Xgridfit (formerly hosted at Sourceforge) is an XML-based TrueType hinting language for font developers who aren’t quite satisfied with auto-hinting, or who feel they’re going to lose it if they have to hint one more serif with a graphical tool. It is about delivering fine-grained control over hinting while relieving developers of the necessity of fiddling with reference pointers and other minutiae, and, perhaps more importantly, about re-using code via macros and user-defined functions.
Version 3 radically reduces the verbosity of the language, eliminates multiple dependencies (its only dependencies, aside from Python 3, are fonttools, lxml and setuptools), adds support for variable fonts, enhances the ability to merge its own instructions with instructions produced by autohinters, and supports the modern practice of hinting only on the y axis.
Version 3.2 adds the ability to identify points by coordinates rather than by index number, improving portability of code (since different programs will index points differently but will in general keep on-curve points at the same location). This feature is especially useful in hinting variable fonts.
Version 3.2.1 indexes only coordinates for on-curve points, saving memory and time; and allows users to suppress the code that enables high-level programming in functions, permitting the creation of small, fast functions. It also fixes a couple of bugs.