as3potrace demo

gistfile1.as

package 
{
	import com.bit101.components.CheckBox;
	import com.bit101.components.ComboBox;
	import com.bit101.components.PushButton;
	import com.powerflasher.as3potrace.POTrace;
	import com.powerflasher.as3potrace.backend.GraphicsDataBackend;

	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.CapsStyle;
	import flash.display.GraphicsEndFill;
	import flash.display.GraphicsSolidFill;
	import flash.display.GraphicsStroke;
	import flash.display.IGraphicsData;
	import flash.display.JointStyle;
	import flash.display.LineScaleMode;
	import flash.display.Loader;
	import flash.display.LoaderInfo;
	import flash.display.PixelSnapping;
	import flash.display.Sprite;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.filters.BitmapFilter;
	import flash.filters.BitmapFilterQuality;
	import flash.filters.BlurFilter;
	import flash.filters.ColorMatrixFilter;
	import flash.geom.Matrix;
	import flash.geom.Point;
	import flash.net.FileFilter;
	import flash.net.FileReference;
	import flash.utils.ByteArray;

	[SWF(backgroundColor="#FFFFFF", frameRate="31", width="475", height="475")]
	
	public class Main extends Sprite
	{
		[Embed(source="../bitmaps/Powerflasher.png")]
		public var Powerflasher:Class;
		[Embed(source="../bitmaps/TheFlash.jpg")]
		public var TheFlash:Class;
		[Embed(source="../bitmaps/Bulldog.jpg")]
		public var Bulldog:Class;
		[Embed(source="../bitmaps/Baby.jpg")]
		public var Baby:Class;
		
		private var canvas:Sprite;
		private var imageContainer:Sprite;

		private var comboBoxImage:ComboBox;
		private var comboBoxZoom:ComboBox;
		
		private var dragStartX:Number;
		private var dragStartY:Number;
		private var imageX:Number;
		private var imageY:Number;
		private var showBitmap:Boolean = true;
		
		public function Main()
		{
			stage.align = StageAlign.TOP_LEFT;
			stage.scaleMode = StageScaleMode.NO_SCALE;
			
			imageContainer = new Sprite();
			
			var canvasMask:Sprite = new Sprite();
			canvasMask.graphics.beginFill(0xffffff, 0);
			canvasMask.graphics.drawRect(-1, -1, stage.stageWidth - 18, stage.stageHeight - 58);
			canvasMask.graphics.endFill();

			canvas = new Sprite();
			canvas.x = 10;
			canvas.y = 40;
			canvas.addChild(imageContainer);
			canvas.addChild(canvasMask);
			canvas.mask = canvasMask;
			addChild(canvas);

			var canvasHitArea:Sprite = new Sprite();
			canvasHitArea.graphics.beginFill(0xffffff, 0);
			canvasHitArea.graphics.drawRect(0, 0, stage.stageWidth - 20, stage.stageHeight - 60);
			canvasHitArea.graphics.endFill();
			canvasHitArea.x = 10;
			canvasHitArea.y = 40;
			canvasHitArea.buttonMode = true;
			canvasHitArea.addEventListener(MouseEvent.MOUSE_DOWN, canvasMouseDownHandler);
			addChild(canvasHitArea);

			comboBoxImage = new ComboBox(this, 10, 10, "Select image", [
				"Powerflasher",
				"TheFlash",
				"Bulldog",
				"Baby"
			]);
			comboBoxImage.addEventListener(Event.SELECT, function(event:Event):void {
				var ImageClass:Class;
				switch(String(comboBoxImage.selectedItem)) {
					case "Powerflasher": ImageClass = Powerflasher; break;
					case "TheFlash": ImageClass = TheFlash; break;
					case "Bulldog": ImageClass = Bulldog; break;
					case "Baby": ImageClass = Baby; break;
				}
				if(ImageClass != null) {
					prepareImage(new ImageClass() as Bitmap);
				}
			});
			comboBoxImage.numVisibleItems = 4;
			comboBoxImage.selectedIndex = 0;
			
			var checkBox:CheckBox = new CheckBox(this, 230, 15, "Hide bitmap", function():void {
				showBitmap = checkBox.selected;
				if(imageContainer.numChildren > 0) {
					imageContainer.getChildAt(0).visible = showBitmap;
				}
			});
			checkBox.selected = true;
			
			comboBoxZoom = new ComboBox(this, stage.stageWidth - 110, 10, "Zoom", ["100%", "200%", "300%", "400%"]);
			comboBoxZoom.addEventListener(Event.SELECT, function(event:Event):void {
				imageContainer.scaleX = imageContainer.scaleY = comboBoxZoom.selectedIndex + 1; 
			});
			comboBoxZoom.numVisibleItems = 4;
			comboBoxZoom.selectedIndex = 2;
			
