Re: list-colors-display: display all color names

[Juri Linkov <juri@jurta.org>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:
>>> Also, users might want to find the color name corresponding to
>>> the known RGB value.
>
>> Is there any reasonably practical way to do that for an arbitrary RGB
>> triplet?
>
> A guess a function that returns the closest color-name would be good enough.
> What that's good for, I don't know.

There is already such a function: `tty-color-approximate' (currently
it works only for tty colors).  I don't know how it is useful from the
user's POV.  What I intended with adding #RRGGBB values was to make it
easier for users getting somewhere a #RRGGBB value to see if there is
a corresponding easily rememberable color name.

With #RRGGBB values printed in the *Colors* buffer it would be possible
to find closer color names even without a function, simply with a regexp
isearch like M-C-s #f.[fe].e.  It will not find the closest color name,
but it is good enough to help to find all closer colors.

Even better would be if the *Colors* buffer was sorted by RGB values.
I don't suggest to do that by default, but different sorting order would
be useful, e.g. by color name, by color intensity.  The latter is good
for finding a darker or brighter color than a given color, but it is not
so obvious since there are too many variants of projecting a color value
from 3-D color space into a 1-D color list.  Perhaps the most useful is
sorting by hue into a rainbow, and inside every hue sorting by value*saturation.

>>> gray                    grey                                   bebebe
>>> light gray              light grey, LightGray, LightGrey       d3d3d3
>
>> First, if we do that, I'd suggest to use #BE12BE34BE56, i.e. prefix
>> with # and use 4 digits per color.
>
> I agree on the `#'.

I omitted the `#' to save more space.  But OK, one character is not
too much to remind the users about the proper format.

-- 
Juri Linkov
http://www.jurta.org/emacs/