Make tile transitions configurable

examples/tile-transitions.html

@@ -0,0 +1,15 @@
+---
+layout: example.html
+title: Tile Transitions
+shortdesc: Custom configuration for opacity transitions on tiles.
+docs: >
+  By default tiles are rendered with an opacity transition - fading in over
+  250 ms.  To disable this behavior, set the <code>transition</code> option
+  of the tile source to 0.
+tags: "fade, transition"
+---
+<div id="map" class="map"></div>
+<label>
+  render with an opacity transition
+  <input id="transition" type="checkbox" checked>
+</label>

examples/tile-transitions.js

@@ -0,0 +1,31 @@
+goog.require('ol.Map');
+goog.require('ol.View');
+goog.require('ol.layer.Tile');
+goog.require('ol.source.XYZ');
+
+var url = 'https://{a-c}.tiles.mapbox.com/v3/mapbox.world-bright/{z}/{x}/{y}.png';
+
+var withTransition = new ol.layer.Tile({
+  source: new ol.source.XYZ({url: url})
+});
+
+var withoutTransition = new ol.layer.Tile({
+  source: new ol.source.XYZ({url: url, transition: 0}),
+  visible: false
+});
+
+var map = new ol.Map({
+  layers: [withTransition, withoutTransition],
+  target: 'map',
+  view: new ol.View({
+    center: [0, 0],
+    zoom: 2,
+    maxZoom: 11
+  })
+});
+
+document.getElementById('transition').addEventListener('change', function(event) {
+  var transition = event.target.checked;
+  withTransition.setVisible(transition);
+  withoutTransition.setVisible(!transition);
+});