PNG_CMAP_RGB_ALPHA_BACKGROUND 2863 pngread.c               if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
PNG_CMAP_RGB_ALPHA_BACKGROUND 3024 pngread.c                              *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
PNG_CMAP_RGB_ALPHA_BACKGROUND 3034 pngread.c                              unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;