**************************************************************************/
+#include <png.h>
+
+#include <math.h>
#include <stdint.h>
#include <fstream>
return true;
}
+bool
+Image::writePNG(const char *filename) const {
+ FILE *fp;
+ png_structp png_ptr;
+ png_infop info_ptr;
+
+ fp = fopen(filename, "wb");
+ if (!fp)
+ goto no_fp;
+
+ png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ if (!png_ptr)
+ goto no_png;
+
+ info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr) {
+ png_destroy_write_struct(&png_ptr, NULL);
+ goto no_png;
+ }
+
+ if (setjmp(png_jmpbuf(png_ptr))) {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ goto no_png;
+ }
+
+ png_init_io(png_ptr, fp);
+
+ png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA,
+ PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ png_set_compression_level(png_ptr, Z_DEFAULT_COMPRESSION);
+
+ png_write_info(png_ptr, info_ptr);
+
+ if (!flipped) {
+ for (unsigned y = 0; y < height; ++y) {
+ png_bytep row = (png_bytep)(pixels + y*width*4);
+ png_write_rows(png_ptr, &row, 1);
+ }
+ } else {
+ unsigned y = height;
+ while (y--) {
+ png_bytep row = (png_bytep)(pixels + y*width*4);
+ png_write_rows(png_ptr, &row, 1);
+ }
+ }
+
+ png_write_end(png_ptr, info_ptr);
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+ fclose(fp);
+ return true;
+
+no_png:
+ fclose(fp);
+no_fp:
+ return false;
+}
+
+
+Image *
+readPNG(const char *filename)
+{
+ FILE *fp;
+ png_structp png_ptr;
+ png_infop info_ptr;
+ png_infop end_info;
+ Image *image;
+
+ fp = fopen(filename, "rb");
+ if (!fp)
+ goto no_fp;
+
+ png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ if (!png_ptr)
+ goto no_png;
+
+ info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr) {
+ png_destroy_read_struct(&png_ptr, NULL, NULL);
+ goto no_png;
+ }
+
+ end_info = png_create_info_struct(png_ptr);
+ if (!end_info) {
+ png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+ goto no_png;
+ }
+
+ if (setjmp(png_jmpbuf(png_ptr))) {
+ png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+ goto no_png;
+ }
+
+ png_init_io(png_ptr, fp);
+
+ png_read_info(png_ptr, info_ptr);
+
+ png_uint_32 width, height;
+ int bit_depth, color_type, interlace_type, compression_type, filter_method;
+
+ png_get_IHDR(png_ptr, info_ptr,
+ &width, &height,
+ &bit_depth, &color_type, &interlace_type,
+ &compression_type, &filter_method);
+
+ image = new Image(width, height);
+ if (!image)
+ goto no_image;
+
+ /* Convert to RGBA8 */
+ 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);
+ if (bit_depth == 16)
+ png_set_strip_16(png_ptr);
+
+ for (unsigned y = 0; y < height; ++y) {
+ png_bytep row = (png_bytep)(image->pixels + y*width*4);
+ png_read_row(png_ptr, row, NULL);
+ }
+
+ png_read_end(png_ptr, info_ptr);
+ png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+ fclose(fp);
+ return image;
+
+no_image:
+ png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+no_png:
+ fclose(fp);
+no_fp:
+ return NULL;
+}
+
+
+double Image::compare(Image &ref)
+{
+ if (width != ref.width ||
+ height != ref.height) {
+ return 0.0;
+ }
+
+ const unsigned char *pSrc = start();
+ const unsigned char *pRef = ref.start();
+
+ unsigned long long error = 0;
+ for (unsigned y = 0; y < height; ++y) {
+ for (unsigned x = 0; x < width; ++x) {
+ // FIXME: Ignore alpha channel until we are able to pick a visual
+ // that matches the traces
+ for (unsigned c = 0; c < 3; ++c) {
+ int delta = pSrc[x*4 + c] - pRef[x*4 + c];
+ error += delta*delta;
+ }
+ }
+
+ pSrc += stride();
+ pRef += ref.stride();
+ }
+
+ double numerator = error*2 + 1;
+ double denominator = height*width*3ULL*255ULL*255ULL*2;
+ double quotient = numerator/denominator;
+
+ // Precision in bits
+ double precision = -log(quotient)/log(2.0);
+
+ return precision;
+}
+
+
} /* namespace Image */