Calibre does not start in Wayland (Linux)

[inte]

I've installed the latest release:
$ calibre --version
calibre (calibre 3.11.1)

I'm running KDE on Wayland (instead of X11). I have Xwayland installed in order to run X11-only programs like e.g. Firefox.
Starting calibre results in a failure:
$ calibre
This application failed to start because it could not find or load the Qt platform plugin "wayland"
in "".

Available platform plugins are: linuxfb, minimal, offscreen, xcb.

Reinstalling the application may fix this problem.


Normally, Calibre should come up in its own Xwayland instance if Wayland ist not supported. In this case, as Qt-app, it should support wayland out of the box if the appropriate platform plugin was installed.
However, as the plugin appears to be missing, I have no idea why it wouldn't come up in Xwayland then (or how to configure that). Is this a misconfiguration?
Thank you in advance.

[sjfan]

Originally Posted by inte

I've installed the latest release:
$ calibre --version
calibre (calibre 3.11.1)

I'm running KDE on Wayland (instead of X11). I have Xwayland installed in order to run X11-only programs like e.g. Firefox.
Starting calibre results in a failure:
$ calibre
This application failed to start because it could not find or load the Qt platform plugin "wayland"
in "".

Available platform plugins are: linuxfb, minimal, offscreen, xcb.

Reinstalling the application may fix this problem.


Normally, Calibre should come up in its own Xwayland instance if Wayland ist not supported. In this case, as Qt-app, it should support wayland out of the box if the appropriate platform plugin was installed.
However, as the plugin appears to be missing, I have no idea why it wouldn't come up in Xwayland then (or how to configure that). Is this a misconfiguration?
Thank you in advance.

Try setting the QT_QPA_PLATFORM="xcb" environment variable. For instance, run this from the command-line (all one line):

QT_QPA_PLATFORM="xcb" calibre

[inte]

That worked, thank you. Calibre does now start in Xwayland. It would be nice if it was possible to include wayland-support in the official build to allow calibre to run under wayland natively (since most distros are implementing wayland now).
Thanks,
-inte-

[kovidgoyal]

Currently the official build is restricted to Qt 5.6 to allow it to work on older distros. When it is bumped up, I will include the Qt wayland plugin. But, IIRC the wayland support in 5.6 was very buggy. Basic things like popup menus did not work correctly.

[inte]

Originally Posted by kovidgoyal

Currently the official build is restricted to Qt 5.6 to allow it to work on older distros. When it is bumped up, I will include the Qt wayland plugin. But, IIRC the wayland support in 5.6 was very buggy. Basic things like popup menus did not work correctly.

Thank you for the explanation!
No hurries, it is eventually working with this workaround and when it's ready, it' will be ready :-)