[]drawToCanvas截屏为何画不出Text文本呢？

我的代码如下：
var p6_work = new Sprite();
Laya.stage.addChild(p6_work);
 
var txt = new Text();
p6_work.addChild(txt);
txt.text = "玉树临风";
txt.pos(86, 15);
txt.fontSize = 45;
txt.color = "#000000";
 
var htmlCanvas:HTMLCanvas = p6_work.drawToCanvas(575, 1472, 0, 0);
            var canvas = htmlCanvas.getCanvas();
            var base64 = canvas.toDataURL("image/png");
 
为什么截屏里不包含txt呢？？如下图suo所示，小图为截屏。