Book Image

Tkinter GUI Application Development Blueprints

By : Bhaskar Chaudhary
Book Image

Tkinter GUI Application Development Blueprints

By: Bhaskar Chaudhary

Overview of this book

Tkinter is the built-in GUI package that comes with standard Python distributions. It is a cross-platform package, which means you build once and deploy everywhere. It is simple to use and intuitive in nature, making it suitable for programmers and non-programmers alike. This book will help you master the art of GUI programming. It delivers the bigger picture of GUI programming by building real-world, productive, and fun applications such as a text editor, drum machine, game of chess, media player, drawing application, chat application, screen saver, port scanner, and many more. In every project, you will build on the skills acquired in the previous project and gain more expertise. You will learn to write multithreaded programs, network programs, database driven programs and more. You will also get to know the modern best practices involved in writing GUI apps. With its rich source of sample code, you can build upon the knowledge gained with this book and use it in your own projects in the discipline of your choice.
Table of Contents (15 chapters)
Tkinter GUI Application Development Blueprints
About the Author
About the Reviewers

Displaying the line number

Let's work towards showing the line numbers to the left of the Text widget. This will require us to tweak the code at various places. So, before we start coding, let's look at what we are trying to achieve here.

The View menu has a menu item that allows users to choose whether to show line numbers. We only want to show the line numbers if the option is selected, as shown in the following screenshot:

If the option is selected, we need to display the line numbers in the left frame that we created earlier.

The line number should update every time a user enters a new line, deletes a line, cuts or pastes text from the line, performs an undo or a redo operation, opens an existing file, or clicks on the new menu item. In short, the line number should be updated after every activity results in change of content.

Therefore, we need to define a function called on_content_changed(). This function should be called after the definitions of every key press, cut, paste, undo, redo...