title: Moving views with constraints
body: <p>I have a couple views in my view controller that move up when an up swipe is detected then down when a down swipe is detected.  I was forcing the views to move by adjusting the y origin using CGRectOffset.  I've now applied constraints to my views with IB and I'm not sure whats the best way to move the views so that they end up in the right position on the iphone 5, 6, and 6+.  </p>
  
  <p>Currently I'm doing something like this:</p>
  
  <pre><code>[self.view layoutIfNeeded];
  
      self.panFrameVerticalConstraint.constant = self.panFrameVerticalConstraint.constant +338;
  
      [UIView animateWithDuration:5
                       animations:^{
                           [self.view layoutIfNeeded];
                       }];
  </code></pre>
  
  <p>Is it better to change the constants using ratios?  So for the constraint above, instead of using 338, would it be better to do this:</p>
  
  <pre><code>    self.panFrameVerticalConstraint.constant = self.panFrameVerticalConstraint.constant + (self.panView.frame.size.height/1.680);
  
      //self.panView.frame.size.height = 568
      //(568/1.680) = 338
  </code></pre>