Created a layer mask on touch in Objective-c

I need to figure out the following:

• Have two layers stacked (Most likely static png's) then in swipe create a feathered layer mask on the top most layer.
• Give the bottom most layer a centered pivot point and have it capable of a full 360 degree rotation. The angle of that bottom most layer will be determined by th开发者_开发问答e angle of the users swipe motion.

This is for a project I'm currently working on and it's these two things that are stumping me. As always, any help is appreciated. Thanks!

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Are you referring to layers as CALayer? Is there any reason you don't just use UIViews?

Anyway, layer masks can be easily created on a view:

CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = frame;
maskLayer.path = maskPath.CGPath;
controller.view.layer.mask = maskLayer;