2000000L unused */
- /* 0x4000000L unused */
- /* 0x8000000L unused */
- /* 0x10000000L unused */
- /* 0x20000000L unused */
- /* 0x40000000L unused */
+#define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000
+#define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000
+#define PNG_FLAG_LIBRARY_MISMATCH 0x20000
+#define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000
+#define PNG_FLAG_STRIP_ERROR_TEXT 0x80000
+#define PNG_FLAG_MALLOC_NULL_MEM_OK 0x100000
+ /* 0x200000 unused */
+ /* 0x400000 unused */
+#define PNG_FLAG_BENIGN_ERRORS_WARN 0x800000 /* Added to libpng-1.4.0 */
+#define PNG_FLAG_ZTXT_CUSTOM_STRATEGY 0x1000000 /* 5 lines added */
+#define PNG_FLAG_ZTXT_CUSTOM_LEVEL 0x2000000 /* to libpng-1.5.4 */
+#define PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL 0x4000000
+#define PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS 0x8000000
+#define PNG_FLAG_ZTXT_CUSTOM_METHOD 0x10000000
+ /* 0x20000000 unused */
+ /* 0x40000000 unused */
#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
PNG_FLAG_CRC_ANCILLARY_NOWARN)
#endif
#endif
-/* Constant strings for known chunk types. If you need to add a chunk,
- * define the name here, and add an invocation of the macro wherever it's
- * needed.
+/* Constants for known chunk types. If you need to add a chunk, define the name
+ * here. For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case. Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
*/
-#define PNG_IHDR PNG_CONST png_byte png_IHDR[5] = { 73, 72, 68, 82, '\0'}
-#define PNG_IDAT PNG_CONST png_byte png_IDAT[5] = { 73, 68, 65, 84, '\0'}
-#define PNG_IEND PNG_CONST png_byte png_IEND[5] = { 73, 69, 78, 68, '\0'}
-#define PNG_PLTE PNG_CONST png_byte png_PLTE[5] = { 80, 76, 84, 69, '\0'}
-#define PNG_bKGD PNG_CONST png_byte png_bKGD[5] = { 98, 75, 71, 68, '\0'}
-#define PNG_cHRM PNG_CONST png_byte png_cHRM[5] = { 99, 72, 82, 77, '\0'}
-#define PNG_gAMA PNG_CONST png_byte png_gAMA[5] = {103, 65, 77, 65, '\0'}
-#define PNG_hIST PNG_CONST png_byte png_hIST[5] = {104, 73, 83, 84, '\0'}
-#define PNG_iCCP PNG_CONST png_byte png_iCCP[5] = {105, 67, 67, 80, '\0'}
-#define PNG_iTXt PNG_CONST png_byte png_iTXt[5] = {105, 84, 88, 116, '\0'}
-#define PNG_oFFs PNG_CONST png_byte png_oFFs[5] = {111, 70, 70, 115, '\0'}
-#define PNG_pCAL PNG_CONST png_byte png_pCAL[5] = {112, 67, 65, 76, '\0'}
-#define PNG_sCAL PNG_CONST png_byte png_sCAL[5] = {115, 67, 65, 76, '\0'}
-#define PNG_pHYs PNG_CONST png_byte png_pHYs[5] = {112, 72, 89, 115, '\0'}
-#define PNG_sBIT PNG_CONST png_byte png_sBIT[5] = {115, 66, 73, 84, '\0'}
-#define PNG_sPLT PNG_CONST png_byte png_sPLT[5] = {115, 80, 76, 84, '\0'}
-#define PNG_sRGB PNG_CONST png_byte png_sRGB[5] = {115, 82, 71, 66, '\0'}
-#define PNG_sTER PNG_CONST png_byte png_sTER[5] = {115, 84, 69, 82, '\0'}
-#define PNG_tEXt PNG_CONST png_byte png_tEXt[5] = {116, 69, 88, 116, '\0'}
-#define PNG_tIME PNG_CONST png_byte png_tIME[5] = {116, 73, 77, 69, '\0'}
-#define PNG_tRNS PNG_CONST png_byte png_tRNS[5] = {116, 82, 78, 83, '\0'}
-#define PNG_zTXt PNG_CONST png_byte png_zTXt[5] = {122, 84, 88, 116, '\0'}
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_CHUNK(b1,b2,b3,b4) \
+ (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+#define png_IHDR PNG_CHUNK( 73, 72, 68, 82)
+#define png_IDAT PNG_CHUNK( 73, 68, 65, 84)
+#define png_IEND PNG_CHUNK( 73, 69, 78, 68)
+#define png_PLTE PNG_CHUNK( 80, 76, 84, 69)
+#define png_bKGD PNG_CHUNK( 98, 75, 71, 68)
+#define png_cHRM PNG_CHUNK( 99, 72, 82, 77)
+#define png_gAMA PNG_CHUNK(103, 65, 77, 65)
+#define png_hIST PNG_CHUNK(104, 73, 83, 84)
+#define png_iCCP PNG_CHUNK(105, 67, 67, 80)
+#define png_iTXt PNG_CHUNK(105, 84, 88, 116)
+#define png_oFFs PNG_CHUNK(111, 70, 70, 115)
+#define png_pCAL PNG_CHUNK(112, 67, 65, 76)
+#define png_sCAL PNG_CHUNK(115, 67, 65, 76)
+#define png_pHYs PNG_CHUNK(112, 72, 89, 115)
+#define png_sBIT PNG_CHUNK(115, 66, 73, 84)
+#define png_sPLT PNG_CHUNK(115, 80, 76, 84)
+#define png_sRGB PNG_CHUNK(115, 82, 71, 66)
+#define png_sTER PNG_CHUNK(115, 84, 69, 82)
+#define png_tEXt PNG_CHUNK(116, 69, 88, 116)
+#define png_tIME PNG_CHUNK(116, 73, 77, 69)
+#define png_tRNS PNG_CHUNK(116, 82, 78, 83)
+#define png_zTXt PNG_CHUNK(122, 84, 88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+ PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[]) This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+ (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
+ ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+ (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLIARY(c) (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLIARY(c))
+#define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
+
+/* Gamma values (new at libpng-1.5.4): */
+#define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
* be found in the files where the functions are located.
*/
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_EXTERN int png_user_version_check(png_structp png_ptr,
+ png_const_charp user_png_ver);
+
/* Allocate memory for an internal libpng struct */
PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
PNG_ALLOCATED);
png_size_t length));
/* Decompress data in a chunk that uses compression */
-#if defined(PNG_zTXt_SUPPORTED) || defined(PNG_iTXt_SUPPORTED) || \
- defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
+#if defined(PNG_READ_COMPRESSED_TEXT_SUPPORTED)
PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
int comp_type, png_size_t chunklength, png_size_t prefix_length,
png_size_t *data_length));
png_const_uint_16p hist, int num_hist));
#endif
+/* Chunks that have keywords */
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
/* Internal use only. Called before first row of data */
PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
-/* Combine a row of data, dealing with alpha, etc. if requested */
+/* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
+ * array of png_ptr->width pixels. If the image is not interlaced or this
+ * is the final pass this just does a png_memcpy, otherwise the "display" flag
+ * is used to determine whether to copy pixels that are not in the current pass.
+ *
+ * Because 'png_do_read_interlace' (below) replicates pixels this allows this
+ * function to achieve the documented 'blocky' appearance during interlaced read
+ * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
+ * are not changed if they are not in the current pass, when display is 0.
+ *
+ * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
+ *
+ * The API always reads from the png_struct row buffer and always assumes that
+ * it is full width (png_do_read_interlace has already been called.)
+ *
+ * This function is only ever used to write to row buffers provided by the
+ * caller of the relevant libpng API and the row must have already been
+ * transformed by the read transformations.
+ *
+ * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
+ * bitmasks for use within the code, otherwise runtime generated masks are used.
+ * The default is compile time masks.
+ */
+#ifndef PNG_USE_COMPILE_TIME_MASKS
+# define PNG_USE_COMPILE_TIME_MASKS 1
+#endif
PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
- int mask));
+ int display));
#ifdef PNG_READ_INTERLACING_SUPPORTED
-/* Expand an interlaced row */
-/* OLD pre-1.0.9 interface:
+/* Expand an interlaced row: the 'row_info' describes the pass data that has
+ * been read in and must correspond to the pixels in 'row', the pixels are
+ * expanded (moved apart) in 'row' to match the final layout, when doing this
+ * the pixels are *replicated* to the intervening space. This is essential for
+ * the correct operation of png_combine_row, above.
+ */
PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
png_bytep row, int pass, png_uint_32 transformations));
- */
-PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr));
#endif
/* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
png_bytep row, int pass));
#endif
-/* Unfilter a row */
-PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
- png_row_infop row_info, png_bytep row, png_const_bytep prev_row,
- int filter));
+/* Unfilter a row: check the filter value before calling this, there is no point
+ * calling it for PNG_FILTER_VALUE_NONE.
+ */
+PNG_EXTERN void png_read_filter_row PNGARG((png_structp pp, png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row, int filter));
+
+PNG_EXTERN void png_read_filter_row_up_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_sub3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_sub4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_avg3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_avg4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_paeth3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_paeth4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
/* Choose the best filter to use and filter the row data */
PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
png_row_infop row_info));
-/* Write out the filtered row. */
-PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,
- png_bytep filtered_row));
/* Finish a row while reading, dealing with interlacing passes, etc. */
PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
/* Initialize the row buffers, etc. */
PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
/* Optional call to update the users info structure */
PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
png_infop info_ptr));
+#endif
/* These are the functions that do the transformations */
#ifdef PNG_READ_FILLER_SUPPORTED
png_bytep row));
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+PNG_EXTERN void png_do_scale_16_to_8 PNGARG((png_row_infop row_info,
+ png_bytep row));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
png_bytep row));
#endif
png_bytep row, png_const_color_8p bit_depth));
#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-# ifdef PNG_READ_GAMMA_SUPPORTED
-PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info,
- png_bytep row, png_const_color_16p trans_color,
- png_const_color_16p background, png_const_color_16p background_1,
- png_const_bytep gamma_table, png_const_bytep gamma_from_1,
- png_const_bytep gamma_to_1, png_const_uint_16pp gamma_16,
- png_const_uint_16pp gamma_16_from_1, png_const_uint_16pp gamma_16_to_1,
- int gamma_shift));
-# else
-PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info,
- png_bytep row, png_const_color_16p trans_color,
- png_const_color_16p background));
-# endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+PNG_EXTERN void png_do_compose PNGARG((png_row_infop row_info,
+ png_bytep row, png_structp png_ptr));
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info,
- png_bytep row, png_const_bytep gamma_table,
- png_const_uint_16pp gamma_16_table, int gamma_shift));
+ png_bytep row, png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+PNG_EXTERN void png_do_encode_alpha PNGARG((png_row_infop row_info,
+ png_bytep row, png_structp png_ptr));
#endif
#ifdef PNG_READ_EXPAND_SUPPORTED
png_uint_32 length));
#endif
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
png_infop info_ptr, png_uint_32 length));
+#endif
PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
- png_const_bytep chunk_name));
+ png_uint_32 chunk_name));
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+/* Exactly as png_handle_as_unknown() except that the argument is a 32-bit chunk
+ * name, not a string.
+ */
+PNG_EXTERN int png_chunk_unknown_handling PNGARG((png_structp png_ptr,
+ png_uint_32 chunk_name));
+#endif
/* Handle the transformations for reading and writing */
-PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));
-PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr,
+ png_row_infop row_info));
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr,
+ png_row_infop row_info));
+#endif
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
+#endif
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
unsigned long *hi_product, unsigned long *lo_product));
#endif
+#ifdef PNG_cHRM_SUPPORTED
+/* Added at libpng version 1.5.5 */
+typedef struct png_xy
+{
+ png_fixed_point redx, redy;
+ png_fixed_point greenx, greeny;
+ png_fixed_point bluex, bluey;
+ png_fixed_point whitex, whitey;
+} png_xy;
+
+typedef struct png_XYZ
+{
+ png_fixed_point redX, redY, redZ;
+ png_fixed_point greenX, greenY, greenZ;
+ png_fixed_point blueX, blueY, blueZ;
+} png_XYZ;
+
+/* The conversion APIs return 0 on success, non-zero on a parameter error. They
+ * allow conversion between the above representations of a color encoding. When
+ * converting from XYZ end points to chromaticities the absolute magnitude of
+ * the end points is lost, when converting back the sum of the Y values of the
+ * three end points will be 1.0
+ */
+PNG_EXTERN int png_xy_from_XYZ PNGARG((png_xy *xy, png_XYZ XYZ));
+PNG_EXTERN int png_XYZ_from_xy PNGARG((png_XYZ *XYZ, png_xy xy));
+PNG_EXTERN int png_XYZ_from_xy_checked PNGARG((png_structp png_ptr,
+ png_XYZ *XYZ, png_xy xy));
+#endif
+
/* Added at libpng version 1.4.0 */
PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
png_uint_32 width, png_uint_32 height, int bit_depth,
png_const_charp name),PNG_NORETURN);
#endif
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end. Always leaves the buffer nul terminated. Never errors out (and
+ * there is no error code.)
+ */
+PNG_EXTERN size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+ png_const_charp string);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string. This utility only
+ * does unsigned values.
+ */
+PNG_EXTERN png_charp png_format_number(png_const_charp start, png_charp end,
+ int format, png_alloc_size_t number);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+ png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u 1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u 2
+#define PNG_NUMBER_FORMAT_d 1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d 2
+#define PNG_NUMBER_FORMAT_x 3
+#define PNG_NUMBER_FORMAT_02x 4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.4 */
+# define PNG_WARNING_PARAMETER_SIZE 32
+# define PNG_WARNING_PARAMETER_COUNT 8
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+ PNG_WARNING_PARAMETER_SIZE];
+
+PNG_EXTERN void png_warning_parameter(png_warning_parameters p, int number,
+ png_const_charp string);
+ /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+ * including the trailing '\0'.
+ */
+PNG_EXTERN void png_warning_parameter_unsigned(png_warning_parameters p,
+ int number, int format, png_alloc_size_t value);
+ /* Use png_alloc_size_t because it is an unsigned type as big as any we
+ * need to output. Use the following for a signed value.
+ */
+PNG_EXTERN void png_warning_parameter_signed(png_warning_parameters p,
+ int number, int format, png_int_32 value);
+
+PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
+ png_warning_parameters p, png_const_charp message);
+ /* 'message' follows the X/Open approach of using @1, @2 to insert
+ * parameters previously supplied using the above functions. Errors in
+ * specifying the paramters will simple result in garbage substitutions.
+ */
+#endif
+
/* ASCII to FP interfaces, currently only implemented if sCAL
* support is required.
*/
#define PNG_FP_SAW_DOT 16 /* Saw a dot in current state */
#define PNG_FP_SAW_E 32 /* Saw an E (or e) in current state */
#define PNG_FP_SAW_ANY 60 /* Saw any of the above 4 */
+
+/* These three values don't affect the parser. They are set but not used.
+ */
#define PNG_FP_WAS_VALID 64 /* Preceding substring is a valid fp number */
-#define PNG_FP_INVALID 128 /* Available for callers as a distinct value */
+#define PNG_FP_NEGATIVE 128 /* A negative number, including "-0" */
+#define PNG_FP_NONZERO 256 /* A non-zero value */
+#define PNG_FP_STICKY 448 /* The above three flags */
+
+/* This is available for the caller to store in 'state' if required. Do not
+ * call the parser after setting it (the parser sometimes clears it.)
+ */
+#define PNG_FP_INVALID 512 /* Available for callers as a distinct value */
/* Result codes for the parser (boolean - true meants ok, false means
* not ok yet.)
#define PNG_FP_MAYBE 0 /* The number may be valid in the future */
#define PNG_FP_OK 1 /* The number is valid */
+/* Tests on the sticky non-zero and negative flags. To pass these checks
+ * the state must also indicate that the whole number is valid - this is
+ * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
+ * is equivalent to PNG_FP_OK above.)
+ */
+#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
+ /* NZ_MASK: the string is valid and a non-zero negative value */
+#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
+ /* Z MASK: the string is valid and a non-zero value. */
+ /* PNG_FP_SAW_DIGIT: the string is valid. */
+#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
+#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
+#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
+
/* The actual parser. This can be called repeatedly, it updates
* the index into the string and the state variable (which must
* be initialzed to 0). It returns a result code, as above. There
png_size_t size, int *statep, png_size_tp whereami));
/* This is the same but it checks a complete string and returns true
- * only if it just contains a floating point number.
+ * only if it just contains a floating point number. As of 1.5.4 this
+ * function also returns the state at the end of parsing the number if
+ * it was valid (otherwise it returns 0.) This can be used for testing
+ * for negative or zero values using the sticky flag.
*/
PNG_EXTERN int png_check_fp_string PNGARG((png_const_charp string,
png_size_t size));
png_fixed_point gamma_value));
PNG_EXTERN png_byte png_gamma_8bit_correct PNGARG((unsigned int value,
png_fixed_point gamma_value));
+PNG_EXTERN void png_destroy_gamma_table(png_structp png_ptr);
PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr,
int bit_depth));
#endif
/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
-
#include "pngdebug.h"
#ifdef __cplusplus
/* pngread.c - read a PNG file
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
#ifdef PNG_SETJMP_SUPPORTED
#ifdef USE_FAR_KEYWORD
- jmp_buf png_jmpbuf;
+ jmp_buf tmp_jmpbuf;
#endif
#endif
- int i;
-
png_debug(1, "in png_create_read_struct");
#ifdef PNG_USER_MEM_SUPPORTED
#ifdef PNG_SETJMP_SUPPORTED
/* Applications that neglect to set up their own setjmp() and then
- encounter a png_error() will longjmp here. Since the jmpbuf is
- then meaningless we abort instead of returning. */
+ * encounter a png_error() will longjmp here. Since the jmpbuf is
+ * then meaningless we abort instead of returning.
+ */
#ifdef USE_FAR_KEYWORD
- if (setjmp(png_jmpbuf))
+ if (setjmp(tmp_jmpbuf))
#else
if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
#endif
PNG_ABORT();
#ifdef USE_FAR_KEYWORD
- png_memcpy(png_jmpbuf(png_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+ png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
#endif
#endif /* PNG_SETJMP_SUPPORTED */
png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
- if (user_png_ver)
- {
- i = 0;
-
- do
- {
- if (user_png_ver[i] != png_libpng_ver[i])
- png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
- } while (png_libpng_ver[i++]);
- }
-
- else
- png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-
-
- if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
- {
- /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
- * we must recompile any applications that use any older library version.
- * For versions after libpng 1.0, we will be compatible, so we need
- * only check the first digit.
- */
- if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
- (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
- (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
- {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[80];
- if (user_png_ver)
- {
- png_snprintf2(msg, 80,
- "Application built with libpng-%.20s"
- " but running with %.20s",
- user_png_ver,
- png_libpng_ver);
- png_warning(png_ptr, msg);
- }
-#else
- png_warning(png_ptr,
- "Incompatible libpng version in application and library");
-#endif
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
- png_ptr->flags = 0;
-#endif
-
- png_cleanup_needed = 1;
- }
- }
+ /* Call the general version checker (shared with read and write code): */
+ if (!png_user_version_check(png_ptr, user_png_ver))
+ png_cleanup_needed = 1;
if (!png_cleanup_needed)
{
for (;;)
{
- PNG_IHDR;
- PNG_IDAT;
- PNG_IEND;
- PNG_PLTE;
-#ifdef PNG_READ_bKGD_SUPPORTED
- PNG_bKGD;
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
- PNG_cHRM;
-#endif
-#ifdef PNG_READ_gAMA_SUPPORTED
- PNG_gAMA;
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
- PNG_hIST;
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
- PNG_iCCP;
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
- PNG_iTXt;
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
- PNG_oFFs;
-#endif
-#ifdef PNG_READ_pCAL_SUPPORTED
- PNG_pCAL;
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
- PNG_pHYs;
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
- PNG_sBIT;
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
- PNG_sCAL;
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
- PNG_sPLT;
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
- PNG_sRGB;
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
- PNG_tEXt;
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
- PNG_tIME;
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
- PNG_tRNS;
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
- PNG_zTXt;
-#endif
png_uint_32 length = png_read_chunk_header(png_ptr);
- PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
+ png_uint_32 chunk_name = png_ptr->chunk_name;
/* This should be a binary subdivision search or a hash for
* matching the chunk name rather than a linear search.
*/
- if (!png_memcmp(chunk_name, png_IDAT, 4))
+ if (chunk_name == png_IDAT)
if (png_ptr->mode & PNG_AFTER_IDAT)
png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
- if (!png_memcmp(chunk_name, png_IHDR, 4))
+ if (chunk_name == png_IHDR)
png_handle_IHDR(png_ptr, info_ptr, length);
- else if (!png_memcmp(chunk_name, png_IEND, 4))
+ else if (chunk_name == png_IEND)
png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- else if (png_handle_as_unknown(png_ptr, chunk_name))
+ else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
+ PNG_HANDLE_CHUNK_AS_DEFAULT)
{
- if (!png_memcmp(chunk_name, png_IDAT, 4))
+ if (chunk_name == png_IDAT)
png_ptr->mode |= PNG_HAVE_IDAT;
png_handle_unknown(png_ptr, info_ptr, length);
- if (!png_memcmp(chunk_name, png_PLTE, 4))
+ if (chunk_name == png_PLTE)
png_ptr->mode |= PNG_HAVE_PLTE;
- else if (!png_memcmp(chunk_name, png_IDAT, 4))
+ else if (chunk_name == png_IDAT)
{
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
}
}
#endif
- else if (!png_memcmp(chunk_name, png_PLTE, 4))
+ else if (chunk_name == png_PLTE)
png_handle_PLTE(png_ptr, info_ptr, length);
- else if (!png_memcmp(chunk_name, png_IDAT, 4))
+ else if (chunk_name == png_IDAT)
{
if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
}
#ifdef PNG_READ_bKGD_SUPPORTED
- else if (!png_memcmp(chunk_name, png_bKGD, 4))
+ else if (chunk_name == png_bKGD)
png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
- else if (!png_memcmp(chunk_name, png_cHRM, 4))
+ else if (chunk_name == png_cHRM)
png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
- else if (!png_memcmp(chunk_name, png_gAMA, 4))
+ else if (chunk_name == png_gAMA)
png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_hIST_SUPPORTED
- else if (!png_memcmp(chunk_name, png_hIST, 4))
+ else if (chunk_name == png_hIST)
png_handle_hIST(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
- else if (!png_memcmp(chunk_name, png_oFFs, 4))
+ else if (chunk_name == png_oFFs)
png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
- else if (!png_memcmp(chunk_name, png_pCAL, 4))
+ else if (chunk_name == png_pCAL)
png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sCAL, 4))
+ else if (chunk_name == png_sCAL)
png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
- else if (!png_memcmp(chunk_name, png_pHYs, 4))
+ else if (chunk_name == png_pHYs)
png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sBIT, 4))
+ else if (chunk_name == png_sBIT)
png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sRGB, 4))
+ else if (chunk_name == png_sRGB)
png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
- else if (!png_memcmp(chunk_name, png_iCCP, 4))
+ else if (chunk_name == png_iCCP)
png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sPLT, 4))
+ else if (chunk_name == png_sPLT)
png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tEXt, 4))
+ else if (chunk_name == png_tEXt)
png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tIME_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tIME, 4))
+ else if (chunk_name == png_tIME)
png_handle_tIME(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tRNS, 4))
+ else if (chunk_name == png_tRNS)
png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_zTXt, 4))
+ else if (chunk_name == png_zTXt)
png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_iTXt, 4))
+ else if (chunk_name == png_iTXt)
png_handle_iTXt(png_ptr, info_ptr, length);
#endif
if (png_ptr == NULL)
return;
- if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
- png_read_start_row(png_ptr);
-
- else
- png_warning(png_ptr,
- "Ignoring extra png_read_update_info() call;"
- " row buffer not reallocated");
+ png_read_start_row(png_ptr);
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
png_read_transform_info(png_ptr, info_ptr);
+#else
+ PNG_UNUSED(info_ptr)
+#endif
}
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
{
png_debug(1, "in png_start_read_image");
- if (png_ptr == NULL)
- return;
-
- if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
- png_read_start_row(png_ptr);
- else
- png_warning(png_ptr,
- "Ignoring extra png_start_read_image() call;"
- " row buffer not reallocated");
+ if (png_ptr != NULL)
+ png_read_start_row(png_ptr);
}
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
void PNGAPI
png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
{
- PNG_IDAT;
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
- 0xff};
- PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
-#endif
int ret;
+ png_row_info row_info;
+
if (png_ptr == NULL)
return;
png_debug2(1, "in png_read_row (row %lu, pass %d)",
(unsigned long)png_ptr->row_number, png_ptr->pass);
+ /* png_read_start_row sets the information (in particular iwidth) for this
+ * interlace pass.
+ */
if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
png_read_start_row(png_ptr);
+ /* 1.5.6: row_info moved out of png_struct to a local here. */
+ row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+ row_info.color_type = png_ptr->color_type;
+ row_info.bit_depth = png_ptr->bit_depth;
+ row_info.channels = png_ptr->channels;
+ row_info.pixel_depth = png_ptr->pixel_depth;
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
if (png_ptr->row_number == 0 && png_ptr->pass == 0)
{
/* Check for transforms that have been set but were defined out */
}
#ifdef PNG_READ_INTERLACING_SUPPORTED
- /* If interlaced and we do not need a new row, combine row and return */
+ /* If interlaced and we do not need a new row, combine row and return.
+ * Notice that the pixels we have from previous rows have been transformed
+ * already; we can only combine like with like (transformed or
+ * untransformed) and, because of the libpng API for interlaced images, this
+ * means we must transform before de-interlacing.
