Fixed colorspace for ImageIO loading

albert Test case: https://gist.github.com/1551241 It should output: Code: $ ./sdlimagetest PixelFormat: BitsPerPixel: 32, BytesPerPixel: 4 R/G/B/A mask: ff0000/ff00/ff/ff000000 R/G/B/A loss: 0/0/0/0 Colorkey: 0, Alpha: 255 FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF FF0000FF Output with bad SDL_image: Code: $ ./sdlimagetest PixelFormat: BitsPerPixel: 32, BytesPerPixel: 4 R/G/B/A mask: ff0000/ff00/ff/ff000000 R/G/B/A loss: 0/0/0/0 Colorkey: 0, Alpha: 255 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 FF1514F4 And I searched a bit around and I found a fix in the Allegro code (http://codesearch.google.com/#w3aXj_apqFs/allegro/tags/5.0.0/addons/image/macosx.m&ct=rc&cd=3&q=CGColorSpaceCreateCalibratedRGB). So I wrote a patch for SDL_image: https://gist.github.com/1551404
libsdl-org · Jan 4, 2012 · 97e7217 · 97e7217
1 parent d98a4dc
commit 97e7217
Showing 1 changed file with 19 additions and 2 deletions.
diff --git a/IMG_ImageIO.m b/IMG_ImageIO.m
@@ -212,8 +212,25 @@ static CFDictionaryRef CreateHintDictionary(CFStringRef uti_string_hint)
 
     CGContextRef bitmap_context;
     CGBitmapInfo bitmap_info;
-    CGColorSpaceRef color_space = CGColorSpaceCreateDeviceRGB();
-
+
+	/* This sets up a color space that results in identical values
+	 * as the image data itself, which is the same as the standalone
+	 * libpng loader.
+	 * Thanks to Allegro. :)
+	 */
+	CGFloat whitePoint[3] = { 1, 1, 1 };
+	CGFloat blackPoint[3] = { 0, 0, 0 };
+	CGFloat gamma[3] = { 2.2, 2.2, 2.2 };
+	CGFloat matrix[9] = {
+		1, 1, 1,
+		1, 1, 1,
+		1, 1, 1
+	};
+	CGColorSpaceRef color_space =
+		CGColorSpaceCreateCalibratedRGB(
+									whitePoint, blackPoint, gamma, matrix
+									);   
+
     if (alpha == kCGImageAlphaNone ||
         alpha == kCGImageAlphaNoneSkipFirst ||
         alpha == kCGImageAlphaNoneSkipLast) {