Re: Change to NS drawing routines

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 13 Aug 2018 20:36:04 +0100
> From: Alan Third <alan@idiocy.org>
> Cc: charles@aurox.ch, emacs-devel@gnu.org
> 
> > > from http://lists.gnu.org/archive/html/emacs-devel/2013-04/msg00435.html
> > > 
> > > I can understand the argument to an extent, but I don’t have another
> > > solution.
> > 
> > We could discuss this again, perhaps the details have changed, or we
> > might be able o find some compromise everybody can live with.
> > 
> > For starters, what changes, if any, would you need to make in the
> > glyph matrices, and why?
> 
> For this none, I can do it all in the NS specific code.
> 
> I’ve changed all the NS drawing functions to check whether they are
> allowed to draw. If not then I mark the area as dirty.
> 
> I’ve added an ns_flush_display function that I believe is called at
> the end of redisplay (flush_frame). I wasn’t sure about this but it
> looks as though it works, (i.e. everything draws OK) so I assume it’s
> safe.
> 
> Anyway, ns_flush_display asks Cocoa/GNUstep to redraw the frame, which
> results in drawRect being called which calls expose_frame on the
> rectangles that have been marked as dirty.

In that case, I don't see why would I object.  My objection was to
introducing platform specific stuff into platform-independent code in
xdisp.c and dispnew.c, and/or into data structures these files use as
part of the display engine.  By contrast, it sounds like you just
caused the expose event to be triggered under special circumstances,
perhaps much more frequently than before, but when exactly the expose
event comes in on different window-systems is not something that is
against Emacs expectations, and certainly doesn't bother me.

Thanks.