From 4754ed1cc2c2e1d92d4cdbdad1fe1497f9a19985 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Wed, 18 Jul 2012 14:07:59 +0200
Subject: [PATCH] Add ol.control.MouseWheelZoom

---
 src/ol/control/mousewheelzoom.js | 39 ++++++++++++++++++++++++++++++++
 src/ol/createmap.js              |  2 ++
 src/ol/map.js                    |  9 ++++++++
 src/ol/ol.js                     |  1 +
 4 files changed, 51 insertions(+)
 create mode 100644 src/ol/control/mousewheelzoom.js

diff --git a/src/ol/control/mousewheelzoom.js b/src/ol/control/mousewheelzoom.js
new file mode 100644
index 0000000000..8b94a52b7a
--- /dev/null
+++ b/src/ol/control/mousewheelzoom.js
@@ -0,0 +1,39 @@
+goog.provide('ol.control.MouseWheelZoom');
+
+goog.require('goog.events.MouseWheelEvent');
+goog.require('goog.events.MouseWheelHandler.EventType');
+goog.require('ol.MapBrowserEvent');
+
+
+
+/**
+ * @constructor
+ * @extends {ol.Control}
+ */
+ol.control.MouseWheelZoom = function() {
+  goog.base(this);
+};
+goog.inherits(ol.control.MouseWheelZoom, ol.Control);
+
+
+/**
+ * @inheritDoc
+ */
+ol.control.MouseWheelZoom.prototype.handleMapBrowserEvent = function(event) {
+  if (event.type == goog.events.MouseWheelHandler.EventType.MOUSEWHEEL) {
+    var map = event.map;
+    var mouseWheelEvent = /** @type {goog.events.MouseWheelEvent} */
+        event.getBrowserEventObject();
+    goog.asserts.assert(mouseWheelEvent instanceof goog.events.MouseWheelEvent);
+    if (mouseWheelEvent.deltaY !== 0) {
+      map.whileFrozen(function() {
+        // FIXME compute correct center for zoom
+        map.setCenter(event.getCoordinate());
+        var scale = mouseWheelEvent.deltaY < 0 ? 0.5 : 2;
+        map.setResolution(scale * map.getResolution());
+      });
+      event.preventDefault();
+      mouseWheelEvent.preventDefault();
+    }
+  }
+};
diff --git a/src/ol/createmap.js b/src/ol/createmap.js
index 4f2eb82926..3a9e9089d9 100644
--- a/src/ol/createmap.js
+++ b/src/ol/createmap.js
@@ -7,6 +7,7 @@ goog.require('ol.Map');
 goog.require('ol.MapProperty');
 goog.require('ol.Projection');
 goog.require('ol.control.DblClickZoom');
+goog.require('ol.control.MouseWheelZoom');
 goog.require('ol.dom');
 goog.require('ol.dom.Map');
 goog.require('ol.webgl');
@@ -66,6 +67,7 @@ ol.createMap = function(target, opt_values, opt_rendererHints) {
   if (!goog.object.containsKey(values, ol.MapProperty.CONTROLS)) {
     var controls = new ol.Array();
     controls.push(new ol.control.DblClickZoom());
+    controls.push(new ol.control.MouseWheelZoom());
     values[ol.MapProperty.CONTROLS] = controls;
   }
 
diff --git a/src/ol/map.js b/src/ol/map.js
index 3e408daa93..3ffcd317dd 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -7,6 +7,9 @@ goog.require('goog.events');
 goog.require('goog.events.BrowserEvent');
 goog.require('goog.events.Event');
 goog.require('goog.events.EventType');
+goog.require('goog.events.MouseWheelEvent');
+goog.require('goog.events.MouseWheelHandler');
+goog.require('goog.events.MouseWheelHandler.EventType');
 goog.require('goog.fx.anim');
 goog.require('goog.fx.anim.Animated');
 goog.require('goog.math.Coordinate');
@@ -73,6 +76,12 @@ ol.Map = function(target, opt_values, opt_viewportSizeMonitor) {
     goog.events.EventType.CLICK
   ], this.handleBrowserEvent, false, this);
 
+  var mouseWheelHandler = new goog.events.MouseWheelHandler(this.eventsPane_);
+  goog.events.listen(mouseWheelHandler,
+      goog.events.MouseWheelHandler.EventType.MOUSEWHEEL,
+      this.handleBrowserEvent, false, this);
+  this.registerDisposable(mouseWheelHandler);
+
   /**
    * @private
    * @type {goog.fx.anim.Animated}
diff --git a/src/ol/ol.js b/src/ol/ol.js
index 33e09481ce..fe31aa9114 100644
--- a/src/ol/ol.js
+++ b/src/ol/ol.js
@@ -25,6 +25,7 @@ goog.require('ol.TileUrlFunction');
 goog.require('ol.TileUrlFunctionType');
 goog.require('ol.TransformFunction');
 goog.require('ol.control.DblClickZoom');
+goog.require('ol.control.MouseWheelZoom');
 goog.require('ol.createMap');
 goog.require('ol.dom');
 goog.require('ol.dom.LayerRenderer');