How to composite several NSImages into one big image?

Question

I have a collection of objects which describe an image-name, its size and it\'s X/Y location. The collection is sorted by \"layers\", so I can composite the images in a sort of

Answer 1

NSImage* resultImage = [[[NSImage alloc] initWithSize:imageSize] autorelease];
[resultImage lockFocus];

[anotherImage drawAtPoint:aPoint fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
// Or any of the other about 6 options; see Apple's guide to pick.

[resultImage unlockFocus];

Check Apple's Drawing Guide for a much longer, more detailed answer.