The project Ada Bar Codes provides a framework for generating various types of bar codes (1D, or 2D, like QR codes) on different output formats and devices.
Alire crate: https://alire.ada.dev/crates/bar_codes
Mirror: https://github.com/zertovitch/ada-bar-codes
A C#/.net-library for encoding and decoding DataMatrix codes (based on a .net-port of libdmtx). DataMatrix.net also contains a small application for generating PDF documents containing different types of 1D- and 2D-codes.