Need Help: VRAM read back in Kernel

[UEFI-code]

I want to read back the VRAM pixel data (Which currently displaying on Monitor) in Kernel Mode but I don't know how to do it. I even don't know how Windows Itself screenshot.

I came out some ideas:

1. Hook GPU vendor's driver kernel callback function to get the VRAM pointer
2. Disasmbly ntoskrnl.exe/win32.sys to find a "Global VRAM symbol" to get the pointer

If you know how to do it, please reply this issue or create a PR which contains the demo code