apitrace README.markdown correct some typos

[apitrace] / image / image_pnm.cpp

diff --git a/image/image_pnm.cpp b/image/image_pnm.cpp
index a0638dc59356c58840b03a539e80a7dead4049ba..58e2cd359058f8ffc9f014fb3db4a697b83447f1 100644 (file)
--- a/image/image_pnm.cpp
+++ b/image/image_pnm.cpp
@@ -62,11 +62,17 @@ Image::writePNM(std::ostream &os, const char *comment) const
         if (channels == 1) {
             identifier = "Pf";
             outChannels = 1;
-        } else {
+        } else if (channels <= 3) {
             identifier = "PF";
-            outChannels = 3;
+            outChannels = 4;
+        } else {
+            // Non-standard extension for 4 floats
+            identifier = "PX";
+            outChannels = 4;
         }
         break;
+    default:
+        assert(0);
     }
 
     os << identifier << "\n";
@@ -78,6 +84,8 @@ Image::writePNM(std::ostream &os, const char *comment) const
 
     if (channelType == TYPE_UNORM8) {
         os << "255" << "\n";
+    } else {
+        os << "1" << "\n";
     }
 
     const unsigned char *row;
@@ -95,7 +103,7 @@ Image::writePNM(std::ostream &os, const char *comment) const
          * Need to add/remove channels, one pixel at a time.
          */
 
-        unsigned char *tmp = new unsigned char[width*bytesPerPixel];
+        unsigned char *tmp = new unsigned char[width*outChannels*bytesPerChannel];
 
         if (channelType == TYPE_UNORM8) {
             /*
@@ -154,6 +162,8 @@ Image::writePNM(std::ostream &os, const char *comment) const
              * General path for float images.
              */
 
+            unsigned copyChannels = std::min(channels, outChannels);
+
             assert(channelType == TYPE_FLOAT);
 
             for (row = start(); row != end(); row += stride()) {
@@ -161,14 +171,14 @@ Image::writePNM(std::ostream &os, const char *comment) const
                 float *dst = (float *)tmp;
                 for (unsigned x = 0; x < width; ++x) {
                     unsigned channel = 0;
-                    for (; channel < channels; ++channel) {
+                    for (; channel < copyChannels; ++channel) {
                         *dst++ = *src++;
                     }
-                    for (; channel < channels; ++channel) {
+                    for (; channel < outChannels; ++channel) {
                         *dst++ = 0;
                     }
                 }
-                os.write((const char *)tmp, width*bytesPerPixel);
+                os.write((const char *)tmp, width*outChannels*bytesPerChannel);
             }
         }
 
@@ -189,24 +199,53 @@ Image::writePNM(const char *filename, const char *comment) const
 }
 
 
+/**
+ * Parse PNM header.
+ *
+ * Returns pointer to data start, or NULL on failure.
+ */
 const char *
-readPNMHeader(const char *buffer, size_t bufferSize, unsigned *channels, unsigned *width, unsigned *height)
+readPNMHeader(const char *buffer, size_t bufferSize, PNMInfo &info)
 {
-    *channels = 0;
-    *width = 0;
-    *height = 0;
+    info.channels = 0;
+    info.width = 0;
+    info.height = 0;
 
     const char *currentBuffer = buffer;
     const char *nextBuffer;
 
     // parse number of channels
-    int scannedChannels = sscanf(currentBuffer, "P%d\n", channels);
+    char c;
+    int scannedChannels = sscanf(currentBuffer, "P%c\n", &c);
     if (scannedChannels != 1) { // validate scanning of channels
         // invalid channel line
-        return buffer;
+        return NULL;
     }
     // convert channel token to number of channels
-    *channels = (*channels == 5) ? 1 : 3;
+    switch (c) {
+    case '5':
+        info.channels = 1;
+        info.channelType = TYPE_UNORM8;
+        break;
+    case '6':
+        info.channels = 3;
+        info.channelType = TYPE_UNORM8;
+        break;
+    case 'f':
+        info.channels = 1;
+        info.channelType = TYPE_FLOAT;
+        break;
+    case 'F':
+        info.channels = 3;
+        info.channelType = TYPE_FLOAT;
+        break;
+    case 'X':
+        info.channels = 4;
+        info.channelType = TYPE_FLOAT;
+        break;
+    default:
+        return NULL;
+    }
 
     // advance past channel line
     nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
@@ -222,10 +261,10 @@ readPNMHeader(const char *buffer, size_t bufferSize, unsigned *channels, unsigne
     }
 
     // parse dimensions of image
-    int scannedDimensions = sscanf(currentBuffer, "%d %d\n", width, height);
+    int scannedDimensions = sscanf(currentBuffer, "%u %u\n", &info.width, &info.height);
     if (scannedDimensions != 2) { // validate scanning of dimensions
         // invalid dimension line
-        return buffer;
+        return NULL;
     }
 
     // advance past dimension line
@@ -233,11 +272,38 @@ readPNMHeader(const char *buffer, size_t bufferSize, unsigned *channels, unsigne
     bufferSize -= nextBuffer - currentBuffer;
     currentBuffer = nextBuffer;
 
-    // skip over "255\n" at end of header
+    // skip scale factor / endianness line
     nextBuffer = (const char *) memchr((const void *) currentBuffer, '\n', bufferSize) + 1;
 
     // return start of image data
     return nextBuffer;
 }
 
+
+Image *
+readPNM(const char *buffer, size_t bufferSize)
+{
+    PNMInfo info;
+
+    const char *headerEnd = readPNMHeader(buffer, bufferSize, info);
+
+    // if invalid PNM header was encountered, ...
+    if (headerEnd == NULL) {
+        std::cerr << "error: invalid PNM header";
+        return NULL;
+    }
+
+    Image *image = new Image(info.width, info.height, info.channels, false, info.channelType);
+
+    size_t rowBytes = info.width * image->bytesPerPixel;
+    for (unsigned char *row = image->start(); row != image->end(); row += image->stride()) {
+        memcpy(row, headerEnd, rowBytes);
+        headerEnd += rowBytes;
+    }
+
+    return image;
+}
+
+
+
 } /* namespace image */