Contains classes that are graphical in nature. Each one displays
something to the user in a visual manner.
The classes in the top package don't have any render-specific code
in them. Each is extended in a sub package and rendered using a specific
graphics library or language. For example, a set of classes are extended
for drawing to the screen using OpenGL, while another set draws to a file
using PostScript commands. Each set is generically assignable using
the base classes in the top package.
The gui sub package contains custom dialogs and components.