Quartz drawing help - CGLayer, UIGraphicsBeginImageContext, UIGraphicsGetCurrentContext

Question

I'm trying to put together a simple example of using some of the quartz api. specifically i'm working on trying to draw an image to a CGLayer to cache it. Then draw that layer to another graphics context more frequently.

Here's some source code for the example:

header: http://pastebin.com/1qKnexDt class: http://pastebin.com/60FRj5dZ

The class source code is really straightforward. but I can't figure out why it's not being displayed.

The ultimate goal is what's happening in the "- (void)touchesMoved:withEvent:" method.

The code is in an UIView, and i've put NSLog's in the touchesMoved method to verify that it's actually being called.

Any ideas?

Thanks!