How is it possible to let an app be displayed in mirror mode, so that you can see through a mirror (i.e. HUD) the image in the “right” way? It would be nice if you could set some option in Window 10/Windows 10 Mobile, but the available orientation “landscape flipped”  just rotates the screen and it does not produce a mirror view …

I saw the following image in a post that shows how it was possible in Windows 7 (http://www.techsupportforum.com/forums/f25/solved-desktop-screen-viewed-in-mirror-image-687706.html; http://www.techsupportforum.com/forums/attachment.php?attachmentid=122558&d=1361596944…), but in more recent versions, it seems to be no longer available for the time being and only the flip option remained in the display setting page!

Mirror view was allowed fromWindows 7 settings

Only flip option are available in Windows 10 display settings page

Note that even the Maps app does not have, among all the options of (e.g. even when setting the navigation), one that allows to use that app with a Head Up Display … and it seems very strange and bad to me 😦

And this is really a pity especially now that HUD will be used more and more in vehicles, even the very cheep ones (about 20€) with a semi mirror glass that reflect the smartphone screen!

Head Up Display (1)

Head Up Display (2)

Head Up Display (3)

Anyway, if you have to do it necessarily internally to any app, from code , what APIs can be used (possibly in C#… even thought there are some in C++)?  In Java there is the AffineTransform method that can help … but what about UWP?

In the following some suggested solutions.

From Windows Dev Center forum :

You can apply a Projection to flip the base element on your page 180 degrees:

<Grid.Projection>
     <PlaneProjection RotationY="-180" /> 
</Grid.Projection>

See the following page for more information on transforms:  https://docs.microsoft.com/en-us/windows/uwp/design/layout/transforms#span-id3-dtransformsspanspan-id3-dtransformsspanspan-id3-dtransformsspan3-d-transforms

Another interesting suggestion comes from stackoverflow forum:

• https://stackoverflow.com/questions/17628538/how-to-mirror-image-preview-coming-on-front-camera-in-my-windows-8-phone-app
• https://stackoverflow.com/questions/3005219/how-to-flip-image-in-wpf