How to animate stuff when using -drawRect:?
<p>I didn't use subviews but painted my things with -drawRect: inside an UIView subclass. Now I want to do some animations in there.</p>

<p>I guess that I can't count on core animation now since I have no subviews. So how would I animate then? Would I set up a timer which fires like 30 times per second? How would I know the animation step? Would I make an ivar which counts the frame of the animation so that I can do my stuff in -drawRect as it gets called?</p>
