My 10-Year Challenge - WriteableBitmapEx turns 10 with v1.6

It was 2009 when I started my first open source project and announced it with this unspectacular blog post. Back then it was developed with Visual Studio 2008 targeting Silverlight and hosted on CodePlex.
Many things have changed and tech comes and goes but during the last 10 years I always adapted, extended it, added bug fixes and reviewed/merged Pull Requests. Even after all the years WriteableBitmapEx is still quite popular, especially with Windows desktop WPF developers.

Version 1.6.2 of WriteableBitmapEx finally adds dedicated libs for UWP and an UWP sample. For WPF it now supports .NET Core, both the .NET Framework and .NET Core libs are part of the NuGet pack.

If you are using the source code and the VS solution directly, you can choose the .NET Framework 4.5 or .NET Core 3 as the target in the VS drop-down.

WriteableBitmapEx supports a variety of Windows platforms and versions.
WPF and Windows 10 Universal Windows Platform (UWP) are actively maintained.
Silverlight, Windows 8/8.1 WinRT, Windows Phone WinRT and Silverlight 7/8/8.1 are not maintained anymore but the latest stable libs are still part of the NuGet package.

You can download the latest via the updated NuGet package. The packages contain the WriteableBitmapEx binaries. All samples and the source code can be found in the GitHub repository.

A huge shout out and thank you to all the contributors, bug issuers and users of the library. ❤

Long time no hear - WriteableBitmapEx 1.5.1 is out

Even after all the years WriteableBitmapEx is still quite popular, especially with WPF developers and I always incorporate bug fixes and also accept Pull Requests if I get some time.
Many contributions were integrated and lots of bugs fixed. Among those are some nice additions like a clipped line drawing or a dotted line renderer.

WriteableBitmapEx supports a variety of Windows platforms and versions: WPF, Silverlight, Windows 10 Universal Windows Platform (UWP), Windows 8/8.1, Windows Phone WinRT and Silverlight 7/8/8.1.

You can download the latest via the updated NuGet package. The packages contain the WriteableBitmapEx binaries. All samples and the source code can be found in the GitHub repository.

A big thank you to all the contributors, bug reporters and users of the library who help with feedback.

We've Come a Long Way Baby - WriteableBitmapEx now on GitHub

The WriteableBitmapEx project is now 6 years old and times have changed since all began. It all started with Silverlight and more XAML flavors were added over time until all XAML flavors were supported including Windows Phone, WPF, WinRT Windows Store XAML, (Windows 10) UWP and still Silverlight.

The version control system and open source services landscape has changed as well and the CodePlex infrastructure has not been too reliable recently. That's why I finally took the time to move the WriteableBitmapEx source code from CodePlex' SVN bridge to Git and make it available on GitHub: https://github.com/teichgraf/WriteableBitmapEx
Additionally was the open source license changed from Ms-PL to MIT which should simplify the usage as well. See the Codeplex Issue Tracker for a list of features that will be added in the future. Please use the GitHub Issues functionality to add new issues which are not already reported. Of course the latest binaries will continue to be distributed via NuGet.

Staying Alive! - WriteableBitmapEx 1.5 is out

After a couple of minor updates on top of version 1.0 which lead to 1.0.14, I'm happy to announce that WriteableBitmapEx 1.5 is now available.
Many contributions were integrated and lots of bugs fixed. Among those are some nice new color modifications and also long awaited DrawLine with variable thickness, pen support, better anti-aliased lines, Cohen-Sutherland line clipping, even-odd polygon filling and alpha-blended shape filling... Read the details at the end of this post or the release notes.

WriteableBitmapEx supports a variety of Windows platforms and versions: WPF, Silverlight, Windows 10 Universal App Platform (UAP), Windows 8/8.1, Windows Phone WinRT and Silverlight 7/8/8.1.


You can download the binaries here or via the NuGet package. The packages contain the WriteableBitmapEx binaries. All samples and the source code can be found in the repository.

A big thank you to all the contributors, bug reporters and users of the library who helped to shape this. You rock!

Changes

• Added lots of contributions including DrawLine with variable thickness, penning, improved anti-aliasing and Wu's anti-aliasing algorithm
• Added usage of CohenSutherland line clipping for DrawLineAa and DrawLine, etc.
• Added support for alpha blended filled shapes and adapted the FillSample for WPF
• Added FillPolygonsEvenOdd() which uses the even-odd algorithm to fill complex polygons with more than one closed outline like for the letter O
• Added AdjustBrightness(), AdjustContrast() and AdjustGamma() methods
• Added Gray() method which returns the gray scaled version the bitmap
• Fixed regression issue with alpha blending for Blit for non-WinRT
• Fixed bug in Blit Alpha code for WPF when source format is not pre-multiplied alpha
• Fixed bug #21778 where FromStream for WPF needs to be called inside Init scope
• Fixed issue with IndexOutOfRangeEx in DrawLine method
• Fixed Invalidate for Silverlight BitmapContext.Dispose
• Fixed many more reported issues
• ...

