Subject: Re: bug#41852: 27.0.50; text-scale commands don't scale header of tabulated-list-mode

From: Stefan Kangas <[email-masked]>
Date: Sat, 31 Oct 2020 09:50:16 -0700

Stefan Kangas <[email-masked]> writes:

> Eli Zaretskii <[email-masked]> writes:
>
>> Try using fixed-pitch and variable-pitch instead of mode-line and
>> bold.  What happens then?  And what does that mean for this
>> discussion?
>
> I tried this with my patch, in emacs -Q:
>
> (progn
>  (setq-local text-scale-remap-header-line-face t)
>  (setq-local header-line-format (concat
>                                  (propertize "foo" 'face 'fixed-pitch) " "
>                                  (propertize "bar" 'face 'variable-pitch))))
>
> They also scale.

So looking at this, I'm not sure we should even say: "This will also
affect any face that inherits from it."  It risks confusing more than
helping, IMHO.

Nor am I so sure we should talk about the 'header-line' face.

I think we should say something closer to what Martin suggested, say:

  *** text-scale-mode can now scale the header line.
  When the new buffer local variable 'text-scale-remap-header-line-face'
  is non-nil, 'text-scale-adjust' will also scale the text in the header
  line when displaying that buffer.

  This is useful for major modes that arrange their display in a tabular
  form below the header-line.  It is therefore enabled by default in
  'tabulated-list-mode' and its derived modes.

  Note that text scaling never affects text using a face where the
  :height attribute is set to an absolute value.

And then adjust the docstring accordingly.