PNG_CMAP_TRANS_BACKGROUND 2853 pngread.c                  background_index != PNG_CMAP_TRANS_BACKGROUND)
PNG_CMAP_TRANS_BACKGROUND 2991 pngread.c                              *outrow = PNG_CMAP_TRANS_BACKGROUND;
PNG_CMAP_TRANS_BACKGROUND 2993 pngread.c                           else if (gray != PNG_CMAP_TRANS_BACKGROUND)
PNG_CMAP_TRANS_BACKGROUND 2997 pngread.c                              *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);