+ */
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
{
switch (png_ptr->pass)
if (png_ptr->row_number & 0x07)
{
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
}
if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
{
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
if ((png_ptr->row_number & 0x07) != 4)
{
if (dsp_row != NULL && (png_ptr->row_number & 4))
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
if ((png_ptr->row_number & 3) || png_ptr->width < 3)
{
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
if ((png_ptr->row_number & 3) != 2)
{
if (dsp_row != NULL && (png_ptr->row_number & 2))
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
{
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row,
- png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
png_read_finish_row(png_ptr);
return;
png_crc_finish(png_ptr, 0);
png_ptr->idat_size = png_read_chunk_header(png_ptr);
- if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ if (png_ptr->chunk_name != png_IDAT)
png_error(png_ptr, "Not enough image data");
}
png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
} while (png_ptr->zstream.avail_out);
- png_ptr->row_info.color_type = png_ptr->color_type;
- png_ptr->row_info.width = png_ptr->iwidth;
- png_ptr->row_info.channels = png_ptr->channels;
- png_ptr->row_info.bit_depth = png_ptr->bit_depth;
- png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
- png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
- png_ptr->row_info.width);
-
- if (png_ptr->row_buf[0])
- png_read_filter_row(png_ptr, &(png_ptr->row_info),
- png_ptr->row_buf + 1, png_ptr->prev_row + 1,
- (int)(png_ptr->row_buf[0]));
+ if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+ {
+ if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+ png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+ else
+ png_error(png_ptr, "bad adaptive filter value");
+ }
- png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
+ /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+ * 1.5.6, while the buffer really is this big in current versions of libpng
+ * it may not be in the future, so this was changed just to copy the
+ * interlaced count:
+ */
+ png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
#ifdef PNG_MNG_FEATURES_SUPPORTED
if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
{
/* Intrapixel differencing */
- png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
}
#endif
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
if (png_ptr->transformations)
- png_do_read_transformations(png_ptr);
+ png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+ /* The transformed pixel depth should match the depth now in row_info. */
+ if (png_ptr->transformed_pixel_depth == 0)
+ {
+ png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+ if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+ png_error(png_ptr, "sequential row overflow");
+ }
+
+ else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+ png_error(png_ptr, "internal sequential row size calculation error");
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Blow up interlaced rows to full size */
(png_ptr->transformations & PNG_INTERLACE))
{
if (png_ptr->pass < 6)
- /* Old interface (pre-1.0.9):
- * png_do_read_interlace(&(png_ptr->row_info),
- * png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
- */
- png_do_read_interlace(png_ptr);
+ png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+ png_ptr->transformations);
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row, png_pass_dsp_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
if (row != NULL)
- png_combine_row(png_ptr, row, png_pass_mask[png_ptr->pass]);
+ png_combine_row(png_ptr, row, 0/*row*/);
}
else
#endif
{
if (row != NULL)
- png_combine_row(png_ptr, row, 0xff);
+ png_combine_row(png_ptr, row, -1/*ignored*/);
if (dsp_row != NULL)
- png_combine_row(png_ptr, dsp_row, 0xff);
+ png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
}
png_read_finish_row(png_ptr);
do
{
- PNG_IHDR;
- PNG_IDAT;
- PNG_IEND;
- PNG_PLTE;
-#ifdef PNG_READ_bKGD_SUPPORTED
- PNG_bKGD;
-#endif
-#ifdef PNG_READ_cHRM_SUPPORTED
- PNG_cHRM;
-#endif
-#ifdef PNG_READ_gAMA_SUPPORTED
- PNG_gAMA;
-#endif
-#ifdef PNG_READ_hIST_SUPPORTED
- PNG_hIST;
-#endif
-#ifdef PNG_READ_iCCP_SUPPORTED
- PNG_iCCP;
-#endif
-#ifdef PNG_READ_iTXt_SUPPORTED
- PNG_iTXt;
-#endif
-#ifdef PNG_READ_oFFs_SUPPORTED
- PNG_oFFs;
-#endif
-#ifdef PNG_READ_pCAL_SUPPORTED
- PNG_pCAL;
-#endif
-#ifdef PNG_READ_pHYs_SUPPORTED
- PNG_pHYs;
-#endif
-#ifdef PNG_READ_sBIT_SUPPORTED
- PNG_sBIT;
-#endif
-#ifdef PNG_READ_sCAL_SUPPORTED
- PNG_sCAL;
-#endif
-#ifdef PNG_READ_sPLT_SUPPORTED
- PNG_sPLT;
-#endif
-#ifdef PNG_READ_sRGB_SUPPORTED
- PNG_sRGB;
-#endif
-#ifdef PNG_READ_tEXt_SUPPORTED
- PNG_tEXt;
-#endif
-#ifdef PNG_READ_tIME_SUPPORTED
- PNG_tIME;
-#endif
-#ifdef PNG_READ_tRNS_SUPPORTED
- PNG_tRNS;
-#endif
-#ifdef PNG_READ_zTXt_SUPPORTED
- PNG_zTXt;
-#endif
png_uint_32 length = png_read_chunk_header(png_ptr);
- PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
+ png_uint_32 chunk_name = png_ptr->chunk_name;
- if (!png_memcmp(chunk_name, png_IHDR, 4))
+ if (chunk_name == png_IHDR)
png_handle_IHDR(png_ptr, info_ptr, length);
- else if (!png_memcmp(chunk_name, png_IEND, 4))
+ else if (chunk_name == png_IEND)
png_handle_IEND(png_ptr, info_ptr, length);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- else if (png_handle_as_unknown(png_ptr, chunk_name))
+ else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
+ PNG_HANDLE_CHUNK_AS_DEFAULT)
{
- if (!png_memcmp(chunk_name, png_IDAT, 4))
+ if (chunk_name == png_IDAT)
{
if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
png_benign_error(png_ptr, "Too many IDATs found");
}
png_handle_unknown(png_ptr, info_ptr, length);
- if (!png_memcmp(chunk_name, png_PLTE, 4))
+ if (chunk_name == png_PLTE)
png_ptr->mode |= PNG_HAVE_PLTE;
}
#endif
- else if (!png_memcmp(chunk_name, png_IDAT, 4))
+ else if (chunk_name == png_IDAT)
{
/* Zero length IDATs are legal after the last IDAT has been
* read, but not after other chunks have been read.
png_crc_finish(png_ptr, length);
}
- else if (!png_memcmp(chunk_name, png_PLTE, 4))
+ else if (chunk_name == png_PLTE)
png_handle_PLTE(png_ptr, info_ptr, length);
#ifdef PNG_READ_bKGD_SUPPORTED
- else if (!png_memcmp(chunk_name, png_bKGD, 4))
+ else if (chunk_name == png_bKGD)
png_handle_bKGD(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_cHRM_SUPPORTED
- else if (!png_memcmp(chunk_name, png_cHRM, 4))
+ else if (chunk_name == png_cHRM)
png_handle_cHRM(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_gAMA_SUPPORTED
- else if (!png_memcmp(chunk_name, png_gAMA, 4))
+ else if (chunk_name == png_gAMA)
png_handle_gAMA(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_hIST_SUPPORTED
- else if (!png_memcmp(chunk_name, png_hIST, 4))
+ else if (chunk_name == png_hIST)
png_handle_hIST(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_oFFs_SUPPORTED
- else if (!png_memcmp(chunk_name, png_oFFs, 4))
+ else if (chunk_name == png_oFFs)
png_handle_oFFs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pCAL_SUPPORTED
- else if (!png_memcmp(chunk_name, png_pCAL, 4))
+ else if (chunk_name == png_pCAL)
png_handle_pCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sCAL_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sCAL, 4))
+ else if (chunk_name == png_sCAL)
png_handle_sCAL(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_pHYs_SUPPORTED
- else if (!png_memcmp(chunk_name, png_pHYs, 4))
+ else if (chunk_name == png_pHYs)
png_handle_pHYs(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sBIT_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sBIT, 4))
+ else if (chunk_name == png_sBIT)
png_handle_sBIT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sRGB_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sRGB, 4))
+ else if (chunk_name == png_sRGB)
png_handle_sRGB(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iCCP_SUPPORTED
- else if (!png_memcmp(chunk_name, png_iCCP, 4))
+ else if (chunk_name == png_iCCP)
png_handle_iCCP(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_sPLT_SUPPORTED
- else if (!png_memcmp(chunk_name, png_sPLT, 4))
+ else if (chunk_name == png_sPLT)
png_handle_sPLT(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tEXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tEXt, 4))
+ else if (chunk_name == png_tEXt)
png_handle_tEXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tIME_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tIME, 4))
+ else if (chunk_name == png_tIME)
png_handle_tIME(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_tRNS_SUPPORTED
- else if (!png_memcmp(chunk_name, png_tRNS, 4))
+ else if (chunk_name == png_tRNS)
png_handle_tRNS(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_zTXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_zTXt, 4))
+ else if (chunk_name == png_zTXt)
png_handle_zTXt(png_ptr, info_ptr, length);
#endif
#ifdef PNG_READ_iTXt_SUPPORTED
- else if (!png_memcmp(chunk_name, png_iTXt, 4))
+ else if (chunk_name == png_iTXt)
png_handle_iTXt(png_ptr, info_ptr, length);
#endif
jmp_buf tmp_jmp;
#endif
png_error_ptr error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
png_error_ptr warning_fn;
+#endif
png_voidp error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_free_ptr free_fn;
if (end_info_ptr != NULL)
png_info_destroy(png_ptr, end_info_ptr);
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ png_destroy_gamma_table(png_ptr);
+#endif
+
png_free(png_ptr, png_ptr->zbuf);
png_free(png_ptr, png_ptr->big_row_buf);
- png_free(png_ptr, png_ptr->prev_row);
+ png_free(png_ptr, png_ptr->big_prev_row);
png_free(png_ptr, png_ptr->chunkdata);
#ifdef PNG_READ_QUANTIZE_SUPPORTED
png_free(png_ptr, png_ptr->quantize_index);
#endif
-#ifdef PNG_READ_GAMMA_SUPPORTED
- png_free(png_ptr, png_ptr->gamma_table);
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- png_free(png_ptr, png_ptr->gamma_from_1);
- png_free(png_ptr, png_ptr->gamma_to_1);
-#endif
-
if (png_ptr->free_me & PNG_FREE_PLTE)
png_zfree(png_ptr, png_ptr->palette);
png_ptr->free_me &= ~PNG_FREE_PLTE;
png_ptr->free_me &= ~PNG_FREE_HIST;
#endif
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (png_ptr->gamma_16_table != NULL)
- {
- int i;
- int istop = (1 << (8 - png_ptr->gamma_shift));
- for (i = 0; i < istop; i++)
- {
- png_free(png_ptr, png_ptr->gamma_16_table[i]);
- }
- png_free(png_ptr, png_ptr->gamma_16_table);
- }
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->gamma_16_from_1 != NULL)
- {
- int i;
- int istop = (1 << (8 - png_ptr->gamma_shift));
- for (i = 0; i < istop; i++)
- {
- png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
- }
- png_free(png_ptr, png_ptr->gamma_16_from_1);
- }
- if (png_ptr->gamma_16_to_1 != NULL)
- {
- int i;
- int istop = (1 << (8 - png_ptr->gamma_shift));
- for (i = 0; i < istop; i++)
- {
- png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
- }
- png_free(png_ptr, png_ptr->gamma_16_to_1);
- }
-#endif
-#endif
-
-#ifdef PNG_TIME_RFC1123_SUPPORTED
- png_free(png_ptr, png_ptr->time_buffer);
-#endif
-
inflateEnd(&png_ptr->zstream);
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
* being used again.
*/
#ifdef PNG_SETJMP_SUPPORTED
- png_memcpy(tmp_jmp, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
+ png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
#endif
error_fn = png_ptr->error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
warning_fn = png_ptr->warning_fn;
+#endif
error_ptr = png_ptr->error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
free_fn = png_ptr->free_fn;
png_memset(png_ptr, 0, png_sizeof(png_struct));
png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
png_ptr->warning_fn = warning_fn;
+#endif
png_ptr->error_ptr = error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_ptr->free_fn = free_fn;
#endif
#ifdef PNG_SETJMP_SUPPORTED
- png_memcpy(png_ptr->png_jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
+ png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
#endif
}
/* -------------- image transformations start here ------------------- */
-#ifdef PNG_READ_16_TO_8_SUPPORTED
- /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
+ */
+ if (transforms & PNG_TRANSFORM_SCALE_16)
+ {
+ /* Added at libpng-1.5.4. "strip_16" produces the same result that it
+ * did in earlier versions, while "scale_16" is now more accurate.
+ */
+ png_set_scale_16(png_ptr);
+ }
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* If both SCALE and STRIP are required pngrtran will effectively cancel the
+ * latter by doing SCALE first. This is ok and allows apps not to check for
+ * which is supported to get the right answer.
*/
if (transforms & PNG_TRANSFORM_STRIP_16)
png_set_strip_16(png_ptr);
#endif
#ifdef PNG_READ_SWAP_SUPPORTED
- /* Swap bytes of 16 bit files to least significant byte first */
+ /* Swap bytes of 16-bit files to least significant byte first */
if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
png_set_swap(png_ptr);
#endif
png_set_gray_to_rgb(png_ptr);
#endif
+/* Added at libpng-1.5.4 */
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ if (transforms & PNG_TRANSFORM_EXPAND_16)
+ png_set_expand_16(png_ptr);
+#endif
+
/* We don't handle adding filler bytes */
/* We use png_read_image and rely on that for interlace handling, but we also
/* pngrtran.c - transforms the data in a row for PNG readers
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
return;
}
- png_ptr->transformations |= PNG_BACKGROUND;
+ png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
png_memcpy(&(png_ptr->background), background_color,
png_sizeof(png_color_16));
png_ptr->background_gamma = background_gamma;
png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
- png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
+ if (need_expand)
+ png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
+ else
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
}
# ifdef PNG_FLOATING_POINT_SUPPORTED
# endif /* FLOATING_POINT */
#endif /* READ_BACKGROUND */
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-/* Strip 16 bit depth files to 8 bit depth */
+/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
+ * one that pngrtran does first (scale) happens. This is necessary to allow the
+ * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+void PNGAPI
+png_set_scale_16(png_structp png_ptr)
+{
+ png_debug(1, "in png_set_scale_16");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+/* Chop 16-bit depth files to 8-bit depth */
void PNGAPI
png_set_strip_16(png_structp png_ptr)
{
return;
png_ptr->transformations |= PNG_16_TO_8;
- png_ptr->transformations &= ~PNG_EXPAND_16;
}
#endif
}
#endif
+#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+static png_fixed_point
+translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma,
+ int is_screen)
+{
+ /* Check for flag values. The main reason for having the old Mac value as a
+ * flag is that it is pretty near impossible to work out what the correct
+ * value is from Apple documentation - a working Mac system is needed to
+ * discover the value!
+ */
+ if (output_gamma == PNG_DEFAULT_sRGB ||
+ output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
+ {
+ /* If there is no sRGB support this just sets the gamma to the standard
+ * sRGB value. (This is a side effect of using this function!)
+ */
+# ifdef PNG_READ_sRGB_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
+# endif
+ if (is_screen)
+ output_gamma = PNG_GAMMA_sRGB;
+ else
+ output_gamma = PNG_GAMMA_sRGB_INVERSE;
+ }
+
+ else if (output_gamma == PNG_GAMMA_MAC_18 ||
+ output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
+ {
+ if (is_screen)
+ output_gamma = PNG_GAMMA_MAC_OLD;
+ else
+ output_gamma = PNG_GAMMA_MAC_INVERSE;
+ }
+
+ return output_gamma;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+static png_fixed_point
+convert_gamma_value(png_structp png_ptr, double output_gamma)
+{
+ /* The following silently ignores cases where fixed point (times 100,000)
+ * gamma values are passed to the floating point API. This is safe and it
+ * means the fixed point constants work just fine with the floating point
+ * API. The alternative would just lead to undetected errors and spurious
+ * bug reports. Negative values fail inside the _fixed API unless they
+ * correspond to the flag values.
+ */
+ if (output_gamma > 0 && output_gamma < 128)
+ output_gamma *= PNG_FP_1;
+
+ /* This preserves -1 and -2 exactly: */
+ output_gamma = floor(output_gamma + .5);
+
+ if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
+ png_fixed_error(png_ptr, "gamma value");
+
+ return (png_fixed_point)output_gamma;
+}
+# endif
+#endif /* READ_ALPHA_MODE || READ_GAMMA */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+void PNGFAPI
+png_set_alpha_mode_fixed(png_structp png_ptr, int mode,
+ png_fixed_point output_gamma)
+{
+ int compose = 0;
+ png_fixed_point file_gamma;
+
+ png_debug(1, "in png_set_alpha_mode");
+
+ if (png_ptr == NULL)
+ return;
+
+ output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
+
+ /* Validate the value to ensure it is in a reasonable range. The value
+ * is expected to be 1 or greater, but this range test allows for some
+ * viewing correction values. The intent is to weed out users of this API
+ * who use the inverse of the gamma value accidentally! Since some of these
+ * values are reasonable this may have to be changed.
+ */
+ if (output_gamma < 70000 || output_gamma > 300000)
+ png_error(png_ptr, "output gamma out of expected range");
+
+ /* The default file gamma is the inverse of the output gamma; the output
+ * gamma may be changed below so get the file value first:
+ */
+ file_gamma = png_reciprocal(output_gamma);
+
+ /* There are really 8 possibilities here, composed of any combination
+ * of:
+ *
+ * premultiply the color channels
+ * do not encode non-opaque pixels
+ * encode the alpha as well as the color channels
+ *
+ * The differences disappear if the input/output ('screen') gamma is 1.0,
+ * because then the encoding is a no-op and there is only the choice of
+ * premultiplying the color channels or not.
+ *
+ * png_set_alpha_mode and png_set_background interact because both use
+ * png_compose to do the work. Calling both is only useful when
+ * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
+ * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
+ */
+ switch (mode)
+ {
+ case PNG_ALPHA_PNG: /* default: png standard */
+ /* No compose, but it may be set by png_set_background! */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ /* The output is linear: */
+ output_gamma = PNG_FP_1;
+ break;
+
+ case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
+ /* output_gamma records the encoding of opaque pixels! */
+ break;
+
+ case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
+ compose = 1;
+ png_ptr->transformations |= PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ default:
+ png_error(png_ptr, "invalid alpha mode");
+ }
+
+ /* Only set the default gamma if the file gamma has not been set (this has
+ * the side effect that the gamma in a second call to png_set_alpha_mode will
+ * be ignored.)
+ */
+ if (png_ptr->gamma == 0)
+ png_ptr->gamma = file_gamma;
+
+ /* But always set the output gamma: */
+ png_ptr->screen_gamma = output_gamma;
+
+ /* Finally, if pre-multiplying, set the background fields to achieve the
+ * desired result.
+ */
+ if (compose)
+ {
+ /* And obtain alpha pre-multiplication by composing on black: */
+ png_memset(&png_ptr->background, 0, sizeof png_ptr->background);
+ png_ptr->background_gamma = png_ptr->gamma; /* just in case */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+
+ if (png_ptr->transformations & PNG_COMPOSE)
+ png_error(png_ptr,
+ "conflicting calls to set alpha mode and background");
+
+ png_ptr->transformations |= PNG_COMPOSE;
+ }
+
+ /* New API, make sure apps call the correct initializers: */
+ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma)
+{
+ png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
+ output_gamma));
+}
+# endif
+#endif
+
#ifdef PNG_READ_QUANTIZE_SUPPORTED
-/* Dither file to 8 bit. Supply a palette, the current number
+/* Dither file to 8-bit. Supply a palette, the current number
* of elements in the palette, the maximum number of elements
* allowed, and a histogram if possible. If the current number
* of colors is greater then the maximum number, the palette will be
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Transform the image from the file_gamma to the screen_gamma. We
- * only do transformations on images where the file_gamma and screen_gamma
- * are not close reciprocals, otherwise it slows things down slightly, and
- * also needlessly introduces small errors.
- *
- * We will turn off gamma transformation later if no semitransparent entries
- * are present in the tRNS array for palette images. We can't do it here
- * because we don't necessarily have the tRNS chunk yet.
- */
-static int /* PRIVATE */
-png_gamma_threshold(png_fixed_point scrn_gamma, png_fixed_point file_gamma)
-{
- /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
- * correction as a difference of the overall transform from 1.0
- *
- * We want to compare the threshold with s*f - 1, if we get
- * overflow here it is because of wacky gamma values so we
- * turn on processing anyway.
- */
- png_fixed_point gtest;
- return !png_muldiv(>est, scrn_gamma, file_gamma, PNG_FP_1) ||
- png_gamma_significant(gtest);
-}
-
void PNGFAPI
png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma,
png_fixed_point file_gamma)
if (png_ptr == NULL)
return;
- if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
- (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
- png_gamma_threshold(scrn_gamma, file_gamma))
- png_ptr->transformations |= PNG_GAMMA;
+ /* New in libpng-1.5.4 - reserve particular negative values as flags. */
+ scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
+ file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+
+#if PNG_LIBPNG_VER >= 10600
+ /* Checking the gamma values for being >0 was added in 1.5.4 along with the
+ * premultiplied alpha support; this actually hides an undocumented feature
+ * of the previous implementation which allowed gamma processing to be
+ * disabled in background handling. There is no evidence (so far) that this
+ * was being used; however, png_set_background itself accepted and must still
+ * accept '0' for the gamma value it takes, because it isn't always used.
+ *
+ * Since this is an API change (albeit a very minor one that removes an
+ * undocumented API feature) it will not be made until libpng-1.6.0.
+ */
+ if (file_gamma <= 0)
+ png_error(png_ptr, "invalid file gamma in png_set_gamma");
+
+ if (scrn_gamma <= 0)
+ png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+#endif
+
+ /* Set the gamma values unconditionally - this overrides the value in the PNG
+ * file if a gAMA chunk was present. png_set_alpha_mode provides a
+ * different, easier, way to default the file gamma.
+ */
png_ptr->gamma = file_gamma;
png_ptr->screen_gamma = scrn_gamma;
}
void PNGAPI
png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
{
- png_set_gamma_fixed(png_ptr,
- png_fixed(png_ptr, scrn_gamma, "png_set_gamma screen gamma"),
- png_fixed(png_ptr, file_gamma, "png_set_gamma file gamma"));
+ png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
+ convert_gamma_value(png_ptr, file_gamma));
}
# endif /* FLOATING_POINT_SUPPORTED */
#endif /* READ_GAMMA */
#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16 bit channels, expand the tRNS chunk too (because otherwise
+/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
* it may not work correctly.)
*/
void PNGAPI
return;
png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
- png_ptr->transformations &= ~PNG_16_TO_8;
-
png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+
+ /* New API, make sure apps call the correct initializers: */
+ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
}
#endif
switch(error_action)
{
- case 1:
+ case PNG_ERROR_ACTION_NONE:
png_ptr->transformations |= PNG_RGB_TO_GRAY;
break;
- case 2:
+ case PNG_ERROR_ACTION_WARN:
png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
break;
- case 3:
+ case PNG_ERROR_ACTION_ERROR:
png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
break;
}
#endif
{
- png_uint_16 red_int, green_int;
- if (red < 0 || green < 0)
+ if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
{
- red_int = 6968; /* .212671 * 32768 + .5 */
- green_int = 23434; /* .715160 * 32768 + .5 */
- }
+ png_uint_16 red_int, green_int;
- else if (red + green < 100000L)
- {
- red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
- green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
+ /* NOTE: this calculation does not round, but this behavior is retained
+ * for consistency, the inaccuracy is very small. The code here always
+ * overwrites the coefficients, regardless of whether they have been
+ * defaulted or set already.
+ */
+ red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
+ green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
+
+ png_ptr->rgb_to_gray_red_coeff = red_int;
+ png_ptr->rgb_to_gray_green_coeff = green_int;
+ png_ptr->rgb_to_gray_coefficients_set = 1;
}
else
{
- png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
- red_int = 6968;
- green_int = 23434;
+ if (red >= 0 && green >= 0)
+ png_warning(png_ptr,
+ "ignoring out of range rgb_to_gray coefficients");
+
+ /* Use the defaults, from the cHRM chunk if set, else the historical
+ * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
+ * png_do_rgb_to_gray for more discussion of the values. In this case
+ * the coefficients are not marked as 'set' and are not overwritten if
+ * something has already provided a default.
+ */
+ if (png_ptr->rgb_to_gray_red_coeff == 0 &&
+ png_ptr->rgb_to_gray_green_coeff == 0)
+ {
+ png_ptr->rgb_to_gray_red_coeff = 6968;
+ png_ptr->rgb_to_gray_green_coeff = 23434;
+ /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
+ }
}
-
- png_ptr->rgb_to_gray_red_coeff = red_int;
- png_ptr->rgb_to_gray_green_coeff = green_int;
- png_ptr->rgb_to_gray_blue_coeff =
- (png_uint_16)(32768 - red_int - green_int);
}
}
}
#endif
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* In the case of gamma transformations only do transformations on images where
+ * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
+ * slows things down slightly, and also needlessly introduces small errors.
+ */
+static int /* PRIVATE */
+png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
+{
+ /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
+ * correction as a difference of the overall transform from 1.0
+ *
+ * We want to compare the threshold with s*f - 1, if we get
+ * overflow here it is because of wacky gamma values so we
+ * turn on processing anyway.
+ */
+ png_fixed_point gtest;
+ return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
+ png_gamma_significant(gtest);
+}
+#endif
+
/* Initialize everything needed for the read. This includes modifying
* the palette.
*/
-void /* PRIVATE */
-png_init_read_transformations(png_structp png_ptr)
+
+/*For the moment 'png_init_palette_transformations' and
+ * 'png_init_rgb_transformations' only do some flag canceling optimizations.
+ * The intent is that these two routines should have palette or rgb operations
+ * extracted from 'png_init_read_transformations'.
+ */
+static void /* PRIVATE */
+png_init_palette_transformations(png_structp png_ptr)
{
- png_debug(1, "in png_init_read_transformations");
+ /* Called to handle the (input) palette case. In png_do_read_transformations
+ * the first step is to expand the palette if requested, so this code must
+ * take care to only make changes that are invariant with respect to the
+ * palette expansion, or only do them if there is no expansion.
+ *
+ * STRIP_ALPHA has already been handled in the caller (by setting num_trans
+ * to 0.)
+ */
+ int input_has_alpha = 0;
+ int input_has_transparency = 0;
- {
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
- defined(PNG_READ_SHIFT_SUPPORTED) || \
- defined(PNG_READ_GAMMA_SUPPORTED)
- int color_type = png_ptr->color_type;
-#endif
+ if (png_ptr->num_trans > 0)
+ {
+ int i;
+
+ /* Ignore if all the entries are opaque (unlikely!) */
+ for (i=0; i<png_ptr->num_trans; ++i)
+ if (png_ptr->trans_alpha[i] == 255)
+ continue;
+ else if (png_ptr->trans_alpha[i] == 0)
+ input_has_transparency = 1;
+ else
+ input_has_alpha = 1;
+ }
+
+ /* If no alpha we can optimize. */
+ if (!input_has_alpha)
+ {
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ if (!input_has_transparency)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+ }
#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- /* Detect gray background and attempt to enable optimization
- * for gray --> RGB case
- *
- * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
- * RGB_ALPHA (in which case need_expand is superfluous anyway), the
- * background color might actually be gray yet not be flagged as such.
- * This is not a problem for the current code, which uses
- * PNG_BACKGROUND_IS_GRAY only to decide when to do the
- * png_do_gray_to_rgb() transformation.
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
*/
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- !(color_type & PNG_COLOR_MASK_COLOR))
+ (png_ptr->transformations & PNG_EXPAND))
{
- png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
- }
+ {
+ png_ptr->background.red =
+ png_ptr->palette[png_ptr->background.index].red;
+ png_ptr->background.green =
+ png_ptr->palette[png_ptr->background.index].green;
+ png_ptr->background.blue =
+ png_ptr->palette[png_ptr->background.index].blue;
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+ if (png_ptr->transformations & PNG_INVERT_ALPHA)
+ {
+ if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+ {
+ /* Invert the alpha channel (in tRNS) unless the pixels are
+ * going to be expanded, in which case leave it for later
+ */
+ int i, istop = png_ptr->num_trans;
- else if ((png_ptr->transformations & PNG_BACKGROUND) &&
- !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
- png_ptr->background.red == png_ptr->background.green &&
- png_ptr->background.red == png_ptr->background.blue)
+ for (i=0; i<istop; i++)
+ png_ptr->trans_alpha[i] = (png_byte)(255 -
+ png_ptr->trans_alpha[i]);
+ }
+ }
+#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
+ }
+ } /* background expand and (therefore) no alpha association. */
+#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+}
+
+static void /* PRIVATE */
+png_init_rgb_transformations(png_structp png_ptr)
+{
+ /* Added to libpng-1.5.4: check the color type to determine whether there
+ * is any alpha or transparency in the image and simply cancel the
+ * background and alpha mode stuff if there isn't.
