On Wed, Apr 29, 2020 at 10:03:00PM +0300, Eli Zaretskii wrote:
> > Date: Wed, 29 Apr 2020 20:51:28 +0200
> > From: tomas@tuxteam.de
> > Cc: emacs-devel@gnu.org
> > 
> > > That's not how Emacs controls what's on display.  It basically
> > > represents each window as a 2D array of glyphs, each one of which has
> > > a certain graphical representation.
> > 
> > ...a display list of sorts.
> 
> It's a far cry from any "list" in my book...

Don't take the "list" too literally. I was possibly misusing (by
extension) some now-obsolete graphics jargon.

> > I think the "interesting" problem is to know (quickly) which
> > graphical objects intersect the (visible) window -- something
> > graphics programs do as their main job.
> 
> That's easy, we have infrastructure for that already -- it is used in
> expose_frame and its subroutines.

This sounds... encouraging :-)

(TBH I was coming from the other side: index the graphics objects
in a way that one doesn't need to look at most of those which
are currently hidden).

Cheers
-- t