Re: Changing font weight with buffer-face-mode-invoke

[Heime <heimeborgia@protonmail.com>]

On Thursday, June 27th, 2024 at 10:24 AM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Thu, 27 Jun 2024 08:48:18 +0000
> > From: Heime heimeborgia@protonmail.com
> > Cc: help-gnu-emacs@gnu.org
> > 
> > > Users are not asked about these attributes, certainly not
> > > "customarily", not in Emacs. In fact, users are not supposed to be
> > > bothered by that at all, they just need to specify the family/families
> > > of font(s) they want to use, and Emacs will do the rest automatically.
> > 
> > Customarily I want to set the height for good visibility which is larger
> > than default. And bold in some cases.
> 
> 
> Selecting font size is easy and doesn't require all this complexity.
> 
> I was talking about the other font attributes: weight, slant, and
> width.
> 
> > > IOW, I think you are talking about a problem that doesn't exist for
> > > most Emacs users. I understand that you decided for some reason to
> > > write some peculiar program that allows selection of these attributes
> > > interactively, and I'm prepared to help you find the related Emacs
> > > functionalities for that program.
> > 
> > > But the problem you are trying to solve is largely an academic one,
> > > because the resulting font will be largely not useful in Emacs, as
> > > you will discover next.
> > 
> > Not useful for the reason that it will not activate. Or because the font
> > characteristics are not useful ?
> 
> 
> Because using such a font in various situations and APIs will not
> necessarily work.
> 
> > > Emacs was not designed to support selection of fonts by fine-tuning their
> > > weight, slant, and other similar attributes, so specifying such fonts works
> > > in some cases but doesn't work in others.
> > 
> > If you do S-<down-mouse-1> to use "Change Buffer Font", one can select those attributes.
> > I just want to do the same automatically in elisp code.
> 
> There's no practical reason for doing so, that's all I'm saying.

Somehow, the "Change Buffer Font" tool allows selection of that information and
gets things to work.  Perhaps there are things missing for correct specification
of weight, slant and width for buffer-face-mode-invoke.

Could it be that using the :family, :height, :weight is not so rodust, and it is better
to just use :font ?  How would I call buffer-face-mode-invoke with :font or similar ?