bug#36304: 27.0.50; request: switch to the superior HTML #RGB convention for colors

[Pip Cet <pipcet@gmail.com>]

On Sat, Jun 22, 2019 at 11:40 AM Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Pip Cet <pipcet@gmail.com>
> > Date: Sat, 22 Jun 2019 11:23:35 +0000
> > Cc: 36304@debbugs.gnu.org
> >
> > Here's a patch. I've read the documentation and it appears already to
> > have been updated by someone so it no longer links to the X
> > documentation.
> >
> > * src/xterm.c (x_parse_color): Translate #RGB notation to rgb:R/G/B
> >   notation, which X handles slightly differently.
>
> Can this change be limited to xterm.c alone?

It'd leave us inconsistently still using the X standard in some
places, but at first glance they appear to be documented to use the X
standard, so maybe that's not wrong.

> I think we assume this color handling also in xfaces.c

Only via tty-color-standard-values, as far as I can see.

> and in lisp/term/tty-colors.el (and perhaps elsewhere, where TTY colors are used/defined).

tty-color-standard-values is documented to use the X convention, and
it does. tty-color-desc is documented to return approximate results,
and it does; and it's only used for text terminals, right?

>  There's also lisp/color.el.

Anything in particular? As far as I can tell, the functions work
properly using the new convention with this patch, although I am sure
there are places that fail to deal with the 65280-as-maximum
convention that nsfns.m uses.

> Am I missing something?

I don't think so, but I don't see anything, so far, that needs
changing. I'm almost certain that some more places will need changing,
but how do we find them?