Re: support for true-color terminals

[Eli Zaretskii <eliz@gnu.org>]

> From: Charles Strahan <charles@cstrahan.com>
> Date: Thu, 10 Mar 2016 20:48:54 -0500
> 
> A while back, there was an effort to add support for true-color
> terminals (by which I mean terminals supporting 16777216 simultaneous
> colors):
> 
> http://emacs.1067599.n5.nabble.com/RFC-Add-tty-True-Color-support-td299962.html
> 
> I've contacted Rüdiger, asking if he wouldn't mind if I pick up from
> where he left off, and he said that was fine as he's been too busy to
> work on this.
> 
> I've attached to this email the patch that I'm using, based on his work.
> Any feedback would be greatly appreciated.
> 
> This is my first (attempted) contribution to Emacs, and I'm very new to
> the code base, so there might be some silly mistakes that I'm unaware
> of. If we can get this polished enough for inclusion, I'd be more than
> happy to assign copyright.

Thanks.

First, I suggest that you start the legal paperwork rolling right now,
because without that, discussing such a non-trivial change would be
rather pointless.  If you agree, I will send you the form off-list.

As for the patch: my first comment is about the changes in
tty_look_up_color and in map_tty_color -- why are these needed?  The
sheer number of the supported colors doesn't necessarily require any
changes in the basic design of TTY color support, so I'm not sure what
was the motivation for these changes.

Also, why do we need the 'true-color' option introduced in
tty-colors.el? why isn't 'auto' enough for supporting this terminal?