bug#57639: [PATCH] Add new command 'toggle-theme'

[Po Lu]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Philip Kaludercic <philipk@posteo.net> writes:
>
>>> I thought we already had support for this under Gtk?  But I may be
>>> misremembering.
>>
>> Am I reading it correctly that `style_changed_cb' in gtkutils.c would be
>> a place to start looking for this functionality?
>
> Ah, yes, I think that's the one...  Po Lu probably know more about this;
> added to the CCs.

What exactly is the wanted feature?

If it's automatically switching between dark and light themes, then
style_changed_cb is probably not the right place.  It's mostly vestigial
code from when we used to update the region face along with the GTK
stylesheet.  Instead, TRT used to be to listen for changes to the
`gtk-application-prefer-dark-theme' property of the GtkSettings object.

However, that has been superseeded by a dbus based interface in recent
versions of GNOME.  I do not understand the details, but it seems like
it could be implemented in Lisp:

  
https://flatpak.github.io/xdg-desktop-portal/#gdbus-org.freedesktop.portal.Settings