TrueType includes a virtual machine [1] for hinting. Text rendering also needs to alter shapes of glyphs for other reasons, like font weight and pseudo-italic.

TrueType includes a virtual machine [1] for hinting. Text rendering also needs to alter shapes of glyphs for other reasons, like font weight and pseudo-italic. [1]: https://en.wikipedia.org/wiki/TrueType#Hinting_language https://en.wikipedia.org/wiki/TrueType#Hinting_language