private function init():void
    {
     stage.scaleMode = StageScaleMode.NO_SCALE;
     stage.align = StageAlign.TOP_LEFT;
     ball = new animation_ch10_Ball();
     addChild(ball);
     ball.x = 100;
     ball.y = 100;
     
     line = new Sprite();
     line.graphics.lineStyle(1);
     line.graphics.lineTo(300, 0);
     addChild(line);
     line.x = 50;
     line.y = 200;
     line.rotation = 30;
     
     addEventListener(Event.ENTER_FRAME, onEnterFrame);
    }