把bitmapData设为canvas背景

var sprite:Sprite=new Sprite();
sprite.graphics.clear();
sprite.graphics.beginBitmapFill(bitmapData,null,true,true);
sprite.graphics.drawRect(0,0,200,200);
sprite.graphics.endFill();

var canvas:Canvas=new Canvas();
canvas.width=550;
canvas.height=400;
canvas.graphics.clear();
canvas.graphics.beginBitmapFill(bitmapData,null,true,true);
canvas.graphics.drawRect(0,0,canvas.width,canvas.height);
canvas.graphics.endFill();