[Qgis-user] QGIS Qt6 Wayland ongoing status

[Andreas Neumann]

Hi Chris, Adam and others,

I am not the technical person to answer details, but I am on the QGIS 
PSC and can assure you that building QGIS on Qt6 is high up on our 
priority list (for at least a year or even longer). You can already 
build QGIS fine on Qt6 (for at least 2-3 versions now) but the core devs 
came across some blockers that had to be solved first, before we can 
bring this to the end users without major regressions:

  	* isues around qt3d and webengine compatibility (one could either use 
3D or the webengine, not both together)
  	* issues around the fact that Qt webengine cannot output HTML/web 
output to vectors when rendering to PDF
  	* PyQt6 bindings had to be done

While the first issue is already solved, the 2nd issue is currently 
being solved by introducing another library 
(https://github.com/JakubMelka/PDF4QT) and the third item is roughly 2/3 
done and still actively being worked on.

Then there is the issue that all QGIS plugins have to be migrated to 
PyQt6 ...

We will probably offer QGIS Qt6 builds as technology previews soon in 
parallel to the normal Qt5 builds.

Now - about wayland: all of this has really nothing to do with Wayland 
but has to be done anyway, because Qt5 isn't developed any further and 
QGIS.ORG already invested in Qt6 improvements from which we cannot yet 
take advantage of until we ship with Qt6.

Moving QGIS to Qt6 doesn't automatically mean that all QGIS wayland 
issues are solved - but probably quite a few of these issues.

Hope this clarifies the situation? If you want more detailed, more 
technical responses, I recommend discussions on the QGIS developers 
mailing list. It would only bore regular QGIS users ...

Greetings,

Andreas
QGIS.ORG treasurer and PSC member

> I don't know if you have recently run QGIS on a Wayland desktop, but 
> there is a stern message strongly suggesting reverting to X.
> 
> So as we seem to be marching away from X and ever forward to Wayland, I 
> would like to start planning ahead a bit, and I would especially like 
> to find some real information, as opposed to "I think this (but I 
> really don't know)", or even worse, the people who can see a bright 
> future for (let's say) Wayland-only desktops and aren't worried about 
> the bumps on the road getting there.
> 
> Fortunately it seems Ubuntu 24.04 will continue to support X 
> https://discourse.ubuntu.com/t/ubuntu-desktop-24-04-lts-roadmap-highlights/41032 
> so in my case at least I know I can drop back to X if / as necessary 
> for the immediate future.
> 
>>> There is some stuff on GitHub but it seems to be at least a year or 
>>> two
>>> old, talking about Qt6.0 and I gather we are at Qt6.6 by now.  Plus 
>>> endless
>>> short conversations in places like Reddit that throw off more heat 
>>> than
>>> light.
>> 
>> Updating to a new Qt version is likely going to be a lot of work, sot
>> imagine nobody is that keen on starting until there's really no 
>> choice.
> 
> As it happens, a search for qt6 in the QGIS repo on GitHub shows work 
> being done on qt6, apparently for QGIS 4.  So maybe someone has started 
> already?  I wonder how that's going?
> 
>>> Does anyone have any suggestions as to where to keep informed on this
>>> topic?  Because it seems like Wayland is coming whether we want it or 
>>> not...
>> 
>> Wayland has been around for many years at this point, and is already 
>> the
>> default on some Linux distributions, which have no problem running
>> QGIS.  There is so much legacy code that they are always going to have
>> compatibility modules to keep non-Wayland programs usable.  I wouldn't
>> worry about any programs suddenly breaking due to Wayland.
> 
> While I appreciate your attempts to reassure me, this isn't helping.
> 
> I'm aware from firsthand experience that Wayland has been around for 
> many years at this point.  I have even used it on and off.  In fact 
> it's my daily driver on my laptop.
> 
> My concern is learning how QGIS development might converge - or not - 
> with a Wayland-only future, since it seems several important Linux 
> distros are leaning away from supporting X to some degree or another.
> 
> As to whether QGIS might break under Wayland, there are 31 issues in 
> the QGIS repo as of this evening related to Wayland in some form or the 
> other.  Plus the warning I mentioned above.
> --
> 
> Chris Hermansen · clhermansen "at" gmail "dot" com
> 
> C'est ma façon de parler.
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