Qt 6.6 Wayland Compositor Handoffs Look Promising For More Robust Experience

[phoronix]

Phoronix: Qt 6.6 Wayland Compositor Handoffs Look Promising For More Robust Experience

KDE developer David Edmundson has written an interesting blog post looking at robustness improvements coming with Qt 6.6 via QtWayland compositor handoffs support...

https://www.phoronix.com/news/Qt-6.6-QtWayland-Handoffs

[avis]

I vaguely remember the feature was first offered and demonstrated over a year ago, are they still hacking it? That's weird.

[slalomsk8er]

Since Enlightenment17 I missed this feature in my window managers.

[skeevy420]

Every release has a killer feature. Qt 6.6 features the opposite - staying alive.

[Vistaus]

Every release has a killer feature. Qt 6.6 features the opposite - staying alive.

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[bug77]

Wth, so to make Wayland work, Kwin is not enough and another compositor in Qt is needed?

[Mitch]

Wth, so to make Wayland work, Kwin is not enough and another compositor in Qt is needed?

I read "new compositor" as a new Kwin instance in the event that an old one crashes. I think all this work makes the migration smoother when Kwin crashes and we need a brand new Kwin instance to migrate to.

[bple2137]

Wth, so to make Wayland work, Kwin is not enough and another compositor in Qt is needed?

No, the titles says about feature implemented in Qt 6.6 called Wayland Compositor Handoffs, that makes Qt6 Wayland clients not die when the compositor is being killed/crashes. Instead they reconnect to a newly started compositor instance - as the video demonstrates. The feature was actually proposed and PoC was presented quite a lot of time ago, but it wasn't universally praised. GNOME/GTK devs (ahh, because who but them) said they don't want that, it's pointless and instead KDE devs should make their compositor to not crash.

[fallingcats]

Wth, so to make Wayland work, Kwin is not enough and another compositor in Qt is needed?

I think you severely misread how it works. Basically there is now a tiny binary that restarts kwin in case it crashed. The changes in QT are needed so applications know to reconnect in case the compositor crashed. That's it.

Like mentioned in the blog post, this is less lines of code than was needed to get middle-click paste to work.

[Arthus]

I recommend everyone reading the complete blog post. There are even cooler features enabled by this than just surviving a crash of the compositor:

Runtime switching between different compositors:

https://www.youtube.com/watch?v=JYfzAuRmBjo

Saving and completely restoring graphical (all?!) programs to disk and resuming:

https://www.youtube.com/watch?v=bWWQT3HamBw

Makes me think of the first 12 seconds of this:

https://www.youtube.com/watch?v=hFDcoX7s6rE