Re: Weird font problem

[Eli Zaretskii <eliz@gnu.org>]

> From: Joost Kremers <joostkremers@fastmail.fm>
> Cc: help-gnu-emacs@gnu.org
> Date: Wed, 05 Jun 2024 22:59:51 +0200
> 
> On Wed, Jun 05 2024, Eli Zaretskii wrote:
> > Does Vertico display the character of the preview's current line in
> > some special face, like bold or italics?  If so, it could be that the
> > font used to show these symbols doesn't have the variant needed for
> > that display.
> 
> I realised that I don't only have vertico, I also use marginalia, which is
> responsible for the faces. Disabling marginalia (but keeping vertico) gives a
> much more spartan look, but the issue remains:
> 
> Moving the highlight still changes the characters to the box with hex
> codepoints, and taking a screen shot changes all of them (with no way of getting
> back the characters).

Then maybe we need to move all this to the bug tracker?  Please submit
a bug report with all the details.  Bonus points for being able to
show a recipe to reproduce the problem starting from "emacs -Q" (and
loading any add-on packages needed for reproduction).

> Vertico doesn't apply any special faces to the candidates, it just uses the
> 'highlight' face for the current selection, which only specifies a background
> colour.

Can you reproduce this in "emacs -Q" with only Vertico loaded?

> > Did you try to use a different font for this range of characters?
> > Like Symbola, for example?
> 
> I'm not sure how to do that.

Using set-fontset-font.

> > Does Emacs have problem displaying these characters in situations
> > other than Vertico completion preview?
> 
> I mentioned Vertico because that's actually the only time the characters are
> displayed. Anywhere else, e.g., if I insert them into a buffer, they
> always appear as hex boxes.

So something Vertico does is special, if it has this effect.  And the
fact that you see these characters as hex codes elsewhere basically
means that you lack a font for displaying these characters reliably.
So maybe, instead of trying to understand how Vertico succeeds to pull
this trick, you should find and install a font capable of displaying
those characters when inserted into a "normal" buffer?