Fullscreen windows with geometry smaller than the output are positioned incorrectly

[danielfrrrr]

...these windows are incorrectly positioned in the top left corner and leaking windows in the background.

Can be reproduced with weston-simple-egl -f -r (well, not entirely. for some reason, the weston-simple-egl is centered, but older games running through winewayland.drv are positioned in the top left corner):

This behavior is out of specification.

	If the surface doesn't cover the whole output, the compositor will
	position the surface in the center of the output and compensate with
	with border fill covering the rest of the output. The content of the
	border fill is undefined, but should be assumed to be in some way that
	attempts to blend into the surrounding area (e.g. solid black).

So the window should be positioned in the center and have a solid black background (this is what COSMIC, GNOME, Niri and Weston do). Optionally, protocol viewporter can be used to scale and fill the window for output resolution (this is what Weston does. Some windows, specifically Wine windows, seem to be scaled by Weston).

And a quick note: Personally, I don't use hyprland. The issue that this affects several older games running through winewayland.drv: https://bugs.winehq.org/show_bug.cgi?id=57456. The main developer of winewayland.drv commented that Wine expects the compositor to comply with the specification, so I believe that Wine will not fix this issue on their end, which is why I am reporting this issue to the most popular compositors.

And the advantage of using protocol viewporter for this is that it will also fix this issue: https://bugs.winehq.org/show_bug.cgi?id=57925. In addition to not having black borders, which I personally think is better!

[danielfrrrr]

A better screenshot of the issue:

[vaxerski]

how can I build the weston app? Is it in weston or a separate repo?

It'll be much easier to fix with a repro case

[danielfrrrr]

that in itself is not a protocol violation

So "transparent" is completely fine by spec

Well, really! So I guess this issue is only about winewayland.drv.

How do I use winewayland.drv in arch? Is latest wine with no xwayland enough or do I need some fork

Just use the latest version of Wine and unset the DISPLAY environment variable, like DISPLAY= wine ./game.exe or env -u DISPLAY ....

[danielfrrrr]

Just commenting to remind you to test it, if possible!

[vaxerski]

thanks, forgot.

[vaxerski]

game I tested has horribly broken damage tracking but other than that I can't see the positioning problem. It's even worse on sway:

for now, I'd really blame wine wayland. It's experimental for a reason...

[danielfrrrr]

I tested SWAT 4 on several compositors and the only ones that don't center the window are hyprland, labwc, and sway. So I don't think it's Wine's fault. I mean, Wine could fix it, but unfortunately I don't think they will, because the main developer of winewayland.drv said that Wine expects compositors to comply with the specification. Since it seems that hyprland already follows the specification, so it may be a specific issue with SWAT 4 (?).