1 files changed, 50 insertions, 0 deletions
diff --git a/extlib/leaflet/src/handler/ScrollWheelZoom.js b/extlib/leaflet/src/handler/ScrollWheelZoom.js
new file mode 100644
index 00000000..dc877e17
--- /dev/null
+++ b/extlib/leaflet/src/handler/ScrollWheelZoom.js
@@ -0,0 +1,50 @@
+/*
+ * L.Handler.ScrollWheelZoom is used internally by L.Map to enable mouse scroll wheel zooming on the map.
+ */
+
+L.Handler.ScrollWheelZoom = L.Handler.extend({
+	enable: function() {
+		if (this._enabled) { return; }
+		L.DomEvent.addListener(this._map._container, 'mousewheel', this._onWheelScroll, this);
+		this._delta = 0;
+		this._enabled = true;
+	},
+	
+	disable: function() {
+		if (!this._enabled) { return; }
+		L.DomEvent.removeListener(this._map._container, 'mousewheel', this._onWheelScroll);
+		this._enabled = false;
+	},
+	
+	_onWheelScroll: function(e) {
+		this._delta += L.DomEvent.getWheelDelta(e);
+		this._lastMousePos = this._map.mouseEventToContainerPoint(e);
+		
+		clearTimeout(this._timer);
+		this._timer = setTimeout(L.Util.bind(this._performZoom, this), 50);
+		
+		L.DomEvent.preventDefault(e);
+	},
+	
+	_performZoom: function() {
+		var delta = Math.round(this._delta);
+		this._delta = 0;
+		
+		if (!delta) { return; }
+		
+		var center = this._getCenterForScrollWheelZoom(this._lastMousePos, delta),
+			zoom = this._map.getZoom() + delta;
+		
+		if (this._map._limitZoom(zoom) == this._map._zoom) { return; }
+
+		this._map.setView(center, zoom);
+	},
+	
+	_getCenterForScrollWheelZoom: function(mousePos, delta) {
+		var centerPoint = this._map.getPixelBounds().getCenter(),
+			viewHalf = this._map.getSize().divideBy(2),
+			centerOffset = mousePos.subtract(viewHalf).multiplyBy(1 - Math.pow(2, -delta)),
+			newCenterPoint = centerPoint.add(centerOffset);
+		return this._map.unproject(newCenterPoint, this._map._zoom, true);
+	}
+});
+\ No newline at end of file