FreeType
FreeType is a mature open font engine reading TrueType, OpenType, and other formats into glyph outlines and bitmaps.
Why use it
Custom UI, text atlases, and offline font tools gain a consistent cross-platform low-level API.
Where it fits
Find engines, frameworks, code libraries, version control, and production automation.
What to check
It does not provide full layout, bidirectional text, or font licensing; pair it with HarfBuzz and review font terms.