bug#57555: 29.0.50; variable-pitch font issue with medium weight default font

[Amin Bandali <bandali@gnu.org>]

Eli Zaretskii writes:

[...]
>
> Thanks, but please show the font setup you are using; without that, the
> "instead of the correct sans-serif variable-pitch font" part is
> impossible to interpret.

Thanks for your reply, Eli.  Globally, I'm basically using the default
font setup that Trisquel GNU/Linux comes with.  Here is a tarball of
the /etc/fonts/ directory on my system:

https://kelar.org/~bandali/tmp/20220903/etc-fonts.tar.gz

Beyond that, I have a few additional local (user-specific) settings in
in my ~/.config/fontconfig/fonts.conf, but this is the main relevant
excerpt, where I specify that sans-serif should be GNU FreeSans (and
this works basically in all applications, including Firefox-based
browsers, and until recently Emacs as well):

  <alias binding="strong">
   <family>sans-serif</family>
   <prefer>
    <family>FreeSans</family>
    <family>Sahel WOL</family>
    <family>Liberation Sans</family>
    <family>Roboto</family>
   </prefer>
  </alias>

The complete file is available from:

https://kelar.org/~bandali/tmp/20220903/fonts.conf

> Also, do you have the medium (not regular) variant of the GNU FreeSans
> font installed?  If not, can you install it and try again?

As far as I can tell, GNU FreeSans does not have a medium variant;
only regular, bold, oblique, and bold oblique:

$ ls /usr/share/fonts/truetype/freefont/FreeSans*.ttf
/usr/share/fonts/truetype/freefont/FreeSansBoldOblique.ttf
/usr/share/fonts/truetype/freefont/FreeSansBold.ttf
/usr/share/fonts/truetype/freefont/FreeSansOblique.ttf
/usr/share/fonts/truetype/freefont/FreeSans.ttf

I suppose what might be happening here is that Emacs now tries to use
a medium variant for the variable-pitch GNU FreeSans as well (even
though I'd expect that 'medium' to only apply to the font I explicitly
mentioned it for, i.e. Source Code Pro), which does not have such a
variant, and then it falls all the way back to "misc-fixed".  What is
a bit curious, though, is that this doesn't seem to affect italic
variable-pitch text, and Emacs correctly picks GNU FreeSans oblique
for that just fine.

> What seems to happen here is that Emacs decides that the font you
> don't like is a better match than the one you do like.  Which is not a
> serious problem from my POV (as long as the text is legible), just a
> minor aesthetic annoyance.  To fix such annoyances, one must tune
> one's font configuration.  But even if the annoyance stays, it's
> definitely less serious than the original problem which that commit
> attempted to fix.
>
> Thanks.
>

Right.  For what it's worth, I find Emacs picking misc-fixed for
variable-pitch text more than just a minor annoyance: for long hours
of use, I find misc-fixed it considerably less comfortable to my eyes
than GNU FreeSans (for proportional/variable-pitch) or Source Code Pro
medium (for monospace).


Thanks again,
-a