+ */
+ int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+ int input_has_transparency = png_ptr->num_trans > 0;
+
+ /* If no alpha we can optimize. */
+ if (!input_has_alpha)
{
- png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
- png_ptr->background.gray = png_ptr->background.red;
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+# endif
+
+ if (!input_has_transparency)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
}
-#endif
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
+
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
+ */
if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
- (png_ptr->transformations & PNG_EXPAND))
+ (png_ptr->transformations & PNG_EXPAND) &&
+ !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+ /* i.e., GRAY or GRAY_ALPHA */
{
- if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */
{
/* Expand background and tRNS chunks */
+ int gray = png_ptr->background.gray;
+ int trans_gray = png_ptr->trans_color.gray;
+
switch (png_ptr->bit_depth)
{
case 1:
- png_ptr->background.gray *= (png_uint_16)0xff;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0xff;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0xff;
+ trans_gray *= 0xff;
break;
case 2:
- png_ptr->background.gray *= (png_uint_16)0x55;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0x55;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0x55;
+ trans_gray *= 0x55;
break;
case 4:
- png_ptr->background.gray *= (png_uint_16)0x11;
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
- {
- png_ptr->trans_color.gray *= (png_uint_16)0x11;
- png_ptr->trans_color.red = png_ptr->trans_color.green
- = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
- }
+ gray *= 0x11;
+ trans_gray *= 0x11;
break;
default:
case 8:
+ /* Already 8 bits, fall through */
case 16:
- png_ptr->background.red = png_ptr->background.green
- = png_ptr->background.blue = png_ptr->background.gray;
+ /* Already a full 16 bits */
break;
}
+
+ png_ptr->background.red = png_ptr->background.green =
+ png_ptr->background.blue = (png_uint_16)gray;
+
+ if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+ {
+ png_ptr->trans_color.red = png_ptr->trans_color.green =
+ png_ptr->trans_color.blue = (png_uint_16)trans_gray;
+ }
}
- else if (color_type == PNG_COLOR_TYPE_PALETTE)
- {
- png_ptr->background.red =
- png_ptr->palette[png_ptr->background.index].red;
- png_ptr->background.green =
- png_ptr->palette[png_ptr->background.index].green;
- png_ptr->background.blue =
- png_ptr->palette[png_ptr->background.index].blue;
+ } /* background expand and (therefore) no alpha association. */
+#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
+}
-#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
- if (png_ptr->transformations & PNG_INVERT_ALPHA)
- {
-#ifdef PNG_READ_EXPAND_SUPPORTED
- if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
-#endif
- {
- /* Invert the alpha channel (in tRNS) unless the pixels are
- * going to be expanded, in which case leave it for later
- */
- int i, istop;
- istop=(int)png_ptr->num_trans;
- for (i=0; i<istop; i++)
- png_ptr->trans_alpha[i] = (png_byte)(255 -
- png_ptr->trans_alpha[i]);
- }
- }
-#endif
+void /* PRIVATE */
+png_init_read_transformations(png_structp png_ptr)
+{
+ png_debug(1, "in png_init_read_transformations");
+
+ /* This internal function is called from png_read_start_row in pngrutil.c
+ * and it is called before the 'rowbytes' calculation is done, so the code
+ * in here can change or update the transformations flags.
+ *
+ * First do updates that do not depend on the details of the PNG image data
+ * being processed.
+ */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
+ * png_set_alpha_mode and this is another source for a default file gamma so
+ * the test needs to be performed later - here. In addition prior to 1.5.4
+ * the tests were repeated for the PALETTE color type here - this is no
+ * longer necessary (and doesn't seem to have been necessary before.)
+ */
+ {
+ /* The following temporary indicates if overall gamma correction is
+ * required.
+ */
+ int gamma_correction = 0;
+
+ if (png_ptr->gamma != 0) /* has been set */
+ {
+ if (png_ptr->screen_gamma != 0) /* screen set too */
+ gamma_correction = png_gamma_threshold(png_ptr->gamma,
+ png_ptr->screen_gamma);
+
+ else
+ /* Assume the output matches the input; a long time default behavior
+ * of libpng, although the standard has nothing to say about this.
+ */
+ png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma);
}
+
+ else if (png_ptr->screen_gamma != 0)
+ /* The converse - assume the file matches the screen, note that this
+ * perhaps undesireable default can (from 1.5.4) be changed by calling
+ * png_set_alpha_mode (even if the alpha handling mode isn't required
+ * or isn't changed from the default.)
+ */
+ png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma);
+
+ else /* neither are set */
+ /* Just in case the following prevents any processing - file and screen
+ * are both assumed to be linear and there is no way to introduce a
+ * third gamma value other than png_set_background with 'UNIQUE', and,
+ * prior to 1.5.4
+ */
+ png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1;
+
+ /* Now turn the gamma transformation on or off as appropriate. Notice
+ * that PNG_GAMMA just refers to the file->screen correction. Alpha
+ * composition may independently cause gamma correction because it needs
+ * linear data (e.g. if the file has a gAMA chunk but the screen gamma
+ * hasn't been specified.) In any case this flag may get turned off in
+ * the code immediately below if the transform can be handled outside the
+ * row loop.
+ */
+ if (gamma_correction)
+ png_ptr->transformations |= PNG_GAMMA;
+
+ else
+ png_ptr->transformations &= ~PNG_GAMMA;
}
#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
- png_ptr->background_1 = png_ptr->background;
+ /* Certain transformations have the effect of preventing other
+ * transformations that happen afterward in png_do_read_transformations,
+ * resolve the interdependencies here. From the code of
+ * png_do_read_transformations the order is:
+ *
+ * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
+ * 2) PNG_STRIP_ALPHA (if no compose)
+ * 3) PNG_RGB_TO_GRAY
+ * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
+ * 5) PNG_COMPOSE
+ * 6) PNG_GAMMA
+ * 7) PNG_STRIP_ALPHA (if compose)
+ * 8) PNG_ENCODE_ALPHA
+ * 9) PNG_SCALE_16_TO_8
+ * 10) PNG_16_TO_8
+ * 11) PNG_QUANTIZE (converts to palette)
+ * 12) PNG_EXPAND_16
+ * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
+ * 14) PNG_INVERT_MONO
+ * 15) PNG_SHIFT
+ * 16) PNG_PACK
+ * 17) PNG_BGR
+ * 18) PNG_PACKSWAP
+ * 19) PNG_FILLER (includes PNG_ADD_ALPHA)
+ * 20) PNG_INVERT_ALPHA
+ * 21) PNG_SWAP_ALPHA
+ * 22) PNG_SWAP_BYTES
+ * 23) PNG_USER_TRANSFORM [must be last]
+ */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+ !(png_ptr->transformations & PNG_COMPOSE))
+ {
+ /* Stripping the alpha channel happens immediately after the 'expand'
+ * transformations, before all other transformation, so it cancels out
+ * the alpha handling. It has the side effect negating the effect of
+ * PNG_EXPAND_tRNS too:
+ */
+ png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
+ PNG_EXPAND_tRNS);
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
+ * so transparency information would remain just so long as it wasn't
+ * expanded. This produces unexpected API changes if the set of things
+ * that do PNG_EXPAND_tRNS changes (perfectly possible given the
+ * documentation - which says ask for what you want, accept what you
+ * get.) This makes the behavior consistent from 1.5.4:
+ */
+ png_ptr->num_trans = 0;
+ }
+#endif /* STRIP_ALPHA supported, no COMPOSE */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
+ * settings will have no effect.
+ */
+ if (!png_gamma_significant(png_ptr->screen_gamma))
+ {
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ }
#endif
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
- && png_gamma_threshold(png_ptr->screen_gamma, png_ptr->gamma))
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+ defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+ /* Detect gray background and attempt to enable optimization for
+ * gray --> RGB case.
+ *
+ * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+ * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+ * background color might actually be gray yet not be flagged as such.
+ * This is not a problem for the current code, which uses
+ * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+ * png_do_gray_to_rgb() transformation.
+ *
+ * TODO: this code needs to be revised to avoid the complexity and
+ * interdependencies. The color type of the background should be recorded in
+ * png_set_background, along with the bit depth, then the code has a record
+ * of exactly what color space the background is currently in.
+ */
+ if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
+ {
+ /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
+ * the file was grayscale the background value is gray.
+ */
+ if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ }
+
+ else if (png_ptr->transformations & PNG_COMPOSE)
{
- int i, k;
- k=0;
- for (i=0; i<png_ptr->num_trans; i++)
+ /* PNG_COMPOSE: png_set_background was called with need_expand false,
+ * so the color is in the color space of the output or png_set_alpha_mode
+ * was called and the color is black. Ignore RGB_TO_GRAY because that
+ * happens before GRAY_TO_RGB.
+ */
+ if (png_ptr->transformations & PNG_GRAY_TO_RGB)
{
- if (png_ptr->trans_alpha[i] != 0 && png_ptr->trans_alpha[i] != 0xff)
- k=1; /* Partial transparency is present */
+ if (png_ptr->background.red == png_ptr->background.green &&
+ png_ptr->background.red == png_ptr->background.blue)
+ {
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ png_ptr->background.gray = png_ptr->background.red;
+ }
}
- if (k == 0)
- png_ptr->transformations &= ~PNG_GAMMA;
}
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */
+
+ /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
+ * can be performed directly on the palette, and some (such as rgb to gray)
+ * can be optimized inside the palette. This is particularly true of the
+ * composite (background and alpha) stuff, which can be pretty much all done
+ * in the palette even if the result is expanded to RGB or gray afterward.
+ *
+ * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
+ * earlier and the palette stuff is actually handled on the first row. This
+ * leads to the reported bug that the palette returned by png_get_PLTE is not
+ * updated.
+ */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ png_init_palette_transformations(png_ptr);
- if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
- png_ptr->gamma != 0)
+ else
+ png_init_rgb_transformations(png_ptr);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ defined(PNG_READ_EXPAND_16_SUPPORTED)
+ if ((png_ptr->transformations & PNG_EXPAND_16) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+ png_ptr->bit_depth != 16)
+ {
+ /* TODO: fix this. Because the expand_16 operation is after the compose
+ * handling the background color must be 8, not 16, bits deep, but the
+ * application will supply a 16-bit value so reduce it here.
+ *
+ * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
+ * present, so that case is ok (until do_expand_16 is moved.)
+ *
+ * NOTE: this discards the low 16 bits of the user supplied background
+ * color, but until expand_16 works properly there is no choice!
+ */
+# define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16))
+ CHOP(png_ptr->background.red);
+ CHOP(png_ptr->background.green);
+ CHOP(png_ptr->background.blue);
+ CHOP(png_ptr->background.gray);
+# undef CHOP
+ }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+ defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+ if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+ png_ptr->bit_depth == 16)
+ {
+ /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+ * component this will also happen after PNG_COMPOSE and so the background
+ * color must be pre-expanded here.
+ *
+ * TODO: fix this too.
+ */
+ png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+ png_ptr->background.green =
+ (png_uint_16)(png_ptr->background.green * 257);
+ png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+ png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+ }
+#endif
+
+ /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
+ * background support (see the comments in scripts/pnglibconf.dfa), this
+ * allows pre-multiplication of the alpha channel to be implemented as
+ * compositing on black. This is probably sub-optimal and has been done in
+ * 1.5.4 betas simply to enable external critique and testing (i.e. to
+ * implement the new API quickly, without lots of internal changes.)
+ */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ /* Includes ALPHA_MODE */
+ png_ptr->background_1 = png_ptr->background;
+# endif
+
+ /* This needs to change - in the palette image case a whole set of tables are
+ * built when it would be quicker to just calculate the correct value for
+ * each palette entry directly. Also, the test is too tricky - why check
+ * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
+ * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
+ * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
+ * the gamma tables will not be built even if composition is required on a
+ * gamma encoded value.
+ *
+ * In 1.5.4 this is addressed below by an additional check on the individual
+ * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
+ * tables.
+ */
+ if ((png_ptr->transformations & PNG_GAMMA)
+ || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
+ && (png_gamma_significant(png_ptr->gamma) ||
+ png_gamma_significant(png_ptr->screen_gamma)))
+ || ((png_ptr->transformations & PNG_COMPOSE)
+ && (png_gamma_significant(png_ptr->gamma)
+ || png_gamma_significant(png_ptr->screen_gamma)
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
+ && png_gamma_significant(png_ptr->background_gamma))
+# endif
+ )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
+ && png_gamma_significant(png_ptr->screen_gamma))
+ )
{
png_build_gamma_table(png_ptr, png_ptr->bit_depth);
#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->transformations & PNG_BACKGROUND)
+ if (png_ptr->transformations & PNG_COMPOSE)
{
- if (color_type == PNG_COLOR_TYPE_PALETTE)
+ /* Issue a warning about this combination: because RGB_TO_GRAY is
+ * optimized to do the gamma transform if present yet do_background has
+ * to do the same thing if both options are set a
+ * double-gamma-correction happens. This is true in all versions of
+ * libpng to date.
+ */
+ if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+ png_warning(png_ptr,
+ "libpng does not support gamma+background+rgb_to_gray");
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
- /* Could skip if no transparency */
+ /* We don't get to here unless there is a tRNS chunk with non-opaque
+ * entries - see the checking code at the start of this function.
+ */
png_color back, back_1;
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
}
if (png_gamma_significant(gs))
+ {
+ back.red = png_gamma_8bit_correct(png_ptr->background.red,
+ gs);
+ back.green = png_gamma_8bit_correct(png_ptr->background.green,
+ gs);
+ back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ gs);
+ }
+
+ else
{
back.red = (png_byte)png_ptr->background.red;
back.green = (png_byte)png_ptr->background.green;
back.blue = (png_byte)png_ptr->background.blue;
}
+ if (png_gamma_significant(g))
+ {
+ back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
+ g);
+ back_1.green = png_gamma_8bit_correct(
+ png_ptr->background.green, g);
+ back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ g);
+ }
+
else
{
- back.red = png_gamma_8bit_correct(png_ptr->background.red,
- gs);
- back.green = png_gamma_8bit_correct(png_ptr->background.green,
- gs);
- back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- gs);
+ back_1.red = (png_byte)png_ptr->background.red;
+ back_1.green = (png_byte)png_ptr->background.green;
+ back_1.blue = (png_byte)png_ptr->background.blue;
}
- back_1.red = png_gamma_8bit_correct(png_ptr->background.red, g);
- back_1.green = png_gamma_8bit_correct(png_ptr->background.green,
- g);
- back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
- g);
}
+
for (i = 0; i < num_palette; i++)
{
if (i < (int)png_ptr->num_trans &&
palette[i].blue = png_ptr->gamma_table[palette[i].blue];
}
}
- /* Prevent the transformations being done again, and make sure
- * that the now spurious alpha channel is stripped - the code
- * has just reduced background composition and gamma correction
- * to a simple alpha channel strip.
+
+ /* Prevent the transformations being done again.
+ *
+ * NOTE: this is highly dubious; it removes the transformations in
+ * place. This seems inconsistent with the general treatment of the
+ * transformations elsewhere.
*/
- png_ptr->transformations &= ~PNG_BACKGROUND;
- png_ptr->transformations &= ~PNG_GAMMA;
- png_ptr->transformations |= PNG_STRIP_ALPHA;
- }
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
+ } /* color_type == PNG_COLOR_TYPE_PALETTE */
/* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
- else
- /* color_type != PNG_COLOR_TYPE_PALETTE */
+ else /* color_type != PNG_COLOR_TYPE_PALETTE */
{
- png_fixed_point g = PNG_FP_1;
- png_fixed_point gs = PNG_FP_1;
+ int gs_sig, g_sig;
+ png_fixed_point g = PNG_FP_1; /* Correction to linear */
+ png_fixed_point gs = PNG_FP_1; /* Correction to screen */
switch (png_ptr->background_gamma_type)
{
png_error(png_ptr, "invalid background gamma type");
}
- png_ptr->background_1.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, g);
+ g_sig = png_gamma_significant(g);
+ gs_sig = png_gamma_significant(gs);
- png_ptr->background.gray = png_gamma_correct(png_ptr,
- png_ptr->background.gray, gs);
+ if (g_sig)
+ png_ptr->background_1.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, g);
+
+ if (gs_sig)
+ png_ptr->background.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, gs);
if ((png_ptr->background.red != png_ptr->background.green) ||
(png_ptr->background.red != png_ptr->background.blue) ||
(png_ptr->background.red != png_ptr->background.gray))
{
/* RGB or RGBA with color background */
- png_ptr->background_1.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, g);
+ if (g_sig)
+ {
+ png_ptr->background_1.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, g);
- png_ptr->background_1.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, g);
+ png_ptr->background_1.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, g);
- png_ptr->background_1.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, g);
+ png_ptr->background_1.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, g);
+ }
- png_ptr->background.red = png_gamma_correct(png_ptr,
- png_ptr->background.red, gs);
+ if (gs_sig)
+ {
+ png_ptr->background.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, gs);
- png_ptr->background.green = png_gamma_correct(png_ptr,
- png_ptr->background.green, gs);
+ png_ptr->background.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, gs);
- png_ptr->background.blue = png_gamma_correct(png_ptr,
- png_ptr->background.blue, gs);
+ png_ptr->background.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, gs);
+ }
}
else
png_ptr->background.red = png_ptr->background.green
= png_ptr->background.blue = png_ptr->background.gray;
}
- }
- }
+
+ /* The background is now in screen gamma: */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
+ } /* color_type != PNG_COLOR_TYPE_PALETTE */
+ }/* png_ptr->transformations & PNG_BACKGROUND */
+
else
/* Transformation does not include PNG_BACKGROUND */
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
- if (color_type == PNG_COLOR_TYPE_PALETTE)
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+ && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+ (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+ )
{
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
int i;
+ /*NOTE: there are other transformations that should probably be in here
+ * too.
+ */
for (i = 0; i < num_palette; i++)
{
palette[i].red = png_ptr->gamma_table[palette[i].red];
/* Done the gamma correction. */
png_ptr->transformations &= ~PNG_GAMMA;
- }
+ } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
}
#ifdef PNG_READ_BACKGROUND_SUPPORTED
else
#endif
#endif /* PNG_READ_GAMMA_SUPPORTED */
+
#ifdef PNG_READ_BACKGROUND_SUPPORTED
- /* No GAMMA transformation */
- if ((png_ptr->transformations & PNG_BACKGROUND) &&
- (color_type == PNG_COLOR_TYPE_PALETTE))
+ /* No GAMMA transformation (see the hanging else 4 lines above) */
+ if ((png_ptr->transformations & PNG_COMPOSE) &&
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
{
int i;
int istop = (int)png_ptr->num_trans;
}
}
- /* Handled alpha, still need to strip the channel. */
- png_ptr->transformations &= ~PNG_BACKGROUND;
- png_ptr->transformations |= PNG_STRIP_ALPHA;
+ png_ptr->transformations &= ~PNG_COMPOSE;
}
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
#ifdef PNG_READ_SHIFT_SUPPORTED
if ((png_ptr->transformations & PNG_SHIFT) &&
- (color_type == PNG_COLOR_TYPE_PALETTE))
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
{
- png_uint_16 i;
- png_uint_16 istop = png_ptr->num_palette;
- int sr = 8 - png_ptr->sig_bit.red;
- int sg = 8 - png_ptr->sig_bit.green;
- int sb = 8 - png_ptr->sig_bit.blue;
+ int i;
+ int istop = png_ptr->num_palette;
+ int shift = 8 - png_ptr->sig_bit.red;
- if (sr < 0 || sr > 8)
- sr = 0;
+ /* significant bits can be in the range 1 to 7 for a meaninful result, if
+ * the number of significant bits is 0 then no shift is done (this is an
+ * error condition which is silently ignored.)
+ */
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].red;
+
+ component >>= shift;
+ png_ptr->palette[i].red = (png_byte)component;
+ }
- if (sg < 0 || sg > 8)
- sg = 0;
+ shift = 8 - png_ptr->sig_bit.green;
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].green;
- if (sb < 0 || sb > 8)
- sb = 0;
+ component >>= shift;
+ png_ptr->palette[i].green = (png_byte)component;
+ }
- for (i = 0; i < istop; i++)
+ shift = 8 - png_ptr->sig_bit.blue;
+ if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
{
- png_ptr->palette[i].red >>= sr;
- png_ptr->palette[i].green >>= sg;
- png_ptr->palette[i].blue >>= sb;
+ int component = png_ptr->palette[i].blue;
+
+ component >>= shift;
+ png_ptr->palette[i].blue = (png_byte)component;
}
}
#endif /* PNG_READ_SHIFT_SUPPORTED */
- }
-#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
- && !defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr)
- return;
-#endif
}
/* Modify the info structure to reflect the transformations. The
{
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
- if (png_ptr->num_trans &&
- (png_ptr->transformations & PNG_EXPAND_tRNS))
+ /* This check must match what actually happens in
+ * png_do_expand_palette; if it ever checks the tRNS chunk to see if
+ * it is all opaque we must do the same (at present it does not.)
+ */
+ if (png_ptr->num_trans > 0)
info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
else
}
#endif
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
- if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
- info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
- {
- info_ptr->bit_depth = 16;
- }
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (png_ptr->transformations & PNG_BACKGROUND)
- {
- info_ptr->color_type = (png_byte)(info_ptr->color_type &
- ~PNG_COLOR_MASK_ALPHA);
- info_ptr->num_trans = 0;
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* The following is almost certainly wrong unless the background value is in
+ * the screen space!
+ */
+ if (png_ptr->transformations & PNG_COMPOSE)
info_ptr->background = png_ptr->background;
- }
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
- if (png_ptr->transformations & PNG_GAMMA)
- {
- info_ptr->gamma = png_ptr->gamma;
- }
+ /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
+ * however it seems that the code in png_init_read_transformations, which has
+ * been called before this from png_read_update_info->png_read_start_row
+ * sometimes does the gamma transform and cancels the flag.
+ */
+ info_ptr->gamma = png_ptr->gamma;
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-#ifdef PNG_READ_16BIT_SUPPORTED
- if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
- info_ptr->bit_depth = 8;
-#else
- /* Force chopping 16-bit input down to 8 */
if (info_ptr->bit_depth == 16)
{
- png_ptr->transformations |=PNG_16_TO_8;
- info_ptr->bit_depth = 8;
+# ifdef PNG_READ_16BIT_SUPPORTED
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+ info_ptr->bit_depth = 8;
+# endif
+
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_16_TO_8)
+ info_ptr->bit_depth = 8;
+# endif
+
+# else
+ /* No 16 bit support: force chopping 16-bit input down to 8, in this case
+ * the app program can chose if both APIs are available by setting the
+ * correct scaling to use.
+ */
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* For compatibility with previous versions use the strip method by
+ * default. This code works because if PNG_SCALE_16_TO_8 is already
+ * set the code below will do that in preference to the chop.
+ */
+ png_ptr->transformations |= PNG_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+ CONFIGURATION ERROR: you must enable at least one 16 to 8 method
+# endif
+# endif
+#endif /* !READ_16BIT_SUPPORTED */
}
-#endif
-#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
if (png_ptr->transformations & PNG_GRAY_TO_RGB)
- info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+ info_ptr->color_type = (png_byte)(info_ptr->color_type |
+ PNG_COLOR_MASK_COLOR);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
- info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_COLOR);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
}
#endif
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
+ info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ info_ptr->bit_depth = 16;
+ }
+#endif
+
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
info_ptr->bit_depth = 8;
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_STRIP_ALPHA)
- info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+ {
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_ALPHA);
+ info_ptr->num_trans = 0;
+ }
#endif
if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+ /* Adding in 1.5.4: cache the above value in png_struct so that we can later
+ * check in png_rowbytes that the user buffer won't get overwritten. Note
+ * that the field is not always set - if png_read_update_info isn't called
+ * the application has to either not do any transforms or get the calculation
+ * right itself.
+ */
+ png_ptr->info_rowbytes = info_ptr->rowbytes;
+
#ifndef PNG_READ_EXPAND_SUPPORTED
if (png_ptr)
return;
* decide how it fits in with the other transformations here.
*/
void /* PRIVATE */
-png_do_read_transformations(png_structp png_ptr)
+png_do_read_transformations(png_structp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_read_transformations");
if (png_ptr->row_buf == NULL)
{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[50];
-
- png_snprintf2(msg, 50,
- "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,
- png_ptr->pass);
- png_error(png_ptr, msg);
-#else
+ /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+ * error is incredibly rare and incredibly easy to debug without this
+ * information.
+ */
png_error(png_ptr, "NULL row buffer");
-#endif
}
-#ifdef PNG_WARN_UNINITIALIZED_ROW
- if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
- /* Application has failed to call either png_read_start_image()
- * or png_read_update_info() after setting transforms that expand
- * pixels. This check added to libpng-1.2.19
+
+ /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+ * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+ * PNG_WARN_UNINITIALIZED_ROW removed. In 1.5 the new flag is set only for
+ * selected new APIs to ensure that there is no API change.
+ */
+ if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+ !(png_ptr->flags & PNG_FLAG_ROW_INIT))
+ {
+ /* Application has failed to call either png_read_start_image() or
+ * png_read_update_info() after setting transforms that expand pixels.
+ * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
*/
-#if (PNG_WARN_UNINITIALIZED_ROW==1)
png_error(png_ptr, "Uninitialized row");
-#else
- png_warning(png_ptr, "Uninitialized row");
-#endif
-#endif
+ }
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
- if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
{
- png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand_palette(row_info, png_ptr->row_buf + 1,
png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
}
{
if (png_ptr->num_trans &&
(png_ptr->transformations & PNG_EXPAND_tRNS))
- png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand(row_info, png_ptr->row_buf + 1,
&(png_ptr->trans_color));
else
- png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_expand(row_info, png_ptr->row_buf + 1,
NULL);
}
}
#endif
- /* Delay the 'expand 16' step until later for efficiency, so that the
- * intermediate steps work with 8 bit data.
- */
-
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
- (png_ptr->row_info.color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
- png_ptr->row_info.color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
- png_do_strip_channel(&(png_ptr->row_info), png_ptr->row_buf + 1,
- 0/*!at_start, because SWAP_ALPHA happens later*/);
+ !(png_ptr->transformations & PNG_COMPOSE) &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
{
int rgb_error =
- png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info),
+ png_do_rgb_to_gray(png_ptr, row_info,
png_ptr->row_buf + 1);
if (rgb_error)
*/
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
- png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if ((png_ptr->transformations & PNG_BACKGROUND) &&
- ((png_ptr->num_trans != 0) ||
- (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
- png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
- &(png_ptr->trans_color), &(png_ptr->background)
-#ifdef PNG_READ_GAMMA_SUPPORTED
- , &(png_ptr->background_1),
- png_ptr->gamma_table, png_ptr->gamma_from_1,
- png_ptr->gamma_to_1, png_ptr->gamma_16_table,
- png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
- png_ptr->gamma_shift
-#endif
- );
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
+ if (png_ptr->transformations & PNG_COMPOSE)
+ png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- !((png_ptr->transformations & PNG_BACKGROUND) &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Because RGB_TO_GRAY does the gamma transform. */
+ !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+#endif
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* Because PNG_COMPOSE does the gamma transform if there is something to
+ * do (if there is an alpha channel or transparency.)
+ */
+ !((png_ptr->transformations & PNG_COMPOSE) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
+ /* Because png_init_read_transformations transforms the palette, unless
+ * RGB_TO_GRAY will do the transform.
+ */
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
- png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
- png_ptr->gamma_table, png_ptr->gamma_16_table,
- png_ptr->gamma_shift);
+ png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA))
+ png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if (png_ptr->transformations & PNG_SCALE_16_TO_8)
+ png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* There is no harm in doing both of these because only one has any effect,
+ * by putting the 'scale' option first if the app asks for scale (either by
+ * calling the API or in a TRANSFORM flag) this is what happens.
+ */
if (png_ptr->transformations & PNG_16_TO_8)
- png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_chop(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
if (png_ptr->transformations & PNG_QUANTIZE)
{
- png_do_quantize(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_quantize(row_info, png_ptr->row_buf + 1,
png_ptr->palette_lookup, png_ptr->quantize_index);
- if (png_ptr->row_info.rowbytes == 0)
+ if (row_info->rowbytes == 0)
png_error(png_ptr, "png_do_quantize returned rowbytes=0");
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
* better accuracy results faster!)
*/
if (png_ptr->transformations & PNG_EXPAND_16)
- png_do_expand_16(&png_ptr->row_info, png_ptr->row_buf + 1);
+ png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ /*NOTE: moved here in 1.5.4 (from much later in this list.) */
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+ (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
- png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
- png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_unshift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_READ_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
- png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_unpack(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
- png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
- png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
-#endif
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
- /*NOTE: this must be in the wrong place - what happens if BGR is set too?
- * Need pngvalid to test this combo.
