XFLTK is an extension to FLTK library which provides generation of GUI based on XML configuration files.

FLTK (pronounced “fulltick”) is a cross-platform C++ GUI toolkit for UNIX®/Linux® (X11), Microsoft® Windows®, and MacOS® X. FLTK provides modern GUI functionality without the bloat and supports 3D graphics via OpenGL® and its built-in GLUT emulation.

More informations and download: http://xfltk.w8.pl/