flash绕中心点旋转（支持多次旋转）

package 
{

	import flash.events.Event;
	import flash.geom.Matrix;
	import flash.geom.Point;
	import flash.display.*;
	
	/**
	 * ...
	 * @author ongsh
	 */
	public class Main extends Sprite 
	{
		
		public function Main():void 
		{
			if (stage) init();
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event = null):void 
		{
			removeEventListener(Event.ADDED_TO_STAGE, init);
			// entry point
			
			var s1:Shape = new Shape();
			s1.graphics.lineStyle(0);
			s1.graphics.beginFill(0);
			s1.graphics.drawRect(0, 0, 100, 100);
			s1.graphics.endFill();
			s1.x = 200;
			s1.y = 200;
			addChild(s1);
			
			var s2:Shape = new Shape();
			s2.graphics.lineStyle(0);
			s2.graphics.beginFill(0xff0000);
			s2.graphics.drawRect(0, 0, 100, 100);
			s2.graphics.endFill();			
			s2.x = s1.x;
			s2.y = s1.y;
			addChild(s2);
			
			var angle:Number = 45;
			
			centerRotate(s2, angle);
			
			centerRotate(s1, 10);
			centerRotate(s2, 60);
		}
		
		/**
		 * 绕中心点旋转
		 * 
		 * @param	mc	元件
		 * @param	angle	角度
		 */
		public function centerRotate(mc:DisplayObject,angle:Number):void 
		{		
			var currentRotation:Number = mc.rotation;
			//获取mc不旋转时候的尺寸
			mc.rotation = 0;
			var mcWidth:Number = mc.width;
			var mcHeight:Number = mc.height;
			mc.rotation = currentRotation;
			
			//获取mc当前中心点坐标
			var pointO:Point = mc.localToGlobal(new Point(mcWidth / 2, mcHeight / 2));
			
			//旋转mc
			mc.rotation = angle;

			//获取mc旋转后中心点坐标
			var pointO2:Point = mc.localToGlobal(new Point(mcWidth / 2, mcHeight / 2));
			//平移到原来中心点O
			var p3:Point = pointO.subtract(pointO2);
			var matrix:Matrix = mc.transform.matrix;
			matrix.translate(p3.x, p3.y);
			
			mc.transform.matrix = matrix;
		}
		
		
	}
	
}