- */
- /* If gray -> RGB, do so now only if we did not do so above */
- if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
- (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
- png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
- png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_read_filler(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->filler, png_ptr->flags);
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
- png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
- png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_16BIT_SUPPORTED
#ifdef PNG_READ_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
- png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#endif
{
if (png_ptr->read_user_transform_fn != NULL)
(*(png_ptr->read_user_transform_fn)) /* User read transform function */
- (png_ptr, /* png_ptr */
- &(png_ptr->row_info), /* row_info: */
+ (png_ptr, /* png_ptr */
+ row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
png_ptr->row_buf + 1); /* start of pixel data for row */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
if (png_ptr->user_transform_depth)
- png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
+ row_info->bit_depth = png_ptr->user_transform_depth;
if (png_ptr->user_transform_channels)
- png_ptr->row_info.channels = png_ptr->user_transform_channels;
+ row_info->channels = png_ptr->user_transform_channels;
#endif
- png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
- png_ptr->row_info.channels);
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+ row_info->channels);
- png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
- png_ptr->row_info.width);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
}
#endif
-
}
#ifdef PNG_READ_PACK_SUPPORTED
png_do_unshift(png_row_infop row_info, png_bytep row,
png_const_color_8p sig_bits)
{
+ int color_type;
+
png_debug(1, "in png_do_unshift");
- if (
- row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+ /* The palette case has already been handled in the _init routine. */
+ color_type = row_info->color_type;
+
+ if (color_type != PNG_COLOR_TYPE_PALETTE)
{
int shift[4];
int channels = 0;
- int c;
- png_uint_16 value = 0;
- png_uint_32 row_width = row_info->width;
+ int bit_depth = row_info->bit_depth;
- if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+ if (color_type & PNG_COLOR_MASK_COLOR)
{
- shift[channels++] = row_info->bit_depth - sig_bits->red;
- shift[channels++] = row_info->bit_depth - sig_bits->green;
- shift[channels++] = row_info->bit_depth - sig_bits->blue;
+ shift[channels++] = bit_depth - sig_bits->red;
+ shift[channels++] = bit_depth - sig_bits->green;
+ shift[channels++] = bit_depth - sig_bits->blue;
}
else
{
- shift[channels++] = row_info->bit_depth - sig_bits->gray;
+ shift[channels++] = bit_depth - sig_bits->gray;
}
- if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+ if (color_type & PNG_COLOR_MASK_ALPHA)
{
- shift[channels++] = row_info->bit_depth - sig_bits->alpha;
+ shift[channels++] = bit_depth - sig_bits->alpha;
}
- for (c = 0; c < channels; c++)
{
- if (shift[c] <= 0)
- shift[c] = 0;
+ int c, have_shift;
- else
- value = 1;
- }
+ for (c = have_shift = 0; c < channels; ++c)
+ {
+ /* A shift of more than the bit depth is an error condition but it
+ * gets ignored here.
+ */
+ if (shift[c] <= 0 || shift[c] >= bit_depth)
+ shift[c] = 0;
- if (!value)
- return;
+ else
+ have_shift = 1;
+ }
- switch (row_info->bit_depth)
+ if (!have_shift)
+ return;
+ }
+
+ switch (bit_depth)
{
default:
+ /* Must be 1bpp gray: should not be here! */
+ /* NOTREACHED */
break;
case 2:
+ /* Must be 2bpp gray */
+ /* assert(channels == 1 && shift[0] == 1) */
{
- png_bytep bp;
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
- for (bp = row, i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp >>= 1;
- *bp++ &= 0x55;
+ int b = (*bp >> 1) & 0x55;
+ *bp++ = (png_byte)b;
}
break;
}
case 4:
+ /* Must be 4bpp gray */
+ /* assert(channels == 1) */
{
png_bytep bp = row;
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
- png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
- (png_byte)((int)0xf >> shift[0]));
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int gray_shift = shift[0];
+ int mask = 0xf >> gray_shift;
+
+ mask |= mask << 4;
- for (i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp >>= shift[0];
- *bp++ &= mask;
+ int b = (*bp >> gray_shift) & mask;
+ *bp++ = (png_byte)b;
}
break;
}
case 8:
+ /* Single byte components, G, GA, RGB, RGBA */
{
png_bytep bp = row;
- png_uint_32 i;
- png_uint_32 istop = row_width * channels;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
- for (i = 0; i < istop; i++)
+ while (bp < bp_end)
{
- *bp++ >>= shift[i%channels];
+ int b = *bp >> shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)b;
}
break;
}
#ifdef PNG_READ_16BIT_SUPPORTED
case 16:
+ /* Double byte components, G, GA, RGB, RGBA */
{
png_bytep bp = row;
- png_uint_32 i;
- png_uint_32 istop = channels * row_width;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
+
+ while (bp < bp_end)
+ {
+ int value = (bp[0] << 8) + bp[1];
+
+ value >>= shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)(value >> 8);
+ *bp++ = (png_byte)(value & 0xff);
+ }
+ break;
+ }
+#endif
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale rows of bit depth 16 down to 8 accurately */
+void /* PRIVATE */
+png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_scale_16_to_8");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+ while (sp < ep)
+ {
+ /* The input is an array of 16 bit components, these must be scaled to
+ * 8 bits each. For a 16 bit value V the required value (from the PNG
+ * specification) is:
+ *
+ * (V * 255) / 65535
+ *
+ * This reduces to round(V / 257), or floor((V + 128.5)/257)
+ *
+ * Represent V as the two byte value vhi.vlo. Make a guess that the
+ * result is the top byte of V, vhi, then the correction to this value
+ * is:
+ *
+ * error = floor(((V-vhi.vhi) + 128.5) / 257)
+ * = floor(((vlo-vhi) + 128.5) / 257)
+ *
+ * This can be approximated using integer arithmetic (and a signed
+ * shift):
+ *
+ * error = (vlo-vhi+128) >> 8;
+ *
+ * The approximate differs from the exact answer only when (vlo-vhi) is
+ * 128; it then gives a correction of +1 when the exact correction is
+ * 0. This gives 128 errors. The exact answer (correct for all 16 bit
+ * input values) is:
+ *
+ * error = (vlo-vhi+128)*65535 >> 24;
+ *
+ * An alternative arithmetic calculation which also gives no errors is:
+ *
+ * (V * 255 + 32895) >> 16
+ */
- for (i = 0; i < istop; i++)
- {
- value = (png_uint_16)((*bp << 8) + *(bp + 1));
- value >>= shift[i%channels];
- *bp++ = (png_byte)(value >> 8);
- *bp++ = (png_byte)(value & 0xff);
- }
- break;
- }
-#endif
+ png_int_32 tmp = *sp++; /* must be signed! */
+ tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
+ *dp++ = (png_byte)tmp;
}
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+ row_info->rowbytes = row_info->width * row_info->channels;
}
}
#endif
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-/* Chop rows of bit depth 16 down to 8 */
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
void /* PRIVATE */
+/* Simply discard the low byte. This was the default behavior prior
+ * to libpng-1.5.4.
+ */
png_do_chop(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_chop");
if (row_info->bit_depth == 16)
{
- png_bytep sp = row;
- png_bytep dp = row;
- png_uint_32 i;
- png_uint_32 istop = row_info->width * row_info->channels;
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
- for (i = 0; i<istop; i++, sp += 2, dp++)
+ while (sp < ep)
{
-#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
- /* This does a more accurate scaling of the 16-bit color
- * value, rather than a simple low-byte truncation.
- *
- * What the ideal calculation should be:
- * *dp = (((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) * 255 + 127)
- * / (png_uint_32)65535L;
- *
- * GRR: no, I think this is what it really should be:
- * *dp = (((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) + 128L)
- * / (png_uint_32)257L;
- *
- * GRR: here's the exact calculation with shifts:
- * temp = (((png_uint_32)(*sp) << 8) |
- * (png_uint_32)(*(sp + 1))) + 128L;
- * *dp = (temp - (temp >> 8)) >> 8;
- *
- * Approximate calculation with shift/add instead of multiply/divide:
- * *dp = ((((png_uint_32)(*sp) << 8) |
- * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
- *
- * What we actually do to avoid extra shifting and conversion:
- */
-
- *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
-#else
- /* Simply discard the low order byte */
- *dp = *sp;
-#endif
+ *dp++ = *sp;
+ sp += 2; /* skip low byte */
}
+
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
row_info->rowbytes = row_info->width * row_info->channels;
}
}
}
- row_info->channels += (png_byte)2;
+ row_info->channels = (png_byte)(row_info->channels + 2);
row_info->color_type |= PNG_COLOR_MASK_COLOR;
row_info->pixel_depth = (png_byte)(row_info->channels *
row_info->bit_depth);
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Reduce RGB files to grayscale, with or without alpha
- * using the equation given in Poynton's ColorFAQ at
- * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008)
- * New link:
- * <http://www.poynton.com/notes/colour_and_gamma/>
+ * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
+ * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
+ * versions dated 1998 through November 2002 have been archived at
+ * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
+ * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
* Charles Poynton poynton at poynton.com
*
* Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
*
- * We approximate this with
+ * which can be expressed with integers as
+ *
+ * Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ * Poynton's current link (as of January 2003 through July 2011):
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * has changed the numbers slightly:
*
- * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B
+ * Y = 0.2126*R + 0.7152*G + 0.0722*B
*
* which can be expressed with integers as
*
- * Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ * Y = (6966 * R + 23436 * G + 2366 * B)/32768
+ *
+ * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
+ * end point chromaticities and the D65 white point. Depending on the
+ * precision used for the D65 white point this produces a variety of different
+ * numbers, however if the four decimal place value used in ITU-R Rec 709 is
+ * used (0.3127,0.3290) the Y calculation would be:
+ *
+ * Y = (6968 * R + 23435 * G + 2366 * B)/32768
+ *
+ * While this is correct the rounding results in an overflow for white, because
+ * the sum of the rounded coefficients is 32769, not 32768. Consequently
+ * libpng uses, instead, the closest non-overflowing approximation:
*
- * The calculation is to be done in a linear colorspace.
+ * Y = (6968 * R + 23434 * G + 2366 * B)/32768
*
- * Other integer coefficents can be used via png_set_rgb_to_gray().
+ * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
+ * (including an sRGB chunk) then the chromaticities are used to calculate the
+ * coefficients. See the chunk handling in pngrutil.c for more information.
+ *
+ * In all cases the calculation is to be done in a linear colorspace. If no
+ * gamma information is available to correct the encoding of the original RGB
+ * values this results in an implicit assumption that the original PNG RGB
+ * values were linear.
+ *
+ * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
+ * the API takes just red and green coefficients the blue coefficient is
+ * calculated to make the sum 32768. This will result in different rounding
+ * to that used above.
*/
int /* PRIVATE */
png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
{
- png_uint_32 i;
-
- png_uint_32 row_width = row_info->width;
int rgb_error = 0;
png_debug(1, "in png_do_rgb_to_gray");
if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
- png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
- png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
- png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
+ PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+ PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+ PNG_CONST png_uint_32 bc = 32768 - rc - gc;
+ PNG_CONST png_uint_32 row_width = row_info->width;
+ PNG_CONST int have_alpha =
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
- if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ if (row_info->bit_depth == 8)
{
- if (row_info->bit_depth == 8)
- {
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ /* Notice that gamma to/from 1 are not necessarily inverses (if
+ * there is an overall gamma correction). Prior to 1.5.5 this code
+ * checked the linearized values for equality; this doesn't match
+ * the documentation, the original values must be checked.
+ */
+ if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
- for (i = 0; i < row_width; i++)
+ if (red != green || red != blue)
{
- png_byte red = png_ptr->gamma_to_1[*(sp++)];
- png_byte green = png_ptr->gamma_to_1[*(sp++)];
- png_byte blue = png_ptr->gamma_to_1[*(sp++)];
-
- if (red != green || red != blue)
- {
- rgb_error |= 1;
- *(dp++) = png_ptr->gamma_from_1[
- (rc*red + gc*green + bc*blue)>>15];
- }
+ red = png_ptr->gamma_to_1[red];
+ green = png_ptr->gamma_to_1[green];
+ blue = png_ptr->gamma_to_1[blue];
- else
- *(dp++) = *(sp - 1);
+ rgb_error |= 1;
+ *(dp++) = png_ptr->gamma_from_1[
+ (rc*red + gc*green + bc*blue + 16384)>>15];
}
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_byte red = *(sp++);
- png_byte green = *(sp++);
- png_byte blue = *(sp++);
- if (red != green || red != blue)
- {
- rgb_error |= 1;
- *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
- }
+ else
+ {
+ /* If there is no overall correction the table will not be
+ * set.
+ */
+ if (png_ptr->gamma_table != NULL)
+ red = png_ptr->gamma_table[red];
- else
- *(dp++) = *(sp - 1);
+ *(dp++) = red;
}
+
+ if (have_alpha)
+ *(dp++) = *(sp++);
}
}
-
- else /* RGB bit_depth == 16 */
+ else
+#endif
{
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_16_to_1 != NULL &&
- png_ptr->gamma_16_from_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, w;
-
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
- if (red == green && red == blue)
- w = red;
-
- else
- {
- png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff)
- >> png_ptr->gamma_shift][red>>8];
- png_uint_16 green_1 =
- png_ptr->gamma_16_to_1[(green&0xff) >>
- png_ptr->gamma_shift][green>>8];
- png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff)
- >> png_ptr->gamma_shift][blue>>8];
- png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
- + bc*blue_1)>>15);
- w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
- png_ptr->gamma_shift][gray16 >> 8];
- rgb_error |= 1;
- }
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
- *(dp++) = (png_byte)((w>>8) & 0xff);
- *(dp++) = (png_byte)(w & 0xff);
- }
- }
- else
-#endif
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, gray16;
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ if (red != green || red != blue)
+ {
+ rgb_error |= 1;
+ /*NOTE: this is the historical approach which simply
+ * truncates the results.
+ */
+ *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+ }
- if (red != green || red != blue)
- rgb_error |= 1;
+ else
+ *(dp++) = red;
- gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = (png_byte)((gray16>>8) & 0xff);
- *(dp++) = (png_byte)(gray16 & 0xff);
- }
+ if (have_alpha)
+ *(dp++) = *(sp++);
}
}
}
- if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+
+ else /* RGB bit_depth == 16 */
{
- if (row_info->bit_depth == 8)
- {
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
{
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_byte red = png_ptr->gamma_to_1[*(sp++)];
- png_byte green = png_ptr->gamma_to_1[*(sp++)];
- png_byte blue = png_ptr->gamma_to_1[*(sp++)];
+ png_uint_16 red, green, blue, w;
- if (red != green || red != blue)
- rgb_error |= 1;
+ red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- *(dp++) = png_ptr->gamma_from_1
- [(rc*red + gc*green + bc*blue)>>15];
+ if (red == green && red == blue)
+ {
+ if (png_ptr->gamma_16_table != NULL)
+ w = png_ptr->gamma_16_table[(red&0xff)
+ >> png_ptr->gamma_shift][red>>8];
- *(dp++) = *(sp++); /* alpha */
+ else
+ w = red;
}
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
+
+ else
+ {
+ png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff)
+ >> png_ptr->gamma_shift][red>>8];
+ png_uint_16 green_1 =
+ png_ptr->gamma_16_to_1[(green&0xff) >>
+ png_ptr->gamma_shift][green>>8];
+ png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff)
+ >> png_ptr->gamma_shift][blue>>8];
+ png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
+ + bc*blue_1 + 16384)>>15);
+ w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+ png_ptr->gamma_shift][gray16 >> 8];
+ rgb_error |= 1;
+ }
+
+ *(dp++) = (png_byte)((w>>8) & 0xff);
+ *(dp++) = (png_byte)(w & 0xff);
+
+ if (have_alpha)
{
- png_byte red = *(sp++);
- png_byte green = *(sp++);
- png_byte blue = *(sp++);
- if (red != green || red != blue)
- rgb_error |= 1;
-
- *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = *(sp++); /* alpha */
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
}
}
}
- else /* RGBA bit_depth == 16 */
+ else
+#endif
{
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
- if (png_ptr->gamma_16_to_1 != NULL &&
- png_ptr->gamma_16_from_1 != NULL)
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
- {
- png_uint_16 red, green, blue, w;
-
- red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
-
- if (red == green && red == blue)
- w = red;
-
- else
- {
- png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
- png_ptr->gamma_shift][red>>8];
-
- png_uint_16 green_1 =
- png_ptr->gamma_16_to_1[(green&0xff) >>
- png_ptr->gamma_shift][green>>8];
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
- png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
- png_ptr->gamma_shift][blue>>8];
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 red, green, blue, gray16;
- png_uint_16 gray16 = (png_uint_16)((rc * red_1
- + gc * green_1 + bc * blue_1)>>15);
+ red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
+ blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
- w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
- png_ptr->gamma_shift][gray16 >> 8];
+ if (red != green || red != blue)
+ rgb_error |= 1;
- rgb_error |= 1;
- }
+ /* From 1.5.5 in the 16 bit case do the accurate conversion even
+ * in the 'fast' case - this is because this is where the code
+ * ends up when handling linear 16 bit data.
+ */
+ gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
+ 15);
+ *(dp++) = (png_byte)((gray16>>8) & 0xff);
+ *(dp++) = (png_byte)(gray16 & 0xff);
- *(dp++) = (png_byte)((w>>8) & 0xff);
- *(dp++) = (png_byte)(w & 0xff);
- *(dp++) = *(sp++); /* alpha */
- *(dp++) = *(sp++);
- }
- }
- else
-#endif
- {
- png_bytep sp = row;
- png_bytep dp = row;
- for (i = 0; i < row_width; i++)
+ if (have_alpha)
{
- png_uint_16 red, green, blue, gray16;
- red = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
- green = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
- blue = (png_uint_16)((*(sp)<<8) | *(sp + 1)); sp += 2;
-
- if (red != green || red != blue)
- rgb_error |= 1;
-
- gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
- *(dp++) = (png_byte)((gray16>>8) & 0xff);
- *(dp++) = (png_byte)(gray16 & 0xff);
- *(dp++) = *(sp++); /* alpha */
+ *(dp++) = *(sp++);
*(dp++) = *(sp++);
}
}
}
}
- row_info->channels -= 2;
+
+ row_info->channels = (png_byte)(row_info->channels - 2);
row_info->color_type = (png_byte)(row_info->color_type &
~PNG_COLOR_MASK_COLOR);
row_info->pixel_depth = (png_byte)(row_info->channels *
return rgb_error;
}
#endif
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
- * of code.
+ * of code. This API is not used internally.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
palette[i].blue = (png_byte)v;
}
}
+#endif
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+ (defined PNG_READ_ALPHA_MODE_SUPPORTED)
/* Replace any alpha or transparency with the supplied background color.
* "background" is already in the screen gamma, while "background_1" is
* at a gamma of 1.0. Paletted files have already been taken care of.
*/
void /* PRIVATE */
-png_do_background(png_row_infop row_info, png_bytep row,
- png_const_color_16p trans_color, png_const_color_16p background
+png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr)
+{
#ifdef PNG_READ_GAMMA_SUPPORTED
- , png_const_color_16p background_1, png_const_bytep gamma_table,
- png_const_bytep gamma_from_1, png_const_bytep gamma_to_1,
- png_const_uint_16pp gamma_16, png_const_uint_16pp gamma_16_from_1,
- png_const_uint_16pp gamma_16_to_1, int gamma_shift
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
+ png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
+ png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
+ png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
+ png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
+ int gamma_shift = png_ptr->gamma_shift;
#endif
- )
-{
- png_bytep sp, dp;
+
+ png_bytep sp;
png_uint_32 i;
png_uint_32 row_width = row_info->width;
+ int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
int shift;
- png_debug(1, "in png_do_background");
+ png_debug(1, "in png_do_compose");
- if (background != NULL &&
- (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
- (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_color)))
{
switch (row_info->color_type)
{
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x01)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
else
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x03)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
else
for (i = 0; i < row_width; i++)
{
if ((png_uint_16)((*sp >> shift) & 0x0f)
- == trans_color->gray)
+ == png_ptr->trans_color.gray)
{
*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
- *sp |= (png_byte)(background->gray << shift);
+ *sp |= (png_byte)(png_ptr->background.gray << shift);
}
if (!shift)
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
- if (*sp == trans_color->gray)
- *sp = (png_byte)background->gray;
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
else
*sp = gamma_table[*sp];
sp = row;
for (i = 0; i < row_width; i++, sp++)
{
- if (*sp == trans_color->gray)
- *sp = (png_byte)background->gray;
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
}
}
break;
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- if (v == trans_color->gray)
+ if (v == png_ptr->trans_color.gray)
{
/* Background is already in screen gamma */
- *sp = (png_byte)((background->gray >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
else
v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- if (v == trans_color->gray)
+ if (v == png_ptr->trans_color.gray)
{
- *sp = (png_byte)((background->gray >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
}
}
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
- if (*sp == trans_color->red &&
- *(sp + 1) == trans_color->green &&
- *(sp + 2) == trans_color->blue)
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
{
- *sp = (png_byte)background->red;
- *(sp + 1) = (png_byte)background->green;
- *(sp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
else
sp = row;
for (i = 0; i < row_width; i++, sp += 3)
{
- if (*sp == trans_color->red &&
- *(sp + 1) == trans_color->green &&
- *(sp + 2) == trans_color->blue)
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
{
- *sp = (png_byte)background->red;
- *(sp + 1) = (png_byte)background->green;
- *(sp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
}
}
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- if (r == trans_color->red && g == trans_color->green &&
- b == trans_color->blue)
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
{
/* Background is already in screen gamma */
- *sp = (png_byte)((background->red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->red & 0xff);
- *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(sp + 3) = (png_byte)(background->green & 0xff);
- *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(sp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
else
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- if (r == trans_color->red && g == trans_color->green &&
- b == trans_color->blue)
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
{
- *sp = (png_byte)((background->red >> 8) & 0xff);
- *(sp + 1) = (png_byte)(background->red & 0xff);
- *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(sp + 3) = (png_byte)(background->green & 0xff);
- *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(sp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
}
}
gamma_table != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 2, dp++)
+ for (i = 0; i < row_width; i++, sp += 2)
{
png_uint_16 a = *(sp + 1);
if (a == 0xff)
- *dp = gamma_table[*sp];
+ *sp = gamma_table[*sp];
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)background->gray;
+ *sp = (png_byte)png_ptr->background.gray;
}
else
png_byte v, w;
v = gamma_to_1[*sp];
- png_composite(w, v, a, background_1->gray);
- *dp = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.gray);
+ if (!optimize)
+ w = gamma_from_1[w];
+ *sp = w;
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 2, dp++)
+ for (i = 0; i < row_width; i++, sp += 2)
{
png_byte a = *(sp + 1);
- if (a == 0xff)
- *dp = *sp;
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else if (a == 0)
- *dp = (png_byte)background->gray;
-
- else
- png_composite(*dp, *sp, a, background_1->gray);
+ if (a == 0)
+ *sp = (png_byte)png_ptr->background.gray;
-#else
- *dp = (png_byte)background->gray;
-#endif
+ else if (a < 0xff)
+ png_composite(*sp, *sp, a, png_ptr->background_1.gray);
}
}
}
gamma_16_to_1 != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ *(sp + 3));
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
else if (a == 0)
-#else
- else
-#endif
{
/* Background is already in screen gamma */
- *dp = (png_byte)((background->gray >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
else
{
png_uint_16 g, v, w;
g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(v, g, a, background_1->gray);
- w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
- *dp = (png_byte)((w >> 8) & 0xff);
- *(dp + 1) = (png_byte)(w & 0xff);
+ png_composite_16(v, g, a, png_ptr->background_1.gray);
+ if (optimize)
+ w = v;
+ else
+ w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
}
-#endif
}
}
else
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ *(sp + 3));
- if (a == (png_uint_16)0xffff)
- png_memcpy(dp, sp, 2);
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else if (a == 0)
-#else
- else
-#endif
+ if (a == 0)
{
- *dp = (png_byte)((background->gray >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->gray & 0xff);
+ *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
}
-#ifdef PNG_READ_GAMMA_SUPPORTED
- else
+ else if (a < 0xffff)
{
png_uint_16 g, v;
g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
- png_composite_16(v, g, a, background_1->gray);
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ png_composite_16(v, g, a, png_ptr->background_1.gray);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
}
-#endif
}
}
}
gamma_table != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_byte a = *(sp + 3);
if (a == 0xff)
{
- *dp = gamma_table[*sp];
- *(dp + 1) = gamma_table[*(sp + 1)];
- *(dp + 2) = gamma_table[*(sp + 2)];
+ *sp = gamma_table[*sp];
+ *(sp + 1) = gamma_table[*(sp + 1)];
+ *(sp + 2) = gamma_table[*(sp + 2)];
}
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)background->red;
- *(dp + 1) = (png_byte)background->green;
- *(dp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
else
png_byte v, w;
v = gamma_to_1[*sp];
- png_composite(w, v, a, background_1->red);
- *dp = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.red);
+ if (!optimize) w = gamma_from_1[w];
+ *sp = w;
v = gamma_to_1[*(sp + 1)];
- png_composite(w, v, a, background_1->green);
- *(dp + 1) = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.green);
+ if (!optimize) w = gamma_from_1[w];
+ *(sp + 1) = w;
v = gamma_to_1[*(sp + 2)];
- png_composite(w, v, a, background_1->blue);
- *(dp + 2) = gamma_from_1[w];
+ png_composite(w, v, a, png_ptr->background_1.blue);
+ if (!optimize) w = gamma_from_1[w];
+ *(sp + 2) = w;
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+ for (i = 0; i < row_width; i++, sp += 4)
{
png_byte a = *(sp + 3);
- if (a == 0xff)
- {
- *dp = *sp;
- *(dp + 1) = *(sp + 1);
- *(dp + 2) = *(sp + 2);
- }
-
- else if (a == 0)
+ if (a == 0)
{
- *dp = (png_byte)background->red;
- *(dp + 1) = (png_byte)background->green;
- *(dp + 2) = (png_byte)background->blue;
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
}
- else
+ else if (a < 0xff)
{
- png_composite(*dp, *sp, a, background->red);
+ png_composite(*sp, *sp, a, png_ptr->background.red);
- png_composite(*(dp + 1), *(sp + 1), a,
- background->green);
+ png_composite(*(sp + 1), *(sp + 1), a,
+ png_ptr->background.green);
- png_composite(*(dp + 2), *(sp + 2), a,
- background->blue);
+ png_composite(*(sp + 2), *(sp + 2), a,
+ png_ptr->background.blue);
}
}
}
gamma_16_to_1 != NULL)
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+ for (i = 0; i < row_width; i++, sp += 8)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
png_uint_16 v;
v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
- *(dp + 2) = (png_byte)((v >> 8) & 0xff);
- *(dp + 3) = (png_byte)(v & 0xff);
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
- *(dp + 4) = (png_byte)((v >> 8) & 0xff);
- *(dp + 5) = (png_byte)(v & 0xff);
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
}
else if (a == 0)
{
/* Background is already in screen gamma */
- *dp = (png_byte)((background->red >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->red & 0xff);
- *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(dp + 3) = (png_byte)(background->green & 0xff);
- *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(dp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
else
{
- png_uint_16 v, w, x;
+ png_uint_16 v, w;
v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
- png_composite_16(w, v, a, background_1->red);
-
- x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- *dp = (png_byte)((x >> 8) & 0xff);
- *(dp + 1) = (png_byte)(x & 0xff);
+ png_composite_16(w, v, a, png_ptr->background_1.red);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
- png_composite_16(w, v, a, background_1->green);
+ png_composite_16(w, v, a, png_ptr->background_1.green);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- *(dp + 2) = (png_byte)((x >> 8) & 0xff);
- *(dp + 3) = (png_byte)(x & 0xff);
+ *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(w & 0xff);
v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
- png_composite_16(w, v, a, background_1->blue);
+ png_composite_16(w, v, a, png_ptr->background_1.blue);
+ if (!optimize)
+ w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
- x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
- *(dp + 4) = (png_byte)((x >> 8) & 0xff);
- *(dp + 5) = (png_byte)(x & 0xff);
+ *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(w & 0xff);
}
}
}
#endif
{
sp = row;
- dp = row;
- for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+ for (i = 0; i < row_width; i++, sp += 8)
{
png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
<< 8) + (png_uint_16)(*(sp + 7)));
- if (a == (png_uint_16)0xffff)
- {
- png_memcpy(dp, sp, 6);
- }
-
- else if (a == 0)
+ if (a == 0)
{
- *dp = (png_byte)((background->red >> 8) & 0xff);
- *(dp + 1) = (png_byte)(background->red & 0xff);
- *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
- *(dp + 3) = (png_byte)(background->green & 0xff);
- *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
- *(dp + 5) = (png_byte)(background->blue & 0xff);
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
}
- else
+ else if (a < 0xffff)
{
png_uint_16 v;
png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ *(sp + 5));
- png_composite_16(v, r, a, background->red);
- *dp = (png_byte)((v >> 8) & 0xff);
- *(dp + 1) = (png_byte)(v & 0xff);
+ png_composite_16(v, r, a, png_ptr->background.red);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
- png_composite_16(v, g, a, background->green);
- *(dp + 2) = (png_byte)((v >> 8) & 0xff);
- *(dp + 3) = (png_byte)(v & 0xff);
+ png_composite_16(v, g, a, png_ptr->background.green);
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
- png_composite_16(v, b, a, background->blue);
- *(dp + 4) = (png_byte)((v >> 8) & 0xff);
- *(dp + 5) = (png_byte)(v & 0xff);
+ png_composite_16(v, b, a, png_ptr->background.blue);
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
}
}
}
default:
break;
}
-
- if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
- {
- row_info->color_type = (png_byte)(row_info->color_type &
- ~PNG_COLOR_MASK_ALPHA);
- row_info->channels--;
- row_info->pixel_depth = (png_byte)(row_info->channels *
- row_info->bit_depth);
- row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
- }
}
}
-#endif
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
#ifdef PNG_READ_GAMMA_SUPPORTED
/* Gamma correct the image, avoiding the alpha channel. Make sure
* build_gamma_table().
