NSBitmapImageRep for iPhone (or direct pixel access for CGImage)?

Question

Is there a good analogue of NSBitmapImageRep ? In particular, I am looking for similar methods for setPixel:atX:y: and getPixel:atX:y: I found this technot and it really helps me in using CGImage, but how to find out in what order the pixels are in

Answer 1

 CGImageGetBitsPerComponent( image ); CGImageGetBitsPerPixel( image ); CGImageGetBytesPerRow( image ); CGImageGetBitmapInfo( image ); CGColorSpaceGetModel( CGImageGetColorSpace( image ) ); CGColorSpaceGetNumberOfComponents( CGImageGetColorSpace( image ) ); 

Using the calls above, you can figure out how each pixel is laid out. Each pixel for x, y starts with:

 length = CGImageGetBitsPerPixel(image)/CHAR_BIT; offset = y*CGImageGetBytesPerRow(image) + x*length; 

A typical 32-bit ARGB PNG could be:

 8 = CGImageGetBitsPerComponent( image ); 32 = CGImageGetBitsPerPixel( image ); kCGImageAlphaFirst = CGImageGetBitmapInfo( image ); 4 = CGColorSpaceGetNumberOfComponents( CGImageGetColorSpace( image ) ); kCGColorSpaceModelRGB = CGColorSpaceGetNumberOfComponents( CGImageGetColorSpace( image ) );