package
{
 import flash.display.Sprite;
 import flash.events.Event;
 import flash.geom.Matrix;
 import flash.display.StageAlign;
 import flash.display.StageScaleMode;

 public class animation_ch18_MatrixRotate extends Sprite
 {
  private var angle:Number = 0;
  private var box:Sprite;
  
  public function animation_ch18_MatrixRotate()
  {
   init();
  }
//@ init(s)  
  private function init():void
  {
   stage.align = StageAlign.TOP_LEFT;
   stage.scaleMode = StageScaleMode.NO_SCALE;
   box = new Sprite();
   box.graphics.beginFill(0xff0000);
   box.graphics.drawRect(-50, -50, 100, 100);
   box.graphics.endFill();
   addChild(box);
   addEventListener(Event.ENTER_FRAME, onEnterFrame);
  }
  
//@ frame(s)
  private function onEnterFrame(event:Event):void
  {
   angle += .05;
   var cos:Number = Math.cos(angle);
   var sin:Number = Math.sin(angle);
   box.transform.matrix = new Matrix(cos, sin,
            -sin, cos,
             stage.stageWidth / 2,
             stage.stageHeight / 2);
  }
 }
}