Detect truecolor support with terminfo

[pascalkuthe]

Followup to #5312 which was closed before I could comment.

Detecting truecololor support is a complete mess and sadly non standardized. There are multiple semo stanard methods and we probably want to support them all to be on.the save side:

• COLORTERM based detection
• using the nonstandard setrgbf/setrgbb terminfo capabilities (commonly used in practice like in nvim)
• using the standard terminfo RGB capability (support since ncurses 6.1 whixh is sadly rarely used as its mutually exclusive with 256 color support. (See Update TERMINFO capabilities for 24-bit color support in emacs. kovidgoyal/kitty#1141 for some discussion)
• a manual setting in case everything else fails (for example when using helix over ssh for some reason)

We handle undecurl support similarly (check both nonstandard capabilities and environment variables) and use termini for that. The same thing should be possible/easy to accomplish for this case (the setting could be implemented later)

[kirawi]

By the way, a setting already exists as config.editor.true-color.

[eliasp]

I'm using:

• Windows Terminal (1.17.11461.0)
• Win11 on the client
• CentOS 9 on the server, where I use Helix
• Helix 23.05

I launch ssh.exe directly within my Microsoft Terminal profile without going through cmd or pwsh first and connect straight to the target system running CentOS9.

By default, $TERM is xterm-256color.
My Helix config contains config.editor.true-color = true

Trying :theme monokai still claims theme requires true color support.
Explicitly setting $COLORTERM changes nothing.

Anything else I could try or any debug data I could provide?

[nkitsaini]

Hi @eliasp, if you have set config.editor.true-color = true, you should not see theme requires true color support error message.

I am guessing that your config might be on your windows machine instead of CentOS (where helix is being run).

Can you try running :get true-color in helix to see if the value is correctly set in config? If this is false you can use :set true-color true to override the value and check if that works.

Also you can try |env (<pipe> followed by env), to check what environment variables are visible to helix.