bug#51821: 29.0.50; Suggest add variable or frame parameter: line-height

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: tumashu@163.com,  luangruo@yahoo.com,  51821@debbugs.gnu.org
> Date: Sat, 20 Nov 2021 10:58:14 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Allow saying:
> >> 
> >> (defface separator-line
> >>   '((((type graphic) (background dark))
> >>      :pixel-height 1 :background "#505050")
> >
> > How is that different from :height?  It uses different units, but
> > that's not a problem for this use case, is it?
> 
> It's a way to say "don't scale this, ever", which was a problem here,
> wasn't it?  (And :height 0.1 doesn't give me a single pixel on this
> display -- we have no way to express that currently.)

No, float values are relative to the default face, which is not what
you want.  I meant ":height 1" or somesuch.  If that is not good
enough, the value of :height can be a function.