Which is called text shaping.
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Until I get a plain and simple C99 implementation in the worse case scenario, I would stay away from those.
But the right way to avoid like hell those c++ abominations (there are still people thinking coding c++ makes them smart, at best toxic, but no less worse) and start with roman script and incrementally add supported languages. I did venture in harfbuzz, there is no salvation, the coding is so much c++ brainf*cked better start clean and lean.