bug#33093: 26.1, 7.2 emacs-mac; M-x list-colors-display RET; L1 is black on black

[Eli Zaretskii]

> From: Van L <van@scratch.space>
> Date: Fri, 19 Oct 2018 21:55:43 +1100
> 
> The *Colors* buffer has black text on color backgrounds that is not always 
> readable.

Each color's name is shown twice, once when the color is used as
background, the other time it is used as foreground.  Are you saying
that you see neither of these two for some colors?  If so, what is
your background color (assuming this isn't in "emacs -Q")?

> I’d like to suggest color contrast arcs through a distorted triangle 
> colorspace for choosing textcolor always in contrast to the background color 
> for easy reading. In the case of black, blue, medium blue background the text 
> color is white. Perhaps, only a dozen special cases are needed to switch 
> black to white text color and the colorspace idea is overkill.

How will this work with our intent to show the color both as
foreground and as background?