Doxygen vs Swift-DocC

Doxygen is a free documentation generator that turns source-code comments into reference material, parsing items such as classes, functions and variables. It supports C/C++, Lex, Java, Python, VHDL, PHP IDL, C#, Fortran, Objective-C 2.0 and some D sources. Output can be generated as HTML, PDF through LaTeX, Word through RTF or structured XML for external tools. Graphviz’s dot tool can add include-dependency, collaboration, call, directory-structure and class-hierarchy diagrams. Doxywizard provides a graphical interface for editing settings and running the generator on Windows, Linux and macOS; Doxygen also works on many Unix flavors. It supports HTML Help, docsets, Qt-Help and Eclipse Help, with more than 100 configurable options. The tool runs without registration and does not collect personal or usage data. It is self-hosted and licensed under the GNU General Public License, without express or implied warranty. Help is listed through Stack Overflow and the doxygen users mailing list; commercial feature and bug-fix support has limited capacity.

Swift-DocC has no write-up on Specifiction yet; its figures are above.