Easy Render! - WriteableBitmapEx now with Better Support for Win 8.1 RenderTargetBitmap

The lack of WriteableBitmap.Render in Windows WinRT 8.0 was quite an issue for many apps, but fortunately did WinRT 8.1 (re-)introduce the RenderTargetBitmap class which provides the functionality of rendering the visual tree of the UI to a bitmap. The new update of WriteableBitmapEx makes it even easier to use with a WriteableBitmap by introducing the FromPixelBuffer method.

WriteableBitmapEx is available for 4 platforms: Windows Phone 8 and 7, WPF, Silverlight and Windows Store WinRT .NET XAML 8 and 8.1.

You can download the binaries here or via the NuGet package. The packages contain the WriteableBitmapEx binaries. As usual all samples and the source code can be found in the repository.

How to use
The below code snippet shows how a part of the UI can be rendered into a WriteableBitmap via RenderTargetBitmap, how it can be modified and then finally presented back into the UI by using an Image control.

// Render some UI to a RenderTargetBitmap
var renderTargetBitmap = new RenderTargetBitmap();
await renderTargetBitmap.RenderAsync(Panel);
            
// Get the pixel buffer and copy it into a WriteableBitmap
var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();
var width = renderTargetBitmap.PixelWidth;
var height = renderTargetBitmap.PixelHeight;
var wbmp = await new WriteableBitmap(1, 1).FromPixelBuffer(pixelBuffer, width, height);

// Modify the WriteableBitmap
wbmp.FillEllipse(10, 10, 256, 256, Colors.Salmon);
// ... More drawing including writeableBitmap.Blit(...) might go here

// Assign WriteableBitmap to an Image control to present it
ImgMirror.Source = wbmp;

Faster! - WriteableBitmapEx for Windows Phone 8 and WinRT Updated

The Windows Phone 8 SDK is now available and with that WriteableBitmapEx was updated too. The performance of the WinRT XAML version was also improved dramatically and an update is highly recommended.
WriteableBitmapEx is available for 4 platforms: Windows Phone 8 and 7, WPF, Silverlight and Windows Store WinRT .NET XAML.
You can download the binaries here or via the NuGet package. The packages contain the WriteableBitmapEx binaries. As usual all samples and the source code can be found in the repository.

Update WriteableBitmapEx for WinRT RTM, WPF, Windows Phone and Silverlight

The RTM version of Windows 8 is now available and with that WriteableBitmapEx was updated too. WriteableBitmapEx is now available for 4 platforms: WPF, Silverlight, Silverlight for Windows Phone and Windows Store Style WinRT .NET.
You can download the binaries here or via the NuGet package. The packages contain the WriteableBitmapEx binaries. As usual all samples and the source code can be found in the repository.



Since the last WinRT release preview version, a couple of bugs were fixed and a new FromStrean method was added which loads an image stream into a WriteableBitmap. The project was also updated for the Windows 8 RTM version. Please read this blog post for more details about the WinRT version.

It's Alive! - WriteableBitmapEx 1.0 for WinRT Metro Style, WPF, Windows Phone and Silverlight

After a few preview versions, I'm happy to announce that the final version of WriteableBitmapEx 1.0 is now available.
A couple of weeks ago we added official WPF support and WinRT Metro Style support. With that WriteableBitmapEx is now available for 4 platforms: WPF, Silverlight, Silverlight for Windows Phone and Metro Style WinRT .NET.
You can download the binaries here or via the NuGet package. The packages contain the WriteableBitmapEx binaries. All samples and the source code can be found in the repository.


Since the last WinRT preview version, a new WinRT sample was added, a couple of bugs were fixed and a new FromStrean method was added which loads an image stream into a WriteableBitmap. The project was also updated for the Windows 8 Release Preview. Please read this blog post for more details (about the WinRT version).

One Bitmap to Rule Them All - WriteableBitmapEx for WinRT Metro Style

A couple of weeks ago we added official WPF support to  WriteableBitmapEx. Today I'm happy to announce that WriteableBitmapEx now also officially supports Windows 8 Metro Stlye WinRT .NET XAML. With that WriteableBitmapEx is now available for 4 platforms: WPF, Silverlight, Silverlight for Windows Phone and Metro Style WinRT .NET.
Although Direct2D is the best solution for fast 2D graphics with Windows 8 Metro Style, I think there are scenarios where the WriteableBitmapEx could be helpful, esp. when using C# with XAML. I also know that some devs were waiting for this to port their Windows Phone apps to Windows 8 Metro Style.

