While resizing Qt apps window contents jitter about erratically (including during animations)

Hmm, resizing slowly you can also see the dash itself is to blame. It's choosing slightly different icon positions as the window size changes.

Aha! Seems the problem is limited to Unity8-dash.

QtMir is resizing my demo clients perfectly smoothly:
sudo mir_demo_client_egltriangle -m /var/run/user/1000/mir_socket -- --desktop_file_hint=unity8
sudo mir_demo_client_fingerpaint -m /var/run/user/1000/mir_socket -- --desktop_file_hint=unity8

> It's choosing slightly different icon positions as the window size changes.
Yes, that's how resizing in the real world behaves, noone wants nor likes opaque resizing.

Nothing else in the real world resizes as poorly as the dash does. I'm not sure what you're talking about.

Moving icons by whole rows to fit new rows is fine. Moving them by single pixels during resizing is what's happening though. And that's obviously a bug.

We've just (as in a few hours ago) improved the performance of dash resizes, try it again please.

As for "moving by single pixels", it's rather a design decision whether you wan the items spread out evenly or on a predefined grid.

I kind of understand what you're trying to do. However it will look bad in environments where the user can live-resize the window. Leave this bug open and you'll eventually just find real users reporting the same complaint.

Sadly I can't log in to Unity8 at all today to test the new version. It's crashing instead (looks like bug 1535297 but happens immediately on login).

For an example of a nicer alternative, just open nautilus in Unity7 (or Windows or a Mac), set the view to icons and resize the window.

Finally got logged into Unity8. And after a full system update I can confirm nothing has improved.

Not sure if that will be any help with fixing the bug but I've noticed the problem is only with right and bottom border of an app window. The top and left are fine whatever side I start resizing from. Also it looks like the title bar does not stutter when resizing, just the rest of the window. I've recorded a short video about it: https://youtu.be/3H48UBpXUUo

Status changed to 'Confirmed' because the bug affects multiple users.

Does it look any better when you resize the same app in Unity 7? If not, I would say it's a problem in Qt, that it's not repositioning and resizing its internal items as fast/smoothly as expected in response to a window resize.

This is how it looks when I start an app from SDK on desktop running 16.04 and resize it: https://youtu.be/qP0ZI28wtUg So basically there's no 'live' update, the window just 'jump' to a new size.

dandrader:

Unity7 avoids 90% of the problem and is usually smooth resizing the same Qt apps. Although 10% of the time the bug is still visible in Unity7 too.

So there are two problems:
  1. Qt apps resize much more poorly than non-Qt apps (just Ubuntu Qt apps??)
  2. Unity7 resizing any window is much smoother than Unity8 resizing the same app.

Status changed to 'Confirmed' because the bug affects multiple users.

I'm experiencing this bug on Yakkety.Video attached

I think the web browser's resizing is uniquely broken in ways not seen in other apps. It might be better to discuss browser resizing in bug 1585278 instead.

Not a Unity8 bug. Qt apps are equally jittery in mir_proving_server.