[AndriyKunitsyn]

So, there's Skia. Skia is a high-level library that converts texts to glyph indices, does high-level text layout, and caches glyphs (and it also makes GPU calls). But the actual parsing of the font file and converting glyphs to bitmaps happens below in FreeType.

Skia is made in C++. It's made by Google.

There's FreeType. It actually measures and renders glyphs, simultaneously supporting various antialiasing modes, hinting, kerning, interpreting TrueType bytecode and other things.

FreeType is made in C. It's not made by Google.

Question: why was it FreeType that got a Rust rewrite first?

[raggi]

It has a smaller API surface into the consuming applications and platforms.

Skia tendrils run deep and leak all over the place.

There's also a different set of work to invest in, next-generation Skia is likely to look quite different, moving much of the work on to the GPU, and this work is being researched and developed: https://github.com/linebender/vello. Some presentations about this work too: https://youtu.be/mmW_RbTyj8c https://youtu.be/OvfNipIcRiQ

[interroboink]

Perhaps since FreeType is the one handling the more untrusted inputs (the font files themselves, downloaded from who-knows-where), it is more at-risk and thus stood to benefit from the conversion more?

But I don't really know anything about how all the parts fit together; just speculating.

[londons_explore]

Skia's inputs are relatively less complex, so there is less risk of dangerous corner cases.

[bawolff]

Format parsing is generally considered some of the most risky type of code to have for memory safety. Skia is probably considered a less risky problem domain.