bug#25890: `color-values` gives wrong value

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Simen Heggestøyl <simenheg@gmail.com>,
>   25890@debbugs.gnu.org,  rasmus@gmx.us
> Date: Sat, 04 Mar 2017 16:44:28 +0100
> 
> I haven't followed this discussion closely, but you've changed the way
> color-rgb-to-rgb works in an incompatible way?

There's no color-rgb-to-rgb.  There's color-rgb-to-hex and
color-name-to-rgb.  And I don't think the changes are incompatible.
Please show examples if you think otherwise.

> If you want to have a function that does something else, I think it
> would make more sense to introduce new functions that does this
> "something new" (i.e., 16 bit component parsing instead of HTML-like
> color parsing, which is what those functions are supposed to do), and
> revert the old functions how they used to work.

The changes make the above 2 functions compatible with all the other
color calculations in Emacs.  IMO it makes no sense to have color.el
make assumptions about RGB components that are different from
everything else in Emacs, as doing so will only produce subtle bugs
such as the one which started this bug report.