Re: High-res Customize icons

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: cpitclaudel@gmail.com,  emacs-devel@gnu.org
> Date: Thu, 23 Apr 2020 16:33:05 -0400
> 
> Other than the problems already mentioned with our SVG support, there's
> also the fact that we don't have any way currently to auto-scale an
> image according to the current face nor do we support using different
> sizes for the same image displayed simultaneously in different frames.

Then let's develop these facilities.  It shouldn't be hard, we already
have most of the infrastructure for scaling images.

It is IMO wrong to revert to tricks instead of adding the required
infrastructure to TDRT.  I can understand why authors of third-party
packages, who can only work in Lisp, use these tricks, but we
shouldn't base core features on such tricks.  They will cause us
trouble down the road.  E.g., what do you think about this advice on
the all-the-icons site:

  (set-fontset-font t 'unicode (font-spec :family "all-the-icons") nil 'append)

Do we really want to tell users to do that?  I shudder by just
thinking what font-related bug reports this will cause.

It's simply wrong to use fonts for these matters.  I very much hope
that we don't go down this road.  FWIW.