*/
void /* PRIVATE */
-png_do_gamma(png_row_infop row_info, png_bytep row,
- png_const_bytep gamma_table, png_const_uint_16pp gamma_16_table,
- int gamma_shift)
+png_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr)
{
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
+ int gamma_shift = png_ptr->gamma_shift;
+
png_bytep sp;
png_uint_32 i;
png_uint_32 row_width=row_info->width;
}
#endif
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* Encode the alpha channel to the output gamma (the input channel is always
+ * linear.) Called only with color types that have an alpha channel. Needs the
+ * from_1 tables.
+ */
+void /* PRIVATE */
+png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr)
+{
+ png_uint_32 row_width = row_info->width;
+
+ png_debug(1, "in png_do_encode_alpha");
+
+ if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ PNG_CONST png_bytep table = png_ptr->gamma_from_1;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
+
+ /* The alpha channel is the last component: */
+ row += step - 1;
+
+ for (; row_width > 0; --row_width, row += step)
+ *row = table[*row];
+
+ return;
+ }
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
+ PNG_CONST int gamma_shift = png_ptr->gamma_shift;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
+
+ /* The alpha channel is the last component: */
+ row += step - 2;
+
+ for (; row_width > 0; --row_width, row += step)
+ {
+ png_uint_16 v;
+
+ v = table[*(row + 1) >> gamma_shift][*row];
+ *row = (png_byte)((v >> 8) & 0xff);
+ *(row + 1) = (png_byte)(v & 0xff);
+ }
+
+ return;
+ }
+ }
+ }
+
+ /* Only get to here if called with a weird row_info; no harm has been done,
+ * so just issue a warning.
+ */
+ png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
+}
+#endif
+
#ifdef PNG_READ_EXPAND_SUPPORTED
/* Expands a palette row to an RGB or RGBA row depending
* upon whether you supply trans and num_trans.
if (row_info->bit_depth == 8)
{
{
- if (trans_alpha != NULL)
+ if (num_trans > 0)
{
sp = row + (png_size_t)row_width - 1;
dp = row + (png_size_t)(row_width << 2) - 1;
*/
void /* PRIVATE */
png_do_expand(png_row_infop row_info, png_bytep row,
- png_const_color_16p trans_value)
+ png_const_color_16p trans_color)
{
int shift, value;
png_bytep sp, dp;
{
if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
- png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);
+ png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0);
if (row_info->bit_depth < 8)
{
row_info->rowbytes = row_width;
}
- if (trans_value != NULL)
+ if (trans_color != NULL)
{
if (row_info->bit_depth == 8)
{
row_width);
}
}
- else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
{
if (row_info->bit_depth == 8)
{
- png_byte red = (png_byte)(trans_value->red & 0xff);
- png_byte green = (png_byte)(trans_value->green & 0xff);
- png_byte blue = (png_byte)(trans_value->blue & 0xff);
+ png_byte red = (png_byte)(trans_color->red & 0xff);
+ png_byte green = (png_byte)(trans_color->green & 0xff);
+ png_byte blue = (png_byte)(trans_color->blue & 0xff);
sp = row + (png_size_t)row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 2) - 1;
for (i = 0; i < row_width; i++)
}
else if (row_info->bit_depth == 16)
{
- png_byte red_high = (png_byte)((trans_value->red >> 8) & 0xff);
- png_byte green_high = (png_byte)((trans_value->green >> 8) & 0xff);
- png_byte blue_high = (png_byte)((trans_value->blue >> 8) & 0xff);
- png_byte red_low = (png_byte)(trans_value->red & 0xff);
- png_byte green_low = (png_byte)(trans_value->green & 0xff);
- png_byte blue_low = (png_byte)(trans_value->blue & 0xff);
+ png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+ png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+ png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+ png_byte red_low = (png_byte)(trans_color->red & 0xff);
+ png_byte green_low = (png_byte)(trans_color->green & 0xff);
+ png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
sp = row + row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 3) - 1;
for (i = 0; i < row_width; i++)
#endif
#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* If the bit depth is 8 and the colour type is not a palette type expand the
+/* If the bit depth is 8 and the color type is not a palette type expand the
* whole row to 16 bits. Has no effect otherwise.
*/
void /* PRIVATE */
}
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing */
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
- png_uint_32 red = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL);
- png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL);
+ png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
+ png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
/* pngrutil.c - utilities to read a PNG file
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
- * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * Last changed in libpng 1.5.9 [February 18, 2012]
+ * Copyright (c) 1998-2012 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
png_get_int_32)(png_const_bytep buf)
{
png_uint_32 uval = png_get_uint_32(buf);
- if ((uval & 0x80000000L) == 0) /* non-negative */
+ if ((uval & 0x80000000) == 0) /* non-negative */
return uval;
- uval = (uval ^ 0xffffffffL) + 1; /* 2's complement: -x = ~x+1 */
+ uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
return -(png_int_32)uval;
}
length = png_get_uint_31(png_ptr, buf);
/* Put the chunk name into png_ptr->chunk_name. */
- png_memcpy(png_ptr->chunk_name, buf + 4, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
- png_debug2(0, "Reading %s chunk, length = %u",
- png_ptr->chunk_name, length);
+ png_debug2(0, "Reading %lx chunk, length = %lu",
+ (unsigned long)png_ptr->chunk_name, (unsigned long)length);
/* Reset the crc and run it over the chunk name. */
png_reset_crc(png_ptr);
- png_calculate_crc(png_ptr, png_ptr->chunk_name, 4);
+ png_calculate_crc(png_ptr, buf + 4, 4);
/* Check to see if chunk name is valid. */
png_check_chunk_name(png_ptr, png_ptr->chunk_name);
if (png_crc_error(png_ptr))
{
- if (((png_ptr->chunk_name[0] & 0x20) && /* Ancillary */
- !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) ||
- (!(png_ptr->chunk_name[0] & 0x20) && /* Critical */
- (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)))
+ if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name) ?
+ !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) :
+ (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE))
{
png_chunk_warning(png_ptr, "CRC error");
}
png_uint_32 crc;
int need_crc = 1;
- if (png_ptr->chunk_name[0] & 0x20) /* ancillary */
+ if (PNG_CHUNK_ANCILLIARY(png_ptr->chunk_name))
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
- else /* critical */
+ else /* critical */
{
if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
need_crc = 0;
return (0);
}
-#if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) || \
- defined(PNG_READ_iCCP_SUPPORTED)
+#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
static png_size_t
png_inflate(png_structp png_ptr, png_bytep data, png_size_t size,
png_bytep output, png_size_t output_size)
{
int ret, avail;
- /* The setting of 'avail_in' used to be outside the loop, by setting it
+ /* The setting of 'avail_in' used to be outside the loop; by setting it
* inside it is possible to chunk the input to zlib and simply rely on
* zlib to advance the 'next_in' pointer. This allows arbitrary amounts o
* data to be passed through zlib at the unavoidable cost of requiring a
* and the error message is dumped into the uncompressed
* buffer if available.
*/
+# ifdef PNG_WARNINGS_SUPPORTED
{
- PNG_CONST char *msg;
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char umsg[52];
-#endif
+ png_const_charp msg;
+
if (png_ptr->zstream.msg != 0)
msg = png_ptr->zstream.msg;
- else
+ else switch (ret)
{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- switch (ret)
- {
- case Z_BUF_ERROR:
- msg = "Buffer error in compressed datastream in %s chunk";
- break;
-
- case Z_DATA_ERROR:
- msg = "Data error in compressed datastream in %s chunk";
- break;
+ case Z_BUF_ERROR:
+ msg = "Buffer error in compressed datastream";
+ break;
- default:
- msg = "Incomplete compressed datastream in %s chunk";
- break;
- }
+ case Z_DATA_ERROR:
+ msg = "Data error in compressed datastream";
+ break;
- png_snprintf(umsg, sizeof umsg, msg, png_ptr->chunk_name);
- msg = umsg;
-#else
- msg = "Damaged compressed datastream in chunk other than IDAT";
-#endif
+ default:
+ msg = "Incomplete compressed datastream";
+ break;
}
- png_warning(png_ptr, msg);
+ png_chunk_warning(png_ptr, msg);
}
+# endif
/* 0 means an error - notice that this code simply ignores
* zero length compressed chunks as a result.
png_size_t expanded_size = png_inflate(png_ptr,
(png_bytep)(png_ptr->chunkdata + prefix_size),
chunklength - prefix_size,
- 0, /*output*/
- 0); /*output size*/
+ 0, /* output */
+ 0); /* output size */
/* Now check the limits on this chunk - if the limit fails the
* compressed data will be removed, the prefix will remain.
*/
+ if (prefix_size >= (~(png_size_t)0) - 1 ||
+ expanded_size >= (~(png_size_t)0) - 1 - prefix_size
#ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
- if (png_ptr->user_chunk_malloc_max &&
+ || (png_ptr->user_chunk_malloc_max &&
(prefix_size + expanded_size >= png_ptr->user_chunk_malloc_max - 1))
#else
# ifdef PNG_USER_CHUNK_MALLOC_MAX
- if ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
+ || ((PNG_USER_CHUNK_MALLOC_MAX > 0) &&
prefix_size + expanded_size >= PNG_USER_CHUNK_MALLOC_MAX - 1)
# endif
#endif
+ )
png_warning(png_ptr, "Exceeded size limit while expanding chunk");
/* If the size is zero either there was an error and a message
* and we have nothing to do - the code will exit through the
* error case below.
*/
-#if defined(PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED) || \
- defined(PNG_USER_CHUNK_MALLOC_MAX)
else if (expanded_size > 0)
-#else
- if (expanded_size > 0)
-#endif
{
/* Success (maybe) - really uncompress the chunk. */
png_size_t new_size = 0;
- png_charp text = png_malloc_warn(png_ptr,
+ png_charp text = (png_charp)png_malloc_warn(png_ptr,
prefix_size + expanded_size + 1);
if (text != NULL)
else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
{
-#ifdef PNG_STDIO_SUPPORTED
- char umsg[50];
-
- png_snprintf(umsg, sizeof umsg,
- "Unknown zTXt compression type %d", comp_type);
- png_warning(png_ptr, umsg);
-#else
- png_warning(png_ptr, "Unknown zTXt compression type");
-#endif
+ PNG_WARNING_PARAMETERS(p)
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type);
+ png_formatted_warning(png_ptr, p, "Unknown compression type @1");
/* The recovery is to simply drop the data. */
}
* amount of compressed data.
*/
{
- png_charp text = png_malloc_warn(png_ptr, prefix_size + 1);
+ png_charp text = (png_charp)png_malloc_warn(png_ptr, prefix_size + 1);
if (text != NULL)
{
*newlength = prefix_size;
}
-#endif
+#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */
/* Read and check the IDHR chunk */
void /* PRIVATE */
# ifdef PNG_READ_sRGB_SUPPORTED
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
{
- if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
+ if (PNG_OUT_OF_RANGE(igamma, 45500, 500))
{
- png_warning(png_ptr,
- "Ignoring incorrect gAMA value when sRGB is also present");
-
-# ifdef PNG_CONSOLE_IO_SUPPORTED
- fprintf(stderr, "gamma = (%d/100000)", (int)igamma);
-# endif
+ PNG_WARNING_PARAMETERS(p)
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma);
+ png_formatted_warning(png_ptr, p,
+ "Ignoring incorrect gAMA value @1 when sRGB is also present");
return;
}
}
else if (png_ptr->mode & PNG_HAVE_PLTE)
/* Should be an error, but we can cope with it */
- png_warning(png_ptr, "Missing PLTE before cHRM");
+ png_warning(png_ptr, "Out of place cHRM chunk");
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
# ifdef PNG_READ_sRGB_SUPPORTED
{
if (PNG_OUT_OF_RANGE(x_white, 31270, 1000) ||
PNG_OUT_OF_RANGE(y_white, 32900, 1000) ||
- PNG_OUT_OF_RANGE(x_red, 64000L, 1000) ||
+ PNG_OUT_OF_RANGE(x_red, 64000, 1000) ||
PNG_OUT_OF_RANGE(y_red, 33000, 1000) ||
PNG_OUT_OF_RANGE(x_green, 30000, 1000) ||
- PNG_OUT_OF_RANGE(y_green, 60000L, 1000) ||
+ PNG_OUT_OF_RANGE(y_green, 60000, 1000) ||
PNG_OUT_OF_RANGE(x_blue, 15000, 1000) ||
PNG_OUT_OF_RANGE(y_blue, 6000, 1000))
{
- png_warning(png_ptr,
- "Ignoring incorrect cHRM value when sRGB is also present");
-
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- fprintf(stderr, "wx=%d, wy=%d, rx=%d, ry=%d\n",
- x_white, y_white, x_red, y_red);
-
- fprintf(stderr, "gx=%d, gy=%d, bx=%d, by=%d\n",
- x_green, y_green, x_blue, y_blue);
-#endif /* PNG_CONSOLE_IO_SUPPORTED */
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white);
+ png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white);
+ png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red);
+ png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red);
+ png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green);
+ png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green);
+ png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue);
+ png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue);
+
+ png_formatted_warning(png_ptr, p,
+ "Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) "
+ "when sRGB is also present");
}
return;
}
#endif /* PNG_READ_sRGB_SUPPORTED */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Store the _white values as default coefficients for the rgb to gray
+ * operation if it is supported. Check if the transform is already set to
+ * avoid destroying the transform values.
+ */
+ if (!png_ptr->rgb_to_gray_coefficients_set)
+ {
+ /* png_set_background has not been called and we haven't seen an sRGB
+ * chunk yet. Find the XYZ of the three end points.
+ */
+ png_XYZ XYZ;
+ png_xy xy;
+
+ xy.redx = x_red;
+ xy.redy = y_red;
+ xy.greenx = x_green;
+ xy.greeny = y_green;
+ xy.bluex = x_blue;
+ xy.bluey = y_blue;
+ xy.whitex = x_white;
+ xy.whitey = y_white;
+
+ if (png_XYZ_from_xy_checked(png_ptr, &XYZ, xy))
+ {
+ /* The success case, because XYZ_from_xy normalises to a reference
+ * white Y of 1.0 we just need to scale the numbers. This should
+ * always work just fine. It is an internal error if this overflows.
+ */
+ {
+ png_fixed_point r, g, b;
+ if (png_muldiv(&r, XYZ.redY, 32768, PNG_FP_1) &&
+ r >= 0 && r <= 32768 &&
+ png_muldiv(&g, XYZ.greenY, 32768, PNG_FP_1) &&
+ g >= 0 && g <= 32768 &&
+ png_muldiv(&b, XYZ.blueY, 32768, PNG_FP_1) &&
+ b >= 0 && b <= 32768 &&
+ r+g+b <= 32769)
+ {
+ /* We allow 0 coefficients here. r+g+b may be 32769 if two or
+ * all of the coefficients were rounded up. Handle this by
+ * reducing the *largest* coefficient by 1; this matches the
+ * approach used for the default coefficients in pngrtran.c
+ */
+ int add = 0;
+
+ if (r+g+b > 32768)
+ add = -1;
+ else if (r+g+b < 32768)
+ add = 1;
+
+ if (add != 0)
+ {
+ if (g >= r && g >= b)
+ g += add;
+ else if (r >= g && r >= b)
+ r += add;
+ else
+ b += add;
+ }
+
+ /* Check for an internal error. */
+ if (r+g+b != 32768)
+ png_error(png_ptr,
+ "internal error handling cHRM coefficients");
+
+ png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
+ png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
+ }
+
+ /* This is a png_error at present even though it could be ignored -
+ * it should never happen, but it is important that if it does, the
+ * bug is fixed.
+ */
+ else
+ png_error(png_ptr, "internal error handling cHRM->XYZ");
+ }
+ }
+ }
+#endif
+
png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red,
x_green, y_green, x_blue, y_blue);
}
#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
{
- if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500L, 500))
+ if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500, 500))
{
- png_warning(png_ptr,
- "Ignoring incorrect gAMA value when sRGB is also present");
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- fprintf(stderr, "incorrect gamma=(%d/100000)\n", info_ptr->gamma);
-#endif
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed,
+ info_ptr->gamma);
+
+ png_formatted_warning(png_ptr, p,
+ "Ignoring incorrect gAMA value @1 when sRGB is also present");
}
}
#endif /* PNG_READ_gAMA_SUPPORTED */
if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
if (PNG_OUT_OF_RANGE(info_ptr->x_white, 31270, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_white, 32900, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->x_red, 64000L, 1000) ||
+ PNG_OUT_OF_RANGE(info_ptr->x_red, 64000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_red, 33000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->x_green, 30000, 1000) ||
- PNG_OUT_OF_RANGE(info_ptr->y_green, 60000L, 1000) ||
+ PNG_OUT_OF_RANGE(info_ptr->y_green, 60000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->x_blue, 15000, 1000) ||
PNG_OUT_OF_RANGE(info_ptr->y_blue, 6000, 1000))
{
}
#endif /* PNG_READ_cHRM_SUPPORTED */
+ /* This is recorded for use when handling the cHRM chunk above. An sRGB
+ * chunk unconditionally overwrites the coefficients for grayscale conversion
+ * too.
+ */
+ png_ptr->is_sRGB = 1;
+
+# ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Don't overwrite user supplied values: */
+ if (!png_ptr->rgb_to_gray_coefficients_set)
+ {
+ /* These numbers come from the sRGB specification (or, since one has to
+ * pay much money to get a copy, the wikipedia sRGB page) the
+ * chromaticity values quoted have been inverted to get the reverse
+ * transformation from RGB to XYZ and the 'Y' coefficients scaled by
+ * 32768 (then rounded).
+ *
+ * sRGB and ITU Rec-709 both truncate the values for the D65 white
+ * point to four digits and, even though it actually stores five
+ * digits, the PNG spec gives the truncated value.
+ *
+ * This means that when the chromaticities are converted back to XYZ
+ * end points we end up with (6968,23435,2366), which, as described in
+ * pngrtran.c, would overflow. If the five digit precision and up is
+ * used we get, instead:
+ *
+ * 6968*R + 23435*G + 2365*B
+ *
+ * (Notice that this rounds the blue coefficient down, rather than the
+ * choice used in pngrtran.c which is to round the green one down.)
+ */
+ png_ptr->rgb_to_gray_red_coeff = 6968; /* 0.212639005871510 */
+ png_ptr->rgb_to_gray_green_coeff = 23434; /* 0.715168678767756 */
+ /* png_ptr->rgb_to_gray_blue_coeff = 2366; 0.072192315360734 */
+
+ /* The following keeps the cHRM chunk from destroying the
+ * coefficients again in the event that it follows the sRGB chunk.
+ */
+ png_ptr->rgb_to_gray_coefficients_set = 1;
+ }
+# endif
+
png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
}
#endif /* PNG_READ_sRGB_SUPPORTED */
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
/* And the following guarantees that profile_size == profile_length. */
if (profile_size > profile_length)
{
+ PNG_WARNING_PARAMETERS(p)
+
png_free(png_ptr, png_ptr->chunkdata);
png_ptr->chunkdata = NULL;
-#ifdef PNG_STDIO_SUPPORTED
- {
- char umsg[80];
-
- png_snprintf2(umsg, 80,
- "Ignoring iCCP chunk with declared size = %u "
- "and actual length = %u",
- (unsigned int) profile_size,
- (unsigned int) profile_length);
- png_warning(png_ptr, umsg);
- }
-#else
- png_warning(png_ptr,
- "Ignoring iCCP chunk with uncompressed size mismatch");
-#endif
+
+ png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size);
+ png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length);
+ png_formatted_warning(png_ptr, p,
+ "Ignoring iCCP chunk with declared size = @1 and actual length = @2");
return;
}
* that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
* potential breakage point if the types in pngconf.h aren't exactly right.
*/
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
{
png_size_t truelen;
png_byte buf[6];
+ png_color_16 background;
png_debug(1, "in png_handle_bKGD");
*/
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
- png_ptr->background.index = buf[0];
+ background.index = buf[0];
if (info_ptr && info_ptr->num_palette)
{
return;
}
- png_ptr->background.red =
- (png_uint_16)png_ptr->palette[buf[0]].red;
+ background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+ background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+ background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
+ }
- png_ptr->background.green =
- (png_uint_16)png_ptr->palette[buf[0]].green;
+ else
+ background.red = background.green = background.blue = 0;
- png_ptr->background.blue =
- (png_uint_16)png_ptr->palette[buf[0]].blue;
- }
+ background.gray = 0;
}
else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
{
- png_ptr->background.red =
- png_ptr->background.green =
- png_ptr->background.blue =
- png_ptr->background.gray = png_get_uint_16(buf);
+ background.index = 0;
+ background.red =
+ background.green =
+ background.blue =
+ background.gray = png_get_uint_16(buf);
}
else
{
- png_ptr->background.red = png_get_uint_16(buf);
- png_ptr->background.green = png_get_uint_16(buf + 2);
- png_ptr->background.blue = png_get_uint_16(buf + 4);
+ background.index = 0;
+ background.red = png_get_uint_16(buf);
+ background.green = png_get_uint_16(buf + 2);
+ background.blue = png_get_uint_16(buf + 4);
+ background.gray = 0;
}
- png_set_bKGD(png_ptr, info_ptr, &(png_ptr->background));
+ png_set_bKGD(png_ptr, info_ptr, &background);
}
#endif
return;
}
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
return;
}
+ /* Need unit type, width, \0, height: minimum 4 bytes */
+ else if (length < 4)
+ {
+ png_warning(png_ptr, "sCAL chunk too short");
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
length + 1);
return;
}
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
/* Validate the ASCII numbers, need two ASCII numbers separated by
* a '\0' and they need to fit exactly in the chunk data.
*/
- i = 0;
+ i = 1;
state = 0;
- if (png_ptr->chunkdata[1] == 45 /* negative width */ ||
- !png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
+ if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
i >= slength || png_ptr->chunkdata[i++] != 0)
png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format");
+ else if (!PNG_FP_IS_POSITIVE(state))
+ png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width");
+
else
{
png_size_t heighti = i;
- if (png_ptr->chunkdata[i] == 45 /* negative height */ ||
- !png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
+ state = 0;
+ if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
i != slength)
png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format");
+ else if (!PNG_FP_IS_POSITIVE(state))
+ png_warning(png_ptr,
+ "Invalid sCAL chunk ignored: non-positive height");
+
else
/* This is the (only) success case. */
png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0],
return;
}
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, skip))
return;
}
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
return;
}
- slength = (png_size_t)length;
+ slength = length;
png_crc_read(png_ptr, (png_bytep)png_ptr->chunkdata, slength);
if (png_crc_finish(png_ptr, 0))
comp_type = *lang++;
}
+ if (comp_type || (comp_flag && comp_flag != PNG_TEXT_COMPRESSION_zTXt))
+ {
+ png_warning(png_ptr, "Unknown iTXt compression type or method");
+ png_free(png_ptr, png_ptr->chunkdata);
+ png_ptr->chunkdata = NULL;
+ return;
+ }
+
for (lang_key = lang; *lang_key; lang_key++)
/* Empty loop */ ;
if (png_ptr->mode & PNG_HAVE_IDAT)
{
- PNG_IDAT;
-
- if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) /* Not an IDAT */
+ if (png_ptr->chunk_name != png_IDAT)
png_ptr->mode |= PNG_AFTER_IDAT;
}
- if (!(png_ptr->chunk_name[0] & 0x20))
+ if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
{
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+ if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
&& png_ptr->read_user_chunk_fn == NULL
)
{
#ifdef PNG_MAX_MALLOC_64K
- if (length > (png_uint_32)65535L)
+ if (length > 65535)
{
png_warning(png_ptr, "unknown chunk too large to fit in memory");
- skip = length - (png_uint_32)65535L;
- length = (png_uint_32)65535L;
+ skip = length - 65535;
+ length = 65535;
}
#endif
- png_memcpy((png_charp)png_ptr->unknown_chunk.name,
- (png_charp)png_ptr->chunk_name,
- png_sizeof(png_ptr->unknown_chunk.name));
-
- png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1]
- = '\0';
-
+ /* TODO: this code is very close to the unknown handling in pngpread.c,
+ * maybe it can be put into a common utility routine?
+ * png_struct::unknown_chunk is just used as a temporary variable, along
+ * with the data into which the chunk is read. These can be eliminated.
+ */
+ PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
png_ptr->unknown_chunk.size = (png_size_t)length;
if (length == 0)
else
{
png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
- png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+ png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
}
#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
if (ret == 0)
{
- if (!(png_ptr->chunk_name[0] & 0x20))
+ if (PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
{
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
- if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+ if (png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name) !=
PNG_HANDLE_CHUNK_ALWAYS)
#endif
png_chunk_error(png_ptr, "unknown critical chunk");
* the chunk name itself is valid.
*/
-#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
+ *
+ * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+ */
void /* PRIVATE */
-png_check_chunk_name(png_structp png_ptr, png_const_bytep chunk_name)
+png_check_chunk_name(png_structp png_ptr, png_uint_32 chunk_name)
{
+ int i;
+
png_debug(1, "in png_check_chunk_name");
- if (isnonalpha(chunk_name[0]) || isnonalpha(chunk_name[1]) ||
- isnonalpha(chunk_name[2]) || isnonalpha(chunk_name[3]))
+
+ for (i=1; i<=4; ++i)
{
- png_chunk_error(png_ptr, "invalid chunk type");
+ int c = chunk_name & 0xff;
+
+ if (c < 65 || c > 122 || (c > 90 && c < 97))
+ png_chunk_error(png_ptr, "invalid chunk type");
+
+ chunk_name >>= 8;
}
}
-/* Combines the row recently read in with the existing pixels in the
- * row. This routine takes care of alpha and transparency if requested.
