Re: Emacs canvas support

[Eli Zaretskii <eliz@gnu.org>]

> From: Arthur Miller <arthur.miller@live.com>
> Cc: tomas@tuxteam.de,  emacs-devel@gnu.org
> Date: Thu, 30 Apr 2020 16:58:10 +0200
> 
> > For example, if the window scrolls, wouldn't you want
> > the graphics drawn by these pre/post-renderers to move on display as
> > well, at least sometimes?  If you do, how can you do that without
> > knowing some details about the scroll?
> Of course. Wouldn't came out automatically, by redisplay engine as it
> already is?

No, of course not.

> No I didn't, I had in mind to redraw stuff, so user can draw below or
> above whatever Emacs normally draws.
> 
> Yeah sure if user chooses to draw two different text buffers on top of
> each other it would be a mess, but I don't think that is an issue
> because, normally, probably nobody want's to draw to text files on top
> of each other.

I think what you describe doesn't fit with how the redisplay works,
but I'm probably missing something, since Stefan also thinks this
could work.