[PATCH v2 0/1] MR8669: Draft: Map low level hooks coordinates correctly in win32u

[Santino Mazza (＠tati)]

Coordinates from mouse low level hook messages are not mapped the same way than WM_MOUSEMOVE or GetCursorPos. This causes problems on programs that make use of both values to calculate mouse movement, like the wine DirectInput implementation.

I'm marking this as a draft since I was not able to find a way to write a test for this. I'm able to easily reproduce it on Proton, because it creates a scaled full screen window, on Wine this doesn't happen so the coordinates are not required to be mapped to a scaled window.

Edit: I didn't realize that modesetting emulation was an experimental option! So, I was able to reproduce the bug by enabling it.

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  v2: win32u: Map raw coordinates to virtual screen in low-level hooks.

https://gitlab.winehq.org/wine/wine/-/merge_requests/8669