FLTK (pronounced "fulltick") is a LGPL'd C++ graphical user interface
toolkit for X (UNIX), OpenGL, and Win32.  FLTK was designed to be small and
modular enough to be statically linked, but also works fine as a shared
library.  FLTK also includes FLUID, an interactive user interface builder
program.

FLTK 2.0 is an experimental branch and has been declared inactive,
superseded by 3.0. Later FLTK 3.0 has been declared inactive too.

New applications should use the FLTK 1.4 API.