[Bug 56198] New: X11 driver seems to assume horizontal multi-screen layout

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56198

Bug ID: 56198
           Summary: X11 driver seems to assume horizontal multi-screen
                    layout
           Product: Wine
           Version: 9.0-rc5
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winex11.drv
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

System info:
Distro: openSUSE Tumbleweed 20240114
WM: Sway 1.8.1
XWayland: 23.2.2 (12302002)

When running on display configurations where screens are not on a horizontal
line (e.g. stacked on top of each other), the X11 driver, at least running
under XWayland, makes it impossible to use part of the screen that a window is
on.

Examples:
[3840x2160]
[3840x2160]
In this case, only the left half of each screen is usable. The right half does
not respond to any mouse events, and programs such as winecfg will not redraw
in that region.

[2160x3840][3840x2160]
           [3840x2160]
Most of each screen is usable, except for a region on the right side.

It appears that Wine divides the total width of the X11 display by the number
of screens in order to determine the active region.

I am not sure if this is an XWayland bug, but I have not observed this behavior
with other X11 applications.

(The Wayland driver unsurprisingly does not have this problem, but is also not
yet ready for general use.)