HarfBuzz 12.3 was just released for ending out 2025 with some nice performance improvements to this widely-used text shaping engine. HarfBuzz in turn is used by the prominent Linux desktop environments, Java, Flutter, various game engines, and apps like Chrome and Firefox for text shaping needs with OpenType fonts and more.

HarfBuzz 12.3 brings various fixes, support for full-instancing fonts with the v2 avar table, and other updates. Exciting me the most with this release are the new performance optimizations:

- AAT shaping: speed up state machine on Apple silicon using a fast-path. 12% faster in LucidaGrande benchmark.

- OpenType shaping: speed up (Chain)Context lookup shaping using a fast-path and Coverage caching. 20% speedup in NotoNastaliqUrdu benchmark.

- Drawing mega variable-fonts: 30% speedup on GoogleSansFlex benchmark.

- Drawing VARC fonts: 5% speedup on varc-hanzi benchmark.

Some nice gains for ending out the year with this widely-used library.

More details on the newly-minted HarfBuzz 12.3 release via [1]GitHub .



[1] https://github.com/harfbuzz/harfbuzz/releases/tag/12.3.0