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I am trying to capture an application's display and stream it to another computer. The application is composed of multiple program windows. I found the following examples and used them to create a window with a composition host that captures multiple windows and combines them into one window.
When I try to capture the new window I am only able to get the new window's background color. I have tried using GDI+ (StretchBlt and BitBlt) and DirectX but they are unable to capture the new window with the combined layers. They just capture the background of the new window. The code I am writing is on a stand alone network so I am unable to post the actual source code.
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Does the new window mean a window you created with a composition host that captures multiple windows and combines them into one window?
And I have verified that the ScreenCaptureforHWND can capture the HelloComposition window. So could you please show a minimal, reproducible sample about the question without private information?
I created a new window and passed the handle to the composition host. That composition host captures multiple windows and combines them. they are all then displayed in the new window that was created. When I try to use GDI+ or even BitBlt it just captures the new window that I created. It doesn't capture the windows added to the composition host.
I will see what I can do about getting a sample of the code I have posted here.
You can post the sample without private information to GitHub or somewhere you prefer.
GDI+ might not capture the window with composition. You can try ScreenCaptureforHWND or DXGIDesktopDuplication to capture.
The HelloComposition project, reference above, is close to the code I am using. I tried a test with the HelloComposition project. I can't capture the pixels of the HelloComposition window using GDI. Is there another option that would allow me to capture the pixel data of that window?
Apart from PrintWindow @Castorix31 mentioned, you can try ScreenCaptureforHWND I've verified or DXGIDesktopDuplication to capture.
I also test GDI Capturing an Image doesn't capture the composition.
Hello @JChild , Any updates?
Using Castorix31 suggestion with PrintWindow I am able to capture the contents of my window. PrintWindow is a pretty slow call. I was hoping there would be something that would allow me to "flatten" the composition host visual tree and get the pixels directly from the root Visual of the host. PrintWindow might be the best way to go at this point. I'm pretty new to the windows runtime library. Is there a way to get the pixels from the root Visual?
I tested with HelloComposition sample, and I can copy the window with
PrintWindow and PW_RENDERFULLCONTENT flag (into a compatible DC with CreateCompatibleDC)
I added a SS_BITMAP Static control where I set the copied bitmap with STM_SETIMAGE :