WinRT Differences
Unlike the Silverlight WriteableBitmap, the Metro Style WriteableBitmap doesn't provide the pixel data directly. Its IBuffer PixelBuffer property doesn't have an interface to get the color information. Fortunately there are a few C# extension methods available which provide the pixel data as byte array or stream in the BGRA pixel format. Yes, BGRA and not like all the other platforms supported by WriteableBitmapEx as ARGB. The BGRA format is mainly used by Direct2D, which might be the reason for this hidden, but important difference of the Metro Style WriteableBitmap.
The WriteableBitmapEx algorithms are written for the ARGB pixel format. Fortunately I was able to keep the details away from the library user by leveraging the BitmapContext concept we introduced with the WPF support. This approach makes it possible to share almost the same code for all 4 platforms without being cluttered with #if directives all over place.  Actually the most significant WinRT adaptation inside the WriteableBitmapEx methods was done in the FromContent method, which loads an image from the app content and provides it as WriteableBitmap. See this StackOverflow question I answered if you're interested in the details.
Nothing comes for free, but if the BitmapContext is used the right way, the performance hit won't be that much thanks to an internal reference counting WriteableBitmapEx' BitmapContext uses. No worries, you don't have to change all your WriteableBitmapEx calls, just wrap your calls in a simple using(writeableBmp.GetBitmapContext()) and you will only have one buffer conversion instead of one for each draw call.
It's really simple to use:

private void Draw()
{
   // Wrap updates in a GetContext call, to prevent invalidation overhead
   using (writeableBmp.GetBitmapContext())
   {
      writeableBmp.Clear();
      DrawPoints();
      DrawBeziers();
  
   } // Invalidates on exit of using block
}

private void DrawPoints()
{
   foreach (var p in points)
   {
      DrawPoint(p, Colors.Green, PointVisualSizeHalf);
   }
}

private void DrawPoint(ControlPoint p, Color color, int halfSizeOfPoint)
{
   var x1 = p.X - halfSizeOfPoint;
   var y1 = p.Y - halfSizeOfPoint;
   var x2 = p.X + halfSizeOfPoint;
   var y2 = p.Y + halfSizeOfPoint;
   writeableBmp.DrawRectangle(x1, y1, x2, y2, color);
}

private void DrawBeziers()
{
   if (points.Count > 3)
   {
      writeableBmp.DrawBeziers(GetPointArray(), Colors.Yellow);
   }
}

Screenshot WinRT Metro Style sample running in the simulator

All samples were tested with the new version, but due to the refactoring more testing is needed. Please test this version with your projects and report the bugs you encounter. You can download the binaries here. Note that this package only contains the WriteableBitmapEx binaries for Silverlight, Windows Phone, WinRT Metro Style .NET and WPF. All the samples can be found in the source code repository in the branch "WBX_1.0_BitmapContext". If all goes well, this branch will become the trunk and the 1.0 RTM in a few weeks.

WinMD / Windows Runtime Component
There's also a WinMD version available which makes it possible to consume the WriteableBitmapEx library from all the WinRT Metro Style projections, although only C# and C++ XAML make actually sense.
I had to move some parts and leave some functionality like the ForEach out, but it contains 99% of the library's features. Unfortunately the C++ sample I created crashes when the WriteableBitmapExWinMD library is loaded. So for now this WinMD version can be found in a separate branch "WBX_1.0_WinMD" in the source code repository and it won't be part of the trunk and release until it works with the sample. I'm a bit running out of time and don't know where to look for, since it seems all is wired up correctly and compiles fine. If you are a WinMD wizard and have a few minutes, I'd appreciate if you could look into the WinMD version.

SLARToolkit Samples Updated

The samples of my open source Windows Phone and Silverlight Augmented Reality Toolkit were updated to the latest version of the WP 7.1 and Silverlight 5 SDKs.
Please note the changed security model in Silverlight 5, which is a big bummer. My Silverlight MVP friend Morten wrote a few true words about it here.
As usual you can find a list of the samples on the project site and also get the code there.

WriteableBitmapEx 1.0 Coming Soon, Test it Now!

