title: Can not read property 'position' undefined, get Coordinates - CustomTile - Openseadragon
body: <p>I am trying to get the coordinates with below code : If i am clicking on the canvas to grab the X and Y position : showing me console error : Uncaught TypeError: Cannot read property 'position' of undefined</p>
  
  <p>screenshot : <a href="http://screencast.com/t/0LHAae5AicRz" rel="nofollow">http://screencast.com/t/0LHAae5AicRz</a></p>
  
  <pre><code>viewer.addHandler('canvas-click', function (target, info) {
              var viewportPoint = viewer.viewport.pointFromPixel(info.position);
              var imagePoint = viewer.viewport.viewportToImageCoordinates(viewportPoint.x, viewportPoint.y);
              console.log(imagePoint.x, imagePoint.y);
          });
  </code></pre>