RE: Colour picker widget

[Drew Adams]

> > 1. http://www.emacswiki.org/emacs/download/palette.el
> > http://www.emacswiki.org/emacs/ColorPalette
> 
> Interesting - my main intent with the colour-grid was to add
> something that could be used in defcustom entries and the like.
> It would be interesting to add some pf palette's funcitonality
> to that.

I agree that it would be good to add this kind of color picking to Customize.
This was brought up long ago, but it is still a good idea.

Customize is good, but its UI could be improved by letting it reach out to get a
resulting value using other UI extensions.

A color picker is one such.  Currently when you choose a color in Customize by
clicking the `Choose' button you get the `list-colors-display' to choose from.
That's good.

You used to be able to choose a color name using completion.  Both possibilities
should be available, IMO.  And completion should show the color names using
their colors as background.

A palette to choose from would also be convenient here.  The palette in
`palette.el' lets you manipulate colors in various ways to choose a color.

`Do Re Mi' incremental color-changing and choosing methods might also be
candidates for a Customize color-chooser plugin.  Likewise some of the Facemenu+
UI features.
http://www.emacswiki.org/emacs/DoReMi
http://www.emacswiki.org/emacs/FaceMenuPlus

The idea should be not just to make Customize use whichever of these (and
similar) we think is best.  Best would be to make Customize pluggable, so users
themselves could easily choose which color-choosing UI features to use.

And likewise for other Customize choices, besides colors.