title: How to crop Image using rectangle?
body: <p><img src="https://i.stack.imgur.com/PP7No.png" alt="Rectangle used to crop"></p>
  
  <p>I am trying to crop an image using this rectangle.But Not getting how to stretch the rectangle.I am having one <code>UIView</code> that is outside and within that other view shown with <code>black border</code>. When I stretch DO i need to change the frame for both <code>UIView</code>s ??</p>
  
  <p>should use <code>Pinchgesture</code> to stretch the rectangle or any other method??</p>
  
  <p>Here four blue handlers are <code>UIView</code> s. How will i determine the dragging of them??
  If there please suggest.</p>