Nuklear
This is a minimal-state, immediate-mode graphical user interface toolkit
written in ANSI C and licensed under public domain. It was designed as a simple
embeddable user interface for application and does not have any dependencies,
a default render backend or OS window/input handling but instead provides a
highly modular, library-based approach, with simple input state for input and
draw commands describing primitive shapes as output. So instead of providing a
layered library that tries to abstract over a number of platform and
render backends, it focuses only on the actual UI.
Features
Single-header library
Small codebase (~18kLOC)
No dependencies (not even the standard library if not wanted)