Re: Retrieving color names and hex values using list-colors-display for coding purposes

> Date: Thu, 16 Jul 2026 20:50:36 +0000
> From: Heime <[email protected]>
> Cc: Eli Zaretskii <[email protected]>, [email protected]
> 
> On Friday, July 17th, 2026 at 3:48 AM, packrat386 <[email protected]> wrote:
> 
> > "Heime" <[email protected]> writes:
> > 
> > > On Thursday, July 16th, 2026 at 5:42 PM, Eli Zaretskii <[email protected]> wrote:
> > >
> > >> > Date: Thu, 16 Jul 2026 02:56:34 +0000
> > >> > From: Heime <[email protected]>
> > >> >
> > >> >
> > >> > How can I get list of colour names and hex numbers (list-colors-display)
> > >> > that I can then use in my code with a loop.
> > >>
> > >> The function defined-colors will return the list of names of supported
> > >> colors.  The function color-values will return the RGB triplet for the
> > >> given color.
> > >
> > > How does the computation for white give 65535 ?
> > >
> > > "white" 65535 65535 65535
> > 
> > 65535 is 0xFFFF. So the RGB values are 16 bit integers and "white" means
> > the max of all three.
> 
> I do not understand this.  If 16-bit numbers require a 4-digit hex value
> like FFFF, why does the hex values for white when calling (list-color-display)
> display #FFFFFF - which is only a 2-big hex value for each colour?
> When I look for white using (list-color-display) I get a hex value of 
> #ffffff.  I do not understand this because if each colour is 16-bit

There are different representations for the RGB specification of a
color, you can have 3 or 6 or 9 or 12 hex digits.  See "Color Names"
in the ELisp manual.  The relations between them are somewhat complex,
and you don't need or want to dig into this in almost all cases.  Just
use 16 bits per component and 12-digit specs all the time, and Emacs
will do the rest.