How to Use Threading with Tkinter for Live Plotting in Python

Discover how to efficiently update Matplotlib plots in a Tkinter GUI using threading, allowing for simultaneous data streaming and user interactivity.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Python: threading and tkinter

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Introduction

When developing a graphical user interface (GUI) using Tkinter and Matplotlib in Python, one common challenge developers face is the ability to continuously update plots while still allowing for user interaction. Specifically, users may want to pause, continue, or stop updates with buttons. This leads to complex threading issues that, if not handled properly, can result in non-responsive UIs or unexpected behavior.

If you're experiencing difficulties getting your threads to function correctly with a Tkinter GUI, you're not alone. In this guide, we will explore the main problems associated with threading in Tkinter, along with a structured solution to effectively implement this functionality.

The Problem

In the code you might be familiar with, the primary issue arises from how global variables, threading, and GUI updates are handled. Users have noted:

Buttons becoming unresponsive when threads execute.

Data threads processing while plots do not update.

The occasional error: “RuntimeError: main thread is not in main loop.”

These issues stem from incorrect thread management and GUI updates not being executed on the main thread.

Solution Breakdown

1. Understanding the Importance of the Main Thread

Tkinter is not thread-safe, meaning that any GUI operations should only be performed in the main thread. Using threads for data acquisition is fine, but updating your GUI elements (like plots) must be done from the main thread.

Here’s how you can set up your data update loop:

[[See Video to Reveal this Text or Code Snippet]]

3. Setting Up State Management with Enums

Using numbers for states can lead to confusion and makes code harder to read. Instead, utilize Python's Enum for better readability and maintainability throughout your code.

[[See Video to Reveal this Text or Code Snippet]]

4. Separate Threads for Data Acquisition

Limit thread usage strictly to tasks like data acquisition. Set up a separate thread to grab data from the microcontroller (or in this case, simulate data). Your GUI elements should not access these shared data structures directly from outside the thread.

Here’s how you can set it up:

[[See Video to Reveal this Text or Code Snippet]]

5. Integrating Everything Together

Using the above concepts, below is a simplified structure for managing data and plots:

[[See Video to Reveal this Text or Code Snippet]]

6. Implementing Buttons for Control

Design buttons for controlling the streaming of data, which are interactive and connected to your state management:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these best practices, you'll create a Tkinter application that can effectively handle live plotting with responsive buttons for controlling data flow. Avoid threading pitfalls by ensuring your GUI updates occur in the main thread and managing your application state clearly through enumerations.

Implementing these strategies will make your GUI not only functional but maintainable and user-friendly. Happy coding!