Re: Buffer-local faces

[Miles Bader <miles@gnu.org>]

On Tue, May 04, 2004 at 08:45:21AM +0300, Juri Linkov wrote:
> Then subtracting face attributes would be useful too.  For example,
> using the `-' symbol before the face name could remove its attributes
> from the composed face, e.g. using (region region - bold) to remove
> all attributes of the `bold' face whose values are equal to attribute
> values of the `region' face.  This may complicate things, but this
> is no less useful than merging faces.

It's a much less obvious operation (what does subtracting red from black
yield?  [Ok, maybe cyan :-]) and I can't offhand think of any obvious uses
for it....

Morever, I don't think would help in this case because face-merging more
specific faces during redisplay will always override the default attributes.

A _different_ feature that might work is a way to mark a face attribute as
`non overridable'.  For instance if a face attribute could be a list like
(fixed VALUE), where VALUE is a normal value for that attribute, face
merging would always use the `base' value for that attribute instead of the
`normally overriding' value.

[Since the face-remapping code just uses normal face merging, this feature
would work with that too, but it wouldn't be specific to it.]

Generally useful?  I'm not sure, but it could probably handle the `no bold
please' case.

-Miles
-- 
"Whatever you do will be insignificant, but it is very important that
 you do it."  Mahatma Ghandi