private function onMouseDown(event:MouseEvent):void
              {
                   drawing = true;
                   hold = null;
                   beginX = event.localX; beginY = event.localY;
                   if (mode == 0) {
                       item = new Sprite();
                       var c:UIComponent = new UIComponent();
                       c.addChild(item);
                       item.graphics.lineStyle(3, 0xFFCC00);
                       item.graphics.moveTo(event.localX, event.localY);
                       video.addChild(c);
                   }
              }