- * This routine also handles the two methods of progressive display
- * of interlaced images, depending on the mask value.
- * The mask value describes which pixels are to be combined with
- * the row. The pattern always repeats every 8 pixels, so just 8
- * bits are needed. A one indicates the pixel is to be combined,
- * a zero indicates the pixel is to be skipped. This is in addition
- * to any alpha or transparency value associated with the pixel. If
- * you want all pixels to be combined, pass 0xff (255) in mask.
+/* Combines the row recently read in with the existing pixels in the row. This
+ * routine takes care of alpha and transparency if requested. This routine also
+ * handles the two methods of progressive display of interlaced images,
+ * depending on the 'display' value; if 'display' is true then the whole row
+ * (dp) is filled from the start by replicating the available pixels. If
+ * 'display' is false only those pixels present in the pass are filled in.
*/
-
void /* PRIVATE */
-png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+png_combine_row(png_structp png_ptr, png_bytep dp, int display)
{
+ unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
+ png_const_bytep sp = png_ptr->row_buf + 1;
+ png_uint_32 row_width = png_ptr->width;
+ unsigned int pass = png_ptr->pass;
+ png_bytep end_ptr = 0;
+ png_byte end_byte = 0;
+ unsigned int end_mask;
+
png_debug(1, "in png_combine_row");
- if (mask == 0xff)
+ /* Added in 1.5.6: it should not be possible to enter this routine until at
+ * least one row has been read from the PNG data and transformed.
+ */
+ if (pixel_depth == 0)
+ png_error(png_ptr, "internal row logic error");
+
+ /* Added in 1.5.4: the pixel depth should match the information returned by
+ * any call to png_read_update_info at this point. Do not continue if we got
+ * this wrong.
+ */
+ if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
+ PNG_ROWBYTES(pixel_depth, row_width))
+ png_error(png_ptr, "internal row size calculation error");
+
+ /* Don't expect this to ever happen: */
+ if (row_width == 0)
+ png_error(png_ptr, "internal row width error");
+
+ /* Preserve the last byte in cases where only part of it will be overwritten,
+ * the multiply below may overflow, we don't care because ANSI-C guarantees
+ * we get the low bits.
+ */
+ end_mask = (pixel_depth * row_width) & 7;
+ if (end_mask != 0)
{
- png_memcpy(row, png_ptr->row_buf + 1,
- PNG_ROWBYTES(png_ptr->row_info.pixel_depth, png_ptr->width));
+ /* end_ptr == NULL is a flag to say do nothing */
+ end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
+ end_byte = *end_ptr;
+# ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */
+ end_mask = 0xff << end_mask;
+
+ else /* big-endian byte */
+# endif
+ end_mask = 0xff >> end_mask;
+ /* end_mask is now the bits to *keep* from the destination row */
}
- else
+ /* For non-interlaced images this reduces to a png_memcpy(). A png_memcpy()
+ * will also happen if interlacing isn't supported or if the application
+ * does not call png_set_interlace_handling(). In the latter cases the
+ * caller just gets a sequence of the unexpanded rows from each interlace
+ * pass.
+ */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) &&
+ pass < 6 && (display == 0 ||
+ /* The following copies everything for 'display' on passes 0, 2 and 4. */
+ (display == 1 && (pass & 1) != 0)))
{
- switch (png_ptr->row_info.pixel_depth)
- {
- case 1:
- {
- png_bytep sp = png_ptr->row_buf + 1;
- png_bytep dp = row;
- int s_inc, s_start, s_end;
- int m = 0x80;
- int shift;
- png_uint_32 i;
- png_uint_32 row_width = png_ptr->width;
-
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
- if (png_ptr->transformations & PNG_PACKSWAP)
- {
- s_start = 0;
- s_end = 7;
- s_inc = 1;
- }
+ /* Narrow images may have no bits in a pass; the caller should handle
+ * this, but this test is cheap:
+ */
+ if (row_width <= PNG_PASS_START_COL(pass))
+ return;
- else
-#endif
- {
- s_start = 7;
- s_end = 0;
- s_inc = -1;
- }
+ if (pixel_depth < 8)
+ {
+ /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
+ * into 32 bits, then a single loop over the bytes using the four byte
+ * values in the 32-bit mask can be used. For the 'display' option the
+ * expanded mask may also not require any masking within a byte. To
+ * make this work the PACKSWAP option must be taken into account - it
+ * simply requires the pixels to be reversed in each byte.
+ *
+ * The 'regular' case requires a mask for each of the first 6 passes,
+ * the 'display' case does a copy for the even passes in the range
+ * 0..6. This has already been handled in the test above.
+ *
+ * The masks are arranged as four bytes with the first byte to use in
+ * the lowest bits (little-endian) regardless of the order (PACKSWAP or
+ * not) of the pixels in each byte.
+ *
+ * NOTE: the whole of this logic depends on the caller of this function
+ * only calling it on rows appropriate to the pass. This function only
+ * understands the 'x' logic; the 'y' logic is handled by the caller.
+ *
+ * The following defines allow generation of compile time constant bit
+ * masks for each pixel depth and each possibility of swapped or not
+ * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
+ * is in the range 0..7; and the result is 1 if the pixel is to be
+ * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
+ * for the block method.
+ *
+ * With some compilers a compile time expression of the general form:
+ *
+ * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
+ *
+ * Produces warnings with values of 'shift' in the range 33 to 63
+ * because the right hand side of the ?: expression is evaluated by
+ * the compiler even though it isn't used. Microsoft Visual C (various
+ * versions) and the Intel C compiler are known to do this. To avoid
+ * this the following macros are used in 1.5.6. This is a temporary
+ * solution to avoid destabilizing the code during the release process.
+ */
+# if PNG_USE_COMPILE_TIME_MASKS
+# define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
+# define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
+# else
+# define PNG_LSR(x,s) ((x)>>(s))
+# define PNG_LSL(x,s) ((x)<<(s))
+# endif
+# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
+ PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
+# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
+ PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
+
+ /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
+ * little endian - the first pixel is at bit 0 - however the extra
+ * parameter 's' can be set to cause the mask position to be swapped
+ * within each byte, to match the PNG format. This is done by XOR of
+ * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
+ */
+# define PIXEL_MASK(p,x,d,s) \
+ (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
- shift = s_start;
+ /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
+ */
+# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
- for (i = 0; i < row_width; i++)
- {
- if (m & mask)
- {
- int value;
+ /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
+ * cases the result needs replicating, for the 4-bpp case the above
+ * generates a full 32 bits.
+ */
+# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
- value = (*sp >> shift) & 0x01;
- *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
- *dp |= (png_byte)(value << shift);
- }
+# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
+ S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
+ S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
- if (shift == s_end)
- {
- shift = s_start;
- sp++;
- dp++;
- }
+# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
+ B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
+ B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
- else
- shift += s_inc;
+#if PNG_USE_COMPILE_TIME_MASKS
+ /* Utility macros to construct all the masks for a depth/swap
+ * combination. The 's' parameter says whether the format is PNG
+ * (big endian bytes) or not. Only the three odd-numbered passes are
+ * required for the display/block algorithm.
+ */
+# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
+ S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
- if (m == 1)
- m = 0x80;
+# define B_MASKS(d,s) { B_MASK(1,d,s), S_MASK(3,d,s), S_MASK(5,d,s) }
- else
- m >>= 1;
- }
- break;
- }
+# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
- case 2:
+ /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
+ * then pass:
+ */
+ static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
{
- png_bytep sp = png_ptr->row_buf + 1;
- png_bytep dp = row;
- int s_start, s_end, s_inc;
- int m = 0x80;
- int shift;
- png_uint_32 i;
- png_uint_32 row_width = png_ptr->width;
- int value;
+ /* Little-endian byte masks for PACKSWAP */
+ { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
+ /* Normal (big-endian byte) masks - PNG format */
+ { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
+ };
+
+ /* display_mask has only three entries for the odd passes, so index by
+ * pass>>1.
+ */
+ static PNG_CONST png_uint_32 display_mask[2][3][3] =
+ {
+ /* Little-endian byte masks for PACKSWAP */
+ { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
+ /* Normal (big-endian byte) masks - PNG format */
+ { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
+ };
+
+# define MASK(pass,depth,display,png)\
+ ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
+ row_mask[png][DEPTH_INDEX(depth)][pass])
+
+#else /* !PNG_USE_COMPILE_TIME_MASKS */
+ /* This is the runtime alternative: it seems unlikely that this will
+ * ever be either smaller or faster than the compile time approach.
+ */
+# define MASK(pass,depth,display,png)\
+ ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
+#endif /* !PNG_USE_COMPILE_TIME_MASKS */
+
+ /* Use the appropriate mask to copy the required bits. In some cases
+ * the byte mask will be 0 or 0xff, optimize these cases. row_width is
+ * the number of pixels, but the code copies bytes, so it is necessary
+ * to special case the end.
+ */
+ png_uint_32 pixels_per_byte = 8 / pixel_depth;
+ png_uint_32 mask;
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
+# ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
- {
- s_start = 0;
- s_end = 6;
- s_inc = 2;
- }
+ mask = MASK(pass, pixel_depth, display, 0);
else
-#endif
+# endif
+ mask = MASK(pass, pixel_depth, display, 1);
+
+ for (;;)
+ {
+ png_uint_32 m;
+
+ /* It doesn't matter in the following if png_uint_32 has more than
+ * 32 bits because the high bits always match those in m<<24; it is,
+ * however, essential to use OR here, not +, because of this.
+ */
+ m = mask;
+ mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
+ m &= 0xff;
+
+ if (m != 0) /* something to copy */
{
- s_start = 6;
- s_end = 0;
- s_inc = -2;
+ if (m != 0xff)
+ *dp = (png_byte)((*dp & ~m) | (*sp & m));
+ else
+ *dp = *sp;
}
- shift = s_start;
+ /* NOTE: this may overwrite the last byte with garbage if the image
+ * is not an exact number of bytes wide; libpng has always done
+ * this.
+ */
+ if (row_width <= pixels_per_byte)
+ break; /* May need to restore part of the last byte */
- for (i = 0; i < row_width; i++)
- {
- if (m & mask)
- {
- value = (*sp >> shift) & 0x03;
- *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
- *dp |= (png_byte)(value << shift);
- }
+ row_width -= pixels_per_byte;
+ ++dp;
+ ++sp;
+ }
+ }
- if (shift == s_end)
- {
- shift = s_start;
- sp++;
- dp++;
- }
+ else /* pixel_depth >= 8 */
+ {
+ unsigned int bytes_to_copy, bytes_to_jump;
- else
- shift += s_inc;
+ /* Validate the depth - it must be a multiple of 8 */
+ if (pixel_depth & 7)
+ png_error(png_ptr, "invalid user transform pixel depth");
- if (m == 1)
- m = 0x80;
+ pixel_depth >>= 3; /* now in bytes */
+ row_width *= pixel_depth;
- else
- m >>= 1;
- }
- break;
+ /* Regardless of pass number the Adam 7 interlace always results in a
+ * fixed number of pixels to copy then to skip. There may be a
+ * different number of pixels to skip at the start though.
+ */
+ {
+ unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
+
+ row_width -= offset;
+ dp += offset;
+ sp += offset;
}
- case 4:
+ /* Work out the bytes to copy. */
+ if (display)
{
- png_bytep sp = png_ptr->row_buf + 1;
- png_bytep dp = row;
- int s_start, s_end, s_inc;
- int m = 0x80;
- int shift;
- png_uint_32 i;
- png_uint_32 row_width = png_ptr->width;
- int value;
+ /* When doing the 'block' algorithm the pixel in the pass gets
+ * replicated to adjacent pixels. This is why the even (0,2,4,6)
+ * passes are skipped above - the entire expanded row is copied.
+ */
+ bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
-#ifdef PNG_READ_PACKSWAP_SUPPORTED
- if (png_ptr->transformations & PNG_PACKSWAP)
- {
- s_start = 0;
- s_end = 4;
- s_inc = 4;
- }
+ /* But don't allow this number to exceed the actual row width. */
+ if (bytes_to_copy > row_width)
+ bytes_to_copy = row_width;
+ }
- else
-#endif
- {
- s_start = 4;
- s_end = 0;
- s_inc = -4;
- }
- shift = s_start;
+ else /* normal row; Adam7 only ever gives us one pixel to copy. */
+ bytes_to_copy = pixel_depth;
- for (i = 0; i < row_width; i++)
- {
- if (m & mask)
+ /* In Adam7 there is a constant offset between where the pixels go. */
+ bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
+
+ /* And simply copy these bytes. Some optimization is possible here,
+ * depending on the value of 'bytes_to_copy'. Special case the low
+ * byte counts, which we know to be frequent.
+ *
+ * Notice that these cases all 'return' rather than 'break' - this
+ * avoids an unnecessary test on whether to restore the last byte
+ * below.
+ */
+ switch (bytes_to_copy)
+ {
+ case 1:
+ for (;;)
{
- value = (*sp >> shift) & 0xf;
- *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
- *dp |= (png_byte)(value << shift);
+ *dp = *sp;
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp += bytes_to_jump;
+ sp += bytes_to_jump;
+ row_width -= bytes_to_jump;
}
- if (shift == s_end)
+ case 2:
+ /* There is a possibility of a partial copy at the end here; this
+ * slows the code down somewhat.
+ */
+ do
{
- shift = s_start;
- sp++;
- dp++;
+ dp[0] = sp[0], dp[1] = sp[1];
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
}
+ while (row_width > 1);
- else
- shift += s_inc;
+ /* And there can only be one byte left at this point: */
+ *dp = *sp;
+ return;
- if (m == 1)
- m = 0x80;
+ case 3:
+ /* This can only be the RGB case, so each copy is exactly one
+ * pixel and it is not necessary to check for a partial copy.
+ */
+ for(;;)
+ {
+ dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
- else
- m >>= 1;
- }
- break;
- }
+ if (row_width <= bytes_to_jump)
+ return;
- default:
- {
- png_bytep sp = png_ptr->row_buf + 1;
- png_bytep dp = row;
- png_size_t pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
- png_uint_32 i;
- png_uint_32 row_width = png_ptr->width;
- png_byte m = 0x80;
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ }
- for (i = 0; i < row_width; i++)
- {
- if (m & mask)
+ default:
+#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
+ /* Check for double byte alignment and, if possible, use a
+ * 16-bit copy. Don't attempt this for narrow images - ones that
+ * are less than an interlace panel wide. Don't attempt it for
+ * wide bytes_to_copy either - use the png_memcpy there.
+ */
+ if (bytes_to_copy < 16 /*else use png_memcpy*/ &&
+ png_isaligned(dp, png_uint_16) &&
+ png_isaligned(sp, png_uint_16) &&
+ bytes_to_copy % sizeof (png_uint_16) == 0 &&
+ bytes_to_jump % sizeof (png_uint_16) == 0)
{
- png_memcpy(dp, sp, pixel_bytes);
+ /* Everything is aligned for png_uint_16 copies, but try for
+ * png_uint_32 first.
+ */
+ if (png_isaligned(dp, png_uint_32) &&
+ png_isaligned(sp, png_uint_32) &&
+ bytes_to_copy % sizeof (png_uint_32) == 0 &&
+ bytes_to_jump % sizeof (png_uint_32) == 0)
+ {
+ png_uint_32p dp32 = (png_uint_32p)dp;
+ png_const_uint_32p sp32 = (png_const_uint_32p)sp;
+ unsigned int skip = (bytes_to_jump-bytes_to_copy) /
+ sizeof (png_uint_32);
+
+ do
+ {
+ size_t c = bytes_to_copy;
+ do
+ {
+ *dp32++ = *sp32++;
+ c -= sizeof (png_uint_32);
+ }
+ while (c > 0);
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp32 += skip;
+ sp32 += skip;
+ row_width -= bytes_to_jump;
+ }
+ while (bytes_to_copy <= row_width);
+
+ /* Get to here when the row_width truncates the final copy.
+ * There will be 1-3 bytes left to copy, so don't try the
+ * 16-bit loop below.
+ */
+ dp = (png_bytep)dp32;
+ sp = (png_const_bytep)sp32;
+ do
+ *dp++ = *sp++;
+ while (--row_width > 0);
+ return;
+ }
+
+ /* Else do it in 16-bit quantities, but only if the size is
+ * not too large.
+ */
+ else
+ {
+ png_uint_16p dp16 = (png_uint_16p)dp;
+ png_const_uint_16p sp16 = (png_const_uint_16p)sp;
+ unsigned int skip = (bytes_to_jump-bytes_to_copy) /
+ sizeof (png_uint_16);
+
+ do
+ {
+ size_t c = bytes_to_copy;
+ do
+ {
+ *dp16++ = *sp16++;
+ c -= sizeof (png_uint_16);
+ }
+ while (c > 0);
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp16 += skip;
+ sp16 += skip;
+ row_width -= bytes_to_jump;
+ }
+ while (bytes_to_copy <= row_width);
+
+ /* End of row - 1 byte left, bytes_to_copy > row_width: */
+ dp = (png_bytep)dp16;
+ sp = (png_const_bytep)sp16;
+ do
+ *dp++ = *sp++;
+ while (--row_width > 0);
+ return;
+ }
}
+#endif /* PNG_ALIGN_ code */
- sp += pixel_bytes;
- dp += pixel_bytes;
+ /* The true default - use a png_memcpy: */
+ for (;;)
+ {
+ png_memcpy(dp, sp, bytes_to_copy);
- if (m == 1)
- m = 0x80;
+ if (row_width <= bytes_to_jump)
+ return;
- else
- m >>= 1;
- }
- break;
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ if (bytes_to_copy > row_width)
+ bytes_to_copy = row_width;
+ }
}
- }
+
+ /* NOT REACHED*/
+ } /* pixel_depth >= 8 */
+
+ /* Here if pixel_depth < 8 to check 'end_ptr' below. */
}
+ else
+#endif
+
+ /* If here then the switch above wasn't used so just png_memcpy the whole row
+ * from the temporary row buffer (notice that this overwrites the end of the
+ * destination row if it is a partial byte.)
+ */
+ png_memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
+
+ /* Restore the overwritten bits from the last byte if necessary. */
+ if (end_ptr != NULL)
+ *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
}
#ifdef PNG_READ_INTERLACING_SUPPORTED
void /* PRIVATE */
-png_do_read_interlace(png_structp png_ptr)
+png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+ png_uint_32 transformations /* Because these may affect the byte layout */)
{
- png_row_infop row_info = &(png_ptr->row_info);
- png_bytep row = png_ptr->row_buf + 1;
- int pass = png_ptr->pass;
- png_uint_32 transformations = png_ptr->transformations;
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Offset to next interlace block */
- PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
png_debug(1, "in png_do_read_interlace");
if (row != NULL && row_info != NULL)
for (i = 0; i < row_info->width; i++)
{
- png_byte v = (png_byte)((*sp >> sshift) & 0xf);
+ png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
int j;
for (j = 0; j < jstop; j++)
}
break;
}
+
default:
{
png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
break;
}
}
+
row_info->width = final_width;
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
}
}
#endif /* PNG_READ_INTERLACING_SUPPORTED */
-void /* PRIVATE */
-png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep row,
- png_const_bytep prev_row, int filter)
+static void
+png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
{
- png_debug(1, "in png_read_filter_row");
- png_debug2(2, "row = %u, filter = %d", png_ptr->row_number, filter);
- switch (filter)
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+ unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_bytep rp = row + bpp;
+
+ PNG_UNUSED(prev_row)
+
+ for (i = bpp; i < istop; i++)
{
- case PNG_FILTER_VALUE_NONE:
- break;
+ *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+ rp++;
+ }
+}
- case PNG_FILTER_VALUE_SUB:
- {
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
- unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
- png_bytep rp = row + bpp;
- png_bytep lp = row;
+static void
+png_read_filter_row_up(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
- for (i = bpp; i < istop; i++)
- {
- *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
- rp++;
- }
- break;
- }
- case PNG_FILTER_VALUE_UP:
- {
- png_size_t i;
- png_size_t istop = row_info->rowbytes;
- png_bytep rp = row;
- png_const_bytep pp = prev_row;
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+ rp++;
+ }
+}
- for (i = 0; i < istop; i++)
- {
- *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
- rp++;
- }
- break;
- }
- case PNG_FILTER_VALUE_AVG:
- {
- png_size_t i;
- png_bytep rp = row;
- png_const_bytep pp = prev_row;
- png_bytep lp = row;
- unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
- png_size_t istop = row_info->rowbytes - bpp;
-
- for (i = 0; i < bpp; i++)
- {
- *rp = (png_byte)(((int)(*rp) +
- ((int)(*pp++) / 2 )) & 0xff);
+static void
+png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_size_t i;
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
+ unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_size_t istop = row_info->rowbytes - bpp;
- rp++;
- }
+ for (i = 0; i < bpp; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) +
+ ((int)(*pp++) / 2 )) & 0xff);
- for (i = 0; i < istop; i++)
- {
- *rp = (png_byte)(((int)(*rp) +
- (int)(*pp++ + *lp++) / 2 ) & 0xff);
+ rp++;
+ }
- rp++;
- }
- break;
- }
- case PNG_FILTER_VALUE_PAETH:
- {
- png_size_t i;
- png_bytep rp = row;
- png_const_bytep pp = prev_row;
- png_bytep lp = row;
- png_const_bytep cp = prev_row;
- unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
- png_size_t istop=row_info->rowbytes - bpp;
-
- for (i = 0; i < bpp; i++)
- {
- *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
- rp++;
- }
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) +
+ (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
- for (i = 0; i < istop; i++) /* Use leftover rp,pp */
- {
- int a, b, c, pa, pb, pc, p;
+ rp++;
+ }
+}
- a = *lp++;
- b = *pp++;
- c = *cp++;
+static void
+png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp_end = row + row_info->rowbytes;
+ int a, c;
- p = b - c;
- pc = a - c;
+ /* First pixel/byte */
+ c = *prev_row++;
+ a = *row + c;
+ *row++ = (png_byte)a;
-#ifdef PNG_USE_ABS
- pa = abs(p);
- pb = abs(pc);
- pc = abs(p + pc);
-#else
- pa = p < 0 ? -p : p;
- pb = pc < 0 ? -pc : pc;
- pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
+ /* Remainder */
+ while (row < rp_end)
+ {
+ int b, pa, pb, pc, p;
- /*
- if (pa <= pb && pa <= pc)
- p = a;
+ a &= 0xff; /* From previous iteration or start */
+ b = *prev_row++;
- else if (pb <= pc)
- p = b;
+ p = b - c;
+ pc = a - c;
- else
- p = c;
- */
+# ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+# else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+# endif
- p = (pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c;
+ /* Find the best predictor, the least of pa, pb, pc favoring the earlier
+ * ones in the case of a tie.
+ */
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
- *rp = (png_byte)(((int)(*rp) + p) & 0xff);
- rp++;
- }
+ /* Calculate the current pixel in a, and move the previous row pixel to c
+ * for the next time round the loop
+ */
+ c = b;
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
+
+static void
+png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_bytep rp_end = row + bpp;
+
+ /* Process the first pixel in the row completely (this is the same as 'up'
+ * because there is only one candidate predictor for the first row).
+ */
+ while (row < rp_end)
+ {
+ int a = *row + *prev_row++;
+ *row++ = (png_byte)a;
+ }
+
+ /* Remainder */
+ rp_end += row_info->rowbytes - bpp;
+
+ while (row < rp_end)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ c = *(prev_row - bpp);
+ a = *(row - bpp);
+ b = *prev_row++;
+
+ p = b - c;
+ pc = a - c;
+
+# ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+# else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+# endif
+
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
+
+ c = b;
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
+
+#ifdef PNG_ARM_NEON
+
+#ifdef __linux__
+#include <stdio.h>
+#include <elf.h>
+#include <asm/hwcap.h>
+
+static int png_have_hwcap(unsigned cap)
+{
+ FILE *f = fopen("/proc/self/auxv", "r");
+ Elf32_auxv_t aux;
+ int have_cap = 0;
+
+ if (!f)
+ return 0;
+
+ while (fread(&aux, sizeof(aux), 1, f) > 0)
+ {
+ if (aux.a_type == AT_HWCAP &&
+ aux.a_un.a_val & cap)
+ {
+ have_cap = 1;
break;
}
- default:
- png_error(png_ptr, "Ignoring bad adaptive filter type");
- /*NOT REACHED */
- break;
}
+
+ fclose(f);
+
+ return have_cap;
+}
+#endif /* __linux__ */
+
+static void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+#ifdef __linux__
+ if (!png_have_hwcap(HWCAP_NEON))
+ return;
+#endif
+
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+ if (bpp == 3)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth3_neon;
+ }
+
+ else if (bpp == 4)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth4_neon;
+ }
+}
+#endif /* PNG_ARM_NEON */
+
+static void
+png_init_filter_functions(png_structp pp)
+{
+ unsigned int bpp = (pp->pixel_depth + 7) >> 3;
+
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
+ if (bpp == 1)
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_1byte_pixel;
+ else
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_multibyte_pixel;
+
+#ifdef PNG_ARM_NEON
+ png_init_filter_functions_neon(pp, bpp);
+#endif
+}
+
+void /* PRIVATE */
+png_read_filter_row(png_structp pp, png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row, int filter)
+{
+ if (pp->read_filter[0] == NULL)
+ png_init_filter_functions(pp);
+ if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
+ pp->read_filter[filter-1](row_info, row, prev_row);
}
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
- PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
- PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif /* PNG_READ_INTERLACING_SUPPORTED */
png_debug(1, "in png_read_finish_row");
{
png_ptr->row_number = 0;
+ /* TO DO: don't do this if prev_row isn't needed (requires
+ * read-ahead of the next row's filter byte.
+ */
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
do
if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
{
- PNG_IDAT;
char extra;
int ret;
{
png_crc_finish(png_ptr, 0);
png_ptr->idat_size = png_read_chunk_header(png_ptr);
- if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+ if (png_ptr->chunk_name != png_IDAT)
png_error(png_ptr, "Not enough image data");
}
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
- PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
- PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif
int max_pixel_depth;
png_debug(1, "in png_read_start_row");
png_ptr->zstream.avail_in = 0;
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
png_init_read_transformations(png_ptr);
+#endif
#ifdef PNG_READ_INTERLACING_SUPPORTED
if (png_ptr->interlaced)
{
max_pixel_depth = png_ptr->pixel_depth;
+ /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
+ * calculations to calculate the final pixel depth, then
+ * png_do_read_transforms actually does the transforms. This means that the
+ * code which effectively calculates this value is actually repeated in three
+ * separate places. They must all match. Innocent changes to the order of
+ * transformations can and will break libpng in a way that causes memory
+ * overwrites.
+ *
+ * TODO: fix this.
+ */
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
max_pixel_depth = 8;
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & (PNG_FILLER))
{
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- max_pixel_depth = 32;
-
- else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+ if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
{
if (max_pixel_depth <= 8)
max_pixel_depth = 16;
max_pixel_depth = 32;
}
- else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+ png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (max_pixel_depth <= 32)
max_pixel_depth = 32;
defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
- int user_pixel_depth = png_ptr->user_transform_depth*
+ int user_pixel_depth = png_ptr->user_transform_depth *
png_ptr->user_transform_channels;
if (user_pixel_depth > max_pixel_depth)
- max_pixel_depth=user_pixel_depth;
+ max_pixel_depth = user_pixel_depth;
}
#endif
+ /* This value is stored in png_struct and double checked in the row read
+ * code.
+ */
+ png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
+ png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
+
/* Align the width on the next larger 8 pixels. Mainly used
* for interlacing
*/
if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
{
png_free(png_ptr, png_ptr->big_row_buf);
+ png_free(png_ptr, png_ptr->big_prev_row);
if (png_ptr->interlaced)
png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
row_bytes + 48);
else
- png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr,
- row_bytes + 48);
+ png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
- png_ptr->old_big_row_buf_size = row_bytes + 48;
+ png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
/* Use 16-byte aligned memory for row_buf with at least 16 bytes
- * of padding before and after row_buf.
