title: UIPinchGestureRecognizer in Swift 3
body: <p>I'm having a few issues with the Stanford 2016 CS193P course online.
  I suspect the issue may be that I'm using Xcode 8.2.1 (So I cannot use identical code from the videos), but I may also have made a slip somewhere. I consulted the documentation and looked over stack overflow, but I just can't work this out.</p>
  
  <p>FaceView represents a cartoon face that should scale along with a pinch (using UIPinchGestureRecognizer). To do this an outlet has been created within FaceViewController (the ViewController for FaceView):</p>
  
  <pre><code>@IBOutlet weak var faceView: FaceView!{
      didSet{
      faceView.addGestureRecognizer(UIPinchGestureRecognizer(target:faceView, action:#selector(FaceView.changeScale(recognizer:))))
      updateUI()
  }
  }
  </code></pre>
  
  <p>Which executes the function changeScale within the FaceView class:</p>
  
  <pre><code>func changeScale(recognizer: UIPinchGestureRecognizer){
      switch recognizer.state {
      case .changed, .ended:
          NSLog("gesture")
          scale *= recognizer.scale
          recognizer.scale=1.0
          let resultString = "pinch - scale = \(scale))"
          NSLog(resultString)
      default:
          break
      }
  }
  </code></pre>
  
  <p>I added an output to the console to see if the scale changes when we punch the view. Indeed it does (sample output from the console: pinch - scale = 1.10142245024732; pinch - scale = 1.11638202852033;)</p>
  
  <p>But the view is not changing at all. </p>
  
  <p>I'm at a complete look at this point... any help appreciated</p>
  
  <p>I've confirmed that 
  UserInteraction is set to True
  The IBOutlet is connected (confirmed through the console output)</p>