How to resize a photo from CameraUI?

Question

Hi there,
i really need som help here. I cant seem understand how to resize an still image taken with the camera. Here are the code so far(also with the upload part). I just need a thumbnail to be uploaded to the server, not the HQ-image. Any ideas?
          Simple AIR for iOS Package for selecting a cameraroll photo or taking a photo and processing it.
          Copyright 2012 FIZIX Digital Agency
          http://www.fizixstudios.com
          For more information see the tutorial at:
          http://www.fizixstudios.com/labs/do/view/id/air-ios-camera-and-uploading-photos
          Notes:
          This is a barebones script and is as generic as possible. The upload process is very basic,
          the tutorial linked above gives information on how to post the image along with data to
          your PHP script.
          The PHP script will collect as $_FILES['Filedata'];
          import flash.display.MovieClip;
          import flash.events.MouseEvent;
          import flash.events.TouchEvent;
          import flash.ui.Multitouch;
    import flash.ui.MultitouchInputMode;
          import flash.media.Camera;
          import flash.media.CameraUI;
          import flash.media.CameraRoll;
          import flash.media.MediaPromise;
    import flash.media.MediaType;
          import flash.events.MediaEvent;
          import flash.events.Event;
          import flash.events.ErrorEvent;
          import flash.utils.IDataInput;
          import flash.events.IEventDispatcher;
          import flash.events.IOErrorEvent;
          import flash.utils.ByteArray;
          import flash.filesystem.File;
          import flash.filesystem.FileMode;
          import flash.filesystem.FileStream;
          import flash.errors.EOFError;
          import flash.net.URLRequest;
          import flash.net.URLVariables;
          import flash.net.URLRequestMethod;
                    // Define properties
                    var cameraRoll:CameraRoll = new CameraRoll();                                        // For Camera Roll
                    var cameraUI:CameraUI = new CameraUI();                                                            // For Taking a Photo
                    var dataSource:IDataInput;                                                                                          // Data Source
                    var tempDir;                                                                                                                        // Our temporary directory
                    CameraTest() ;
                    function CameraTest()
                              Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;
                              // Start the home screen
                              startHomeScreen();
                    // =================================================================================
                    // startHomeScreen
                    // =================================================================================
                    function startHomeScreen()
                              trace("Main Screen Initialized");
                              // Add main screen event listeners
                              if(Multitouch.supportsGestureEvents)
                                        mainScreen.startCamera.addEventListener(TouchEvent.TOUCH_TAP, initCamera);
                                        mainScreen.startCameraRoll.addEventListener(TouchEvent.TOUCH_TAP, initCameraRoll);
                              else
                                        mainScreen.startCamera.addEventListener(MouseEvent.CLICK, initCamera);
                                        mainScreen.startCameraRoll.addEventListener(MouseEvent.CLICK, initCameraRoll);
                    // =================================================================================
                    // initCamera
                    // =================================================================================
                    function initCamera(evt:Event):void
                              trace("Starting Camera");
                              if( CameraUI.isSupported )
                                        cameraUI.addEventListener(MediaEvent.COMPLETE, imageSelected);
                                        cameraUI.addEventListener(Event.CANCEL, browseCancelled);
                                        cameraUI.addEventListener(ErrorEvent.ERROR, mediaError);
                                        cameraUI.launch(MediaType.IMAGE);
                              else
                                        mainScreen.feedbackText.text = "This device does not support Camera functions.";
                    // =================================================================================
                    // initCameraRoll
                    // =================================================================================
                    function initCameraRoll(evt:Event):void
                              trace("Opening Camera Roll");
                              if(CameraRoll.supportsBrowseForImage)
                                        mainScreen.feedbackText.text = "Opening Camera Roll.";
                                        // Add event listeners for camera roll events
                                        cameraRoll.addEventListener(MediaEvent.SELECT, imageSelected);
                                        cameraRoll.addEventListener(Event.CANCEL, browseCancelled);
                                        cameraRoll.addEventListener(ErrorEvent.ERROR, mediaError);
                                        // Open up the camera roll
                                        cameraRoll.browseForImage();
                              else
                                        mainScreen.feedbackText.text = "This device does not support CameraRoll functions.";
                    // =================================================================================
                    // imageSelected
                    // =================================================================================
                    function imageSelected(evt:MediaEvent):void
                              mainScreen.feedbackText.text = "Image Selected";
                              // Create a new imagePromise
                              var imagePromise:MediaPromise = evt.data;
                              // Open our data source
                              dataSource = imagePromise.open();
                              if(imagePromise.isAsync )
