bug#57781: missing wallpaper command

[Stefan Kangas <stefankangas@gmail.com>]

Felix <felix.dick@web.de> writes:

> Neither swaybg nor wgb is running under gnome-shell with wayland.
> Gnome has it's own way of setting wallpapers.
> As kind of expected wbg depends on wlroots i guess.
> I'm not shure how to check which wm/desktop is running.

Does that mean that setting the wallpaper using `wallpaper-set' doesn't
work when running gnome-shell under Wayland?

If you still have access to it, what is the value of the environment
variables $XDG_CURRENT_DESKTOP, $WAYLAND_DISPLAY and $SWAYSOCK in this
configuration?

If you like, perhaps you could send the output of the `env' command to
me privately.  Just edit out anything sensitive before sending it.

> wmctrl would be very usefull, but there is not garantee for it to be
> installed.

Thanks, I did not know about wmctrl.  I took a look at its website

    https://sites.google.com/site/tstyblo/wmctrl

but I could not find any way to set the wallpaper using it.  Maybe I
missed it.  Do you know if it can be done, and if so, how?

(We can check if it installed with `executable-find'.)

> Another point is that:
> ("gsettings" "set" "org.gnome.desktop.background" "picture-uri" "file://%f")
> only effects the light scheme of gnome.
> If you want to change the wallpaper of the dark scheme
> ("gsettings" "set" "org.gnome.desktop.background" "picture-uri-dark" "file://%f")
> is the command.
> 'gsettings get org.gnome.desktop.interface color-scheme'
> can be used to check which of both schemes is active.
> It returns either 'prefer-dark' or 'prefer-light'
> One could think about setting the wallpaper for both themes, or
> only for the active color-scheme.

Hmm, this is interesting.  It is clear that we need to extend
wallpaper.el to run another command first, to decide which command
should be run in various situations.  I will look into it.

> I can check KDE later, but I don't expect wgb or swaybg to work there.

That will be much appreciated.

Thanks for all of the above, this is very useful.