Fullscreen applications with HDX 3D Pro – Part 2

In my previous post about full screen applications in HDX 3D Pro, I explained possible solutions to the “Full Screen Applications are not supported in Citrix HDX 3D Pro” message. In short, the issue is due to the fact that the application does not use the same resolution as your HDX session.

Full Screen Applications are not supported in Citrix HDX 3D Pro
Full Screen Applications are not supported in Citrix HDX 3D Pro

In the mean time, Citrix release XenDesktop 7.6. The XenDesktop HDX 3D Pro VDA now contains an experimental fix to support full screen applications in any resolution. This fix is explained by Rachel Berry (Product Manager HDX Graphics for XenDesktop/XenApp, twitter @rhbBSE) on the Citrix Blog: http://blogs.citrix.com/2014/10/24/hdx-3d-pro-experimental-support-for-full-screen-apps/

Enable support for full screen applications

As described in Rachel’s blog post, you have to modify the registry on the machine where your VDA is installed. Insert the following value:

[HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\HDX3D\BitmapRemotingConfig]
“HKLM_EnableFSA”=dword:00000001

To check this feature out, I’ve upgraded my lab environment to 7.6 (both DDC and VDA) and injected the registry value.

Note that this configuration is experimental and currently not officially supported by Citrix.

Lower resolution

My first test was to launch an application (Unigine Valley Benchmark) in full screen mode, but in a different resolution than my session (since using the same resolution works anyway). My session resolution is 1280×720, while I ran Unigine in 1024×576. I was pleasantly surprised. It launched without issue, no error whatsoever. It ran my application, but with blank screen where the application didn’t “touch” the session.

Fullscreen application in HDX, application resolution lower than session resolution
Fullscreen application in HDX, application resolution lower than session resolution

Sure, it doesn’t look as pretty as a “real” fullscreen application because of the black bars on either side of the application, but it works perfectly.

Normally, when you launch a fullscreen application on your local machine, the resolution of your display is modified to fit the application. In an HDX session, you just can’t modify the client’s resolution from inside the session. So I would say that this is Citrix’s best solution at the moment.

Higher resolution

Next test is to launch an application in a higher resolution as my session resolution. Again, my session resolution is 1280×720, but I’m launching Unigine in 1366×768 resolution. And again, the application launches without problems.

Fullscreen application in HDX, application resolution higher than session resolution
Fullscreen application in HDX, application resolution higher than session resolution

You briefly see the screen distort when the application is launched, but this only lasts for a few milliseconds. No big issue at all, since it launched the application without any issue. (you can see the same if you would launch a fullscreen application locally on your PC)

Short display distort
Short display distort

Even higher resolution

There is a small challenge here, but that’s more a functional one. If you launch the application in a resolution higher than your session’s resolution, the right and bottom sides of the application are “cut off”. This challenge is more visible when launching applications in a much higher resolution. Again, my session resolution is in 1280×720, while I launch the application in full HD resolution (1920×1080).

Again the application launches, but the right and bottom sides are trimmed off.

At high resolution, the right and bottom sides are trimmed off
At high resolution, the right and bottom sides are trimmed off

It can’t be seen that well in this screenshot, but normally there would be a frame counter on the right-hand side of the image. Once you close the application, you can see how it affects the application.

Text not readable because of trimming
Text not readable because of trimming

In case of Unigine, it does not really matter. But if you have an application with navigation/buttons/important information on the right or bottom side of the application, it could provide an interesting challenge.

Possible solution

I understand why the application behaves in this way. The best way to fix such an challenge is to “scale” the application (I don’t even know if this would be possible programmatically) so that it scales while it maintains the aspect ratio. This way you would always see the entire application, no matter what the resolution is.

Rachel Berry sent me a suggestion based on this solution, check out part 3 of the “Fullscreen applications with HDX 3D Pro” series.

A different approach could be to have the application launch in the center of the screen like this:

Application trimmed on all sides
Application trimmed on all sides

Where the red region would be the original session resolution, the blue regions would be “cut off” from the application. But then again, what happens when your fullscreen application has the navigation/menu at the top of the application? Some kind of per-application configuration would be nice.

Issues

While Citrix did an excellent job implementing this feature, I did encounter some issues.

Small resolution

First issue I saw was that my application used a smaller resolution as my session had, but the application did not create the “blank” space next to the application. I saw the application at the left side of the screen, but my desktop on the right side of the application. This is something I only saw once and I even couldn’t reproduce the issue.

Application not at the top left position

One application which I launched without configuring any resolution, shifted way down. It did not launch at the top left position of my session.

Application in wrong position on-screen
Application in wrong position on-screen

Once I defined the correct resolution, it started at the top-left corner of my session (in this case the application was using the same resolution as my session).

Correct displayed fullscreen application
Correct displayed fullscreen application

Session resizing

When resizing the session window (my HDX session from windowed to fullscreen), while I had an application running in fullscreen mode, showed some weird results. When I resized my Receiver window from fullscreen to windowed, I couldn’t see the windows desktop once the fullscreen application was closed (when I resized the session window from windowed to fullscreen again, it did show my desktop).

The other way around, resizing from windowed to fullscreen while the application was running, displayed my desktop with a “blank” border once the fullscreen application was closed. By resizing the window from fullscreen to windowed and back to fullscreen again, the issue was gone.

Resize session window issue
Resize session window issue

Conclusion

Citrix did a great job implementing this feature, it was easy to configure and every application I tried launch without giving any error message. However, you will still need to figure out what is the best resolution for your end-users, since in some cases, application content can “fall off” the session screen.

I hope this post was usefull. If you have any questions or remarks, feel free to leave a comment or drop me an email.

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