flash动态改变注册点

这是一个动态改变注册点的类

package {

	//动态改变注册点类

	import flash.display.DisplayObject;

	import flash.geom.Point;

	//动态设置注册点

	public class DynamicRegistration {

		//需更改的注册点位置

		private var regpoint:Point;

		//更改注册的显示对象

		private var target:DisplayObject;

		private var Height:Number;

		private var Width:Number;

		//首先要确定初始状态

		public function DynamicRegistration(target:DisplayObject,regpoint:Point,iWidth:Number=320,iHeight:Number=240) {

			Width=iWidth;

			Height=iHeight;

			this.target=target;

			this.regpoint=regpoint;

		}

		//设置显示对象的属性

		public function flush(prop:String,value:Number):void {

			var mc=this.target;

			//转换为全局坐标

			var A:Point=mc.parent.globalToLocal(mc.localToGlobal(regpoint));

			if (prop=="x"||prop=="y") {

				mc[prop]=value-regpoint[prop];

			} else if (prop=="scaleX" || prop=="scaleY") {

				if (mc[prop]>value) {

					//放大过程

					mc.x+=((Width*(value+0.1))-(Width*value))/4;

					mc.y+=((Height*(value+0.1))-(Height*value))/4;

				} else {

					//缩小过程

					mc.x-=((Width*value)-(Width*(value-0.1)))/4;

					mc.y-=((Height*value)-(Height*(value-0.1)))/4;

				}

				mc[prop]=value;

			} else {

				mc[prop]=value;

				//执行旋转等属性后，再重新计算全局坐标

				var B:Point=mc.parent.globalToLocal(mc.localToGlobal(regpoint));

				//把注册点从B点移到A点

				mc.x+=A.x-B.x;

				mc.y+=A.y-B.y;

			}

		}

	}
}

用法如下：

在舞台上放个mc、btn、btn2

package{
	
	import flash.display.*;
	import flash.events.*;
	import flash.geom.*;
	import flash.system.fscommand;
	
	public class Test extends MovieClip{
		
		private var reg:DynamicRegistration;
		private var speed:Number=1;
		
		public function Test(){
			reg=new DynamicRegistration(mc,new Point(mc.width/2,mc.height/2),mc.width,mc.height);
			btn.addEventListener(MouseEvent.CLICK,clickHandler);
			btn2.addEventListener(MouseEvent.CLICK,lessenHandler);
		}
		
		private function clickHandler(e:MouseEvent):void{
			//mc.scaleX+=0.2;
			//mc.scaleY+=0.2;
			speed+=0.2;
            reg.flush("scaleX",speed); 
            reg.flush("scaleY",speed);
		}
		
		private function lessenHandler(e:MouseEvent):void{
			speed-=0.2;
            reg.flush("scaleX",speed);
			//mc.scaleX-=0.2;
			//mc.scaleY-=0.2;
		}
	}
}