Method handleBrowserEvent

src/common/commontypes/Events.js:401–426

* @function Events.prototype.handleBrowserEvent * @description 对 triggerEvent 函数的包装，给事件对象设置了 xy 属性（即当前鼠标点的 xy 坐标）。 * @param {Event} evt - 事件对象。

(evt)

     * @param {Event} evt - 事件对象。
     */
    handleBrowserEvent(evt) {
        var type = evt.type, listeners = this.listeners[type];
        if (!listeners || listeners.length == 0) {
            // noone's listening, bail out
            return;
        }
        // add clientX & clientY to all events - corresponds to average x, y
        var touches = evt.touches;
        if (touches && touches[0]) {
            var x = 0;
            var y = 0;
            var num = touches.length;
            var touch;
            for (var i = 0; i < num; ++i) {
                touch = touches[i];
                x += touch.clientX;
                y += touch.clientY;
            }
            evt.clientX = x / num;
            evt.clientY = y / num;
        }
        if (this.includeXY) {
            evt.xy = this.getMousePosition(evt);
        }
        this.triggerEvent(type, evt);
    }


    /**