+ * of padding before and after row_buf; treat prev_row similarly.
+ * NOTE: the alignment is to the start of the pixels, one beyond the start
+ * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
+ * was incorrect; the filter byte was aligned, which had the exact
+ * opposite effect of that intended.
*/
- png_ptr->row_buf = png_ptr->big_row_buf + 32 -
- (((png_alloc_size_t)png_ptr->big_row_buf + 15) & 0x0F);
+ {
+ png_bytep temp = png_ptr->big_row_buf + 32;
+ int extra = (int)((temp - (png_bytep)0) & 0x0f);
+ png_ptr->row_buf = temp - extra - 1/*filter byte*/;
+
+ temp = png_ptr->big_prev_row + 32;
+ extra = (int)((temp - (png_bytep)0) & 0x0f);
+ png_ptr->prev_row = temp - extra - 1/*filter byte*/;
+ }
- png_ptr->old_big_row_buf_size = row_bytes + 48;
#else
- /* Use 32 bytes of padding before and 16 bytes after row_buf. */
- png_ptr->row_buf = png_ptr->big_row_buf + 32;
+ /* Use 31 bytes of padding before and 17 bytes after row_buf. */
+ png_ptr->row_buf = png_ptr->big_row_buf + 31;
+ png_ptr->prev_row = png_ptr->big_prev_row + 31;
#endif
png_ptr->old_big_row_buf_size = row_bytes + 48;
}
if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
png_error(png_ptr, "Row has too many bytes to allocate in memory");
- if (png_ptr->rowbytes + 1 > png_ptr->old_prev_row_size)
- {
- png_free(png_ptr, png_ptr->prev_row);
-
- png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
-
- png_ptr->old_prev_row_size = png_ptr->rowbytes + 1;
- }
-
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
png_debug1(3, "width = %u,", png_ptr->width);
/* pngset.c - storage of image information into info struct
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
}
}
+void PNGFAPI
+png_set_cHRM_XYZ_fixed(png_structp png_ptr, png_infop info_ptr,
+ png_fixed_point int_red_X, png_fixed_point int_red_Y,
+ png_fixed_point int_red_Z, png_fixed_point int_green_X,
+ png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+ png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+ png_fixed_point int_blue_Z)
+{
+ png_XYZ XYZ;
+ png_xy xy;
+
+ png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ XYZ.redX = int_red_X;
+ XYZ.redY = int_red_Y;
+ XYZ.redZ = int_red_Z;
+ XYZ.greenX = int_green_X;
+ XYZ.greenY = int_green_Y;
+ XYZ.greenZ = int_green_Z;
+ XYZ.blueX = int_blue_X;
+ XYZ.blueY = int_blue_Y;
+ XYZ.blueZ = int_blue_Z;
+
+ if (png_xy_from_XYZ(&xy, XYZ))
+ png_error(png_ptr, "XYZ values out of representable range");
+
+ png_set_cHRM_fixed(png_ptr, info_ptr, xy.whitex, xy.whitey, xy.redx, xy.redy,
+ xy.greenx, xy.greeny, xy.bluex, xy.bluey);
+}
+
# ifdef PNG_FLOATING_POINT_SUPPORTED
void PNGAPI
png_set_cHRM(png_structp png_ptr, png_infop info_ptr,
png_fixed(png_ptr, blue_x, "cHRM Blue X"),
png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
}
+
+void PNGAPI
+png_set_cHRM_XYZ(png_structp png_ptr, png_infop info_ptr, double red_X,
+ double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
+ double blue_X, double blue_Y, double blue_Z)
+{
+ png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
+ png_fixed(png_ptr, red_X, "cHRM Red X"),
+ png_fixed(png_ptr, red_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, red_Z, "cHRM Red Z"),
+ png_fixed(png_ptr, green_X, "cHRM Red X"),
+ png_fixed(png_ptr, green_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, green_Z, "cHRM Red Z"),
+ png_fixed(png_ptr, blue_X, "cHRM Red X"),
+ png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
+}
# endif /* PNG_FLOATING_POINT_SUPPORTED */
#endif /* PNG_cHRM_SUPPORTED */
if (png_ptr == NULL || info_ptr == NULL)
return;
- /* Previously these values were limited, however they must be
- * wrong, therefore storing them (and setting PNG_INFO_gAMA)
- * must be wrong too.
+ /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
+ * occur. Since the fixed point representation is assymetrical it is
+ * possible for 1/gamma to overflow the limit of 21474 and this means the
+ * gamma value must be at least 5/100000 and hence at most 20000.0. For
+ * safety the limits here are a little narrower. The values are 0.00016 to
+ * 6250.0, which are truly ridiculous gammma values (and will produce
+ * displays that are all black or all white.)
*/
- if (file_gamma > (png_fixed_point)PNG_UINT_31_MAX)
- png_warning(png_ptr, "Gamma too large, ignored");
-
- else if (file_gamma <= 0)
- png_warning(png_ptr, "Negative or zero gamma ignored");
+ if (file_gamma < 16 || file_gamma > 625000000)
+ png_warning(png_ptr, "Out of range gamma value ignored");
else
{
if (unit != 1 && unit != 2)
png_error(png_ptr, "Invalid sCAL unit");
- if (swidth == NULL || (lengthw = png_strlen(swidth)) <= 0 ||
- swidth[0] == 45 /*'-'*/ || !png_check_fp_string(swidth, lengthw))
+ if (swidth == NULL || (lengthw = png_strlen(swidth)) == 0 ||
+ swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
png_error(png_ptr, "Invalid sCAL width");
- if (sheight == NULL || (lengthh = png_strlen(sheight)) <= 0 ||
- sheight[0] == 45 /*'-'*/ || !png_check_fp_string(sheight, lengthh))
+ if (sheight == NULL || (lengthh = png_strlen(sheight)) == 0 ||
+ sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
png_error(png_ptr, "Invalid sCAL height");
info_ptr->scal_unit = (png_byte)unit;
png_set_sRGB(png_ptr, info_ptr, srgb_intent);
# ifdef PNG_gAMA_SUPPORTED
- png_set_gAMA_fixed(png_ptr, info_ptr, 45455L);
+ png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
# endif
# ifdef PNG_cHRM_SUPPORTED
png_set_cHRM_fixed(png_ptr, info_ptr,
/* color x y */
- /* white */ 31270L, 32900L,
- /* red */ 64000L, 33000L,
- /* green */ 30000L, 60000L,
- /* blue */ 15000L, 6000L
+ /* white */ 31270, 32900,
+ /* red */ 64000, 33000,
+ /* green */ 30000, 60000,
+ /* blue */ 15000, 6000
);
# endif /* cHRM */
}
{
png_charp new_iccp_name;
png_bytep new_iccp_profile;
- png_uint_32 length;
+ png_size_t length;
png_debug1(1, "in %s storage function", "iCCP");
{
int i;
- png_debug1(1, "in %s storage function", ((png_ptr == NULL ||
- png_ptr->chunk_name[0] == '\0') ?
- "text" : (png_const_charp)png_ptr->chunk_name));
+ png_debug1(1, "in %lx storage function", png_ptr == NULL ? "unexpected" :
+ (unsigned long)png_ptr->chunk_name);
if (png_ptr == NULL || info_ptr == NULL || num_text == 0)
return(0);
(png_ptr->mode & PNG_WROTE_tIME))
return;
+ if (mod_time->month == 0 || mod_time->month > 12 ||
+ mod_time->day == 0 || mod_time->day > 31 ||
+ mod_time->hour > 23 || mod_time->minute > 59 ||
+ mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Ignoring invalid time value");
+ return;
+ }
+
png_memcpy(&(info_ptr->mod_time), mod_time, png_sizeof(png_time));
info_ptr->valid |= PNG_INFO_tIME;
}
{
png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
png_const_sPLT_tp from = entries + i;
- png_uint_32 length;
+ png_size_t length;
length = png_strlen(from->name) + 1;
- to->name = (png_charp)png_malloc_warn(png_ptr, (png_size_t)length);
+ to->name = (png_charp)png_malloc_warn(png_ptr, length);
if (to->name == NULL)
{
png_memcpy(to->name, from->name, length);
to->entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
- (png_size_t)(from->nentries * png_sizeof(png_sPLT_entry)));
+ from->nentries * png_sizeof(png_sPLT_entry));
if (to->entries == NULL)
{
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.9 [February 18, 2012]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
struct png_struct_def
{
#ifdef PNG_SETJMP_SUPPORTED
- jmp_buf png_jmpbuf; /* used in png_error */
+ jmp_buf longjmp_buffer; /* used in png_error */
png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
#endif
png_error_ptr error_fn; /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
png_error_ptr warning_fn; /* function for printing warnings */
+#endif
png_voidp error_ptr; /* user supplied struct for error functions */
png_rw_ptr write_data_fn; /* function for writing output data */
png_rw_ptr read_data_fn; /* function for reading input data */
z_stream zstream; /* pointer to decompression structure (below) */
png_bytep zbuf; /* buffer for zlib */
uInt zbuf_size; /* size of zbuf (typically 65536) */
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Added in 1.5.4: state to keep track of whether the zstream has been
+ * initialized and if so whether it is for IDAT or some other chunk.
+ */
+#define PNG_ZLIB_UNINITIALIZED 0
+#define PNG_ZLIB_FOR_IDAT 1
+#define PNG_ZLIB_FOR_TEXT 2 /* anything other than IDAT */
+#define PNG_ZLIB_USE_MASK 3 /* bottom two bits */
+#define PNG_ZLIB_IN_USE 4 /* a flag value */
+
+ png_uint_32 zlib_state; /* State of zlib initialization */
+/* End of material added at libpng 1.5.4 */
+
int zlib_level; /* holds zlib compression level */
int zlib_method; /* holds zlib compression method */
int zlib_window_bits; /* holds zlib compression window bits */
int zlib_mem_level; /* holds zlib compression memory level */
int zlib_strategy; /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#if defined(PNG_WRITE_COMPRESSED_TEXT_SUPPORTED) || \
+ defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
+ int zlib_text_level; /* holds zlib compression level */
+ int zlib_text_method; /* holds zlib compression method */
+ int zlib_text_window_bits; /* holds zlib compression window bits */
+ int zlib_text_mem_level; /* holds zlib compression memory level */
+ int zlib_text_strategy; /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
png_uint_32 width; /* width of image in pixels */
png_uint_32 height; /* height of image in pixels */
png_size_t rowbytes; /* size of row in bytes */
png_uint_32 iwidth; /* width of current interlaced row in pixels */
png_uint_32 row_number; /* current row in interlace pass */
- png_bytep prev_row; /* buffer to save previous (unfiltered) row */
- png_bytep row_buf; /* buffer to save current (unfiltered) row */
+ png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */
+ png_bytep prev_row; /* buffer to save previous (unfiltered) row.
+ * This is a pointer into big_prev_row
+ */
+ png_bytep row_buf; /* buffer to save current (unfiltered) row.
+ * This is a pointer into big_row_buf
+ */
png_bytep sub_row; /* buffer to save "sub" row when filtering */
png_bytep up_row; /* buffer to save "up" row when filtering */
png_bytep avg_row; /* buffer to save "avg" row when filtering */
png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */
- png_row_info row_info; /* used for transformation routines */
+ png_size_t info_rowbytes; /* Added in 1.5.4: cache of updated row bytes */
png_uint_32 idat_size; /* current IDAT size for read */
png_uint_32 crc; /* current chunk CRC value */
png_colorp palette; /* palette from the input file */
png_uint_16 num_palette; /* number of color entries in palette */
png_uint_16 num_trans; /* number of transparency values */
- png_byte chunk_name[5]; /* null-terminated name of current chunk */
png_byte compression; /* file compression type (always 0) */
png_byte filter; /* file filter type (always 0) */
png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
png_byte do_filter; /* row filter flags (see PNG_FILTER_ below ) */
png_byte color_type; /* color type of file */
png_byte bit_depth; /* bit depth of file */
- png_byte usr_bit_depth; /* bit depth of users row */
+ png_byte usr_bit_depth; /* bit depth of users row: write only */
png_byte pixel_depth; /* number of bits per pixel */
png_byte channels; /* number of channels in file */
- png_byte usr_channels; /* channels at start of write */
+ png_byte usr_channels; /* channels at start of write: write only */
png_byte sig_bytes; /* magic bytes read/written from start of file */
+ png_byte maximum_pixel_depth;
+ /* pixel depth used for the row buffers */
+ png_byte transformed_pixel_depth;
+ /* pixel depth after read/write transforms */
+ png_byte io_chunk_string[5];
+ /* string name of chunk */
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
png_uint_16 filler; /* filler bytes for pixel expansion */
#endif
-#ifdef PNG_bKGD_SUPPORTED
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
png_byte background_gamma_type;
png_fixed_point background_gamma;
png_color_16 background; /* background color in screen gamma space */
png_uint_32 flush_rows; /* number of rows written since last flush */
#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED
int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
png_fixed_point gamma; /* file gamma value */
png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
-#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
png_bytep gamma_table; /* gamma table for 8-bit depth files */
+ png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
png_bytep gamma_from_1; /* converts from 1.0 to screen */
png_bytep gamma_to_1; /* converts from file to 1.0 */
- png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
#endif
#ifdef PNG_TIME_RFC1123_SUPPORTED
- png_charp time_buffer; /* String to hold RFC 1123 time text */
+ char time_buffer[29]; /* String to hold RFC 1123 time text */
#endif
/* New members added in libpng-1.0.6 */
png_bytep chunk_list;
#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+ /* Added in 1.5.5 to record an sRGB chunk in the png. */
+ png_byte is_sRGB;
+#endif
+
/* New members added in libpng-1.0.3 */
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
png_byte rgb_to_gray_status;
+ /* Added in libpng 1.5.5 to record setting of coefficients: */
+ png_byte rgb_to_gray_coefficients_set;
/* These were changed from png_byte in libpng-1.0.6 */
png_uint_16 rgb_to_gray_red_coeff;
png_uint_16 rgb_to_gray_green_coeff;
- png_uint_16 rgb_to_gray_blue_coeff;
+ /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
#endif
/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
-#if defined(PNG_MNG_FEATURES_SUPPORTED) || \
- defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
- defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
/* Changed from png_byte to png_uint_32 at version 1.2.0 */
png_uint_32 mng_features_permitted;
#endif
png_unknown_chunk unknown_chunk;
#endif
-/* New members added in libpng-1.2.26 */
+/* New member added in libpng-1.2.26 */
png_size_t old_big_row_buf_size;
- png_size_t old_prev_row_size;
/* New member added in libpng-1.2.30 */
png_charp chunkdata; /* buffer for reading chunk data */
/* New member added in libpng-1.4.0 */
png_uint_32 io_state;
#endif
+
+/* New member added in libpng-1.5.6 */
+ png_bytep big_prev_row;
+
+ void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row);
};
#endif /* PNGSTRUCT_H */
/* pngtrans.c - transforms the data in a row (used by both readers and writers)
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.4 [July 7, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
/* At the start sp will point to the first byte to copy and dp to where
* it is copied to. ep always points just beyond the end of the row, so
* the loop simply copies (channels-1) channels until sp reaches ep.
+ *
+ * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+ * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
*/
+
/* GA, GX, XG cases */
if (row_info->channels == 2)
{
{
if (at_start) /* Skip initial filler */
++sp;
- else /* Skip initial channels and, for sp, the filler */
+ else /* Skip initial channel and, for sp, the filler */
sp += 2, ++dp;
/* For a 1 pixel wide image there is nothing to do */
else if (row_info->bit_depth == 16)
{
- if (at_start)
+ if (at_start) /* Skip initial filler */
sp += 2;
- else
+ else /* Skip initial channel and, for sp, the filler */
sp += 4, dp += 2;
while (sp < ep)
else if (row_info->bit_depth == 16)
{
- if (at_start)
+ if (at_start) /* Skip initial filler */
sp += 2;
- else
+ else /* Skip initial channels and, for sp, the filler */
sp += 8, dp += 6;
while (sp < ep)
/* pngwrite.c - general routines to write a PNG file
*
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
int keep = png_handle_as_unknown(png_ptr, up->name);
if (keep != PNG_HANDLE_CHUNK_NEVER &&
- up->location && !(up->location & PNG_HAVE_PLTE) &&
+ up->location &&
+ !(up->location & PNG_HAVE_PLTE) &&
!(up->location & PNG_HAVE_IDAT) &&
+ !(up->location & PNG_AFTER_IDAT) &&
((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
(png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
{
{
int keep = png_handle_as_unknown(png_ptr, up->name);
if (keep != PNG_HANDLE_CHUNK_NEVER &&
- up->location && (up->location & PNG_HAVE_PLTE) &&
+ up->location &&
+ (up->location & PNG_HAVE_PLTE) &&
!(up->location & PNG_HAVE_IDAT) &&
+ !(up->location & PNG_AFTER_IDAT) &&
((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
(png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
{
{
int keep = png_handle_as_unknown(png_ptr, up->name);
if (keep != PNG_HANDLE_CHUNK_NEVER &&
- up->location && (up->location & PNG_AFTER_IDAT) &&
+ up->location &&
+ (up->location & PNG_AFTER_IDAT) &&
((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
(png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
{
png_structp png_ptr;
#ifdef PNG_SETJMP_SUPPORTED
#ifdef USE_FAR_KEYWORD
- jmp_buf png_jmpbuf;
+ jmp_buf tmp_jmpbuf;
#endif
#endif
- int i;
png_debug(1, "in png_create_write_struct");
#ifdef PNG_SETJMP_SUPPORTED
/* Applications that neglect to set up their own setjmp() and then
- encounter a png_error() will longjmp here. Since the jmpbuf is
- then meaningless we abort instead of returning. */
+ * encounter a png_error() will longjmp here. Since the jmpbuf is
+ * then meaningless we abort instead of returning.
+ */
#ifdef USE_FAR_KEYWORD
- if (setjmp(png_jmpbuf))
+ if (setjmp(tmp_jmpbuf))
#else
if (setjmp(png_jmpbuf(png_ptr))) /* sets longjmp to match setjmp */
#endif
#ifdef USE_FAR_KEYWORD
- png_memcpy(png_jmpbuf(png_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+ png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
#endif
PNG_ABORT();
#endif
#endif /* PNG_USER_MEM_SUPPORTED */
png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
- if (user_png_ver)
- {
- i = 0;
- do
- {
- if (user_png_ver[i] != png_libpng_ver[i])
- png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
- } while (png_libpng_ver[i++]);
- }
-
- if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
- {
- /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
- * we must recompile any applications that use any older library version.
- * For versions after libpng 1.0, we will be compatible, so we need
- * only check the first digit.
- */
- if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
- (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
- (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
- {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[80];
-
- if (user_png_ver)
- {
- png_snprintf2(msg, 80,
- "Application built with libpng-%.20s"
- " but running with %.20s",
- user_png_ver,
- png_libpng_ver);
- png_warning(png_ptr, msg);
- }
-#else
- png_warning(png_ptr,
- "Incompatible libpng version in application and library");
-#endif
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
- png_ptr->flags = 0;
-#endif
- png_cleanup_needed = 1;
- }
- }
+ if (!png_user_version_check(png_ptr, user_png_ver))
+ png_cleanup_needed = 1;
/* Initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
void PNGAPI
png_write_row(png_structp png_ptr, png_const_bytep row)
{
+ /* 1.5.6: moved from png_struct to be a local structure: */
+ png_row_info row_info;
+
if (png_ptr == NULL)
return;
#endif
/* Set up row info for transformations */
- png_ptr->row_info.color_type = png_ptr->color_type;
- png_ptr->row_info.width = png_ptr->usr_width;
- png_ptr->row_info.channels = png_ptr->usr_channels;
- png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;
- png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
- png_ptr->row_info.channels);
-
- png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
- png_ptr->row_info.width);
-
- png_debug1(3, "row_info->color_type = %d", png_ptr->row_info.color_type);
- png_debug1(3, "row_info->width = %u", png_ptr->row_info.width);
- png_debug1(3, "row_info->channels = %d", png_ptr->row_info.channels);
- png_debug1(3, "row_info->bit_depth = %d", png_ptr->row_info.bit_depth);
- png_debug1(3, "row_info->pixel_depth = %d", png_ptr->row_info.pixel_depth);
- png_debug1(3, "row_info->rowbytes = %lu",
- (unsigned long)png_ptr->row_info.rowbytes);
+ row_info.color_type = png_ptr->color_type;
+ row_info.width = png_ptr->usr_width;
+ row_info.channels = png_ptr->usr_channels;
+ row_info.bit_depth = png_ptr->usr_bit_depth;
+ row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+ png_debug1(3, "row_info->color_type = %d", row_info.color_type);
+ png_debug1(3, "row_info->width = %u", row_info.width);
+ png_debug1(3, "row_info->channels = %d", row_info.channels);
+ png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
+ png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
+ png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
/* Copy user's row into buffer, leaving room for filter byte. */
- png_memcpy(png_ptr->row_buf + 1, row, png_ptr->row_info.rowbytes);
+ png_memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* Handle interlacing */
if (png_ptr->interlaced && png_ptr->pass < 6 &&
(png_ptr->transformations & PNG_INTERLACE))
{
- png_do_write_interlace(&(png_ptr->row_info),
- png_ptr->row_buf + 1, png_ptr->pass);
+ png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
/* This should always get caught above, but still ... */
- if (!(png_ptr->row_info.width))
+ if (!(row_info.width))
{
png_write_finish_row(png_ptr);
return;
}
#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
/* Handle other transformations */
if (png_ptr->transformations)
- png_do_write_transformations(png_ptr);
+ png_do_write_transformations(png_ptr, &row_info);
+#endif
+
+ /* At this point the row_info pixel depth must match the 'transformed' depth,
+ * which is also the output depth.
+ */
+ if (row_info.pixel_depth != png_ptr->pixel_depth ||
+ row_info.pixel_depth != png_ptr->transformed_pixel_depth)
+ png_error(png_ptr, "internal write transform logic error");
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Write filter_method 64 (intrapixel differencing) only if
(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
{
/* Intrapixel differencing */
- png_do_write_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
}
#endif
/* Find a filter if necessary, filter the row and write it out. */
- png_write_find_filter(png_ptr, &(png_ptr->row_info));
+ png_write_find_filter(png_ptr, &row_info);
if (png_ptr->write_row_fn != NULL)
(*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
{
/* Write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
- png_ptr->zstream.next_out = png_ptr->zbuf;
- png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
wrote_IDAT = 1;
}
} while (wrote_IDAT == 1);
/* Write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf,
png_ptr->zbuf_size - png_ptr->zstream.avail_out);
- png_ptr->zstream.next_out = png_ptr->zbuf;
- png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
}
png_ptr->flush_rows = 0;
png_flush(png_ptr);
png_debug(1, "in png_destroy_write_struct");
if (png_ptr_ptr != NULL)
- {
png_ptr = *png_ptr_ptr;
-#ifdef PNG_USER_MEM_SUPPORTED
- free_fn = png_ptr->free_fn;
- mem_ptr = png_ptr->mem_ptr;
-#endif
- }
#ifdef PNG_USER_MEM_SUPPORTED
if (png_ptr != NULL)
jmp_buf tmp_jmp; /* Save jump buffer */
#endif
png_error_ptr error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
png_error_ptr warning_fn;
+#endif
png_voidp error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_free_ptr free_fn;
png_debug(1, "in png_write_destroy");
/* Free any memory zlib uses */
- deflateEnd(&png_ptr->zstream);
+ if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
+ deflateEnd(&png_ptr->zstream);
/* Free our memory. png_free checks NULL for us. */
png_free(png_ptr, png_ptr->zbuf);
png_free(png_ptr, png_ptr->paeth_row);
#endif
-#ifdef PNG_TIME_RFC1123_SUPPORTED
- png_free(png_ptr, png_ptr->time_buffer);
-#endif
-
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
/* Use this to save a little code space, it doesn't free the filter_costs */
png_reset_filter_heuristics(png_ptr);
#ifdef PNG_SETJMP_SUPPORTED
/* Reset structure */
- png_memcpy(tmp_jmp, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
+ png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
#endif
error_fn = png_ptr->error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
warning_fn = png_ptr->warning_fn;
+#endif
error_ptr = png_ptr->error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
free_fn = png_ptr->free_fn;
png_memset(png_ptr, 0, png_sizeof(png_struct));
png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
png_ptr->warning_fn = warning_fn;
+#endif
png_ptr->error_ptr = error_ptr;
#ifdef PNG_USER_MEM_SUPPORTED
png_ptr->free_fn = free_fn;
#endif
#ifdef PNG_SETJMP_SUPPORTED
- png_memcpy(png_ptr->png_jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
+ png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
#endif
}
png_ptr->zlib_strategy = strategy;
}
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
void PNGAPI
png_set_compression_window_bits(png_structp png_ptr, int window_bits)
{
png_ptr->zlib_method = method;
}
+/* The following were added to libpng-1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_text_compression_level(png_structp png_ptr, int level)
+{
+ png_debug(1, "in png_set_text_compression_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_LEVEL;
+ png_ptr->zlib_text_level = level;
+}
+
+void PNGAPI
+png_set_text_compression_mem_level(png_structp png_ptr, int mem_level)
+{
+ png_debug(1, "in png_set_text_compression_mem_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL;
+ png_ptr->zlib_text_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_text_compression_strategy(png_structp png_ptr, int strategy)
+{
+ png_debug(1, "in png_set_text_compression_strategy");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_STRATEGY;
+ png_ptr->zlib_text_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_text_compression_window_bits(png_structp png_ptr, int window_bits)
+{
+ if (png_ptr == NULL)
+ return;
+
+ if (window_bits > 15)
+ png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+
+ else if (window_bits < 8)
+ png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+
+#ifndef WBITS_8_OK
+ /* Avoid libpng bug with 256-byte windows */
+ if (window_bits == 8)
+ {
+ png_warning(png_ptr, "Text compression window is being reset to 512");
+ window_bits = 9;
+ }
+
+#endif
+ png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS;
+ png_ptr->zlib_text_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_text_compression_method(png_structp png_ptr, int method)
+{
+ png_debug(1, "in png_set_text_compression_method");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (method != 8)
+ png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+ png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_METHOD;
+ png_ptr->zlib_text_method = method;
+}
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+/* end of API added to libpng-1.5.4 */
+
void PNGAPI
png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
{
#endif
#ifdef PNG_WRITE_FILLER_SUPPORTED
- /* Pack XRGB/RGBX/ARGB/RGBA into * RGB (4 channels -> 3 channels) */
+ /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
/* pngwtran.c - transforms the data in a row for PNG writers
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.6 [November 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
/* Transform the data according to the user's wishes. The order of
* transformations is significant.
*/
void /* PRIVATE */
-png_do_write_transformations(png_structp png_ptr)
+png_do_write_transformations(png_structp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_write_transformations");
if (png_ptr->write_user_transform_fn != NULL)
(*(png_ptr->write_user_transform_fn)) /* User write transform
function */
- (png_ptr, /* png_ptr */
- &(png_ptr->row_info), /* row_info: */
+ (png_ptr, /* png_ptr */
+ row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
#ifdef PNG_WRITE_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
- png_do_strip_channel(&(png_ptr->row_info), png_ptr->row_buf + 1,
- !(png_ptr->flags & PNG_FILLER_AFTER));
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
#endif
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
- png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
- png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_pack(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->bit_depth);
#endif
#ifdef PNG_WRITE_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
- png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
- png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ png_do_shift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
- png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
- png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
- png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
- png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+ png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
}
}
}
#endif
+#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing */
/* pngwutil.c - utilities to write a PNG file
*
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.6 [November 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
}
-/* Write a PNG chunk all at once. The type is an array of ASCII characters
- * representing the chunk name. The array must be at least 4 bytes in
- * length, and does not need to be null terminated. To be safe, pass the
- * pre-defined chunk names here, and if you need a new one, define it
- * where the others are defined. The length is the length of the data.