A new version of the WriteableBitmapEx open source library has just been released, but that isn't the last release for this year. No, Andrew Burnett-Thompson and I refactored the library to make it easier portable and we added full WPF support. Andrew did most of the work since he needed the current WriteableBitmapEx library for one of his WPF projects. As a result of the refactoring, WriteableBitmapEx will have maintained support for WPF starting with version 1.0.
I'd have loved to add support for WinRT too, but unfortunately it seems that WinRT only supports streamed reading / writing of the pixel buffer at the moment. I will wait until Microsoft ships the Windows 8 beta early next year and see what they have in there. Many WriteableBitmapEx algorithms need random buffer index access and I don't want to waste my time with massive memory copying now. Who knows what else comes in the beta and it might be better to use a whole different approach for immediate rendering with Windows 8 and WinRT.

All samples were tested with the new version, but due to the massive refactoring more testing is needed. Please test the beta version with your projects and report any bugs you find. You can download the binaries here. Note that this package only contains the WriteableBitmapEx binaries for Silverlight, Windows Phone and WPF. All the samples can be found in the source code repository in the branch "WBX_1.0_BitmapContext". If all goes well this branch will become the trunk in a couple of weeks.

Windows Phone Sites Around the World

I recently released an update of my Windows Phone app Pictures Lab which brings some nice new features like effect combination, two Christmas and a New Year frame and most importantly 7 new languages. Pictures Lab 4.0 now supports 9 languages: English, German, Japanese, Russian, Dutch, French, Italian, Spanish, Portuguese. This was made possible by a group of awesome native-speaking translators: Alan Mendelevich, Takeshi Miyauchi, David Salazar, Joost van Schaik, Johan Peeters, Paolo Barone, Simone Chiaretta, Pedro Lamas and Quentin Calvez.


I also asked my translators if they know any local Windows Phone news sites / blogs. Below is a list of international and regional Windows Phone news sites we collected. Note, that those are primarily consumer sites read by consumers and not only for developers. This list could be useful if you plan to release a localized version of your app and want to promote it a bit. Most sites have a "Tip Us" or contact form and are mostly happy about new content to write posts about.

Forget this list! 
Head over to @ailon's awesome dedicated site: http://windowsphonesites.com

English

• 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

German

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

Russian

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

Japanese

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

Dutch

• http://wp7.nl

Spanish

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

Portuguese (Brazilian)

• http://windowsphonebrasil.com.br

Italian

• 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

French

• http://www.monwindowsphone.com

Danish

• http://www.windowsphonefan.dk

If you know more sites, please leave a comment and I'll update the list.

Telerik published a nice whitepaper with more resources about app promotion.

WriteableBitmapEx 0.9.8.5 Now Available

The WriteableBitmapEx open source library has come a long way since I created the CodePlex site in December 2009. A lot of features and the support for new platforms were added in subsequent releases. The package is also available via NuGet since this year.
The new release v0.9.8.5 was just made public. A few new features were added and many small, uncritical issues were fixed (see the list below). The binaries can be downloaded from here or via the NuGet package. Please note that this package only contains the WriteableBitmapEx binaries for Silverlight and Windows Phone. All the samples can be found in the source code repository.


Feature list version 0.9.8.5

• 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.

Community Community Community!
Thanks to the community for constantly reporting bugs, suggesting new features and contributing code. That's exactly why open source software is just awesome.

Welcome to Zombieland, the Metro Style Land of WinRT and the Undead

Silverlight is dead! WPF is dead! .NET is dead! Hey, they didn't talk about SharePoint or SQL Server at the BUILD conference, those must be dead too. Welcome our new Metro-id overlords!
We read such FUD everywhere these days. Actually none of these technologies are dead for the next several years! And you'll probably agree if you know the facts and not the FUD. So here are my thoughts based only on the facts I got from watching BUILD sessions, reading posts that stick to the facts and not listening to people who obviously didn't inform themselves, but nevertheless spread FUD around.

What happened
Microsoft announced the new version of Windows at the BUILD conference and the new Windows 8 runtime called WinRT, which is used to develop Metro style Apps. Metro style Apps are primarily focused on consumers, designed touch first and therefore perfect for modern multi-touch devices like tablets.
The good ol' desktop is still there and the usual Windows applications are now called Desktop Apps.
There's a lot confusion out there at the moment and many think only Metro style Apps are the future. Actually both models can exist side-by-side and I'm sure the mainly used UI will be the classic desktop for the usual business client. Metro is for tablets, maybe later for the phone. Desktop Apps will still work better for the classic business PC scenario in an office.
After trying Windows 8 I don't see myself using Metro style Apps a lot on my PC when I work at the desk. However, I will love to use it when I'm hanging out on my couch with a tablet. The good news is, both models are supported by Windows 8 and therefore can run on one device, including ARM hardware. Awesome!

