see: https://stackoverflow.com/questions/40543176/does-opengl-use-xlib-to-draw-windows-and-render-things-or-is-it-the-other-way-a APIs Transclude of graphics／rendering-libraries／apis#^excerpt Widget Toolkit Systems Widget Library GUI Toolkit UX Library is a library or a collection of libraries containing a set of graphical control elements (called widgets) used to construct the graphical user interface (GUI) of programs Link to original Desktop Environments (DE) is an implementation of the desktop metaphor Link to original