[henrikeh]

This made me think of Metafont[1] which D. Knuth developed in conjunction with TeX. The idea was to do font-design by drawing with a virtual brush -- but with perfectly smooth curves and a build-in constraint solver. The end result is that the entire Computer Modern family is parameterized (and generated on-demand) as TeX is using it. As an example, the serif, sans-serif and typewriter fonts are the same Metafont program, but just with different parameters.

Looking at the repo for these Indian fonts you can see that they use FontLab Studio[2] for the work. Browsing the homepage reveals how complicated and involved font crafting is -- let alone the design!

[1] Metafont: https://en.wikipedia.org/wiki/Metafont

[2] FontLab Studio: https://www.fontlab.com/font-editor/fontlab-studio/

[svat]

Some Indic typefaces were created using METAFONT in fact, in the 80s and 90s. They used the abilities of METAFONT to provide multiple specific fonts. Some of them have features (variants for conjunct style, e.g. the “Bombay” versus “Calcutta” styles for Devanagari, etc.) that are still not present in any modern (TrueType/OpenType) font available today.