Question

I’m trying to use a Google Map as a background, with a fixed overlay. Have a look-see.

You can see the problem — whilst it’s loading, the text is unreadable. The overlay is loaded by Google’s JS. How can I hide the map until the overlay has loaded? (Or a better solution?)

Answer 1

Actually, you can use JavaScript to make sure the map only displays when the overlay is loaded:

document.observe('dom:loaded', function()
{
  if (GBrowserIsCompatible()) {
    var overlaySrc = 'img/contact_map_overlay.png';
    var preloadOverlay = new Image();

    preloadOverlay.onload = function() {
      var map = new GMap2(document.getElementById("map_canvas"));
      map.setCenter(new GLatLng(-33.82568, 151.2180955505371), 14, G_PHYSICAL_MAP);
      var mapTypeControl = new GMapTypeControl();
      var topRight = new GControlPosition(G_ANCHOR_TOP_RIGHT, new GSize(80, 250));
      map.addControl(new GSmallMapControl(), topRight);
      var mapTarget = new GScreenOverlay(overlaySrc, new GScreenPoint(0.0, 0.0, 'fraction', 'fraction'), // screenXY
      new GScreenPoint(0, 0),                                                                                               // overlayXY
      new GScreenSize(1, 1, 'fraction', 'fraction')                                                                         // size on screen
      );
      map.addOverlay(mapTarget);

      var pin = new GIcon(G_DEFAULT_ICON);
      pin.image = "img/pin.png";
      pin.shadow = "no-shadow";
      pin.iconSize = new GSize(34, 43);
      markerOptions = {
        icon: pin
      };

      var marker = new GMarker(new GLatLng(-33.82568, 151.240635), markerOptions);
      map.addOverlay(marker);
    }

    preloadOverlay.src = overlaySrc;
  }
});

Google simply displays the image from the server, so having it loaded into the cache before displaying the map will solve your problem.