title: Stacking UIViews with blend modes in iOS
body: <p>I have two different <code>UIImageViews</code>. I'd like to make the top <code>UIImageView</code> blend in using the Screen blend mode with the bottom <code>UIImageView</code>.</p>
  
  <p>I know of the property of <code>CALayer</code>: <code>compositingFilter</code> and I know that it doesn't work in iOS. I've searched a lot for solutions, and I've found how one should subclass <code>UIView</code> and override <code>drawRect</code>.</p>
  
  <p>I've tried to set the context in <code>drawRect</code> to the screen blend mode, although it still draws every one of the images normally. Perhaps I am doing something wrong, or the approach should be different. Maybe I need OpenGL or CALayer to achieve this. Could someone assist?</p>