Re: Wine creating windows offscreen when "multiwindow" is used?

[Jon TURNEY <jon.turney@dronecode.org.uk>]

On 03/07/2014 23:46, Matt D. wrote:
> I have a monitor configuration with three 1920x1080 monitors aligned
> side-by-side horizontally with a fourth above the center. The primary
> monitor is the center one at the bottom. xinit generates a single screen
> 5760x2160 to cover the area. The root window is hidden and all windows
> in the buffer are drawn with native Windows decorations.
>
> When an X window is created at 0,0, it is visible on the primary
> monitor, despite 0,0 in the buffer being offscreen. This is great.
> However, when Wine creates a window at 0,0, it is aligned to 0,0 in the
> buffer (-1920x-1080 screen coordinates on Windows) and is not visible.
>
> Is there a solution for this? This is a discrepancy between what regular
> X windows do and where Wine positions its windows.
>
> I also noticed that when creating a window with XCreateSimpleWindow, the
> x and y coordinates are ignored. For example, I would expect a window
> created at 0,0 in the X buffer to be visible at 0,0 screen coordinates;
> but instead it's just somewhere offset slightly from the top left of the
> primary monitor. Any x/y coordinates specified do not seem to affect
> where it goes.

Normally, an X window manager ignores the x,y position specified for the 
window when it's created, and places the window according to some 
heuristic (for example, try to ensure that windows don't completely overlap)

The -multiwindow mode window manager defers to Windows native window 
placement (which appears to be something like placing the ith window 
created at x=y=30+26*(i%9))

But, if the PPosition or USPosition flags in WM_NORMAL_HINTS are set, 
the -multiwindow mode window manager places the window as requested.

(Most toolkits will set USPosition if you explicitly specify a window 
position e.g. using a -geometry option)

I guess that Wine is setting one of these flags so it can emulate 
Windows window placement.

> The behavior I would expect is for 0,0 in the buffer to be mapped to 0,0
> in screen coordinates, 1920x, 1080y in my configuration.

Unfortunately, X window coordinates are defined to be positive, with 0,0 
being the top-left of the desktop.

So, while you could do this with the -screen option (e.g -screen 0 @1), 
to move the origin to your primary monitor, windows which are moved to 
the left or above of that probably won't render correctly.

If you can't turn off the placement behaviour in Wine, perhaps the best 
compromise might be to use something like '-screen 0 5760x1080+0+1080' 
so you have an X desktop which covers the bottom 3 screens, and avoid 
moving X windows into the 4th screen?

> To clarify my use of Wine, I connected to a remote CentOS 6.5 machine
> via ssh with x forwarding for testing.
>
> Can anyone provide some insight on this?

There is some code in XWin which attempts to ensure that the window is 
placed somewhere visible, but that assumes that the Window virtual 
desktop is a rectangle of size GetSystemMetrics(SM_CXVIRTUALSCREEN) x 
GetSystemMetrics(SM_CYVIRTUALSCREEN).

I think it should be pretty straightforward to change this, perhaps to 
use MonitorFromPoint() to determine if the window will be visible on a 
non-rectangular virtual desktop.

-- 
Jon TURNEY
Volunteer Cygwin/X X Server maintainer

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