At the TUG2025 conference, I presented a talk about the development of a new colour font, which does automatic syntax highlighting for TeX documents/snippets. The idea was floated by CVR, and was inspired by a prior-art of HTML/CSS syntax highlighting font by Heikki Lotvonen.

Syntax highlighting is achieved by specialized grammar files or packages on desktop applications, code editors, the Web, and typesetting systems like TeX. Some of these tools are heavy (e.g. prism.js or pygmentize package). A light-weight alternative would be a font that uses recent OpenType technologies to do syntax highlighting of code snippets. I developed such a font, for highlighting TeX code snippets.

There are some novelties in the developed font:

1. It supports both COLRv0 and COLRv1 colour format specifications (separate fonts, but generated from the same source).
2. Supports plain TeX, LaTeX2 and LaTeX3 macro names.
3. A novel set of OpenType shaping rules for TeX syntax colouring.

The base font used is M+ Code Latin by Coji Morishita. The details of the development, use cases, and limitations can be found in the 46:2 issue of the TUGboat journal publication. The binary font and sources are available at RIT fonts repository.