learning Cocoa:

This is the main introduction to Cocoa: | http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CocoaFundamentals/Introduction/Introduction.html#//apple_ref/doc/uid/TP40002974

It recommends knowing about the Mac OS X Technologies, described in the following document: | http://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/OSX_Technology_Overview/About/About.html#//apple_ref/doc/uid/TP40001067-CH204-TPXREF101

In particular, the following section on Graphics and Multimedia Technologies seems relevant: | http://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/OSX_Technology_Overview/GraphicsTechnologies/GraphicsTechnologies.html#//apple_ref/doc/uid/TP40001067-CH273-SW1 | Talking about Quartz, the 2D rendering engine for window layouts.