WinRT

First and foremost, .NET plays a significant role in both development models and is not only used for Desktop Apps. I guess the FUD comes from the architectural picture above, where .NET and Silverlight are only represented by a small box in the lower right corner. Of course Microsoft wants to push the new Metro style Apps, the WinRT model and wants to get web developers into the boat, so they adjusted the graphic and marketing message accordingly.
WinRT is actually a new native COM library, plus some extra infrastructure. Therefore an app developer has not to deal with the COM stuff directly, instead you get a thin / fast projection layer (binding) for each of the supported programming languages. This projection layer is automatically built using WinMD metadata and provides projections for JavaScript, .NET (C# / VB) or C / C++. The UI can be designed with XAML or HTML / CSS in case of JavaScript.
The rendering is completely done using DirectX 11.1 (Direct2D) which results in great performance. In Windows 8 the rendering job is finally fully executed by the right processor. This architecture makes it also possible to implement the complete UI just with DirectX, which will usually be done by games. At the moment it's not possible in the Windows 8 Developer Preview to mix a XAML app with DirectX, which doesn't make much sense since the XAML rendering is done by DirectX. Fortunately all hints that it'll be possible in a later version of Windows 8, maybe in the beta.

The below picture by Doug Seven is a way more accurate picture of the Windows 8 platform architecture.

There are a few good, unbiased posts about WinRT out there, which stick to the facts:
WinRT: An Object Orientated Replacement for Win32
WinRT, the C++ Component Extensions
WinRT demystified 
A bad picture is worth a thousand long discussions.
WinRT reference with all namespaces at the unbiased MSDN, where JaveScript is just another language one can use for Metro style Apps.

WinRT and .NET
From what I have seen so far, coding Metro style Apps using C# / .NET seems pretty straightforward if you've done Silverlight, WPF or esp. Windows Phone development before. The BCL used by .NET WinRT is not the full Desktop version of .NET 4.5, it's a reduced set similar to the Silverlight types.
The design of the native WinRT COM library was heavily influenced by .NET. You see it everywhere. Type names, Properties, Events... Even WinMD is the .NET assembly metadata format.
WinRT types map to .NET types and copying of data structures at the boundaries is avoided by the projection layer to get the best performance. Only two types need to be converted using built-in extension methods. The System.IO.Stream can't be mapped to the WinRT stream, so there's an extension method. A Byte[] to WinRT IBuffer conversion is the other extension method.
You can even write your own, custom WinRT components in C# without decorating the classes with ugly COM attributes. Those components are then automatically exposed to the other languages using the generic WinMD metadata. So you can write a component in C++ or in C# and use it from a JavaScript WinRT project. Pretty cool concept if you ask me.
Many WinRT classes look like their origin is .NET / Silverlight and the WinRT WriteableBitmap is also very similar to Silverlight's implementation. So expect a WinRT version of my open source WriteableBitmapEx library in a few weeks when I'm done with the Mango updates for all my Windows Phone apps. After that I will probably port / rewrite some of my WP7 apps for WinRT.

The lifecycle of a WinRT app should  be quite familiar for a WP7 developer, since it's similar to the WP 7.5 Mango Fast App Switching. The lifecycle states are: Running > Suspended in RAM > Terminated. Apps get an event for suspending, not for terminate, so the state has to be saved during suspending. Of course an app should only be resurrected from the tombstone state if the app was launched, not when resumed. Apps get 5s for suspending and need to launch within 15s. Unfortunately we don't know the reference machine where those values are measured. Probably the low end configuration.
By the way, the Windows Store will be the better version of the WP7 Marketplace. It will include In-App offers, time limited trials and a very nice dashboard with a lot of analytic capabilities and insights.
In general should a WP7 developer feel most familiar with WinRT. Many concepts made it into WinRT and were improved and actually cleaned up.
My Silverlight MVP friend Morten Nielsen started a blog post series about how to port Silverlight / WPF apps to WinRT.
You should also read this post: WinRT and .NET and watch the ton of great BUILD sessions.

Conclusion

I welcome the new possibilities and great performance we get in Windows 8 with the WinRT. I'm sure Windows 8 will be an awesome tablet OS.
XAML has become a first class citizen and .NET is now installed with Windows 8. Microsoft is also working on a next version of .NET. Version 4.5 of .NET will bring better performance for WPF's ItemsControl for example. Seems not very dead to me. In fact, a Silverlight / WPF / WP7 developer's knowledge of XAML and the Silverlight runtime is more valuable than ever before with WinRT.
Silverlight 5 is still in development and wasn't even released. We don't know if it will be the last version or if Silverlight 6 will see the light of the day. For now I'm quite happy with all the features of Silverlight 5 and we can develop a ton of applications for our customers for the next several years.

