[patch] explicitly defines 'gray' value when reading a png

htmldoc-png.patch (text/plain), 2.72 KB, created by Sibren Polders on 2012-07-24 19:37:45 UTC

--- ../htmldoc-orig-with-patches/htmldoc/image.cxx	2012-07-24 16:13:24.522576169 +0000
+++ htmldoc/image.cxx	2012-07-24 15:02:05.476727262 +0000
@@ -1475,7 +1475,7 @@
   png_bytep trans_alpha;
   int num_trans;
   png_color_16p trans_color;
-
+  int color_type;		
 
  /*
   * Setup the PNG data structures...
@@ -1528,8 +1528,11 @@
   */
 
   png_read_info(pp, info);
-
-  if (png_get_color_type(pp, info) & PNG_COLOR_MASK_PALETTE)
+  
+  color_type = png_get_color_type(pp, info);
+  gray = color_type == PNG_COLOR_TYPE_GRAY;
+  
+  if (color_type & PNG_COLOR_MASK_PALETTE)
   {
     png_set_expand(pp);
 
@@ -1543,10 +1546,10 @@
     png_set_packing(pp);
     png_set_expand(pp);
   }
-  else if (png_get_bit_depth(pp, info) == 16)
+  else if (png_get_bit_depth(pp, info) == 16) {
     png_set_strip_16(pp);
-
-  if (png_get_color_type(pp, info) & PNG_COLOR_MASK_COLOR)
+  }
+  if (color_type & PNG_COLOR_MASK_COLOR)
   {
     depth      = 3;
     img->depth = gray ? 1 : 3;
@@ -1561,7 +1564,7 @@
   img->height = png_get_image_height(pp, info);
 
   png_get_tRNS(pp, info, &trans_alpha, &num_trans, &trans_color);
-  if ((png_get_color_type(pp, info) & PNG_COLOR_MASK_ALPHA) || num_trans)
+  if ((color_type & PNG_COLOR_MASK_ALPHA) || num_trans)
   {
     if ((PSLevel == 0 && PDFVersion >= 14) || PSLevel == 3)
       image_need_mask(img, 8);
@@ -1575,14 +1578,14 @@
 
 #ifdef DEBUG
   printf("color_type=0x%04x, depth=%d, img->width=%d, img->height=%d, img->depth=%d\n",
-         png_get_color_type(pp, info), depth, img->width, img->height, img->depth);
-  if (png_get_color_type(pp, info) & PNG_COLOR_MASK_COLOR)
+         color_type, depth, img->width, img->height, img->depth);
+  if (color_type & PNG_COLOR_MASK_COLOR)
     puts("    COLOR");
   else
     puts("    GRAYSCALE");
-  if ((png_get_color_type(pp, info) & PNG_COLOR_MASK_ALPHA) || num_trans)
+  if (color_type & PNG_COLOR_MASK_ALPHA) || num_trans)
     puts("    ALPHA");
-  if (png_get_color_type(pp, info) & PNG_COLOR_MASK_PALETTE)
+  if (color_type & PNG_COLOR_MASK_PALETTE)
     puts("    PALETTE");
 #endif // DEBUG
 
@@ -1614,7 +1617,7 @@
   * Generate the alpha mask as necessary...
   */
 
-  if ((png_get_color_type(pp, info) & PNG_COLOR_MASK_ALPHA) || num_trans)
+  if ((color_type & PNG_COLOR_MASK_ALPHA) || num_trans)
   {
 #ifdef DEBUG
     for (inptr = img->pixels, i = 0; i < img->height; i ++)
@@ -1643,12 +1646,11 @@
   * Reformat the data as necessary for the reader...
   */
 
-  if (gray && png_get_color_type(pp, info) & PNG_COLOR_MASK_COLOR)
+  if (gray && color_type & PNG_COLOR_MASK_COLOR)
   {
    /*
     * Greyscale output needed...
     */
-
     for (inptr = img->pixels, outptr = img->pixels, i = img->width * img->height;
          i > 0;
          inptr += depth, outptr ++, i --)