			addChild(new PushButton(this, 120, 10, "Upload Image", function():void {
				var ref:FileReference = new FileReference();
				ref.addEventListener(Event.SELECT, function(e:Event):void { ref.load(); });
				ref.addEventListener(Event.COMPLETE, function(e:Event):void { loadBytes(ref.data); });
				ref.browse([new FileFilter("PNG (*.png)", "*.png"), new FileFilter("JPG (*.jpg)", "*.jpg"), new FileFilter("GIF (*.gif)", "*.gif")]);
			}));
		}

		private function canvasMouseDownHandler(event:MouseEvent):void
		{
			dragStartX = event.stageX;
			dragStartY = event.stageY;
			imageX = imageContainer.x;
			imageY = imageContainer.y;
			stage.addEventListener(MouseEvent.MOUSE_UP, canvasMouseUpHandler);
			stage.addEventListener(MouseEvent.MOUSE_MOVE, mouseMoveHandler);
		}

		private function mouseMoveHandler(event:MouseEvent):void
		{
			imageContainer.x = imageX + event.stageX - dragStartX;
			imageContainer.y = imageY + event.stageY - dragStartY;
		}

		private function canvasMouseUpHandler(event:MouseEvent):void
		{
			stage.removeEventListener(MouseEvent.MOUSE_UP, canvasMouseUpHandler);
			stage.removeEventListener(MouseEvent.MOUSE_MOVE, mouseMoveHandler);
		}
		
		protected function loadBytes(image:ByteArray):void
		{
			comboBoxImage.selectedIndex = -1;
			
			var loader:Loader = new Loader();
			loader.contentLoaderInfo.addEventListener(Event.INIT, initHandler);
			loader.loadBytes(image);
		}

		protected function initHandler(event:Event):void
		{
			var loaderInfo:LoaderInfo = event.target as LoaderInfo;
			var loader:Loader = loaderInfo.loader;
			
			prepareImage(loader.content as Bitmap);
		}
		
		protected function prepareImage(bitmap:Bitmap):void
		{
			imageContainer.x = imageContainer.y = 0;
	
			if(comboBoxZoom != null) {
				comboBoxZoom.selectedIndex = 0;
			}
			
			var xs:Number = (stage.stageWidth - 20) / bitmap.width;
			var ys:Number = (stage.stageHeight - 60) / bitmap.height;
			var s:Number = Math.min(xs, ys, 1);
			
			var bmd:BitmapData = new BitmapData(bitmap.width * s, bitmap.height * s, false);
			var matrix:Matrix = new Matrix();
			matrix.createBox(s, s);
			bmd.draw(bitmap, matrix, null, null, null, true);
			bmd.applyFilter(bmd, bmd.rect, new Point(0, 0), grayscaleFilter);
			bmd.applyFilter(bmd, bmd.rect, new Point(0, 0), blurFilter);
			
			var bm:Bitmap = new Bitmap(bmd, PixelSnapping.AUTO, true);
			
			traceImage(bm);
		}
		
		protected function traceImage(bitmap:Bitmap):void
		{
			while(imageContainer.numChildren > 0) {
				imageContainer.removeChildAt(0);
			}
			
			var bm:Bitmap = bitmap;
			bm.visible = showBitmap;
			imageContainer.addChild(bm);
			
			var curves:Sprite = new Sprite();
			imageContainer.addChild(curves);
			
			var gd:Vector.<IGraphicsData> = new Vector.<IGraphicsData>();
			var strokeFill:GraphicsSolidFill = new GraphicsSolidFill(0x008800, 1);
			gd.push(new GraphicsStroke(1, false, LineScaleMode.NONE, CapsStyle.ROUND, JointStyle.ROUND, 3, strokeFill));
			gd.push(new GraphicsSolidFill(0x00ff00, 0.75));
			
			var potrace:POTrace = new POTrace();
			potrace.backend = new GraphicsDataBackend(gd);
			potrace.potrace_trace(bitmap.bitmapData);
			
			gd.push(new GraphicsEndFill());
			
			curves.graphics.drawGraphicsData(gd);
		}

		protected function get grayscaleFilter():BitmapFilter
		{
			var r:Number = 0.212671;
			var g:Number = 0.715160;
			var b:Number = 0.072169;
			
			return new ColorMatrixFilter([
				r, g, b, 0, 0,
				r, g, b, 0, 0,
				r, g, b, 0, 0,
				0, 0, 0, 1, 0
			]);
		}
		
		protected function get blurFilter():BitmapFilter
		{
			return new BlurFilter(2, 2, BitmapFilterQuality.HIGH);
		}
	}
}

import com.bit101.components.CheckBox;
import com.bit101.components.ComboBox;
import com.bit101.components.PushButton;