//Hide the mouse
Mouse.hide();
 
//maskContainer holds all the masks
var maskContainer:Sprite = new Sprite();
 
//Set the maskContainer to be the original image's mask
origImage.mask = maskContainer;
 
//Create a new rectangle mask
var recMask:RectangleMask = new RectangleMask();
 
//Add recMask onto the maskContainer
maskContainer.addChild(recMask);
 
//Add the maskContainer onto the stage
addChild(maskContainer);
 
//Easing factore, used in animation
var easing:Number = 0.1;
 
//Create a timer that is called every 0.2 seconds
var timer:Timer = new Timer(200, 0);
timer.addEventListener(TimerEvent.TIMER, timerEvent);
timer.start();
 
//We need ENTER_FRAME for the animation
addEventListener(Event.ENTER_FRAME, onEnterFrame);
 
//This function is called in each frame
function onEnterFrame(event:Event):void {
	//Calculate the speed we want to move the rectangle
	var vx:Number = (mouseX - recMask.x) * easing;
	//Assign the new x position
	recMask.x += vx;
}
 
//This function is called every 0.2 seconds
function timerEvent(e:Event):void {
	//Create a new rectangle mask
	var rc:RectangleMask = new RectangleMask();
	//Assign it to the same position as our original mask
	rc.x = recMask.x;
	//Add it to the container
	maskContainer.addChild(rc);
	//ENTER_FRAME is used to animtate the scale of the mask
	rc.addEventListener(Event.ENTER_FRAME, scaleDown);
}
 
function scaleDown(e:Event):void {
	//Get the rectangle mask
	var rc:RectangleMask = (RectangleMask)(e.target);
	//Reduce scale
	rc.scaleX -= 0.05;
	//If the scale is below 0, we remove the rectangle mask
	//from the stage
	if(rc.scaleX < 0) {
		rc.removeEventListener(Event.ENTER_FRAME, scaleDown);
		maskContainer.removeChild(rc);
	}
}