bug#41544: 26.3; Possible incorrect results from color-distance

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Mattias Engdegård <mattiase@acm.org>,
>   simenheg@runbox.com,
>   tom@tromey.com,  41544@debbugs.gnu.org
> Date: Tue, 18 Aug 2020 15:44:50 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I gave all the reasons I have.  They are serious, at least to me.
> > They have nothing to do with the quality of your research or of the
> > resulting code.  They have everything to do with considerations of
> > stability, and with weighing risks and efforts vs advantages.  If you
> > don't regard such considerations as technical arguments, so be it.
> 
> I understand your objections to changing this behaviour, but the new,
> correct calculations make things a lot better.

How do they make things better, and what things, exactly?  My
recollection is that this was about consistency, not correctness.
Also, the original discussion was about quite a few separate changes,
some of which were installed, so I don't think I have a clear idea
which parts you allude to.

> Would it be possible to add the new calculations with a defcustom to
> say whether to use the new or old methods?

I don't think defcustom is the proper way of handling differences in
behavior at this low level.