title: Google Maps v3: How to tell when an ImageMapType overlay's tiles are finished loading?
body: <p>I'm working with the Google Maps v3 API, and I have a custom overlay layer based on the ImageMapType class. I would like to show a loading indicator of some sort while the overlay's tiles are loading, but I don't see any way to know when they are finished.</p>
  
  <p>The code to create the overlay looks similar to the following:</p>
  
  <pre><code>var myOverlay = new google.maps.ImageMapType({
      getTileUrl: myGetTileUrl,
      tileSize: new google.maps.Size(256, 256),
      isPng: true
  });
  
  myMap.overlayMapTypes.push(myOverlay);
  </code></pre>
  
  <p>The above works just fine, and the overlay successfully loads; it just seems that no events are emitted by the map to indicate anything about the ImageMapType overlay's status. </p>
  
  <p>I would expect the map to at least emit an "idle" event when the tiles are finished loading, but as far as I can tell it does not.</p>
  
  <p>How may I know when the ImageMapType overlay is finished loading? </p>
  
  <p>EDIT</p>
  
  <p>I wrote a test case on jsFiddle: <a href="http://jsfiddle.net/6yvcB/" rel="noreferrer">http://jsfiddle.net/6yvcB/</a> — Watch your console output for the word "idled" to see when the idle event fires. Notice that it never fires when you click the button to add an overlay. </p>
  
  <p>Also, kittens.</p>