Before exploring the various examples and applications, let's first acquire a brief, high-level understanding of the GTK+3.

GTK+3 contains a set of graphical control elements (widgets) and is a highly usable, feature-rich toolkit used to develop graphical user interfaces. It has cross-platform compatibility and is relatively easy to use. GTK+3 is an object-oriented widget toolkit written in the C programming language. Therefore, when running GTK+3 in Python, we need a wrapper to call the functions in the GTK+3 library. In this case, PyGObject is a Python module that serves as the wrapper and saves us time by not having to learn two languages to plot our figures. PyGObject exclusively supports GTK+3 or later versions. If you prefer to use GTK+2 in your application, we recommend using PyGTK instead.

Together with the Glade GUI builder, they provide a very powerful application development environment.