How to implement Lion style swipe and slide away animation

I am wanting to implement history navigation in my app that mimics the slide away animation found in Safari on Lion and in XCode where a top view slides away at the speed of swipe to reveal the view underneath it.

I was looking for pointers on how to do this. I know how to detect the swipe. I assume I could implement the animation via a CALayer animation slide transition on the top 开发者_如何学JAVAview revealing a view underneath it. Has anybody else done this and can offer some further pointers?

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It's a new NSEvent method, -trackSwipeEventWithOptions:.... You should call it from within your regular scroll/swipe event handler, whenever you decide the gesture should begin. Unfortunately it doesn't automatically handle the page animations — it just gives you updates with the gesture amount, and you have to do the animations yourself (using layers or views or somesuch). You'll probably want to save images of each page so you can animate them around during a gesture.