Animation Toolbox 2.0

Animation Toolbox - Three Objective-C classes to easily and quickly build visual animations in Mac OS X’s Cocoa framework. Includes a sample project for Xcode/Interface Builder.
The classes in the Animation Toolbox are a by-product of my Tetris-like game Quinn. When I started writing Quinn, which contains quite a lot of short visual animations, I found myself producing the same sort of code over and over again—for example, dealing with NSTimers, calculating the time elapsed, or the progress made—, so I encapsulated these tasks in reusable classes which turned out to be very useful for many purposes.
The code has been rewritten many times since its first version (Summer 2002) to become more versatile and robust, so that almost nothing of my original approach is left now. I designed the interface to allow quickly creating animations of very different kinds, and extended the code to also support more complex scenarios. The classes still form the backbone for the quite complex interplay of animations in Quinn.
The download includes a sample project to show some possible kinds of animations, and how little code it takes to get them running.