Animation Kit

Animation Kit solves those problems. The backbone is timers, calculations are done in units of time, not a number of frames, and the framework is very expandable. But why are these things important?

Animation Kit uses timers because it is the only way to achieve truly asynchronous animation. This means that while your animation is running, your user interface still works. It also means multiple animations can occur at the same time and animations can be stopped if you need, such as the result of another user action. You can't do that with loops.

All calculations are done in units of time, not frames. Many animation tricks will work based on a number of frames. For example, assuming that you want your animation to run for half a second, at 30 frames per second, you'll need 15 frames right? Wrong. What if the computer is running slow? Or maybe the user is mousing on a menu. These things affect the timing of your animation. Animation Kit guarantees your animation will complete at the duration you specified, no matter what.

Lastly, all animation is built upon a class called AKTask. A number of subclasses are provided that will cover 90% of all animation you could want, but you can also create your own subclasses to do entirely custom animation while utilizing the powerful animation framework already in your code.

And it's all free and open source!