                                        mainScreen.feedbackText.text += "Asynchronous Mode Media Promise.";
                                        var eventSource:IEventDispatcher = dataSource as IEventDispatcher;
                                        eventSource.addEventListener( Event.COMPLETE, onMediaLoaded );
                              else
                                        mainScreen.feedbackText.text += "Synchronous Mode Media Promise.";
                                        readMediaData();
                    // =================================================================================
                    // browseCancelled
                    // =================================================================================
                    function browseCancelled(event:Event):void
                              mainScreen.feedbackText.text = "Browse CameraRoll Cancelled";
                    // =================================================================================
                    // mediaError
                    // =================================================================================
                    function mediaError(event:Event):void
                              mainScreen.feedbackText.text = "There was an error";
                    // =================================================================================
                    // onMediaLoaded
                    // =================================================================================
                    function onMediaLoaded( event:Event ):void
                              mainScreen.feedbackText.text += "Image Loaded.";
                              readMediaData();
                    // =================================================================================
                    // readMediaData
                    // =================================================================================
                    function readMediaData():void
                              mainScreen.feedbackText.text += "Reading Image Data.";
                              var imageBytes:ByteArray = new ByteArray();
                              dataSource.readBytes( imageBytes );
                              tempDir = File.createTempDirectory();
                              // Set the userURL
                              var serverURL:String = "http://www.hidden_in_this_example.com/upload.php";
                              // Get the date and create an image name
                              var now:Date = new Date();
                              var filename:String = "IMG" + now.fullYear + now.month + now.day + now.hours + now.minutes + now.seconds;
                              // Create the temp file
                              var temp:File = tempDir.resolvePath(filename);
                              // Create a new FileStream
                              var stream:FileStream = new FileStream();
                              stream.open(temp, FileMode.WRITE);
                              stream.writeBytes(imageBytes);
                              stream.close();
                              // Add event listeners for progress
                              temp.addEventListener(Event.COMPLETE, uploadComplete);
                              temp.addEventListener(IOErrorEvent.IO_ERROR, ioError);
                              // Try to upload the file
                              try
                                        mainScreen.feedbackText.text += "Uploading File";
                                        //temp.upload(new URLRequest(serverURL), "Filedata");
                                        // We need to use URLVariables
                                        var params:URLVariables = new URLVariables();
                                        // Set the parameters that we will be posting alongside the image
                                        params.userid = "1234567";
                                        // Create a new URLRequest
                                        var request:URLRequest = new URLRequest(serverURL);
                                        // Set the request method to POST (as opposed to GET)
                                        request.method = URLRequestMethod.POST;
                                        // Put our parameters into request.data
                                        request.data = params;
                                        // Perform the upload
                                        temp.upload(request, "Filedata");
                              catch( e:Error )
                                        trace(e);
                                        mainScreen.feedbackText.text += "Error Uploading File: " + e;
                                        removeTempDir();
                    // =================================================================================
                    // removeTempDir
                    // =================================================================================
                    function removeTempDir():void
                              tempDir.deleteDirectory(true);
                              tempDir = null;
                    // ==================================================================================
                    // uploadComplete()
                    // ==================================================================================
                    function uploadComplete(event:Event):void
                              mainScreen.feedbackText.text += "Upload Complete";
                    // ==================================================================================
                    // ioError()
                    // ==================================================================================
                    function ioError(event:Event):void
                              mainScreen.feedbackText.text += "Unable to process photo";

Answer 1

1. Create a BitmapData of the correct size of the full image
2. Use BitmapData.setPixels to create pixel data from your byteArray
3. Make a new Bitmap, Bitmap.bitmapData = BitmapData
4. Create a matrix with the correct scaling factors for your thumbnail
5. Create a new BitmapData the size of your thumb
6. Use BitmapData.draw to draw your image data from the Bitmap to the new BitmapData with the scaling matrix
7. Use BitmapData.getPixels to create a bytearray from your thumb BitmapData
8. save it
You'll have to look up the AS3 reference to see how all these methods work.