title: ARKit – Viewport Size vs Real Screen Resolution
body: <p>I am writing an ARKit app that uses ARSCNView <code>hitTest</code> function. Also the app sends captured images to the server for some analysis.</p>
  
  <p>I notices when I do:</p>
  
  <pre><code>let viewportSize = sceneView.snapshot().size
  let viewSize = sceneView.bounds.size 
  </code></pre>
  
  <p>then the first one is twice as large as the second one.</p>
  
  <p>The questions are:</p>
  
  <ul>
  <li>1.Why there is a difference?</li>
  <li>2.What "size" (e.g. coordinates) is used in hitTest?</li>
  </ul>