The GTK3+ library uses Gobject but the GTK2+ library does not. GObject provides GTK+ with object-oriented C-based APIs and automatic transparent API bindings to other compiled or interpreted languages (such as Python).

GObject is the GLib Object system, where GLib provides the core application building blocks for libraries and applications written in C. Note that some environments might not show application icon, in some the application icons must be enabled. An application icon is a small image which is usually shown in the titlebar of the application. Essentially it autogenerates Python bindings from the underlying C source code. Figure: Python Gtk simple application Python Gtk icon. The Python GObject Introspection module (aka gi or gi.repository) is a middleware layer between C libraries (using GObject) and language bindings. Offering a complete set of widgets, GTK is suitable for projects ranging from small one-off projects to complete application suites. For Python 3 you need to use Gtk+ through the gi GObject Introspection module. GTK is a multi-platform toolkit for creating graphical user interfaces. The gtk and pytk modules apply to Python 2 only. pygtk is another module, also part of PyGTK, that can (but doesn't need to) be used to ensure a certain version of the Gtk+ library. I now realise that gtk means PyGTK, the Python module that contains bindings to the Gtk+ 2.x library. I was confused by pygtk vs gtk because my test app worked fine with gtk.

Python gtk