Code coverage report for src/map/handler/Map.ScrollWheelZoom.js

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All files » src/map/handler/ » Map.ScrollWheelZoom.js
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/*
 * L.Handler.ScrollWheelZoom is used by L.Map to enable mouse scroll wheel zoom on the map.
 */
 
L.Map.mergeOptions({
	scrollWheelZoom: true
});
 
L.Map.ScrollWheelZoom = L.Handler.extend({
	addHooks: function () {
		L.DomEvent.on(this._map._container, 'mousewheel', this._onWheelScroll, this);
		this._delta = 0;
	},
 
	removeHooks: function () {
		L.DomEvent.off(this._map._container, 'mousewheel', this._onWheelScroll);
	},
 
	_onWheelScroll: function (e) {
		var delta = L.DomEvent.getWheelDelta(e);
 
		this._delta += delta;
		this._lastMousePos = this._map.mouseEventToContainerPoint(e);
 
		if (!this._startTime) {
			this._startTime = +new Date();
		}
 
		var left = Math.max(40 - (+new Date() - this._startTime), 0);
 
		clearTimeout(this._timer);
		this._timer = setTimeout(L.bind(this._performZoom, this), left);
 
		L.DomEvent.preventDefault(e);
		L.DomEvent.stopPropagation(e);
	},
 
	_performZoom: function () {
		var map = this._map,
		    delta = this._delta,
		    zoom = map.getZoom();
 
		delta = delta > 0 ? Math.ceil(delta) : Math.round(delta);
		delta = Math.max(Math.min(delta, 4), -4);
		delta = map._limitZoom(zoom + delta) - zoom;
 
		this._delta = 0;
 
		this._startTime = null;
 
		if (!delta) { return; }
 
		var newZoom = zoom + delta,
		    newCenter = this._getCenterForScrollWheelZoom(newZoom);
 
		map.setView(newCenter, newZoom);
	},
 
	_getCenterForScrollWheelZoom: function (newZoom) {
		var map = this._map,
		    scale = map.getZoomScale(newZoom),
		    viewHalf = map.getSize()._divideBy(2),
		    centerOffset = this._lastMousePos._subtract(viewHalf)._multiplyBy(1 - 1 / scale),
		    newCenterPoint = map._getTopLeftPoint()._add(viewHalf)._add(centerOffset);
 
		return map.unproject(newCenterPoint);
	}
});
 
L.Map.addInitHook('addHandler', 'scrollWheelZoom', L.Map.ScrollWheelZoom);