One should also not forget how long it will take until Windows 8 is finally out and reached a critical mass. A lot of machines out there still run Windows XP. Windows 7 is way better and I guess the transition to Windows 8 will take even longer. Windows 8 will probably mainly pushed by non-PC multi-touch consumer devices in the near future.

This flowchart by the Telerik guys sums it up pretty nicely.

So get yourself informed and start coding away. Don't give FUD a chance!

Cubelicious - Silverlight 5 + Balder + Physics + SLARToolkit Augmented Reality = Triple Win!

Two months ago I released a new Silverlight 5 sample for my open source Silverlight Augmented Reality Toolkit - SLARToolkit. It uses the new Silverlight 5 hardware accelerated 3D API. You can read more about the new Silverlight 5 XNA 3D API in this blog post.
This post here provides a new demo for SLARToolkit which uses the open source 3D engine Balder by my friend Einar Ingebrigsten. This demo also leverages the open source physics engine JigLibX my buddy Andy Beaulieu ported over to Silverlight. You can try the live sample if you have the Silverlight 5 beta installed or watch a video instead.

I actually spent most of the time on this project a couple of weeks ago. My good Silverlight MVP friend Einar Ingebrigtsen used it in his talk at The Gathering 2011. Now I finally had a bit time to finish the demo, make a video and this blog post.

The SLARToolkit project description from the CodePlex site:

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. 

Live

A webcam and at least the Silverlight 5 beta runtime must be installed to run the sample. It's available here. Alternatively there is also a video of the new sample embedded below.

If you want to try it yourself you need do download the SLAR and / or L marker, print them and hold them in front of the camera. The marker(s) should be printed non-scaled at the original size (80 x 80 mm) and centered for a small white border. As an alternative it's also possible to open a marker file on a mobile device and to use the device's screen as marker. Also make sure the camera is set up properly and the scene is illuminated well without hard shadows. See the SLARToolkit Markers documentation for more details.

Open the sample in a new page.

Simply press the "Start Cam" Button to start the webcam. The properties of the particle system can  be changed with Sliders. The "Flip x-axis" Checkbox can be used to flip the video (the webcam output is mirror-reversed by default). 

If you click the "Start Cam" Button for the first time you need to give your permission for the capturing. This application uses the default Silverlight capture device. You can specify the video and audio devices that are used by default with the Silverlight Configuration. Just press the right mouse button over the application, click "Silverlight" in the context menu and select the "Webcam / Mic" tab to set them.

Video

I've recorded a short video of the new sample with Expression Encoder's Screen Capture feature. Please keep in mind that the screen recording software eats up a lot of resources while recording and that the actual frame rate is even better. The video is also available at YouTube.

Background music is Lullaby by _ghost

This demo shows how the new Silverlight 5 3D API, the Balder engine and the JigLibX physics library can be used to augment the reality with the help of SLARToolkit.

How it works

This sample uses the webcam video stream which fills a Rectangle shape, the video stream is also constantly captured and fed to the SLARToolkit BitmapMarkerDetector to detect the markers. The detection result contains a transformation matrix for each found marker which is then used to apply a global transformation to the cubes and the plane.
I implemented a particle system with a flexible directed emitter which can be controlled through various properties. The particle system is quite generic and can be used for all kinds of particles (3D objects). The particle collision detection and resolving is based on rigid body physics that was implemented with the help of the JigLibX library my Silverlight MVP buddy Andy Beaulieu ported over to Silverlight.
The rendering and the model loading is done by the 3D engine Balder. It's a fantastic open source engine by Einar Ingebrigtsen. You just need to write a couple lines of XAML and you're good to go. This sample only uses a simple cube model, but Balder has built-in model loaders to load complex 3D models and Einar provides a big sample library. He also brought the engine to a few more platforms like Windows Phone 7, OpenGL and has even a neat software rendering fallback. Read his blog post here.
As part of this sample I needed some vector and quaternion methods which were missing in Balder. I contributed those and the generic particle system to the Balder project. Feel free to use the particle system and the other methods in your Balder projects.

Download it, build your app and augment your reality

The open source SLARToolkit library and all samples are hosted at CodePlex. If you have any comments, questions or suggestions don't hesitate and write a comment, use the Issue Tracker on the CodePlex site or contact me via any other media.
Have fun with the library and please keep me updated if you use it anywhere so I can put a link on the project site.

Nodo vs Mango - Windows Phone ListBox Performance Improvements in Action

There were quite a few complaints about the Windows Phone's ListBox scrolling performance in the past. The Windows Phone team obviously heard it and heavily worked on the performance and responsiveness of the whole platform and the ListBox in particular. The touch input processing was loaded off from the UI thread to a new separate thread. Additionally the BitmapImage doesn't load the data on the UI thread anymore. I'm sure lots of other tweaks were implemented to increase the performance and the responsiveness of the platform. I think the Windows Phone team did a very good job!

