title: In Core Animation, how can I get the layer frame and rotations?
body: <p>I'm using Core Animation to animate some layers, some of them will be used to display video.</p>
  
  <p>I heard that it's not a good idea (inefficient) to use multiple layers to play multiple movies. After some search I find a way to create Open GL textures with the video frames. So I would like to access the layer properties to display them with Open GL using textures (avoiding having multiple CAOpenGLLayers with OpenGL contexts for each one).</p>
  
  <p>I have subclassed CALayer to place breakpoints on setFrame: but it doesn't break each time the value change. How can I determine the frame of a CALayer as it changes during an animation?</p>
  
  <p>PS: I'm using CARenderer because I have to create frames by mixing all my layers and not in real time.</p>