Re: High-res Customize icons

[Eli Zaretskii]

> Date: Thu, 23 Apr 2020 19:49:51 +0200 (CEST)
> Cc: address@hidden, address@hidden, address@hidden,
>  address@hidden, address@hidden, address@hidden
> From: Werner LEMBERG <address@hidden>
> 
> > So installing an additional font (or a set of them, actually --
> > won't we also need bold, italic, etc. variants?) affects the entire
> > system and affects Emacs itself, by adding a font that isn't really
> > meant to be used for displaying readable text in any script.  It's a
> > trick that we would use to work around the need to display an image.
> > I'm asking whether this is such a good idea?  Won't this font get in
> > the way?
> 
> I think it is a good idea.  Today, OpenType fonts are standard on all
> major platforms;

That's not exactly why I asked whether it's a good idea.  I'm asking
whether it's a good idea to use characters as if they were small
images.  That is not what fonts were designed for, and that is
definitely not what font-selection code in Emacs was designed for.

> To conform to the standard, glyphs that are not in Unicode would be
> put into the PUA (Private User Area), again ensuring that there are no
> conflicts with other applications.

I'm very much against using PUA codepoints for this purpose (or any
purpose, really) in Emacs.  To say nothing of the fact that we
currently simply cannot.  That's a non-starter, from my POV.

> > What other applications are known to come with their own fonts and
> > install them into the global font space of the system?  Is this
> > considered a good practice?
> 
> Well, on MacOS and GNU/Linux, it wouldn't be necessary to install the
> font globally; instead, the Emacs binary can programmatically add a
> local directory to the list of font directories scanned by
> fontconfig.

Don't you also need to run fontconfig to pick that up?  Won't that be
a complication for users?

>   
> https://docs.microsoft.com/en-us/windows/win32/directwrite/custom-font-sets-win10

We don't (and won't) use DirectWrite.  We've switched to using
HarfBuzz, a free shaping engine, for that reason (and many others).

Anyway, I th9ink you understand by now that I dislike this idea, and
prefer to use image files.  Let's leave the characters and their
glyphs for what they were intended: text.