I publish a 2D rendering engine that I developed in C (works natively in C ++) with SDL, and is cross-platform (UNIX, Linux, Windows).
The idea is simple, allow C / C ++ developers to easily create a beautiful graphical interface. Without departing from the fundamental concepts that make the strength of C.
1 - Manually or in your C / C ++ code, you “write” XML- (like) in a file,
2 - You call the engine’s “read” function,
3 - You call the engine’s “display” function
Inclusion in your C / C ++ project is simple, only one include.
In short with a little imagination, and I know you have a lot of it, you can build all the 2D interfaces you want. Messaging software encrypted by AES perhaps?
The git repository is here https://gitlab.com/HeryZoMichael/sdl_xgui
And a discussion on another forum is here: https://www.developpez.net/forums/d2032829/applications/developpement-2d-3d-jeux/api-graphiques/sdl/moteur-rendu-2d-c-cpp-sdl_2-a