We have reached the final chapter of this book. Let's end our discussion on Tkinter by looking at some concepts that, though very common in many graphical user interface (GUI) programs, did not appear in the previous chapters.

We will cover the following in this chapter:

• Tracing Tkinter variables and attaching callbacks that are triggered when the value of a variable changes
• Understanding the default keyboard widget traversal rules to provide a consistent user experience
• Validating user inputs using built-in Tkinter mechanisms
• Formatting a widget's content as the user interacts with the widget
• Understanding how Tkinter handles fonts and the best practices involved in using custom fonts in Tkinter
• Redirecting the command-line output to Tkinter
• Taking a look at the source code of Tkinter to understand class hierarchy
• Highlighting some current best practices involved in program design and implementation
• Getting an insight into code cleanup and program optimization
• Distributing Tkinter applications as standalone programs to end users
• Understanding the limitations of Tkinter
• Exploring alternatives to Tkinter and understanding when it is better to use them instead of Tkinter and the tradeoffs involved
• Backporting Tkinter programs are written in Python 3.x versions to older Python 2.x versions

Let's begin!