as3.0中的碰撞重叠问题,大家看看，帮忙出出主意~

如果有两个不规则的图形经过鼠标拖拽，触发了hittestobject，重叠的面积以矩形的形状颜色加深，代码该如何写呀？？
以下是碰撞检验，没有重叠面积加深的。

tuxing.addEventListener(MouseEvent.MOUSE_DOWN, tuo);

stage.addEventListener(MouseEvent.MOUSE_UP, ting);

function tuo(event:MouseEvent):void {
stage.addEventListener(MouseEvent.MOUSE_MOVE , dong);

}
function dong(event:MouseEvent):void {
tuxing.x=mouseX;
tuxing.y=mouseY;
if (tuxing.hitTestObject(tuxing2)) {
trace("碰到");
} else {
trace("没碰到");
}
}

function ting(event:MouseEvent):void {
stage.removeEventListener(MouseEvent.MOUSE_MOVE , dong);
}

ws.tink.display.HitTest  　直接完成