Add 'heading' property to ol.DeviceOrientation

examples/device-orientation.html

@@ -43,6 +43,7 @@
           <p>&alpha; : <code id="alpha"></code></p>
           <p>&beta; : <code id="beta"></code></p>
           <p>&gamma; : <code id="gamma"></code></p>
+          <p>heading : <code id="heading"></code></p>
           <p id="shortdesc">Listen to DeviceOrientation events</p>
           <div id="docs">
             <p>See the <a href="device-orientation.js" target="_blank">device-orientation.js source</a> to see how this is done.</p>

examples/device-orientation.js

@@ -29,4 +29,5 @@ deviceOrientation.on('changed', function() {
   document.getElementById('alpha').innerHTML = deviceOrientation.getAlpha();
   document.getElementById('beta').innerHTML = deviceOrientation.getBeta();
   document.getElementById('gamma').innerHTML = deviceOrientation.getGamma();
+  document.getElementById('heading').innerHTML = deviceOrientation.getHeading();
 });

src/ol/deviceorientation.js

@@ -1,4 +1,3 @@
-// FIXME: event.absolute
 goog.provide('ol.DeviceOrientation');
 goog.provide('ol.DeviceOrientationProperty');
 
@@ -14,6 +13,7 @@ ol.DeviceOrientationProperty = {
   ALPHA: 'alpha',
   BETA: 'beta',
   GAMMA: 'gamma',
+  HEADING: 'heading',
   TRACKING: 'tracking'
 };
 
@@ -67,8 +67,12 @@ ol.DeviceOrientation.prototype.orientationChange_ = function(browserEvent) {
   var event = /** @type {DeviceOrientationEvent} */
       (browserEvent.getBrowserEvent());
   if (goog.isDefAndNotNull(event.alpha)) {
-    this.set(ol.DeviceOrientationProperty.ALPHA,
-        goog.math.toRadians(event.alpha));
+    var alpha = goog.math.toRadians(event.alpha);
+    this.set(ol.DeviceOrientationProperty.ALPHA, alpha);
+    // event.absolute is undefined in iOS.
+    if (goog.isBoolean(event.absolute) && event.absolute) {
+      this.set(ol.DeviceOrientationProperty.HEADING, alpha);
+    }
   }
   if (goog.isDefAndNotNull(event.beta)) {
     this.set(ol.DeviceOrientationProperty.BETA,
@@ -120,6 +124,19 @@ goog.exportProperty(
     ol.DeviceOrientation.prototype.getGamma);
 
 
+/**
+ * @return {number|undefined} heading.
+ */
+ol.DeviceOrientation.prototype.getHeading = function() {
+  return /** @type {number} */ (
+      this.get(ol.DeviceOrientationProperty.HEADING));
+};
+goog.exportProperty(
+    ol.DeviceOrientation.prototype,
+    'getHeading',
+    ol.DeviceOrientation.prototype.getHeading);
+
+
 /**
  * @return {boolean|undefined} tracking.
  */