As a Python developer, sooner or later you’ll want to write an application with a graphical user interface. Fortunately, there are a lot of options on the tools front: The Python wiki on GUI programming lists over 30 cross-platform frameworks, as well as Pyjamas, a tool for cross-browser Web development based on a port of the Google Web Toolkit.
How to choose between all these options for Python GUIs? I started by narrowing it down to those that included all three platforms (Windows, Mac, and Linux) and, where possible, Python 3. After that filtering, I found four toolkits (Gtk, Qt, Tk, and wxWidgets) and five frameworks (Kivy, PyQt, gui2Py, libavg and wxPython). Here’s why I like them.
One of the more interesting projects, the liberal MIT-licensed Kivy is based on OpenGL ES 2 and includes native multi-touch for each platform and Android/iOS. It’s an event-driven framework based around a main loop, and is thus very suitable for game development. Your application adds callbacks from the main loop at a scheduled frequency, or by one-off trigger. The Kivy framework is very powerful for handling everything from widgets to animation, and includes its own language for describing user interface and interactions.
If you want to create cross-platform graphical applications, or just need a very powerful cross-platform GUI, Kivy is highly recommended.
Qt is a multi-licensed cross-platform framework written in C++. If your application is completely open source, you can use Qt for free under the community license; otherwise you’ll need a commercial license. Qt has been around for a long time and was owned by Nokia for a while; it’s a very comprehensive library of tools and APIs, widely used in many industries, and covers many platforms including mobile. If a gadget such as a SatNav has a GUI, there’s a good chance it’ll be Qt based.
Compared to Kivy and PyQt, PyGUI is considerably simpler and just for Unix, Macintosh and Windows platforms. Developed by Dr. Greg Ewing at the University of Canterbury in New Zealand, the MVC framework focuses on fitting into the Python ecosystem as easily as possible.
One of the platform’s aims is to interpose as little code as possible between the Python application and the platform’s underlying GUI so the application’s display always reflects the native GUI of the platform. If you’re after a simple and quick way to learn GUI, start with this one.