Contents

/*
 * L.Handler.ScrollWheelZoom is used internally by L.Map to enable mouse scroll wheel zooming on the map.
 */

L.Map.ScrollWheelZoom = L.Handler.extend({
	addHooks: function () {
		L.DomEvent.addListener(this._map._container, 'mousewheel', this._onWheelScroll, this);
		this._delta = 0;
	},

	removeHooks: function () {
		L.DomEvent.removeListener(this._map._container, 'mousewheel', this._onWheelScroll);
	},

	_onWheelScroll: function (e) {
		var delta = L.DomEvent.getWheelDelta(e);
		this._delta += delta;
		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 map = this._map,
			delta = Math.round(this._delta),
			zoom = map.getZoom();

		delta = Math.max(Math.min(delta, 4), -4);
		delta = map._limitZoom(zoom + delta) - zoom;

		this._delta = 0;

		if (!delta) {
			return;
		}

		var newCenter = this._getCenterForScrollWheelZoom(this._lastMousePos, delta),
			newZoom = zoom + delta;

		map.setView(newCenter, newZoom);
	},

	_getCenterForScrollWheelZoom: function (mousePos, delta) {
		var map = this._map,
			centerPoint = map.getPixelBounds().getCenter(),
			viewHalf = map.getSize().divideBy(2),
			centerOffset = mousePos.subtract(viewHalf).multiplyBy(1 - Math.pow(2, -delta)),
			newCenterPoint = centerPoint.add(centerOffset);

		return map.unproject(newCenterPoint, map._zoom, true);
	}
});

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
leaflet-ruby-0.3.beta4	lib/leaflet/src/map/handler/Map.ScrollWheelZoom.js
leaflet-ruby-0.3.beta3	lib/leaflet/src/map/handler/Map.ScrollWheelZoom.js
leaflet-ruby-0.3.beta1	lib/leaflet/src/map/handler/Map.ScrollWheelZoom.js