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After my talk about TeX syntax-highlighting font at TUG2025 conference, then vice-president of TeX Users Group, Boris Veytsman approached me with a proposal to develop a Math counterpart for the beautiful Arsenal font designed by Andrij Shevchenko.

What followed was a deep dive into the TeXbook to learn about math font parameters, OpenType Math specification, and related documentation & resources. Fortunately, FontForge has really good support for editing Math tables; and the base font used (KpMath-Sans by Daniel Flippo) already had all the critical parameters set (which needed slight adjustments). I started the development of Arsenal Math by integrating the glyphs for Latin letters, Arabic numerals, some symbols etc. and with proper scaling & stem thickness corrections, for regular, bold, italic and bolditalic variants, plus math calligraphic letters. In addition, a lot of Math kerning (known as ‘cut-ins’ in OpenType parlance) was added to improve the spacing.

Being an OpenType font — XeTeX, LuaTeX or some Unicode math typesetting engine (e.g. MS Word) is required to use Arsenal Math. Boris did testing and provided many feedback, and Vaishnavy Murthy graciously reviewed the glyph changes I made. The CTAN admins were quite helpful to get the font accepted into the repository. There is a style file and fontspec file supplied with the fonts to make the usage easy. The sources are available at RIT fonts repository.

Boris also donated funding for the project, but he had already paid me many folds by mailing The TeXbook autographed by Donald Knuth for me, so I requested the LaTeX devfund team to use funding for another project. Karl Berry suggested to write an article about the development process, which is published in the issue 46:3 of the TUGboat journal, and has a lot more technical details.

The learning experience of Math typesetting internals, and contributing to the TeX ecosystem has been a fulfilling spare-time work for me in 2025. Many thanks to all those involved!

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.

I’m very glad to participate in the 2025 edition of the International Calligraphy Festival of Kerala, and present a talk to a great audience.

ICFK is organized by KaChaTaThaPa foundation headed by master calligrapher Narayana Bhattathiri. The event usually takes place on 2–5 October in Kochi. Varying talks, workshops, demonstration sessions, exhibitions, and above all meeting and learning from exemplary calligraphers is the best part of the event. The venue always bursts with beauty, energy, and fun; where everyone is approachable.

Reconnected with old friends and made new friends. Ashok Parab was traveling pan-India and documenting scripts, that lead to teaching scripts — including Malayalam — as well. Abhishek Vardhan is doing research on Nāgarī script. Syam is doing research on Malayalam calligraphy. They promised to share their findings and public/open resources, which would be very interesting to look at. Vinoth Kumar, Michel D’Anastasio, Nikheel Aphale, Muqtar Ahammed, and Shipra Rohtagi gave me souvenirs — thank you! I had chances for interesting long chats with Uday Kumar (who asked me about Sayahna Foundation after the t-shirt I wore), Achyut Palav, Sarang Kulkarni, Brody Neuenschwander, and also Shyam Patel of Kochi Biennale Foundation.

On many occasions delegates approached and asked me about font development process, complex text shaping and related topics. It was also too tempting to not buy fountain pens and Bhattathiri’s merchandise on sale, as gift to friends. The dinner with the ICFK team at Boulangerie Art Cafe was delicious. TM Krishna’s carnatic music concert on Saturday evening was a heavenly experience — Krishna Seth sitting next to me was spontaneously drawing on the notebook for the entire duration of the concert.

For the last edition, I presented a talk about font development, font engineering, complex text shaping, and such back-end tasks that designers generally find difficult. This year, I talked about the ‘Fundamentals of Typography’. I hope the talk succeeded to some extent in making everyone unhappy when they look at a badly typeset page .

The slides for the presentation are available here.