<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/09/19/comparing-two-bitmap-images-using-the-bitmapdata-class/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
		layout="vertical"
		verticalAlign="middle"
		backgroundColor="white" 
		creationComplete="init();" viewSourceURL="srcview/index.html">

	<mx:Script>
		<![CDATA[
			import flash.display.BitmapData;

			[Bindable]
			[Embed(source="assets/bug.png")]
			private var BugIcon:Class;

			[Bindable]
			[Embed(source="assets/bug_add.png")]
			private var BugAddIcon:Class;

			private var diff:BitmapData;

			private function init():void {
				var bmd1:BitmapData = new BugIcon().bitmapData;
				var bmd2:BitmapData = new BugAddIcon().bitmapData;
				diff = BitmapData(bmd1.compare(bmd2));
				img3.source = new Bitmap(diff);
			}			
		]]>
	</mx:Script>

	<mx:ApplicationControlBar dock="true">
		<mx:Form>
			<mx:FormItem label="image 1 alpha:"
					direction="horizontal">
				<mx:HSlider id="img1_alpha"
						minimum="0"
						maximum="1"
						value="1.0"
						snapInterval="0.1"
						tickInterval="0.1"
						liveDragging="true"
						change="img1.alpha = img1_alpha.value;" />
				<mx:Image source="{BugIcon}" />
			</mx:FormItem>
			<mx:FormItem label="image 2 alpha:"
					direction="horizontal">
				<mx:HSlider id="img2_alpha"
						minimum="0"
						maximum="1"
						value="1.0"
						snapInterval="0.1"
						tickInterval="0.1"
						liveDragging="true"
						change="img2.alpha = img2_alpha.value;" />
				<mx:Image source="{BugAddIcon}" />
			</mx:FormItem>
			<mx:FormItem label="diff image alpha:">
				<mx:HSlider id="img3_alpha"
						minimum="0"
						maximum="1"
						value="1.0"
						snapInterval="0.1"
						tickInterval="0.1"
						liveDragging="true"
						change="img3.alpha = img3_alpha.value;" />
			</mx:FormItem>
			<mx:FormItem label="scale:">
				<mx:HSlider id="scale"
						minimum="1"
						maximum="4"
						value="1"
						liveDragging="true"
						tickInterval="1"
						showTrackHighlight="true" />
			</mx:FormItem>
		</mx:Form>
	</mx:ApplicationControlBar>	

	<mx:Canvas>
		<mx:Image id="img1"
				source="{BugIcon}"
				scaleX="{scale.value}"
				scaleY="{scale.value}" />
		<mx:Image id="img2"
				source="{BugAddIcon}"
				scaleX="{scale.value}"
				scaleY="{scale.value}" />
		<mx:Image id="img3"
				scaleX="{scale.value}"
				scaleY="{scale.value}" />
	</mx:Canvas>

</mx:Application>