egret 开发阶段 显示屏幕像素坐标

<pre name="code" class="javascript">    private showMousePos() {

var canvas = document.getElementsByTagName('canvas')[0];
var ctx = canvas.getContext('2d');
var tips:egret.TextField = new egret.TextField();
tips.size = 32;
tips.x = 0;
tips.y = 380;
tips.width = this.stage.stageWidth - 40;
this.addChild(tips);

canvas.addEventListener('mousemove', function (e) {
// 偏移值一直变。。。 不准,是因为egret引擎使用了屏幕适配策略，需要开发阶段需要屏蔽适配:data-scale-mode="noScale"
tips.text = "x:" + (e.x) + ", y:" + e.y;
}.bind(this))
}