Python session kept open after closing tkinter window with a matplotlib graph

Question

I want to put a matplotlib figure in a tkinter user interface. This is my code, based on the matplotlib documentation:

import tkinter as tk
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2Tk
import sys

root = tk.Tk()

fig = plt.figure(figsize=(4,4))
ax = fig.add_subplot()
line, = ax.plot([1,2,3],[1,4,9])

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()

toolbar = NavigationToolbar2Tk(canvas, root, pack_toolbar=False)
toolbar.update()

canvas.get_tk_widget().pack()
toolbar.pack()

tk.Button(root, text="Exit", command=lambda:sys.exit()).pack()

root.mainloop()

I runs correctly. The problem comes when I close the window. If I press the "X" button of the window, the terminal never finishes, but if I press the "Exit" button I added, it finishes. If instead I use root.destroy(), it neither works. How can I solve this issue?

Thanks!

Edit:

I uploaded a video in YouTube, so you can see my problem: https://youtu.be/qUkm-lnXRR8

I'm using Windows 11 PowerShell, version:

Name                           Value
----                           -----
PSVersion                      5.1.22621.963
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.22621.963
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Python version 3.11.1

It shouldn't have that behaviour. How do you run it in the terminal? What OS are you using? Can't reproduce the problem on Ubuntu. — TheLizzard, Jan 01 '23 at 20:11
Add a print statement after the `mainloop()`. Does the print statement get called? A temporary work around would be to use [this](https://stackoverflow.com/a/4643082/11106801) — TheLizzard, Jan 03 '23 at 14:02
@TheLizzard the print statement after the `mainloop` is never printed. Following the accepted answer on the question you shared, I can use `root.protocol("WM_DELETE_WINDOW", lambda: sys.exit())` and it works. But this cannot be the "final" solution because therefore I cannot run any code after the mainloop is finished. — Abel Gutiérrez, Jan 03 '23 at 15:25
instead of `lambda:sys.exit()`, have a function with the code that you want to run after the GUI is closed and make sure the function ends with `sys.exit()`. But that is a work around. For a proper solution, someone needs to look at `matplotlib`'s code and maybe file a bug report. — TheLizzard, Jan 03 '23 at 15:27
Thanks for your comments @TheLizzard , I will report this bug. — Abel Gutiérrez, Jan 03 '23 at 15:32
You can track this issue at https://github.com/matplotlib/matplotlib/issues/24874 — Abel Gutiérrez, Jan 03 '23 at 16:18

Abel Gutiérrez · Accepted Answer · 2023-01-05T16:29:25.967

0

Following this GitHub issue, this solves the issue

import tkinter as tk
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2Tk
import sys
from matplotlib.figure import Figure #### This is the difference

root = tk.Tk()

fig = Figure() # plt.figure()
ax = fig.add_subplot()

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()

toolbar = NavigationToolbar2Tk(canvas, root, pack_toolbar=False)
toolbar.update()

canvas.get_tk_widget().pack()
toolbar.pack()

tk.Button(root, text="Exit", command=lambda:sys.exit()).pack()

root.mainloop()

print("Hello")

edited Jan 05 '23 at 16:29

answered Jan 04 '23 at 14:16

Abel Gutiérrez

159
8

1

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jan 04 '23 at 15:30

Python session kept open after closing tkinter window with a matplotlib graph

1 Answers1