title: Animate circular mask of UIImageView in iOS
body: <p>I am wondering how to animate the scale of a mask on a uiimageview. Example images attached. The gray boxes are the image background of my uiviewcontroller and is not part of the issue.</p>
  
  <p><img src="https://i.stack.imgur.com/TQArX.jpg" alt="enter image description here"></p>
  
  <p>I assume creation of a uiview subclass that I pass an image, a radius and a center point. And then (?) create a mask, and then animate it back and forth?</p>
  
  <p>Can anyone point me in the right direction? The circle can be placed anywhere, at any size, but the image to be revealed is always full screen.</p>
  
  <p>Eventually I will add a method to shrink the circle back down. But one step at a time.</p>
  
  <p>Thank you for the direction,</p>
  
  <p>-e</p>