bug#28872: 26.0.90; non-native-fullscreen does not play well with ns-transparent-titlebar on macOS

[Alan Third <alan@idiocy.org>]

On Fri, Oct 20, 2017 at 07:35:35AM -0400, Aaron Jensen wrote:
> On October 19, 2017 at 4:17:13 AM, Alan Third
> (alan@idiocy.org(mailto:alan@idiocy.org)) wrote:
> 
> > Non‐native fullscreen uses another NSWindow (like we were discussing
> > for undecorated frames), so when it switches back out of fullscreen it
> > changes back to the original NSWindow.
> 
> Oh, why is that? I believe that is the time that iTerm2 does not
> create a new window. It sets borderless and resizes to full screen. If
> that were done instead, would it help with the toolbar issue?

Yeah, we could probably do it without creating a new NSWindow for
macOS and I think it would be better behaved, but GNUstep doesn’t
allow you to change the styleMask at all so it still needs to do the
new NSWindow thing.

In order to use lisp to do the fullscreen thing we’d need to keep
track of various ‘windowed’ frame parameters, ie. undecorated, width,
height, origin, maybe others. I assume it would be OK to stick them
into the frame-parameters alist under a special key, so we know where
they are when we want to switch back.

Anyway, I’ve pushed a fix for this particular issue. It does produce
another odd bug, though:

Set non‐native fullscreen, turn off the toolbar, switch to fullscreen
then back to windowed, re‐enable the toolbar and watch a gap appear
between the top of the Emacs window and the toolbar.

It’s weird, but harder to cause than the current bad behaviour.
-- 
Alan Third