What I don't get is: which library lets you draw stuff on the screen. GLib or GTK+? I thought that was GLib, and GTK+ was using GLib to implement controls. Wh

What I don't get is: which library lets you draw stuff on the screen. GLib or GTK+? I thought that was GLib, and GTK+ was using GLib to implement controls. Which library does one need to build their own controls?