GNOME+Wayland: Adwaita decorator hides text in QMessageBox, aboutQt, etc.

ridderhoff

With Wayland GNOME (40.4 RHEL 9.8), using the default Qt Adwaita window decorator the text in QMessageBox overflows and gets hidden (and not resizeable). This is definitely a bug that should get fixed (if not already fixed in upstream), but at least it's easy for me to work around with QSS or even just adding newlines to the end. However, I found that the same bug also impacts the QApplication::aboutQt() dialog (entire last line truncated) and I have no clue how to fix that one.

alt text

So far I've only seen this with the Adwaita wayland client decorator, however, I can't use the radient decorator as it doesn't add borders, shadows, etc. making it basically unusable with stacked windows and susceptibility to migraines. Is there a fix/workaround for this or is my only option to force xcb on wayland?

I mostly use C++ but here's a pyqt6 demonstration:

import sys
from PyQt6.QtWidgets import QApplication, QMessageBox

app = QApplication(sys.argv)
app.aboutQt()
QMessageBox.question(
    None, 
    "GNOME40 RHEL 9.8 PyQt6.10.2 / Qt6.6.2", 
    "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
)

ridderhoff

Also is there a way to get native window drop shadows in wayland gnome with Qt6?

IgKh

Regarding QMessageBox text overflow, there was this ticket: https://qt-project.atlassian.net/browse/QTBUG-137253. It was closed due to lack of reproducibility since at least Qt 6.9.2. I also cannot reproduce any issues with Qt 6.11.1 under GNOME 50 in Arch Linux with your code sample. I'm not sure how Qt is packaged in RHEL, but be sure that you are using the Adwaita decorations plugin from the upstream qt6-qtwayland package.

@ridderhoff said in GNOME+Wayland: Adwaita decorator hides text in QMessageBox, aboutQt, etc.:

So far I've only seen this with the Adwaita wayland client decorator, however, I can't use the radient decorator as it doesn't add borders, shadows, etc. making it basically unusable with stacked windows and susceptibility to migraines. Is there a fix/workaround for this or is my only option to force xcb on wayland?

Not use GNOME, or not use Qt. Yes, seriously. Qt's client side decorations plugins for Wayland exist because all Wayland applications must be able to draw their own decorations according to the basic protocol rules, but they are just a fallback.

Qt, across all desktop platforms, was made with the position that window decorations are the responsibility of the window manager / platform as they are key part of the consistency of a GUI platform's user experience. GNOME's developers however won't even entertain the concept of Server Side Decorations, and refuse to implement the relevant Wayland protocol. My understanding of the project's position is that applications that want to have good window decorations (or work well in the environment in general) must be built with libadwaita; the existence of any other application toolkit is an afterthought at best.

Whatever Qt can provide will always be playing catch-up. It is not that it can't be improved, just that it needs someone who cares about it enough to keep at it for a long time.

You can indeed force going through XWayland (where Mutter has no choice but to provide server side decorations), or perhaps see if KDE or COSMIC are to your liking.

ridderhoff

I installed Qt 6.11.1 with the maintenance tool and made a simple C++ aboutQt() demo RHEL9. I then used patchelf --set-rpath and LD_DEBUG=libs to confirm that it was not using the system's Qt 6.6.2 libraries. The text clipping bug was still present. So maybe the underlying problem is/was a change/bug in Gnome/Mutter/Wayland/etc.? The EPEL package for qt6-qtwayland doesn't include the adwaita decorator despite having it set as the default. So maybe it's something they knew about.

$ cat demo.pro
TEMPLATE = app
QT += gui widgets core
SOURCES += main.cpp
TARGET = demo

$ cat main.cpp
#include <QApplication>
int main(int argc, char** argv) {
    QApplication app(argc, argv);
    app.aboutQt();
}

$ /opt/Qt/6.11.1/gcc_64/bin/qmake
$ make
$ patchelf --set-rpath "/opt/Qt/6.11.1/gcc_64/lib:/opt/Qt/6.11.1/gcc_64/plugins" ./demo
$ LD_DEBUG=libs ./demo 2>&1| grep adwaita
calling init: /opt/Qt/6.11.1/gcc_64/plugins/wayland-decoration-client/libadwaita.so

I also don't experience the text clipping issue on Arch, but it would be nice to have drop shadows. Totally understand your points about GNOME devs randomly removing things and not providing workarounds (don't get me started on tray icons). Unfortunately I've given up on trying to convince everyone to use tiling WMs and RHEL9 w/ GNOME is something I'm required to support.

I think xcb is fine but do you have any pointers for dynamically picking the right platform plugin / decorator to use? Or maybe I should just assume Wayland users have xwayland installed.

IgKh

Yes, your setup seems alright. Do note that the ticket was closed due to lack of reproduction, not due to a fix being made. It is quite possible that the bug is there, but not on all distributions. I'd suggest commenting there with your own findings, and you might want to tag Jan Grulich as well.

Assuming that users have XWayland installed anyway is a safe assumption, and will probably keep being so for at least a few more years.

SGaist

Hi,

Did you set the QT_DEBUG_PLUGINS environment variable to 1 before starting your application ?
It might give you additional clues.