Pango

HarfBuzz   (Compare Project)

Mostly written in C++

License: mit

The FreeType Project   (Compare Project)

Mostly written in C

License: ftl

Codepoints.net   (Compare Project)

Mostly written in PHP

License: Bitstream_Vera_Fonts_Copyright, CC-BY-NC-SA-20, GPL-1-0plus, unicode

PascalType   (Compare Project)

Mostly written in Pascal

License: lgpl21le, mit

fontconfig   (Compare Project)

Mostly written in C

License: BSD-3-Clause

Tsukurimashou   (Compare Project)

License: gpl3_or_later

XeTeX   (Compare Project)

Mostly written in C

License: mit

Fontmatrix   (Compare Project)

Mostly written in TypeScript

License: gpl

ICU for C/C++/Java   (Compare Project)

Mostly written in C++

License: mit

GNU FriBidi   (Compare Project)

Mostly written in C

License: gpl