bug#20628: 25.0.50; Incorrect line height for some fonts

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 22 May 2015 19:55:24 -0400
> From: Clément Pit--Claudel
>  <clement.pitclaudel@live.com>
> CC: Eli Zaretskii <eliz@gnu.org>, 20628@debbugs.gnu.org
> 
> > BTW, I think that using something like
> > 
> >     (set-fontset-font fontset 'unicode (font-spec :name "Symbola") nil 'append)
> > or
> >     (set-fontset-font "fontset-default" '(#x1d400 . #x1d7ff) "Symbola")
> > 
> > just sucks: we don't want to say "use Symbola", but we instead want to
> > say something like "avoid Latin Modern Math" or "ignore Latin Modern
> > Math's ascent/descent information".
> 
> I don't think so; this forces us to maintain a list of misbehaving fonts. If we just say "Avoid Latin Modern Math" and the next selected font is also broken, then the problem remains (Asana Math, for example, is broken too, albeit a bit less). Ideally, we would also want to be able to use Latin Modern Math: ignoring the height issue, it's a nice font for maths symbols.

But the proposed patch, to which you agreed, did precisely that: it
singled out a particular font where the ascent/descent information was
to be ignored (and suggested to extend the list if needed).  How's
that different from what Stefan proposes?  And what's wrong with
maintaining a list of fonts that are known to misbehave?  There a lot
of broken fonts out there, and so far we relied on users configuring
the fonts on their machines to avoid negative effects, something
that's not always possible.