Re: What is a default font?

[Eli Zaretskii <eliz@gnu.org>]

> Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Sun, 8 Dec 2019 10:03:46 +0100
> 
>  > This is a misunderstanding.  What I meant to say was that when a new
>  > frame is created, we usually apply frame-parameters from all kinds of
>  > sources, and that is what I referred to as "unknowns".  barring that,
>  > the above line is accurate, albeit you may see it as useless in your
>  > use case.
> 
> It took me some time to find out why it didn't work as advertised.
> And it's not our usual practice to advertise things that might work
> only if they were implemented.  As far as the face code is concerned,
> I now got the feeling that it's strictly for connoisseurs only.

It's not for the faint at heart, for sure.

>  > It depends on what you are going to use the results of
>  > default-font-height etc. for.  And I'd consider it a bug, or at least
>  > a misfeature, to have the default face filtered like that anyway.
> 
> It's probably the remapped face that would get filtered here but I
> have no idea about how such filters would be used in practice.

The node "Face Remapping" in the ELisp manual tries to explain that.