From 127a2c9606b5e9e935d2f8ebd955cf68a15dbb12 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89ric=20Lemoine?= <eric.lemoine@gmail.com>
Date: Mon, 9 Jul 2012 20:50:59 +0200
Subject: [PATCH] [ol.handler.Drag] receive mousemove/touchmove events when
 dragstart and dragend only

---
 src/ol/handler/Drag.js | 38 ++++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/src/ol/handler/Drag.js b/src/ol/handler/Drag.js
index a08e0377c7..1e4f0d88c7 100644
--- a/src/ol/handler/Drag.js
+++ b/src/ol/handler/Drag.js
@@ -1,9 +1,8 @@
 /**
  * @fileoverview Drag Handler.
  *
- * A drag handler uses a goog.fx.Dragger object to receive dragstart, drag, dragend
- * events for a DOM element, and re-dispatches these events to the map.
- *
+ * Provides a class for listening to drag events on a DOM element and
+ * re-dispatching to a map instance.
  */
 
 goog.provide('ol.handler.Drag');
@@ -22,12 +21,17 @@ goog.require('goog.Disposable');
 ol.handler.Drag = function(map, elt) {
 
     var dragger = new goog.fx.Dragger(elt);
-    this.registerDisposable(dragger);
-
     dragger.defaultAction = function() {};
 
+    this.registerDisposable(dragger);
+
+    var touchmove = goog.events.EventType.TOUCHMOVE,
+        mousemove = goog.events.EventType.MOUSEMOVE;
+
     var prevX = 0, prevY = 0;
 
+    var preventDefault = function(e) { e.preventDefault(); };
+
     var handleDragStart = function(e) {
         prevX = e.clientX;
         prevY = e.clientY;
@@ -35,6 +39,8 @@ ol.handler.Drag = function(map, elt) {
             type: 'dragstart'
         };
         goog.events.dispatchEvent(map, newE);
+        // this to prevent page scrolling
+        goog.events.listen(elt, [touchmove, mousemove], preventDefault);
     };
 
     var handleDrag = function(e) {
@@ -53,6 +59,11 @@ ol.handler.Drag = function(map, elt) {
             type: 'dragend'
         };
         goog.events.dispatchEvent(map, newE);
+        goog.events.unlisten(elt, [touchmove, mousemove], preventDefault);
+    };
+
+    var handleDragEarlyCancel = function(e) {
+        goog.events.unlisten(elt, [touchmove, mousemove], preventDefault);
     };
 
     goog.events.listen(dragger, goog.fx.Dragger.EventType.START,
@@ -61,20 +72,7 @@ ol.handler.Drag = function(map, elt) {
                        handleDrag, false, this);
     goog.events.listen(dragger, goog.fx.Dragger.EventType.END,
                        handleDragEnd, false, this);
-
-
-    // prevent page scrolling
-    this.moveListenerKey_ = goog.events.listen(
-                                elt,
-                                [goog.events.EventType.TOUCHMOVE,
-                                 goog.events.EventType.MOUSEMOVE],
-                                function(e) { e.preventDefault(); });
+    goog.events.listen(dragger, goog.fx.Dragger.EventType.EARLY_CANCEL,
+                       handleDragEarlyCancel, false, this);
 };
 goog.inherits(ol.handler.Drag, goog.Disposable);
-
-/**
- * @inheritDoc
- */
-ol.handler.Drag.prototype.disposeInternal = function() {
-    goog.events.unlistenByKey(this.moveListenerKey_);
-};