bug#9366: Display geometry change hook

[Eli Zaretskii]

> Cc: larsi@gnus.org, david@harpegolden.net, 9366@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Wed, 23 Sep 2020 09:15:16 +0200
> 
>  > Do we use XRANDR to query the display geometry?
> 
> If they are available, Emacs tries XRANDR first and, if that fails,
> XINERAMA next.

Then maybe the proposed method is not a big deal.  But I'd like to
understand the situation on macOS first -- is there an equivalent
feature there?

>  > I didn't mean MS-Windows events (a.k.a. "messages"), I meant events in
>  > the Emacs event queue.  A message coming from the window manager
>  > doesn't have to be converted to an Emacs event, it can be handled
>  > directly.
> 
> You mean that we'd have to put a function running the hook into the
> event queue when no input is allowed?

Sorry, I don't think I understand this.  Can you explain what you
mean?

> And running 'gui_set_fullscreen' OTOH can be handled directly?

We already do that, no?