Re: colors using -nw in 21.3

[Eli Zaretskii <eliz@elta.co.il>]

> Date: Wed, 24 Mar 2004 18:12:28 -0800
> From: KC Braunschweig <kbraunsc@usc.edu>
> 
> I've recently installed emacs 21.3, compiled on Solaris 2.6 to run on 
> 2.6, 8 and 9 (SPARC). When running with the -nw option, color support 
> produces unexpected results. Our previous version (20.2.1) supported a 
> wide range of colors (for example $ emacs -fg DarkSlateGrey -bg wheat 
> -nw). The 21.3 installation seems to only support the the 8 standard 
> colors listed via M-x list-colors-display and selecting any other 
> colors, such as those in my example results in a bright green color 
> being used.

Emacs before version 21.1 didn't support colors in -nw sessions at
all.  I don't know how you got colors in Emacs 20.2.1 (was that, by
any chance, XEmacs?), but finding that out would be a useful first
step.  Perhaps the previous version used some site-specific hack to
achieve that.

Emacs 21.x uses the number of colors reported by the termcap/terminfo
database you have on that platform.  If it reports 8 colors, that is
all you will see (list-colors-display shows the number of colors
reported by the terminal capability database).

> The man page leads me to believe that all colors listed in 
> /usr/lib/X11/rgb.txt should be supported.

What man page is that?

Anyway, to use colors on a text terminal, Emacs needs a way to issue
terminal commands that switch colors.  These commands are executed by
the terminal device driver on your system, so only the colors
supported by that driver and the terminal device you run Emacs on can
be used.  If you run on an xterm, the terminfo entry for that version
of xterm needs to define the number of colors and commands to switch
to those colors, in order for Emacs to use them.