libffi is a library that really only provides the lowest, machine dependent layer of a fully featured foreign function interface. A layer must exist above libffi that handles type conversions for values passed between the two languages. ffi stands for Foreign Function Interface. A foreign function interface is the popular name for the interface that allows code written in one language to call code written in another language.
The libfreespace library enables rapid development of motion control applications for in-air remote controls and mice that embed Hillcrest Labs' Freespace technology. libfreespace provides access to calibrated acceleration, rotational velocity measurements, and sensor orientation. Advanced uses include statistics collection, configuration, and firmware upgrades.
libgeotiff is a library (normally built on top of libtiff) for reading and writing coordinate system information from/to GeoTIFF files. It includes CSV files for expanding projected coordinate system codes into full projections definitions and examples of transforming the definitions into a form that can be used with the PROJ.4 projections library. It also includes the sample applications listgeo (for dumping GeoTIFF information in readable form) and geotifcp (for applying geotiff tags to an existing TIFF or GeoTIFF file).
Libgta implements the Generic Tagged Arrays (GTA) file format. GTAs can store any kind of data in multidimensional arrays, optionally with simple tags to store rich metadata. GTAs are streamable and support mupltiple compression methods. Uncompressed GTAs allow easy out-of-core data access for very large arrays.
libhid is a user-space HID access library. It provides a generic and flexible way to access and interact with USB HID devices, much like libusb does for plain USB devices. It is based on libusb, thus it requires no HID support in the kernel. Furthermore, it aims to support all operating system supported by libusb: Linux, BSD, OS X, and Windows. Python bindings are provided, and other high-level bindings are available upon request.