absolute positioning and other "missing features" of Wayland

[Carsten Haitzler]

On Mon, 22 Feb 2021 12:14:56 +0200 Pekka Paalanen <ppaalanen at gmail.com> said:

> On Fri, 19 Feb 2021 11:46:56 -0800
> Dima Ryazanov <dima at gmail.com> wrote:
> 
> > Most Wayland compositors support XWayland, and therefore, are ok with
> > applications using absolute positioning
> 
> Hi,
> 
> I don't think that is exactly true. With rootless Xwayland (the usual
> case), the Wayland compositor also takes the explicit role of the X11
> window manager through X11 protocol. This is even how X11 is intended
> to work and not some backdoor. Therefore, the Wayland compositor is
> still in full control of all window management, including positioning,
> even if X11 exposes a global coordinate system to X11 applications that
> the Wayland compositor needs to fake.

Kind of true... but override-redirect windows will bypass that positioning
control the WM has... it's common to abuse these for all sorts of fun and
games.

> If Wine could really benefit from some optional hand-holding, I think
> it would be okay to have a Windows-specific interface to help fill the
> gaps. It wouldn't be that different from what Wayland compositors need
> to do today to support Xwayland; a foreign window system integration.

I also would want to avoid baking explicit absolute positioning into wayland
protocol - be it as a core agreed to add-on to xdg-shell or even a "commonly
supported extension". What I'd like it some better solution. For example - if
an app wants to absolute position a window because it's doing a custom "my own
notification popup" much like Chrome and Firefox now like to do in X11, then I'd
prefer this be explicitly exposed as a "notification surface with requested
screen location hints" and so the compositor can decide to do something more
intelligent with it. I am sure this list of use cases will probably be
extensive and also depend on the API in wine that is being wrapped and
intercepted - the higher level it is, the more it knows about the intended use
case.

> Even better if that's not necessary.
> 
> 
> Thanks,
> pq


-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
Carsten Haitzler - raster at rasterman.com