<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="absolute" initialize="initNew()"
    width="320" height="370">
    <mx:Script>
        <![CDATA[
            import mx.controls.Image;

            private const image_path:String = "fxr.png";
            private var loader:Loader;
            private var request:URLRequest;  

            private var loadBD:BitmapData;
            private var cropBD:BitmapData;  

            private var startPoint:Point;
            private var posPoint:Point;
            private var square: int;
            private var mtrx: Matrix;

            private function initNew():void
            {
                loader=new Loader();
                request=new URLRequest(image_path);
                loader.contentLoaderInfo.addEventListener(
                    Event.COMPLETE,onComplete);
                loader.load(request);
            }

            private function onComplete(event:Event):void {
                loadBD = Bitmap(event.currentTarget.content).bitmapData;

                imageHolder.graphics.beginBitmapFill(loadBD);
                imageHolder.graphics.drawRect(0, 0,
                    loadBD.width, loadBD.height);
                imageHolder.graphics.endFill(); 

                //make initial image
                drawImage();

            }

             private function drawImage():void
             {
                 //crop square
                startPoint = new Point(xSelector.value,    ySelector.value);
                square = sizeSelector.value;
                cropImage(startPoint,square);

                //resize image and show it
                resizeImage();
             }

             private function cropImage(startPoint:Point, squareSize:int):void
             {
                 // Make a new bitmap data using square size
                cropBD = new BitmapData(squareSize, squareSize, true, 0x00000000);
                // Position where will be dispayed in the new object, in our case (0,0)
                posPoint = new Point(0,0);
                // copy pixels from loaded bitmap data to our new object
                cropBD.copyPixels(loadBD,
                    new Rectangle(startPoint.x, startPoint.y, squareSize, squareSize),
                    posPoint); 

                //draw crop area selected
                imageCrop.graphics.clear();
                imageCrop.graphics.lineStyle(1, 0xFFFFFF,0.5);
                imageCrop.graphics.drawRect(0, 0, cropBD.width, cropBD.height);
                imageCrop.move(imageHolder.x+startPoint.x,imageHolder.y+startPoint.y);

             }

             private function resizeImage():void
             {
                // make scale matrix
                mtrx = new Matrix();
                mtrx.scale(imageView.width/cropBD.width,imageView.height/cropBD.height);

                // Fill in image
                imageView.graphics.clear();
                imageView.graphics.beginBitmapFill(cropBD,mtrx,false);
                imageView.graphics.drawRect(0, 0, imageView.width, imageView.height);
                imageView.graphics.endFill();
             }

        ]]>
    </mx:Script>

    <mx:Canvas id="imageView"   x="210" y="10" width="100" height="100" />
    <mx:Canvas id="imageHolder" x="10" y="120" width="300" height="240" />
    <mx:Canvas id="imageCrop"   x="0" y="0" width="0" height="0" /> 

    <mx:Label x="10" y="15" width="60" text="X position"/>
    <mx:HSlider id="xSelector" x="80" y="10" width="120"
            minimum="0" maximum="290" snapInterval="10" enabled="true"
            value="170" change="drawImage()" />

    <mx:Label x="10" y="55" width="60" text="Y position"/>
    <mx:HSlider id="ySelector" x="80" y="50" width="120"
            minimum="0" maximum="230" snapInterval="10" enabled="true"
            value="20" change="drawImage()" />

    <mx:Label x="10" y="95" width="60" text="Area size"/>
    <mx:HSlider id="sizeSelector" x="80" y="90" width="120"
            minimum="10" maximum="240" snapInterval="10" enabled="true"
            value="100" change="drawImage()" />

</mx:Application>