AS 运动的圆

package
{
 import flash.display.Sprite;
 import flash.events.Event;
 import flash.events.MouseEvent;
 import flash.text.TextField;

 [SWF(width="888", height="888")]
 public class runRound extends Sprite
 {
  private var t:int=0; //起始
  private var r:int=100; //运行圆圈半径
  private var rd:Sprite=new Sprite(); //圆

  public function runRound()
  {
   rd.graphics.beginFill(0x123123);
   rd.graphics.drawCircle(100, 100, 30) //画圆
   addChild(rd);

   var start:TextField=new TextField;
   start.text="开始";
   start.x=10;
   start.y=20;
   start.addEventListener(MouseEvent.CLICK, startGo);
   addChild(start);

   var pause:TextField=new TextField;
   pause.text="暂停";
   pause.x=50;
   pause.y=20;
   pause.addEventListener(MouseEvent.CLICK, pauseGo);
   addChild(pause);
   graphics.moveTo(100,200);
   graphics.lineStyle(0);
  }

  private function startGo(e:Event):void
  {
   rd.addEventListener(Event.ENTER_FRAME, move);
  }

  private function pauseGo(e:Event):void
  {
   rd.removeEventListener(Event.ENTER_FRAME, move);
  }

  private function move(evt:Event):void
  {
   rd.x=r  - (r * Math.cos((t++) * Math.PI / 180)); //关键 坐标变化函式
   rd.y=r * Math.sin((t++) * Math.PI / 180);
   graphics.lineTo(rd.x+100,rd.y+100);//轨迹
  }

 }
}

 

  分析如下图: