René Schulte

1. Steadily releasing updates with new functionality and being featured at the Windows Phone sites has a big impact on the downloads. Keep in mind the major Pictures Lab updates were featured at least at 3-5 of the top Windows Phone sites.
2. Being featured at the Marketplace also has a significant positive impact on downloads. Of course this depends on how big the local Marketplace is. Unfortunately does the AppHub not provide the information when an app has been featured. There is the Distimo service which tracks that too, but that service needs your live id credentials and I won't give a 3rd party site my live id to store it in their database. Fortunately some of my friends ping me when they see my apps being featured in their local marketplace. I think it's pretty much safe to say that all the graph peaks without a label nearby are related to a Marketplace feature.  
3. The base line increased not only after the 3.0, but also after the peak of the 4.0 update. The 4.0 update brought the multi-language support with 10 languages. The steady download jump after 4.0 is a pretty good indication that localization can help to increase downloads.
4. The price drop to $0.99 was followed by the highest peak in the graph, but after that it went down pretty quickly. I think the price point is the hardest thing to get right and it largely varies for different kind of apps, so the above Pictures Lab pricing information shouldn't be generalized.   
5. Of course Christmas, the holidays and New Year also resulted in nice peaks. Customers have time to browse the marketplace or just want to fill up their brand new Windows Phones with some apps.

public Uri GetLogoutUri(FacebookCredentials credentials)
{
   var sessionkey = ExtractSessionKeyFromAccessToken(credentials.AccessToken);
   var url = String.Format("http://facebook.com/logout.php?app_key={0}&session_key={1}&next={2}", EndpointData.FacebookAppId, sessionkey, EndpointData.FacebookLogoutCallbackUrl);
   return new Uri(url);
}

private static string ExtractSessionKeyFromAccessToken(string accessToken)
{
   if (!String.IsNullOrEmpty(accessToken))
   {
      var parts = accessToken.Split('|');
      if (parts.Length > 2)
      { 
         return parts[1];
      }
   }
   return String.Empty;
}

Browser.Navigate(FacebookService.GetLogoutUri(EndpointData.Settings.Facebook));

• http://wmpoweruser.com
• http://mobilitydigest.com
• http://www.wpcentral.com
• http://allaboutwindowsphone.com
• http://windowsphonegeek.com
• http://zomgitscj.com
• http://www.mykindofphone.com
• http://www.windowsphonemetro.com
• http://windowsphoneparent.com
• http://www.1800pocketpc.com
• http://pocketnow.com
• http://www.wp7connect.com
• http://www.windowsphonedaily.com
• http://www.wpsauce.com (India)
• http://ilovewindowsphone.in (India)
• http://www.windowsphonerocks.com

• http://wp7app.de
• http://worldofppc.de
• http://www.phoneseven.de
• http://wp7de.com
• http://www.windows-smartphones.de
• http://www.pocketpc.ch

• http://WP7Rocks.com
• http://WP7Forum.ru
• http://W7Phone.ru
• http://W7Ph.ru

• http://nanapho.jp
• http://blogs.shintak.info
• http://blogs.msdn.com/b/aonishi

• http://wp7.nl

• http://wphone.es
• http://www.miwindowsphone.net
• http://www.windowsphoneforos.com
• http://wp7total.info
• http://www.xataka.com/moviles/windows-phone-7

• http://windowsphonebrasil.com.br

• http://www.windowsphoneitaly.com
• http://www.plaffo.com
• http://www.wpmitalia.com
• http://www.windows7blog.it
• http://www.cellularemagazine.it
• http://www.tecnophone.it
• http://cellulariadhoc.blogosfere.it
• http://webmobile.blogosfere.it
• http://www.mobileblog.it
• http://mobile.hdblog.it
• http://www.hi-techitaly.com

• http://www.monwindowsphone.com

• Added a Rotate method for arbitrary angles (RotateFree). Provided by montago.
• Added Nokola's anti-aliased line drawing implementation.
• Updated the Windows Phone project to WP 7.1 Mango.
• Added an extension code file for the Windows Phone specific extensions and added SaveToMediaLibrary extensions including support for saveToCameraRoll.
• Added an Invert method, which creates an inverted version of the input bitmap. This is useful for WP7 Theme-awareness checks using Application.Current.Resources["PhoneBackgroundBrush"].
• Added FromContent method, which provides an easy interface to load a WriteableBitmap from the content of the app.
• Added a static overload for the Resize method which takes the pixels array as argument.
• Optimized the DrawLine algorithm.
• Fixed some issues with DrawRectangle, FillRectangle, DrawEllipse, FillEllipse and DrawPolyline.
• Fixed a bug in the bilinear Resize method that appeared when the alpha value is zero.
• Fixed other minor issues.

• DREGON by team "Digitron-WP7" from Belgium.
• Peekaboo by team "HOMERUN" from Korea.
• Hot Potato by team "Zipi Zigi" from Korea.
• Recyclocator by team "Code Instincts" from Singapore.
• Lifelens by team "The LifeLens Project" from USA.

SLARToolkit is a flexible Augmented Reality library for Silverlight with the aim to make real time Augmented Reality applications with Silverlight as easy and fast as possible. It can be used with Silverlight's Webcam API or with any other CaptureSource or a WriteableBitmap. SLARTookit is based on the established NyARToolkit and ARToolkit. 

Performance FLARManager: Not good enough for action games
Performance SLARToolkit: Very fast and accurate marker tracking

SLARToolkit is a flexible marker-based Augmented Reality library for Silverlight and Windows Phone with the aim to make real time Augmented Reality applications with Silverlight as easy and fast as possible. It can be used with Silverlight's Webcam API or with any other CaptureSource, WriteableBitmap or with the Windows Phone's PhotoCamera. SLARTookit is based on the established NyARToolkit and ARToolkit. 

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
   base.OnNavigatedTo(e);

   // Initialize the webcam
   photoCamera = new PhotoCamera();
   photoCamera.Initialized += PhotoCameraInitialized;
   isInitialized = false;

   // Fill the Viewport Rectangle with the VideoBrush
   var vidBrush = new VideoBrush();
   vidBrush.SetSource(photoCamera);
   Viewport.Fill = vidBrush;

   // Start timer
   dispatcherTimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(50) };
   dispatcherTimer.Tick += (sender, e1) => Detect();
   dispatcherTimer.Start();
}

void Detect()
{
   if (!isInitialized)
   {
      return;
   }

   // Update buffer size
   var pixelWidth = photoCamera.PreviewBufferResolution.Width;
   var pixelHeight = photoCamera.PreviewBufferResolution.Height;
   if (buffer == null || buffer.Length != pixelWidth * pixelHeight)
   {
      buffer = new byte[pixelWidth * pixelHeight];
   }

   // Grab snapshot
   photoCamera.GetPreviewBufferY(buffer);

   // Detect
   var dr = arDetector.DetectAllMarkers(buffer, pixelWidth, pixelHeight);

   // Calculate the projection matrix
   if (dr.HasResults)
   {
      // Center at origin of the 256x256 controls
      var centerAtOrigin = Matrix3DFactory.CreateTranslation(-128, -128, 0);

      // Swap the y-axis and scale down by half
      var scale = Matrix3DFactory.CreateScale(0.5, -0.5, 0.5);

      // Calculate the complete transformation matrix based on the first detection result
      var world = centerAtOrigin * scale * dr[0].Transformation;

      // Viewport transformation
      var viewport = Matrix3DFactory.CreateViewportTransformation(pixelWidth, pixelHeight);

      // Calculate the final transformation matrix by using the camera projection matrix 
      var m = Matrix3DFactory.CreateViewportProjection(world, Matrix3D.Identity, arDetector.Projection, viewport);

      // Apply the final transformation matrix to the controls
      var matrix3DProjection = new Matrix3DProjection { ProjectionMatrix = m };
      Txt.Projection = matrix3DProjection;
      Img.Projection = matrix3DProjection;
   }
}

void PhotoCameraInitialized(object sender, CameraOperationCompletedEventArgs e)
{
   //  Initialize the Detector
   arDetector = new GrayBufferMarkerDetector();

   // Load the marker pattern. It has 16x16 segments and a width of 80 millimeters
   var marker = Marker.LoadFromResource("data/Marker_SLAR_16x16segments_80width.pat", 16, 16, 80);

   // The perspective projection has the near plane at 1 and the far plane at 4000
   arDetector.Initialize(photoCamera.PreviewBufferResolution.Width, photoCamera.PreviewBufferResolution.Height, 1, 4000, marker);

   isInitialized = true;
}

SLARToolkit is a flexible Augmented Reality library for Silverlight with the aim to make real time Augmented Reality applications with Silverlight as easy and fast as possible. It can be used with Silverlight's Webcam API or with any other CaptureSource or a WriteableBitmap. SLARTookit is based on the established NyARToolkit and ARToolkit. 

• XNA 3D Graphics API
• Improved Graphics stack – The graphics stack has been re-architected to bring over improvements from WP7, such as Independent Animations.
• Hardware video decode for H.264 playback.
• Multi-core background JIT support for improved startup performance.
• Realtime Sound (low-latency Audio)
• Variable Speed Playback (“Trick Play”)
• XAML Binding Debugging
• Multiple Window Support
• Ancestor RelativeSource Binding
• Implicit DataTemplates
• ClickCount
• Binding on Style Setter
• Linked Text Containers
• Custom Markup Extensions
• ComboBox type ahead with text searching.
• Full keyboard support in full-screen for trusted in-browser applications, enables richer kiosk and media viewing applications in-browser.
• Default filename in SaveFileDialog – Specify a default filename when you launch the SaveFileDialog.
• Unrestricted filesystem access – trusted applications can Read write to files in any directory on the filesystem.
• More performance optimizations:
• XAML Parser performance optimizations.
• Network Latency optimizations.
• Text layout performance improvements.
• Hardware acceleration is enabled in windowless mode with Internet Explorer 9.

• Fixed many bugs.
• Added the Rotate method which rotates the bitmap in 90° steps clockwise and returns a new rotated WriteableBitmap.
• Added a Flip method with support for FlipMode.Vertical and FlipMode.Horizontal.
• Added a new Filter extension file with a convolution method and some kernel templates (Gaussian, Sharpen).
• Added the GetBrightness method, which returns the brightness / luminance of the pixel at the x, y coordinate as byte.
• Added the ColorKeying BlendMode.
• Added boundary checks to the Crop() function to avoid OutOfRangeExceptions if the passed parameters are outside the boundaries of the original bitmap.
• Optimized the DrawLine algorithm.
• Optimized the Resize algorithms (NearestNeighbor is now 10x faster).
• Optimized the Clear(Color) method.

private static void SendEmailScreenshot(FrameworkElement element)
{
   // Render the element at the maximum possible size
   ScaleTransform transform = null;
   if (element.ActualWidth * element.ActualHeight > 240 * 400)
   {
      // Calculate a uniform scale with the minimum possible size
      var scaleX = 240.0 / element.ActualWidth;
      var scaleY = 400.0 / element.ActualHeight;
      var scale = scaleX < scaleY ? scaleX : scaleY;
      transform = new ScaleTransform { ScaleX = scale, ScaleY = scale };
   }
   var wb = new WriteableBitmap(element, transform);

   using (var memoryStream = new MemoryStream())
   {
      // Encode the screenshot as JPEG with a quality of 60%
      wb.SaveJpeg(memoryStream, wb.PixelWidth, wb.PixelHeight, 0, 60);
      memoryStream.Seek(0, SeekOrigin.Begin);

      // Convert binary data to Base64 string
      var bytes = memoryStream.ToArray();
      var base64String = Convert.ToBase64String(bytes);

      // Invoke email task
      var emailComposeTask = new EmailComposeTask
                              {
                                 Subject = "Screenshot from my app",
                                 Body = base64String,
                                 To = "foo@bar.com",
                              };
      emailComposeTask.Show();
   }
}

/9j/4AAQSkZJRgABAQEBBgEGAAD/2wBDAA0JCgsKCA0LCgsODg0PEyAVExISEyccHhcgLikxMC4pLSwzOko
+MzZGNywtQFdBRkxOUlNSMj5aYVpQYEpRUk//2wBDAQ4ODhMREyYVFSZPNS01T09PT09PT09PT09PT09PT09PT09PT
09PT09PT09PT09PT09PT09PT09PT09PT09PT0//wAARCAFsAPADASIAAhEBAxEB/8QAHwAAAQUBAQEBAQEAAAAAAAA
AAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM
2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJW
Wl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAw

...

public class SystemInformation
{
   public static string Dump()
   {
      var builder = new StringBuilder();
      builder.AppendLine("***** System Infos *****");
      builder.AppendLine();
      builder.AppendFormat("Time: {0}", DateTime.Now.ToUniversalTime().ToString("r"));
      builder.AppendLine();
      builder.AppendFormat("Culture: {0}", CultureInfo.CurrentCulture);
      builder.AppendLine(); 
      builder.AppendFormat("App Version: {0}", WmAppManifestHelper.GetVersion());
      builder.AppendLine();  
      builder.AppendFormat("Manufacturer: {0}", DevicePropertiesHelper.GetDeviceManufacturer());
      builder.AppendLine(); 
      builder.AppendFormat("Model: {0}", DevicePropertiesHelper.GetDeviceModel());
      builder.AppendLine(); 
      builder.AppendFormat("DeviceHardwareVersion: {0}", DevicePropertiesHelper.GeDeviceHardwareVersion());
      builder.AppendLine(); 
      builder.AppendFormat("DeviceFirmwareVersion: {0}", DevicePropertiesHelper.GeDeviceFirmwareVersion());
      builder.AppendLine(); 
      builder.AppendFormat("OS  Version: {0}", Environment.OSVersion);
      builder.AppendLine(); 
      builder.AppendFormat("CLR Version: {0}", Environment.Version);
      builder.AppendLine(); 
      builder.AppendFormat("Device Type: {0}", Microsoft.Devices.Environment.DeviceType);
      builder.AppendLine(); 
      builder.AppendFormat("Network Type: {0}", NetworkInterface.NetworkInterfaceType);
      builder.AppendLine(); 
      builder.AppendFormat("DeviceTotalMemory: {0:f3} MB", DevicePropertiesHelper.GetTotalMemoryMb());
      builder.AppendLine(); 
      builder.AppendFormat("ApplicationPeakMemoryUsage: {0:f3} MB", DevicePropertiesHelper.GetPeakMemoryUsageMb());
      builder.AppendLine(); 
      builder.AppendFormat("ApplicationCurrentMemoryUsage: {0:f3} MB", DevicePropertiesHelper.GetCurrentMemoryUsageMb());
      builder.AppendLine(); 
      using (var appStorage = IsolatedStorageFile.GetUserStoreForApplication())
      {
         builder.AppendFormat("Iso Storage AvailableFreeSpace: {0:f3} MB", appStorage.AvailableFreeSpace / 1024f / 1024f);
         builder.AppendLine();
      }
      return builder.ToString();
   }
}

public class EmailService
{
   private readonly EmailComposeTask emailComposeTask;

   public string Addressee { get; set; }

   public EmailService()
   {      
      Addressee = "foo@bar.com";
      emailComposeTask = new EmailComposeTask();
   }

   public void ShowTask(string subject, string body)
   {
      // Add system infos add the end of the email
      body += Environment.NewLine;
      body += Environment.NewLine;
      body += Environment.NewLine;
      body += Environment.NewLine;
      body += SystemInformation.Dump();

      // Fill email
      emailComposeTask.To = Addressee;
      emailComposeTask.Subject = subject;
      emailComposeTask.Body = body;

      // Invoke Mail Task
      emailComposeTask.Show();
   }
}

private static void Application_UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
{
   var result = MessageBox.Show("An error occured. Do you want to send the error details to the developer?", "Meh", MessageBoxButton.OKCancel);
   if (result == MessageBoxResult.OK)
   {
      new EmailService().ShowTask("App error", e.ExceptionObject.ToString());
   } 
   e.Handled = true;
}

System.ArgumentException: The parameter is incorrect. 
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.SetValue(INativeCoreTypeWrapper obj, DependencyProperty property, DependencyObject doh)
   at MS.Internal.XcpImports.SetValue(INativeCoreTypeWrapper doh, DependencyProperty property, Object obj)
...


***** System Infos *****

Time: 12/11/2010 5:50:02 PM
Culture: en-US
App Version: 1.9.0.0
Manufacturer: SAMSUNG
Modell: SGH-i917
DeviceHardwareVersion: 3.1.0.7
DeviceFirmwareVersion: 2103.10.10.1
OS  Version: Microsoft Windows CE 7.0.7004
CLR Version: 3.7.10218.0
Device Type: Device
Network Type: MobileBroadbandGsm
DeviceTotalMemory: 475.469 MB
ApplicationPeakMemoryUsage: 63.055 MB
ApplicationCurrentMemoryUsage: 41.223 MB
Iso Storage AvailableFreeSpace: 601.641 MB

int w = desiredOutputWidth;
int h = desiredOutputHeight;

// Workaround for issue in DecodeJpeg method:
// Swap width and height for landscape pictures.
if (originalWidth > originalHeight)
{
   w ^= h;
   h ^= w;
   w ^= h;
}
var writeableBitmap = PictureDecoder.DecodeJpeg(jpegStream, w, h);

private static void Save(WriteableBitmap bitmap)
{
   try
   {
      SaveToMediaLibrary(bitmap, "mySuperCoolPic.jpg");
   }
   catch (InvalidOperationException)
   {
      MessageBox.Show("The Zune software is running and the picture can't be saved. Please close Zune or disconnect the phone.");
   }
}

private void PhotoProviderTaskCompleted(object sender, PhotoResult e)
{
   try
   {
      if (e != null)
      {
         if (e.TaskResult == TaskResult.OK)
         {
            // Do something with the JPEG stream in e.ChosenPhoto
         }
         else if (e.Error is InvalidOperationException)
         {
            throw e.Error;
         }
         else if (e.TaskResult == TaskResult.Cancel)
         {
            // Try to get an image from the Pictures Hub. 
            // If this fails, the device is connected and Zune is running.
            var pictures = new MediaLibrary().Pictures;
            if(pictures.Count > 0)
            {
               pictures[0].GetThumbnail();
            }
         }
      }
   }
   catch (InvalidOperationException)
   {
      MessageBox.Show("The Zune software is running and the picture can't be saved. Please close Zune or disconnect the phone.");
   }
}

I wish all a merry christmas and a happy new year.
Ich wünsche allen ein frohes Weihnachtsfest und einen guten Rutsch ins neue Jahr.

Und nun viel Spaß...