Add feature cli fit mode

[badele]

This PR adds an optional fit mode to the CLI that ranks and previews fonts based on how closely their rendered output matches a target width and/or height, letting users quickly find the best font and scale for a desired dimension, with optional display of measured dimensions and distance to the target.

[superstarryeyes]

interesting. this is certainly a cool idea. i'm just thinking if it's useful enough to merge to the main. what are you using this for yourself?

[badele]

@superstarryeyes I’m using this mainly in the context of my own projects, particularly a new format called neotex, which aims to make ANSI files easier to read without requiring a dedicated ANSI viewer: https://github.com/badele/neotex

I’m also working on an ANSI compositor: https://github.com/badele/ansi-compositor

The font-dimension matching feature is important for me because the compositor relies on precise width and height constraints to assemble ANSI content correctly. Being able to automatically find a font that satisfies those constraints simplifies the workflow and avoids manual adjustments.

You can find examples in the repositories, including:

• A sample configuration file for ansi-compositor,
• The generated neotex output,
• And the resulting ANSI rendering exported as PNG.

In short, this feature allows me to maintain consistent layout constraints across tools and ensures predictable rendering.

I’ve switched the PR to draft mode so I can properly test the tool’s viability. This will allow me to provide you with more concrete feedback in the future. Would that be okay for you ?

[superstarryeyes]

very interesting projects you have! take your time, draft mode i fine.