Fixed handling of grayscale images with alpha

slouken · slouken · commit 39c8ebb0e912 · 2024-08-05T07:03:18.000-07:00
Fixes libsdl-org#460
diff --git a/src/IMG_png.c b/src/IMG_png.c
@@ -336,14 +336,14 @@ static void LIBPNG_LoadPNG_IO(SDL_IOStream *src, struct loadpng_vars *vars)
                 /* more than one transparent index, or translucency */
                 lib.png_set_expand(vars->png_ptr);
             }
+        } else if (color_type == PNG_COLOR_TYPE_GRAY) {
+            /* This will be turned into PNG_COLOR_TYPE_GRAY_ALPHA, so expand to RGBA */
+            lib.png_set_gray_to_rgb(vars->png_ptr);
         } else {
             ckey = 0; /* actual value will be set later */
         }
     }
 
-    if ( color_type == PNG_COLOR_TYPE_GRAY_ALPHA )
-        lib.png_set_gray_to_rgb(vars->png_ptr);
-
     lib.png_read_update_info(vars->png_ptr, vars->info_ptr);
 
     lib.png_get_IHDR(vars->png_ptr, vars->info_ptr, &width, &height, &bit_depth,

Original file line number	Diff line number	Diff line change
`@@ -336,14 +336,14 @@ static void LIBPNG_LoadPNG_IO(SDL_IOStream src, struct loadpng_vars vars)`
`336`	`336`	`/* more than one transparent index, or translucency */`
`337`	`337`	`lib.png_set_expand(vars->png_ptr);`
`338`	`338`	`}`
	`339`	`+ } else if (color_type == PNG_COLOR_TYPE_GRAY) {`
	`340`	`+ /* This will be turned into PNG_COLOR_TYPE_GRAY_ALPHA, so expand to RGBA */`
	`341`	`+ lib.png_set_gray_to_rgb(vars->png_ptr);`
`339`	`342`	`} else {`
`340`	`343`	`ckey = 0; /* actual value will be set later */`
`341`	`344`	`}`
`342`	`345`	`}`
`343`	`346`
`344`		`- if ( color_type == PNG_COLOR_TYPE_GRAY_ALPHA )`
`345`		`- lib.png_set_gray_to_rgb(vars->png_ptr);`
`346`		`-`
`347`	`347`	`lib.png_read_update_info(vars->png_ptr, vars->info_ptr);`
`348`	`348`
`349`	`349`	`lib.png_get_IHDR(vars->png_ptr, vars->info_ptr, &width, &height, &bit_depth,`