Re: face-attribute and face-remapping-alist

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 30 Mar 2021 22:05:00 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> Thanks, but unconditionally changing the behavior of face-attribute in
> such fundamental ways is a non-starter.  There must be a way to still
> get the frame-specific face attributes, un-effected by buffer-specific
> remapping.  face-attribute is quite a low-level API, and face
> remapping is a higher-level feature.
> 
> So if we want face-attribute to pay attention to face remapping, that
> must be an optional behavior under control of some optional argument
> or a variable that could be let-bound.
> 
> Alternatively, we could introduce a new API for what you want.

And btw, I don't really understand the difficulty: fetching the
remapped face from face-remapping-alist is trivial.  Thereafter,
face-attribute will do what you want.  So I don't even think I
understand the problem you are trying to solve.  I guess a detailed
description of some specific example would help here.

In any case, please don't forget that frame-local and buffer-local
values cannot be intermixed without producing undesirable effects.
Face remapping was introduced to allow finer resolution in face
attributes than the per-frame one, under the control of the
application.  Your proposal pushes the buffer-local aspects to the
lower levels, and out of the application's control, which I don't
think is TRT.