Showdown

The video below shows a side-by-side comparison of a Nodo device with build 7392 and a prototype device with a Mango prebuild. The Nodo device on the left side is a Samsung Omnia 7, the Mango device on the right side is the ASUS prototype.

For comparison I use the official Twitter app build against 7.0 and in the second half of the video I show the effects preview list of my Pictures Lab app. This effects pivot item only uses a ListBox with a DataTemplate that contains an Image control with a fixed size and a TextBox for each item. So there's no background image loading being performed or any other heavy computing, just a static list with a lot of redrawing.

Background music is Taiga by SMILETRON

As you can see, it's quite a huge difference and even this Mango prebuild  runs very smooth on this rather old ASUS hardware. There's still some room left for more improvement, like the rasterizer, but imagine the boost on production devices with the final Mango version.

MANGO, MANGO, MANGO!

I don't have a deal with Microsoft or are paid to blog or tweet this. I'm just exited about all the goodies that are coming with Mango. Good times.

Unity 3D and Silverlight in Harmony with SLARToolkit's Augmented Reality

If you read this blog regularly, you might have noticed a lot of SLARToolkit posts recently. But I'm not the only one using the open source Silverlight Augmented Reality Toolkit. There's great stuff happening out there and I see quite a few projects, especially in the academic field. You can find a full list of projects (I know of) on the SLARToolkit project site at CodePlex.
I love when people use my open source work, adapt or learn from it. This is what open source is all about for me.



One project recently caught my attention in particular. Ioulian Alexeev made a very amazing action game using the Unity 3D game engine and he combined it with SLARToolkit to control the spaceship with a marker. Ioulian studies Multimedia at the Arteveldehogeschool in Belgium and the game "StarFighter" was his bachelors test.

He recorded this nice video.

Note how he compares the performance of the Flash Augmented Reality Tookit and SLARToolkit:

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

Both toolkits use the same marker-based AR algorithms from the ARToolkit.

Live
You can play the game here. If you want to try it yourself you need do download the SLAR and / or L marker, print them and point the camera toward these. The marker(s) should be printed non-scaled at the original size (80 x 80 mm) and centered for a small white border. As an alternative it's also possible to open a marker file on a different device and to use the device's screen as marker.
See the SLARToolkit Markers documentation for more details.

Why is a Y in the Windows Phone Mango Camera API

The release of the new Mango tools brings Windows Phone development on par with Silverlight 4 and will therefore add many great features to the Windows Phone platform. This means it will also contain the Webcam CaptureSource and VideoSink API from Silverlight 4. Additionally it also introduces the new FileSink class which can be used to record the video stream as MP4 to the Isolated Storage. Most important a new PhotoCamera class with a lot of functionality is present in Mango.
This class is used in the latest SLARToolkit Windows Phone sample and in some other new projects I'm working on.

Don't Reinvent the Wheel
The Silverlight 4 webcam API was explained in this detailed blog post almost a year ago. The techniques and concepts I described there can now also be used with Windows Phone Mango.
The updated MSDN documentation has quite a few articles and samples about the new camera API. My MVP buddy Alex Golesh also has a nice write up about the new Camera API.
This blog post tries to fill the gaps and provides some information especially about the PhotoCamera's YCrCb capture methods.

YCbCr vs ARGB
In the well-known RGB color space the red, green and blue information is stored in separate components which also contains the redundant luminance data for each channel. In the YCbCr color space (or YCrCb) the luminance information is stored in the Y component and the chroma (color) information in the Cb component as blue-difference and in Cr component as red-difference. The RGB-YCbCr conversion can be done with simple addition and multiplication operations. The Y component usually ranges from 0 to 1, Cb and Cr from -0.5 to 0.5.

Y = 0.5, Cr [-0.5, 0.5], Cb[-0.5, 0.5]

Humans are more sensitive to luminance information than to chroma, therefore the resolution of the color information can be reduced and only the luminance needs to be stored in full resolution. Many digital camera sensors use the YCrCb color space and make use of this reduced chroma information.

PhotoCamera
The PhotoCamera class has a lot of useful methods to either capture a full resolution image from the camera or to get a smaller (and faster) preview buffer snapshot. The GetPreviewBufferY and GetPreviewBufferYCrCb methods provide the direct data from the camera without a transformation to 32 bit ARGB. Not only is the alpha channel left out in the YCrCb buffer, also the Cr and Cb color components are stored with reduced resolution. This keeps the buffer size smaller and is way faster, but also makes it a bit trickier when the color components (and brightness) need to be extracted from the byte buffer. Fortunately there's the YCbCrPixelLayout property which contains alls the offsets, strides and other needed information.

