title: Best way to mirror a UIWebView
body: <p>I need to mirror a UIWebView's CALayers to a smaller CALayer. The smaller CALayer is essentially a pip of the larger UIWebView. I'm having difficulty in doing this. The only thing that comes close is CAReplicatorLayer, but given the original and the copy have to have CAReplicatorLayer as a parent, I cannot split the original and copy on different screens.</p>
  
  <p>An illustration of what I'm trying to do:</p>
  
  <p><img src="https://i.stack.imgur.com/dxPyh.png" alt="enter image description here"></p>
  
  <p>The user needs to be able to interact with the smaller CALayer and both need to be in sync.</p>
  
  <p>I've tried doing this with renderInContext and CADisplayLink. Unfortunately there is some lag/stutter because it's trying to re-draw every frame, 60 times a second. I need a way to do the mirroring without re-drawing on each frame, unless something has actually changed. So I need a way of knowing when the CALayer (or child CALayers) become dirty.</p>
  
  <p>I cannot simply have two UIWebView's because two pages may be different (timing is off, different background, etc...). I have no control over the web page being displayed. I also cannot display the entire iPad screen as there are other elements on the screen that should not show on the external screen.</p>
  
  <p>Both the larger CALayer and smaller "pip" CALayer need to match smoothly frame-for-frame in iOS 6. I do not need to support earlier versions.</p>
  
  <p>The solution needs to be app-store passable.</p>