[Qgis-user] QGIS Qt6 Wayland ongoing status

[Nyall Dawson]

> Thanks very much for this detailed authoritative explanation, Nyall.  I
have a couple of specific comments below...

>  It's disappointing to read this as there's clearly a disconnect between
what e.g. QGIS developers are experiencing and what Fedora, Gentoo and
maybe others are saying about Qt5 and Wayland.  For example, this on the
Gentoo Wiki here https://wiki.gentoo.org/wiki/Wayland

That gentoo page is fairly optimistic in that it's considering wayland
support "complete" just because it works for common use cases.

>> For Qt an additional package called dev-qt/qtwayland is required. In the
Qt Wiki it says: "QtWayland is a Qt 5 module that wraps the functionality
of Wayland. QtWayland is separated into a client and server side. The
client side is the wayland platform plugin, and provides a way to run Qt
applications as Wayland clients. The server side is the QtCompositor API,
and allows users to write their own Wayland compositors."

This is definitely incorrect. Qt5 on wayland, regardless of whether or not
QtWayland is in play, will still be broken. It will "kind of" work in some
circumstances, but eg docks/toolbars are broken and will NEVER work
correctly under this setup.

> And this on Fedora here
https://fedoraproject.org/wiki/Changes/Qt_Wayland_By_Default_On_Gnome
>
>> Qt Wayland plugin has been available for a long time, but it hasn't been
in condition where it could be enabled by default. With Qt 5.12 the state
of the Wayland plugin is much better and it's becoming more and more
reliable.

"becoming more reliable" does not equate to "reliable" 🤣

>  It now supports all the needed protocols and has been enabled by default
for non-Gnome Wayland sessions. With Qt Wayland on Gnome Wayland session we
need to support CSD, it's actually the only way how decorations are going
to work in Qt apps right now. Qt Wayland implements basic decorations,
which really doesn't match Gnome Adwaita theme, therefore there are new CSD
being implemented as part of QGnomePlatform.
>>
>> To make Qt applications run natively on Wayland we need to modify Qt 5,
specifically qt5-qtbase module, where we allow the Wayland plugin to be
used also for Gnome sessions. The new decorations from QGnomePlatform will
be used automatically once they are fully implemented and updated in Fedora.
>
> (the above dated 2019!!!)

Right, but that's all focusing on a very narrow topic -- getting client
side decorations working under wayland and allowing Qt applications to
open. Once again, trying to use anything but a very simple single window /
"hello world" type application will quickly run into breakage. That
particular page is written from a "running Qt apps on Wayland under gnome"
viewpoint, and isn't trying to consider the lower lying topics about
getting full functionality for any qt app (on any platform) working under
Wayland.

>>
>> Read about the sorry state of it here:
https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/247
>
>
> An exceptionally informative pull request.  I was particularly struck by
this comment:
>
>>  Of course you could argue that all of these applications should be
rewritten from the ground up, but especially in science this is not
feasible - people will use X11 indefinitely rather than going to Wayland
with a much degraded user experience.
>
>
> Maybe it's just me, but I have to think that the lack of a placement
protocol (when X, Windows and OSX all support this) is a design mis-feature
in Wayland, rather than a decision taken to guide the architecture of
future desktop applications...

I should have linked to the original posting relating to this (couldn't
find it yesterday). Here's the full gory details:
https://blog.tenstral.net/2024/01/wayland-really-breaks-things-just-for-now.html


Nyall



>
>>
>> So yeah, not a happy situation. At least on the QGIS side we're making
progress toward Qt 6 compatibility, and that's all we can really do from
our end.
>
>
> Well as always, extreme thank-yous to all QGIS developers.  And again the
information you provide here is very valuable at least to me, so thanks
again for taking the time to write this!
>>
>>
>> Nyall
>
>
> [previous stuff deleted]
>
>
> --
> Chris Hermansen · clhermansen "at" gmail "dot" com
>
> C'est ma façon de parler.
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