[RFC] OpenType Variable font support and new UI for choosing fonts

[kovidgoyal]

Hi all,

I have added support to kitty for OpenType variable fonts. This means that, for fonts that support it, you can precisely control the weight, spacing, italic angle, etc. There is also a new UI in the form of the choose-fonts kitten to make selecting fonts and setting their features and variable values easier. Run it with:

kitten choose-fonts

See the docs for the this kitten

Some screenshots of the kitten:

The code works on both Linux and macOS. Note that this required extensive re-writing of font selection internals so there could be regressions.

I would appreciate some testing from those of you in a position to do so, as there are two platforms and dozens of fonts and settings and thousands of lines of code involved, it's hard for me to cover everything.

You can use the kitty nightly build or build kitty from source.

Note that the existing font_features setting in kitty.conf still works, but is obsoleted by the new choose fonts kitten. It should only be used for fallback fonts. The main fonts should have their features configured via choose-fonts.

Thanks, and enjoy.