bug#59347: 29.0.50; `:family` face setting ignored

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Gregory Heytings <gregory@heytings.org>,  59347@debbugs.gnu.org
> Date: Sun, 20 Nov 2022 13:30:41 -0500
> 
> >> I'd have to investigate this, is it really worth the effort given that a 
> >> proper fix has already been found?
> > I'd like to hear Stefan say that this is fixed on his system as well.
> 
> As mentioned in my other message, it does fix it for me.

Good to know, thanks.

> > Thanks, it's indeed the other cases that I worry about.  We had a lot of
> > changes in this area which solved one problem only to create others.
> 
> BTW, when scoring fonts, I'd expect that the different weights get
> turned into a number and we then look at the difference between the
> requested number and the font's number.

We do that, yes.  But the problem is not the conversion to numbers, the
problem is the balance between the numerical value of a given difference in
weight vs the numerical value of a given difference in width or slant.  They
should follow some reasonable considerations of selecting suitable fonts in
various use cases.  When we start considering 'normal' in addition to
'medium', or vice versa, we introduce changes into the relative scores of
fonts, and the results could be not what we want.

> [ tho, to be honest,
> I have no idea which of `regular`, `normal`, and `medium` is supposed to
> be heavier or lighter.

See the beginning off font.c, where the numerical values we use are spelled
out.

> The same problem can affect the width attribute where many of the possible
> choices seem to use just arbitrarily different names for the same thing.

We score by values, not by names.