Welcome to the exciting world of GUI programming with Tkinter. This chapter aims to get you acquainted with Tkinter, the built-in Graphical User Interface (GUI) library for all standard Python distributions.

Tkinter (pronounced tea-kay-inter) is the Python interface to Tk, the GUI toolkit for Tcl/Tk.

Tcl (Tool command language), which is pronounced as tickle, is a popular scripting language in the domains of embedded applications, testing, prototyping, and GUI development. On the other hand, Tk is an open source, multiplatform widget toolkit that is used by many different languages to build GUI programs.

The Tkinter interface is implemented as a Python module— Tkinter.py in Python 2.x Versions and tkinter/__init__.py in Python 3.x Versions. If you look at the source code, Tkinter is just a wrapper around a C extension that uses the Tcl/Tk libraries.

Tkinter is suitable for a wide variety of areas, ranging from small desktop applications to scientific modeling and research endeavors across various disciplines.

When a person learning Python needs to graduate to GUI programming, Tkinter seems to be the easiest and fastest way to get the work done.

Tkinter is a great tool for the programming of GUI applications in Python. The features that make Tkinter a great choice for GUI programming include the following:

• It is simple to learn (simpler than any other GUI package for Python)
• Relatively little code can produce powerful GUI applications
• Layered design ensures that it is easy to grasp
• It is portable across all operating systems
• It is easily accessible, as it comes pre-installed with the standard Python distribution

None of the other Python GUI toolkits have all of these features at the same time.

The purpose of this chapter is to make you comfortable with Tkinter. It aims to introduce you to the various components of GUI programming with Tkinter.

We believe that the concepts that you will develop in this chapter will enable you to apply and develop GUI applications in your area of interest.

The key aspects that we want you to learn from this chapter include the following:

• Understanding the concept of a root window and the main loop
• Understanding widgets—the building blocks of programs
• Getting acquainted with a list of available widgets
• Developing layouts by using different geometry managers
• Applying events and callbacks to make a program functional
• Styling widgets by using styling options and configuring the root widget