No support for 16 colours

[henrebotha]

It appears src either uses no colours (NO_COLOR=1), or 256 colours. This means that if the colours chosen for 256-colour mode are hard to read, I have no choice but to turn colour off entirely and lose some valuable readability-enhancing information in the output.

I would really appreciate an option to stick to 16 colours (4-bit colour), so that src only uses colours defined by my terminal theme.

[linear]

OSS-24166 No support for 16 colours

[jojosenthusiast]

I'm interested in picking this up. Before opening a PR, would you prefer 16-colour support to be exposed as an explicit flag (for example alongside the existing colour mode handling), an environment/config option, or something else?

The minimal change I would aim for is to keep current defaults unchanged and add a user-selected 4-bit/16-colour mode, with tests around the colour-mode selection path.

[henrebotha]

I would prefer this as a config option, as I'm unlikely to want to change it on a per-invocation basis.