Subject: Re: bug#44664: 28.0.50; troubles with some chars in term

From: Lars Ingebrigtsen <[email-masked]>
Date: Wed, 25 Nov 2020 07:55:13 +0100

Eli Zaretskii <[email-masked]> writes:

> Can you tell which font(s) does Terminal use for non-Latin characters,
> such as the one above?  Maybe we could learn something from that.

The gnome-terminal interface claims to be using "Monospace", which is a
font that fc-list says doesn't exist on my system, so I don't really
know what's up with that.

But I was just experimenting a bit, and I wondered how you can force
Emacs into using a specific font for some text.  The following does not
work:

(insert (propertize "fooѾx" 'face '(:family "Futura")))

Now, that font doesn't have the Ѿ glyph, so I'd expect Emacs to tofu
that character, but instead it renders it using DejaVu Sans?

Anyway, I found a mono font on my system with full coverage:

(insert (propertize "fooѾx" 'face '(:family "Noto Sans Mono")))

This renders all these characters with equal width, but using it in the
test case also fails, because amusingly enough, the tofu character it
uses isn't monospaced:

So that's a font that advertises itself as monospaced, but isn't really.

Let's see..  Oh, there's also "Noto Mono":

Success!  With this font, the test case in this bug report works fine:
There are no display glitches when running mutt under term.

But as you can see, this isn't really monospaced, either -- the tofu
glyphs here are narrower than the other glyphs.  And...  hang on --
there's still some glitches, but they are much smaller than before.

I've tried a couple more monospaced fonts, but none seem to have full
coverage.

I'm starting to wonder whether gnome-terminal is just faking the
monospaceness?  That is -- if the glyph is too wide, it's just narrowing
it?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no