bug#47291: bug#51404: Support system dark mode on Windows 10

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> I'm not sure I understand why 'light' necessarily means the old
> behavior: we didn't set any theme before this change, we just used the
> Windows default.  So maybe there should be 4 values:
>
>   nil: never follow the system theme (use Windows default)
>   t: always follow the system theme
>   light: force light theme (currently the same as nil)
>   dark: force dark theme.

For a similar bug report, see bug#47291.  And we really should support
this on GNU/Linux, too, so having three different methods to support
this seems sub-optimal.

dynamic-setting.el seems like the most likely place to centralise all
this, I think?  I've had a look at what happens when you change the
theme in Gnome, and dynamic-setting-handle-config-changed-event gets
called with an

 (config-changed-event theme-name ":1")

event.  (But not what the event name is -- anybody know how to get at
that?)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no