C++ GUI API Aimed at Games
Agui is an Object Oriented Graphical User Interface library for games written in C++. It has full UTF8 Unicode support and is back end independent. Comes with many widgets by default.
Agui uses the CMAKE build system.
Currently Allegro5 and SFML2 backends are implemented and supported.
Agui is used in Stemwater Spades https://github.com/jmasterx/StemwaterSpades and the popular commercial game Factorio: http://www.factorio.com/credits