Conclusion
The GetPreviewBufferYCrCb method is approximately 4 times faster than the GetPreviewBufferArgb32 method and also takes a smaller buffer, therefore the YCrCb methods are the way to go when only the luminance data is needed or the YCbCr color space can be used for the given scenario. For example many computer vision techniques only need the luminance information for processing.
I like that both color spaces are supported by the API. On mobile devices you need all the performance you can get. I actually helped the Windows Phone camera team with quite a bit feedback to decide about this API design. Very smart people by the way.

Augmented Mango - SLARToolkit for Windows Phone

The beta of the new Windows Phone Developer Tools was just publicly released. The update with the codename "Mango" comes with many new APIs and will finally contain an API for real-time camera access what a lot of developers have been asking for. The new runtime gives us the needed functionality to implement many cool scenarios. One of these scenarios is Augmented Reality, which leads to my open source Silverlight Augmented Reality Toolkit (SLARToolkit).
This post announces the new Windows Phone version of SLARToolkit and also provides a sample. If you're one of those lucky people with a Mango-enabled device you can download the XAP here or just watch a video instead.

The SLARToolkit project description from the CodePlex site:

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. 

Demo

The sample XAP can be deployed to a Mango-enabled device (tested with build 7629). Alternatively there's also a video of the new sample embedded below.

If you want to try it yourself you need do download the SLAR and / or L marker, print them and point the camera toward these. The marker(s) should be printed non-scaled at the original size (80 x 80 mm) and centered for a small white border. As an alternative it's also possible to open a marker file on a different device and to use the device's screen as marker.
See the SLARToolkit Markers documentation for more details.

Video

I've recorded a short video of the new sample with my Samsung Omnia 7. It's a bit blurry, but it demonstrates how well the sample works even on this quite old ASUS prototype, which's camera pipeline seems a bit slow.
The video is also available at YouTube.

Background music is Melo by Mosaik

This demo shows how the new Windows Phone Mango real-time camera API can be used  to augment the reality with the help of the SLARToolkit. This can be nice for educational projects and it's actually no problem to add correctly transformed videos or other content to the demo.
The demo demonstrates just some basic UIElements like a TextBox and an Image control. Mango will also enable the combination of Silverlight and XNA, which means that nice 3D AR games can be developed with the help of the SLARToolkit. 

How it works

This sample uses the new PhotoCamera and a timer to constantly get a snapshot of the real-time camera stream. This snapshot is then passed to the SLARToolkit algorithms to get the 3D spatial information of the marker. The computed detection results are used to transform the elements perspectively correct.

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();
}

The PhotoCamera instance is set up in the OnNavigatedTo event handler of the page and the DispatcherTimer is started. The timer will constantly call the Detect method every 50 milliseconds. Additionally a viewfinder Rectangle is filled with a VideoBrush which in turn has the photoCamera video stream set as source.

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;
   }
}

A snapshot of the current preview buffer is taken in the Detect method using the GetPreviewBufferY method. This method fills up a byte buffer with the luminance data of the current viewfinder frame. This buffer is then passed to the SLARToolkit's MarkerDetector Detect method, which returns the detected marker information. This transformation data is then used to transform the UIElement perspectively correct in 3D.
Read more about the PhotoCamera's YCbCr methods in this blog post.

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;
}

The SLARToolkit's GrayBufferMarkerDetector is created and set up in the PhotoCamera's Initialized event handler. The brand new GrayBufferMarkerDetector uses the byte buffer with luminance data directly without the need of an ARGB 32 bit pixel conversion.

Checkout the source code at CodePlex if you want to see all the details of the sample which were left out for clarity.

Download it, build your app and augment your reality

The open source SLARToolkit library and all samples are hosted at CodePlex. If you have any comments, questions or suggestions don't hesitate and write a comment, use the Issue Tracker on the CodePlex site or contact me via any other media.

Have fun with the library and please keep me updated if you use it anywhere so I can put a link on the project site.

WriteableBitmapEx goes NuGet

The WriteableBitmapEx library is now available as a NuGet package. The package contains the Silverlight and the Windows Phone binaries. The sources and the PDB are also available at SymbolSource.org.
NuGet is a neat package management system for the .Net platform which makes the life of a .Net developer much easier. If you haven't tried NuGet until now, you should definitely give it a try. I'm sure you won't regret it. To install NuGet, open Visual Studio's Tools -> Extension Manager and search the Online Gallery for NuGet. You can then open a project, right click the References and select "Add Library Package Reference".