- * All the data must be present. If that is not possible, use the
- * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
- * functions instead.
- */
-void PNGAPI
-png_write_chunk(png_structp png_ptr, png_const_bytep chunk_name,
- png_const_bytep data, png_size_t length)
-{
- if (png_ptr == NULL)
- return;
-
- png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
- png_write_chunk_data(png_ptr, data, (png_size_t)length);
- png_write_chunk_end(png_ptr);
-}
-
/* Write the start of a PNG chunk. The type is the chunk type.
* The total_length is the sum of the lengths of all the data you will be
* passing in png_write_chunk_data().
*/
-void PNGAPI
-png_write_chunk_start(png_structp png_ptr, png_const_bytep chunk_name,
+static void
+png_write_chunk_header(png_structp png_ptr, png_uint_32 chunk_name,
png_uint_32 length)
{
png_byte buf[8];
- png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
- (unsigned long)length);
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+ PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
+ png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
+#endif
if (png_ptr == NULL)
return;
/* Write the length and the chunk name */
png_save_uint_32(buf, length);
- png_memcpy(buf + 4, chunk_name, 4);
- png_write_data(png_ptr, buf, (png_size_t)8);
+ png_save_uint_32(buf + 4, chunk_name);
+ png_write_data(png_ptr, buf, 8);
/* Put the chunk name into png_ptr->chunk_name */
- png_memcpy(png_ptr->chunk_name, chunk_name, 4);
+ png_ptr->chunk_name = chunk_name;
/* Reset the crc and run it over the chunk name */
png_reset_crc(png_ptr);
- png_calculate_crc(png_ptr, chunk_name, 4);
+ png_calculate_crc(png_ptr, buf + 4, 4);
#ifdef PNG_IO_STATE_SUPPORTED
/* Inform the I/O callback that chunk data will (possibly) be written.
#endif
}
-/* Write the data of a PNG chunk started with png_write_chunk_start().
+void PNGAPI
+png_write_chunk_start(png_structp png_ptr, png_const_bytep chunk_string,
+ png_uint_32 length)
+{
+ png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_header().
* Note that multiple calls to this function are allowed, and that the
* sum of the lengths from these calls *must* add up to the total_length
- * given to png_write_chunk_start().
+ * given to png_write_chunk_header().
*/
void PNGAPI
png_write_chunk_data(png_structp png_ptr, png_const_bytep data,
}
}
-/* Finish a chunk started with png_write_chunk_start(). */
+/* Finish a chunk started with png_write_chunk_header(). */
void PNGAPI
png_write_chunk_end(png_structp png_ptr)
{
png_write_data(png_ptr, buf, (png_size_t)4);
}
-#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
+/* Write a PNG chunk all at once. The type is an array of ASCII characters
+ * representing the chunk name. The array must be at least 4 bytes in
+ * length, and does not need to be null terminated. To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined. The length is the length of the data.
+ * All the data must be present. If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structp png_ptr, png_uint_32 chunk_name,
+ png_const_bytep data, png_size_t length)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+ if (length > PNG_UINT_32_MAX)
+ png_error(png_ptr, "length exceeds PNG maxima");
+
+ png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+ png_write_chunk_data(png_ptr, data, length);
+ png_write_chunk_end(png_ptr);
+}
+
+/* This is the API that calls the internal function above. */
+void PNGAPI
+png_write_chunk(png_structp png_ptr, png_const_bytep chunk_string,
+ png_const_bytep data, png_size_t length)
+{
+ png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
+ length);
+}
+
+/* Initialize the compressor for the appropriate type of compression. */
+static void
+png_zlib_claim(png_structp png_ptr, png_uint_32 state)
+{
+ if (!(png_ptr->zlib_state & PNG_ZLIB_IN_USE))
+ {
+ /* If already initialized for 'state' do not re-init. */
+ if (png_ptr->zlib_state != state)
+ {
+ int ret = Z_OK;
+ png_const_charp who = "-";
+
+ /* If actually initialized for another state do a deflateEnd. */
+ if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
+ {
+ ret = deflateEnd(&png_ptr->zstream);
+ who = "end";
+ png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
+ }
+
+ /* zlib itself detects an incomplete state on deflateEnd */
+ if (ret == Z_OK) switch (state)
+ {
+# ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+ case PNG_ZLIB_FOR_TEXT:
+ ret = deflateInit2(&png_ptr->zstream,
+ png_ptr->zlib_text_level, png_ptr->zlib_text_method,
+ png_ptr->zlib_text_window_bits,
+ png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
+ who = "text";
+ break;
+# endif
+
+ case PNG_ZLIB_FOR_IDAT:
+ ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
+ png_ptr->zlib_method, png_ptr->zlib_window_bits,
+ png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+ who = "IDAT";
+ break;
+
+ default:
+ png_error(png_ptr, "invalid zlib state");
+ }
+
+ if (ret == Z_OK)
+ png_ptr->zlib_state = state;
+
+ else /* an error in deflateEnd or deflateInit2 */
+ {
+ size_t pos = 0;
+ char msg[64];
+
+ pos = png_safecat(msg, sizeof msg, pos,
+ "zlib failed to initialize compressor (");
+ pos = png_safecat(msg, sizeof msg, pos, who);
+
+ switch (ret)
+ {
+ case Z_VERSION_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") version error");
+ break;
+
+ case Z_STREAM_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") stream error");
+ break;
+
+ case Z_MEM_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") memory error");
+ break;
+
+ default:
+ pos = png_safecat(msg, sizeof msg, pos, ") unknown error");
+ break;
+ }
+
+ png_error(png_ptr, msg);
+ }
+ }
+
+ /* Here on success, claim the zstream: */
+ png_ptr->zlib_state |= PNG_ZLIB_IN_USE;
+ }
+
+ else
+ png_error(png_ptr, "zstream already in use (internal error)");
+}
+
+/* The opposite: release the stream. It is also reset, this API will warn on
+ * error but will not fail.
+ */
+static void
+png_zlib_release(png_structp png_ptr)
+{
+ if (png_ptr->zlib_state & PNG_ZLIB_IN_USE)
+ {
+ int ret = deflateReset(&png_ptr->zstream);
+
+ png_ptr->zlib_state &= ~PNG_ZLIB_IN_USE;
+
+ if (ret != Z_OK)
+ {
+ png_const_charp err;
+ PNG_WARNING_PARAMETERS(p)
+
+ switch (ret)
+ {
+ case Z_VERSION_ERROR:
+ err = "version";
+ break;
+
+ case Z_STREAM_ERROR:
+ err = "stream";
+ break;
+
+ case Z_MEM_ERROR:
+ err = "memory";
+ break;
+
+ default:
+ err = "unknown";
+ break;
+ }
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, ret);
+ png_warning_parameter(p, 2, err);
+
+ if (png_ptr->zstream.msg)
+ err = png_ptr->zstream.msg;
+ else
+ err = "[no zlib message]";
+
+ png_warning_parameter(p, 3, err);
+
+ png_formatted_warning(png_ptr, p,
+ "zlib failed to reset compressor: @1(@2): @3");
+ }
+ }
+
+ else
+ png_warning(png_ptr, "zstream not in use (internal error)");
+}
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
/* This pair of functions encapsulates the operation of (a) compressing a
* text string, and (b) issuing it later as a series of chunk data writes.
* The compression_state structure is shared context for these functions
comp->max_output_ptr = 0;
comp->output_ptr = NULL;
comp->input = NULL;
- comp->input_len = 0;
+ comp->input_len = text_len;
/* We may just want to pass the text right through */
if (compression == PNG_TEXT_COMPRESSION_NONE)
{
comp->input = (png_const_bytep)text;
- comp->input_len = text_len;
return((int)text_len);
}
if (compression >= PNG_TEXT_COMPRESSION_LAST)
{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[50];
- png_snprintf(msg, 50, "Unknown compression type %d", compression);
- png_warning(png_ptr, msg);
-#else
- png_warning(png_ptr, "Unknown compression type");
-#endif
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d,
+ compression);
+ png_formatted_warning(png_ptr, p, "Unknown compression type @1");
}
/* We can't write the chunk until we find out how much data we have,
* data, or if the input string is incredibly large (although this
* wouldn't cause a failure, just a slowdown due to swapping).
*/
+ png_zlib_claim(png_ptr, PNG_ZLIB_FOR_TEXT);
/* Set up the compression buffers */
/* TODO: the following cast hides a potential overflow problem. */
png_ptr->zstream.avail_in = (uInt)text_len;
+
/* NOTE: assume zlib doesn't overwrite the input */
png_ptr->zstream.next_in = (Bytef *)text;
png_ptr->zstream.avail_out = png_ptr->zbuf_size;
return;
}
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ /* The zbuf_size test is because the code below doesn't work if zbuf_size is
+ * '1'; simply skip it to avoid memory overwrite.
+ */
+ if (comp->input_len >= 2 && comp->input_len < 16384 && png_ptr->zbuf_size > 1)
+ {
+ unsigned int z_cmf; /* zlib compression method and flags */
+
+ /* Optimize the CMF field in the zlib stream. This hack of the zlib
+ * stream is compliant to the stream specification.
+ */
+
+ if (comp->num_output_ptr)
+ z_cmf = comp->output_ptr[0][0];
+ else
+ z_cmf = png_ptr->zbuf[0];
+
+ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+ {
+ unsigned int z_cinfo;
+ unsigned int half_z_window_size;
+ png_size_t uncompressed_text_size = comp->input_len;
+
+ z_cinfo = z_cmf >> 4;
+ half_z_window_size = 1 << (z_cinfo + 7);
+
+ while (uncompressed_text_size <= half_z_window_size &&
+ half_z_window_size >= 256)
+ {
+ z_cinfo--;
+ half_z_window_size >>= 1;
+ }
+
+ z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+ if (comp->num_output_ptr)
+ {
+
+ if (comp->output_ptr[0][0] != z_cmf)
+ {
+ int tmp;
+
+ comp->output_ptr[0][0] = (png_byte)z_cmf;
+ tmp = comp->output_ptr[0][1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ comp->output_ptr[0][1] = (png_byte)tmp;
+ }
+ }
+ else
+ {
+ int tmp;
+
+ png_ptr->zbuf[0] = (png_byte)z_cmf;
+ tmp = png_ptr->zbuf[1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ png_ptr->zbuf[1] = (png_byte)tmp;
+ }
+ }
+
+ else
+ png_error(png_ptr,
+ "Invalid zlib compression method or flags in non-IDAT chunk");
+ }
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+
/* Write saved output buffers, if any */
for (i = 0; i < comp->num_output_ptr; i++)
{
(png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
/* Reset zlib for another zTXt/iTXt or image data */
- deflateReset(&png_ptr->zstream);
- png_ptr->zstream.data_type = Z_BINARY;
+ png_zlib_release(png_ptr);
}
-#endif
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
/* Write the IHDR chunk, and update the png_struct with the necessary
* information. Note that the rest of this code depends upon this
int bit_depth, int color_type, int compression_type, int filter_type,
int interlace_type)
{
- PNG_IHDR;
- int ret;
-
png_byte buf[13]; /* Buffer to store the IHDR info */
png_debug(1, "in png_write_IHDR");
buf[12] = (png_byte)interlace_type;
/* Write the chunk */
- png_write_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+ png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
/* Initialize zlib with PNG info */
png_ptr->zstream.zalloc = png_zalloc;
if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
png_ptr->zlib_method = 8;
- ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
- png_ptr->zlib_method, png_ptr->zlib_window_bits,
- png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_STRATEGY))
+ png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
- if (ret != Z_OK)
- {
- if (ret == Z_VERSION_ERROR)
- png_error(png_ptr,
- "zlib failed to initialize compressor -- version error");
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_LEVEL))
+ png_ptr->zlib_text_level = png_ptr->zlib_level;
- if (ret == Z_STREAM_ERROR)
- png_error(png_ptr,
- "zlib failed to initialize compressor -- stream error");
-
- if (ret == Z_MEM_ERROR)
- png_error(png_ptr,
- "zlib failed to initialize compressor -- mem error");
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL))
+ png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
- png_error(png_ptr, "zlib failed to initialize compressor");
- }
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS))
+ png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
- png_ptr->zstream.next_out = png_ptr->zbuf;
- png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
- /* libpng is not interested in zstream.data_type, so set it
- * to a predefined value, to avoid its evaluation inside zlib
- */
- png_ptr->zstream.data_type = Z_BINARY;
-
- png_ptr->mode = PNG_HAVE_IHDR;
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_METHOD))
+ png_ptr->zlib_text_method = png_ptr->zlib_method;
+#else
+ png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_text_level = png_ptr->zlib_level;
+ png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
+ png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
+ png_ptr->zlib_text_method = png_ptr->zlib_method;
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+
+ /* Record that the compressor has not yet been initialized. */
+ png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
+
+ png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
}
/* Write the palette. We are careful not to trust png_color to be in the
png_write_PLTE(png_structp png_ptr, png_const_colorp palette,
png_uint_32 num_pal)
{
- PNG_PLTE;
png_uint_32 i;
png_const_colorp pal_ptr;
png_byte buf[3];
png_ptr->num_palette = (png_uint_16)num_pal;
png_debug1(3, "num_palette = %d", png_ptr->num_palette);
- png_write_chunk_start(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+ png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
#ifdef PNG_POINTER_INDEXING_SUPPORTED
for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
void /* PRIVATE */
png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
{
- PNG_IDAT;
-
png_debug(1, "in png_write_IDAT");
- /* Optimize the CMF field in the zlib stream. */
- /* This hack of the zlib stream is compliant to the stream specification. */
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
{
+ /* Optimize the CMF field in the zlib stream. This hack of the zlib
+ * stream is compliant to the stream specification.
+ */
unsigned int z_cmf = data[0]; /* zlib compression method and flags */
+
if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
{
/* Avoid memory underflows and multiplication overflows.
if (length >= 2 &&
png_ptr->height < 16384 && png_ptr->width < 16384)
{
+ /* Compute the maximum possible length of the datastream */
+
+ /* Number of pixels, plus for each row a filter byte
+ * and possibly a padding byte, so increase the maximum
+ * size to account for these.
+ */
+ unsigned int z_cinfo;
+ unsigned int half_z_window_size;
png_uint_32 uncompressed_idat_size = png_ptr->height *
((png_ptr->width *
png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
- unsigned int z_cinfo = z_cmf >> 4;
- unsigned int half_z_window_size = 1 << (z_cinfo + 7);
+
+ /* If it's interlaced, each block of 8 rows is sent as up to
+ * 14 rows, i.e., 6 additional rows, each with a filter byte
+ * and possibly a padding byte
+ */
+ if (png_ptr->interlaced)
+ uncompressed_idat_size += ((png_ptr->height + 7)/8) *
+ (png_ptr->bit_depth < 8 ? 12 : 6);
+
+ z_cinfo = z_cmf >> 4;
+ half_z_window_size = 1 << (z_cinfo + 7);
+
while (uncompressed_idat_size <= half_z_window_size &&
half_z_window_size >= 256)
{
png_error(png_ptr,
"Invalid zlib compression method or flags in IDAT");
}
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
- png_write_chunk(png_ptr, png_IDAT, data, length);
+ png_write_complete_chunk(png_ptr, png_IDAT, data, length);
png_ptr->mode |= PNG_HAVE_IDAT;
+
+ /* Prior to 1.5.4 this code was replicated in every caller (except at the
+ * end, where it isn't technically necessary). Since this function has
+ * flushed the data we can safely reset the zlib output buffer here.
+ */
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
}
/* Write an IEND chunk */
void /* PRIVATE */
png_write_IEND(png_structp png_ptr)
{
- PNG_IEND;
-
png_debug(1, "in png_write_IEND");
- png_write_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+ png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
png_ptr->mode |= PNG_HAVE_IEND;
}
void /* PRIVATE */
png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
{
- PNG_gAMA;
png_byte buf[4];
png_debug(1, "in png_write_gAMA");
/* file_gamma is saved in 1/100,000ths */
png_save_uint_32(buf, (png_uint_32)file_gamma);
- png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
+ png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
}
#endif
void /* PRIVATE */
png_write_sRGB(png_structp png_ptr, int srgb_intent)
{
- PNG_sRGB;
png_byte buf[1];
png_debug(1, "in png_write_sRGB");
"Invalid sRGB rendering intent specified");
buf[0]=(png_byte)srgb_intent;
- png_write_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
+ png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
}
#endif
png_write_iCCP(png_structp png_ptr, png_const_charp name, int compression_type,
png_const_charp profile, int profile_len)
{
- PNG_iCCP;
png_size_t name_len;
png_charp new_name;
compression_state comp;
(png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
/* Make sure we include the NULL after the name and the compression type */
- png_write_chunk_start(png_ptr, png_iCCP,
+ png_write_chunk_header(png_ptr, png_iCCP,
(png_uint_32)(name_len + profile_len + 2));
new_name[name_len + 1] = 0x00;
(png_size_t)(name_len + 2));
if (profile_len)
+ {
+ comp.input_len = profile_len;
png_write_compressed_data_out(png_ptr, &comp);
+ }
png_write_chunk_end(png_ptr);
png_free(png_ptr, new_name);
void /* PRIVATE */
png_write_sPLT(png_structp png_ptr, png_const_sPLT_tp spalette)
{
- PNG_sPLT;
png_size_t name_len;
png_charp new_name;
png_byte entrybuf[10];
return;
/* Make sure we include the NULL after the name */
- png_write_chunk_start(png_ptr, png_sPLT,
+ png_write_chunk_header(png_ptr, png_sPLT,
(png_uint_32)(name_len + 2 + palette_size));
png_write_chunk_data(png_ptr, (png_bytep)new_name,
void /* PRIVATE */
png_write_sBIT(png_structp png_ptr, png_const_color_8p sbit, int color_type)
{
- PNG_sBIT;
png_byte buf[4];
png_size_t size;
buf[size++] = sbit->alpha;
}
- png_write_chunk(png_ptr, png_sBIT, buf, size);
+ png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
}
#endif
png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
png_fixed_point blue_y)
{
- PNG_cHRM;
png_byte buf[32];
png_debug(1, "in png_write_cHRM");
png_save_uint_32(buf + 24, (png_uint_32)blue_x);
png_save_uint_32(buf + 28, (png_uint_32)blue_y);
- png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
+ png_write_complete_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
}
}
#endif
png_write_tRNS(png_structp png_ptr, png_const_bytep trans_alpha,
png_const_color_16p tran, int num_trans, int color_type)
{
- PNG_tRNS;
png_byte buf[6];
png_debug(1, "in png_write_tRNS");
}
/* Write the chunk out as it is */
- png_write_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans);
+ png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans);
}
else if (color_type == PNG_COLOR_TYPE_GRAY)
}
png_save_uint_16(buf, tran->gray);
- png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
}
else if (color_type == PNG_COLOR_TYPE_RGB)
return;
}
- png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
}
else
void /* PRIVATE */
png_write_bKGD(png_structp png_ptr, png_const_color_16p back, int color_type)
{
- PNG_bKGD;
png_byte buf[6];
png_debug(1, "in png_write_bKGD");
}
buf[0] = back->index;
- png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
}
else if (color_type & PNG_COLOR_MASK_COLOR)
return;
}
- png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
}
else
}
png_save_uint_16(buf, back->gray);
- png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
}
}
#endif
void /* PRIVATE */
png_write_hIST(png_structp png_ptr, png_const_uint_16p hist, int num_hist)
{
- PNG_hIST;
int i;
png_byte buf[3];
return;
}
- png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+ png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
for (i = 0; i < num_hist; i++)
{
if ((png_byte)*ikp < 0x20 ||
((png_byte)*ikp > 0x7E && (png_byte)*ikp < 0xA1))
{
-#ifdef PNG_CONSOLE_IO_SUPPORTED
- char msg[40];
+ PNG_WARNING_PARAMETERS(p)
- png_snprintf(msg, 40,
- "invalid keyword character 0x%02X", (png_byte)*ikp);
- png_warning(png_ptr, msg);
-#else
- png_warning(png_ptr, "invalid character in keyword");
-#endif
+ png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_02x,
+ (png_byte)*ikp);
+ png_formatted_warning(png_ptr, p, "invalid keyword character 0x@1");
*dp = ' ';
}
png_write_tEXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
png_size_t text_len)
{
- PNG_tEXt;
png_size_t key_len;
png_charp new_key;
text_len = png_strlen(text);
/* Make sure we include the 0 after the key */
- png_write_chunk_start(png_ptr, png_tEXt,
+ png_write_chunk_header(png_ptr, png_tEXt,
(png_uint_32)(key_len + text_len + 1));
/*
* We leave it to the application to meet PNG-1.0 requirements on the
png_write_zTXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
png_size_t text_len, int compression)
{
- PNG_zTXt;
png_size_t key_len;
png_byte buf;
png_charp new_key;
&comp);
/* Write start of chunk */
- png_write_chunk_start(png_ptr, png_zTXt,
+ png_write_chunk_header(png_ptr, png_zTXt,
(png_uint_32)(key_len+text_len + 2));
/* Write key */
png_write_chunk_data(png_ptr, &buf, (png_size_t)1);
/* Write the compressed data */
+ comp.input_len = text_len;
png_write_compressed_data_out(png_ptr, &comp);
/* Close the chunk */
png_write_iTXt(png_structp png_ptr, int compression, png_const_charp key,
png_const_charp lang, png_const_charp lang_key, png_const_charp text)
{
- PNG_iTXt;
png_size_t lang_len, key_len, lang_key_len, text_len;
png_charp new_lang;
png_charp new_key = NULL;
* and the NULs after the key, lang, and lang_key parts
*/
- png_write_chunk_start(png_ptr, png_iTXt, (png_uint_32)(
+ png_write_chunk_header(png_ptr, png_iTXt, (png_uint_32)(
5 /* comp byte, comp flag, terminators for key, lang and lang_key */
+ key_len
+ lang_len
png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
int unit_type)
{
- PNG_oFFs;
png_byte buf[9];
png_debug(1, "in png_write_oFFs");
png_save_int_32(buf + 4, y_offset);
buf[8] = (png_byte)unit_type;
- png_write_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+ png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
}
#endif
#ifdef PNG_WRITE_pCAL_SUPPORTED
png_int_32 X1, int type, int nparams, png_const_charp units,
png_charpp params)
{
- PNG_pCAL;
png_size_t purpose_len, units_len, total_len;
- png_uint_32p params_len;
+ png_size_tp params_len;
png_byte buf[10];
png_charp new_purpose;
int i;
png_debug1(3, "pCAL units length = %d", (int)units_len);
total_len = purpose_len + units_len + 10;
- params_len = (png_uint_32p)png_malloc(png_ptr,
- (png_alloc_size_t)(nparams * png_sizeof(png_uint_32)));
+ params_len = (png_size_tp)png_malloc(png_ptr,
+ (png_alloc_size_t)(nparams * png_sizeof(png_size_t)));
/* Find the length of each parameter, making sure we don't count the
* null terminator for the last parameter.
params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
png_debug2(3, "pCAL parameter %d length = %lu", i,
(unsigned long)params_len[i]);
- total_len += (png_size_t)params_len[i];
+ total_len += params_len[i];
}
png_debug1(3, "pCAL total length = %d", (int)total_len);
- png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len);
- png_write_chunk_data(png_ptr, (png_const_bytep)new_purpose,
- (png_size_t)purpose_len);
+ png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, (png_const_bytep)new_purpose, purpose_len);
png_save_int_32(buf, X0);
png_save_int_32(buf + 4, X1);
buf[8] = (png_byte)type;
for (i = 0; i < nparams; i++)
{
- png_write_chunk_data(png_ptr, (png_const_bytep)params[i],
- (png_size_t)params_len[i]);
+ png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
}
png_free(png_ptr, params_len);
png_write_sCAL_s(png_structp png_ptr, int unit, png_const_charp width,
png_const_charp height)
{
- PNG_sCAL;
png_byte buf[64];
png_size_t wlen, hlen, total_len;
png_memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
- png_write_chunk(png_ptr, png_sCAL, buf, total_len);
+ png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
}
#endif
png_uint_32 y_pixels_per_unit,
int unit_type)
{
- PNG_pHYs;
png_byte buf[9];
png_debug(1, "in png_write_pHYs");
png_save_uint_32(buf + 4, y_pixels_per_unit);
buf[8] = (png_byte)unit_type;
- png_write_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+ png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
}
#endif
void /* PRIVATE */
png_write_tIME(png_structp png_ptr, png_const_timep mod_time)
{
- PNG_tIME;
png_byte buf[7];
png_debug(1, "in png_write_tIME");
buf[5] = mod_time->minute;
buf[6] = mod_time->second;
- png_write_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+ png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
}
#endif
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
- int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
- int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif
- png_size_t buf_size;
+ png_alloc_size_t buf_size;
+ int usr_pixel_depth;
png_debug(1, "in png_write_start_row");
- buf_size = (png_size_t)(PNG_ROWBYTES(
- png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
+ usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
+ buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
+
+ /* 1.5.6: added to allow checking in the row write code. */
+ png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
+ png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
/* Set up row buffer */
- png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
- (png_alloc_size_t)buf_size);
+ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
{
/* Set up previous row buffer */
- png_ptr->prev_row = (png_bytep)png_calloc(png_ptr,
- (png_alloc_size_t)buf_size);
+ png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
if (png_ptr->do_filter & PNG_FILTER_UP)
{
png_ptr->usr_width = png_ptr->width;
}
+ png_zlib_claim(png_ptr, PNG_ZLIB_FOR_IDAT);
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
png_ptr->zstream.next_out = png_ptr->zbuf;
}
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
/* Start of interlace block in the y direction */
- int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
/* Offset to next interlace block in the y direction */
- int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif
int ret;
png_ptr->zstream.avail_out);
}
- deflateReset(&png_ptr->zstream);
+ png_zlib_release(png_ptr);
png_ptr->zstream.data_type = Z_BINARY;
}
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* Start of interlace block */
- int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
/* Offset to next interlace block */
- int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
png_debug(1, "in png_do_write_interlace");
* been specified by the application, and then writes the row out with the
* chosen filter.
*/
+static void png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
+ png_size_t row_bytes);
+
#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
#define PNG_HISHIFT 10
#define PNG_LOMASK ((png_uint_32)0xffffL)
png_byte filter_to_do = png_ptr->do_filter;
png_size_t row_bytes = row_info->rowbytes;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
- int num_p_filters = (int)png_ptr->num_prev_filters;
+ int num_p_filters = png_ptr->num_prev_filters;
#endif
png_debug(1, "in png_write_find_filter");
}
}
#endif /* PNG_WRITE_FILTER_SUPPORTED */
- /* Do the actual writing of the filtered row data from the chosen filter. */
- png_write_filtered_row(png_ptr, best_row);
+ /* Do the actual writing of the filtered row data from the chosen filter. */
+ png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
#ifdef PNG_WRITE_FILTER_SUPPORTED
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
/* Do the actual writing of a previously filtered row. */
-void /* PRIVATE */
-png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
+static void
+png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
+ png_size_t avail/*includes filter byte*/)
{
- png_size_t avail;
-
png_debug(1, "in png_write_filtered_row");
png_debug1(2, "filter = %d", filtered_row[0]);
png_ptr->zstream.next_in = filtered_row;
png_ptr->zstream.avail_in = 0;
- avail = png_ptr->row_info.rowbytes + 1;
/* Repeat until we have compressed all the data */
do
{
{
/* Write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
- png_ptr->zstream.next_out = png_ptr->zbuf;
- png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
}
/* Repeat until all data has been compressed */
} while (avail > 0 || png_ptr->zstream.avail_in > 0);
projects / apitrace / commitdiff