Detect if a window is using hardware-accelerated graphic context

Question

I'm using BitBlt winapi function to take a screenshot of a given window, even if the window is partially overlapped.
I have everything working fine already, except that, on Windows 10, for some windows (like the Edge browser) the screenshot turns out completely black.

A number of other questions concur on attributing this problem to the use of a hardware-accelerated graphics context on those windows.

• BitBlt screen capture not working on Windows 10
• Screenshot with BitBlt results in black image on Windows 10
• Screenshot captured using BitBlt in C# results a black image on Windows 10
• BitBlt not capturing windows in Hardware accelerated mode
• AutoHotkey-GDIp: Capture a screenshot from a hardware accelerated window

Apparently the GDI library is incompatible with that kind of graphics context so a different library has to be used.

My question is specifically about how to detect if a window is using a graphics context that's incompatible with the GDI library.

If I'm able to detect this, then I can choose which library to use for capturing the screenshot correctly (GDI, ActiveX or other).

Otherwise, the only way I could detect this is by scanning the screenshot pixel by pixel to check that's completely black. Then using a different capture method till I get some content on the screenshot.
But this sounds like an awful solution.

Countermove

Take your screenshot from GetDC(nullptr) and then clip out the target window. – Galiot

@JonathanPotter, unfortunately that technique doesn't work with partially overlapped windows. – Countermove

You can't use BitBlt to capture an overlapped window in any event. – Galiot

"for some windows ... the screenshot turns out completely black" - hardware acceleration is not the only reason that can happen. In Windows 7+, apps can simply choose to opt-out of their windows being rendered anywhere other than the actual display monitor (think DRM protection, for instance). – Urinate

@JonathanPotter, yes, you can. That's been possible since the introduction of DWM composition in Windows Vista. – Countermove

Have you tried using PrintWindow with PW_RENDERFULLCONTENT as suggested in the answer to the related question? – Identity

@AntonK, that looks promising. I'll try it and report back. – Countermove

@AntonK, the PW_RENDERFULLCONTENT trick is indeed able to capturing hardware-accelerated windows. Although not an answer to the question, it's a useful workaround for Windows 10. – Countermove

Answer 1

I have everything working fine already, except that, on Windows 10, for some windows (like the Edge browser) the screenshot turns out completely black.

You can use DwmRegisterThumbnail to capture hidden/overlapped windows, in particular UWP (like Edge, Calc, etc...)

I use it on Windows 10 without problem (+ D3D to save the bitmap)

Vacate

I thought DwmRegisterThumbnail let you show a thumbnail in a window of yours, but it didn't give you access to the pixel data. How do you obtain the image data after calling DwmUpdateThumbnailProperties? – Countermove

I tested with D3DXSaveSurfaceToFile (VS 2015, Windows 10) – Vacate