jonas/tig

Support for True Color (16 millions colors)

XVilka opened this issue · 7 comments

XVilka commented

Now more terminals bring support for 16 million colors (see references below).

Here's a test case for terminal:

printf "\x1b[${bg};2;${red};${green};${blue}m\n"

The 256 colour palete is configured at start, and it's a 666 cube of
colours, each of them defined as a 24bit (888 rgb) colour.

This means that current support can only display 256 different colours
in the terminal, while truecolour means that you can display 16 milion
different colours at the same time.

Truecolour escape codes doesnt uses a colour palete. It just specifies the
colour itself.

Here's a test case:

printf "\x1b[38;2;255;100;0mTRUECOLOR\x1b[0m\n"

awk 'BEGIN{
    s="/\\/\\/\\/\\/\\"; s=s s s s s s s s;
    for (colnum = 0; colnum<77; colnum++) {
        r = 255-(colnum*255/76);
        g = (colnum*510/76);
        b = (colnum*255/76);
        if (g>255) g = 510-g;
        printf "\033[48;2;%d;%d;%dm", r,g,b;
        printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
        printf "%s\033[0m", substr(s,colnum+1,1);
    }
    printf "\n";
}'

Keep in mind that it is possible to use both ';' and ':' as parameters delimiter.

According to Wikipedia[1], this is only supported by xterm and konsole.

[1] https://en.wikipedia.org/wiki/ANSI_color

Currently, there is no support for the 24-bit colour descriptions in the terminfo/termcap database and utilites.
See the discussion thread here: https://lists.gnu.org/archive/html/bug-ncurses/2013-10/msg00007.html

Here are terminals discussions:

Now supporting truecolour

But there are bunch of libvte-based terminals for GTK2 so they are listed in the another section.

Also, while this one is not exactly a terminal, but a terminal replayer, it still worth mentioning:

Parsing ANSI colour sequences, but approximating them to 256 palette

Note about colour differences: a) RGB axes are not orthogonal, so you cannot use sqrt(R^2+G^2+B^2) formula, b) for colour differences there is more correct (but much more complex) CIEDE2000 formula (which may easily blow up performance if used blindly) [2].

[2] neovim/neovim#793 (comment)

Terminal multiplexers

  • tmux - starting from version 2.2 (support since 427b820...)
  • screen - has support in 'master' branch, need to be enabled (see 'truecolor' option)
  • pymux - tmux clone in pure Python (to enable truecolour run pymux with --truecolor option)
  • dvtm - not yet supporting True Colour martanne/dvtm#10

NOT supporting truecolour

[3] You can download patched version here https://github.com/rdebath/PuTTY

[4] You can download patched version here https://github.com/halcy/PuTTY

Here are another console programs discussions:

Supporting True Colour:

Not supporting True Colour:

ZyX-I commented

Provided bug number for konsole is incorrect: correct one is https://bugs.kde.org/show_bug.cgi?id=107487.

XVilka commented

@ZyX-I thx! fixed.

jonas commented

Unless ncurses supports True Color, it sounds like it will take a lot of work to get Tig to support it.

XVilka commented

@jonas starting from version 6.1 ncurses supports this mode.

jonas commented

@XVilka That's great news, thanks for the update.

jmera commented

@jonas is this going to be picked up at some point? This would be a pretty nice feature.

  • 👍2
spidey commented

What is the purpose of adding RGB support to tig? Is it only for specifying theme colors with more control/options?

  • 👍1