title: UIViewController half screen "drawer slide" animation
body: <p>I am trying to have a <code>UIViewController</code> that appears with a "slide" animation from the right. Not like a Push segue, not like the Facebook app. I want the new ViewController to slide ON TOP of the current one (not push it away), but only cover PART of the screen, leaving the other part showing the first ViewController.</p>
  
  <p><strong>What I have tried:</strong> The closest that I have gotten is by creating a custom segue with the following:</p>
  
  <pre><code>- (void)perform
  {
      __block UIViewController *src = (UIViewController *) self.sourceViewController;
      __block UIViewController *dst = (UIViewController *) self.destinationViewController;
  
      CATransition* transition = [CATransition animation];
      transition.duration = .50;
      transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
      transition.type = kCATransitionMoveIn;
      transition.subtype = kCATransitionFromRight;
  
      [src.navigationController.view.layer addAnimation:transition forKey:@"SwitchToView1"];
      [src.navigationController pushViewController:dst animated:NO];
  }
  </code></pre>
  
  <p>This achieves the animation that I am going for, but it covers the entire first ViewController. How would I make it stop at a certain point and not cover the entire thing?</p>
  
  <p>I am using Storyboards, and I this is my first time trying any sort of new animation.</p>