Share displayObject

1

Hi. I need to share croped area of DisplayObject, for multipla DisplayObjects I have solution, but its too slow, maybe there is some as3 base functionality to do my problem

this._img.addEventListener(Event.ENTER_FRAME,onFrame);
function onFrame(e:Event){

var i:int = this._maska.numChildren;
for(var j:int = 0; j<i; j++){
    share(MovieClip(this._maska.getChildAt(j)));
}

}

function share(_targetObject:MovieClip){
var mat:Matrix = new Matrix();
mat.translate(-_targetObject.x,-_targetObject.y);
var bmp1:BitmapData = new BitmapData(_targetObject.width,_targetObject.height,true,0x000000);
bmp1.draw(this._img,mat);

var bmpLayer:Bitmap = new Bitmap(bmp1);
    bmpLayer.name = 'bmp';
    
var tmpChild:DisplayObject;
if(tmpChild = _targetObject.getChildByName('bmp')){
    _targetObject.removeChild(tmpChild);
}
_targetObject.addChild(bmpLayer);

}