[ Bug ] - Closing External Matplotlib window causes segfault within python

[patrickjimenez]

Error

Closing an external Matplotlib window causes segfault within python

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Operating System

MacOs 13.0

PySimpleGUI Port (tkinter, Qt, Wx, Web)

tinter

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Versions

*** Version information copied to your clipboard. Paste into your GitHub Issue. ***

Python version: 3.9.7 (default, Sep 16 2021, 08:50:36)
[Clang 10.0.0 ]
port: tkinter
tkinter version: 8.6.11
PySimpleGUI version: 4.60.4
PySimpleGUI filename: /Users/patrickjimenez/Documents/_Capstone/ui/env/lib/python3.9/site-packages/PySimpleGUI/PySimpleGUI.py

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Your Experience In Months or Years (optional)

Years Python programming experience
5
Years Programming experience overall
5
Have used another Python GUI Framework? (tkinter, Qt, etc) (yes/no is fine)
no
Anything else you think would be helpful?

The segfault also occurs in the Demo_Matplotlib_Two_Windows.py demo file

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Troubleshooting

These items may solve your problem. Please check those you've done by changing - [ ] to - [X]

• Searched main docs for your problem www.PySimpleGUI.org
• Looked for Demo Programs that are similar to your goal. It is recommend you use the Demo Browser! Demos.PySimpleGUI.org
• If not tkinter - looked for Demo Programs for specific port
• For non tkinter - Looked at readme for your specific port if not PySimpleGUI (Qt, WX, Remi)
• Run your program outside of your debugger (from a command line)
• Searched through Issues (open and closed) to see if already reported Issues.PySimpleGUI.org
• Have upgraded to the latest release of PySimpleGUI on PyPI (lastest official version)
• Tried using the PySimpleGUI.py file on GitHub. Your problem may have already been fixed but not released

Detailed Description

I run the demo program. I click "Plot". Matplotlib shows a plot. I close the Matplotlib plot. Python crashes.

Code To Duplicate

A short program that isolates and demonstrates the problem (Do not paste your massive program, but instead 10-20 lines that clearly show the problem)

This pre-formatted code block is all set for you to paste in your bit of code:

from matplotlib import use
import PySimpleGUI as sg
# import PySimpleGUIQt as sg; use('qt5agg')
import matplotlib.pyplot as plt

"""
    Simultaneous PySimpleGUI Window AND a Matplotlib Interactive Window
    A number of people have requested the ability to run a normal PySimpleGUI window that
    launches a MatplotLib window that is interactive with the usual Matplotlib controls.
    It turns out to be a rather simple thing to do.  The secret is to add parameter block=False to plt.show()
"""

def draw_plot():
    plt.plot([0.1, 0.2, 0.5, 0.7])
    plt.show(block=False)

layout = [[sg.Button('Plot'), sg.Cancel(), sg.Button('Popup')]]

window = sg.Window('Have some Matplotlib....', layout)

while True:
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break
    elif event == 'Plot':
        draw_plot()
    elif event == 'Popup':
        sg.popup('Yes, your application is still running')
window.close()

Screenshot, Sketch, or Drawing

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Watcha Makin?

If you care to share something about your project, it would be awesome to hear what you're building.

[patrickjimenez]

Found a similar issue but on Linux not MacOs. It was never addressed

[patrickjimenez]

Fixed!

import PySimpleGUI as sg
import matplotlib
matplotlib.use('Qt5Agg')

matplotlib's use function makes the plot popup qt based and now it doesn't crash

[PySimpleGUI]

What matplotlib version are you using?

[PySimpleGUI]

This is the code I tested with python 3.9 and matplotlib 3.6.2. I don't seem to be able to replicate the problem with this code. Maybe you can provide some additional code/info that shows the problem.

from matplotlib import use
import PySimpleGUI as sg
# import PySimpleGUIQt as sg; use('qt5agg')
import matplotlib.pyplot as plt

"""
    Simultaneous PySimpleGUI Window AND a Matplotlib Interactive Window
    A number of people have requested the ability to run a normal PySimpleGUI window that
    launches a MatplotLib window that is interactive with the usual Matplotlib controls.
    It turns out to be a rather simple thing to do.  The secret is to add parameter block=False to plt.show()
"""

def draw_plot():
    plt.plot([0.1, 0.2, 0.5, 0.7])
    plt.show(block=False)

layout = [[sg.Button('Plot'), sg.Cancel(), sg.Button('Popup')]]

window = sg.Window('Have some Matplotlib....', layout)

while True:
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break
    elif event == 'Plot':
        draw_plot()
    elif event == 'Popup':
        sg.popup('Yes, your application is still running')
window.close()

cmd_itcZACV5AU.mp4

[PySimpleGUI]

So it sounds like it's limited to Linux and Mac? Specific versions of Matplotlib would be helpful. If running the latest, I suggest backing up to the older version and trying again.

[SuperZooper3]

I am also replicating the same issue. After closing my matplotlib window, the GUI crashes consistently (even when block=false is there for the .show). The GUI does still respond (using the Popup test you are all using) during the MatPlotLib visualization, but then after it closes, the GUI crashes.

Using PySimpleGUI==4.60.5 and matplotlib==3.7.2 on macOS 13.4.1

[jason990420]

Maybe it will be better if also provided the version of Python and tkinter, and any exception information.

I don't have a Mac to test anything about it. Maybe you can try this code

import matplotlib
print(matplotlib.get_backend())
matplotlib.use('Qt5Agg')            # Qt5Agg or TkAgg here
# matplotlib.use('TkAgg')
print(matplotlib.get_backend())
import matplotlib.pyplot as plt
plt.rcParams['keymap.quit'] = ''    # It may help or not.

import PySimpleGUI as sg


window = sg.Window('Demo', [[sg.Button('Show')]], font=('Courier New', 20))

while True:

    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break
    elif event == 'Show':
        x = [1, 2, 3, 4, 5, 6, 7, 8]
        y = [2, 3, 1, 3, 1, 4, 2, 3]
        plt.scatter(x, y)
        plt.show()
        plt.clf()

window.close()

[SuperZooper3]

I'm using Python 3.10.11 and tkinter 8.6.

If I run the code with matplotlib.use('Qt5Agg'), it crashed, telling me that it Failed to import any of the following Qt binding modules: PyQt6, PySide6, PyQt5, PySide2

Commenting out that line as well as the next one lets it run, and when I close the MatPlotLib window, the GUI crashed. The execution printed:

MacOSX
MacOSX
Mac OS Version is 13.4.1 and patch enabled so applying the patch
zsh: segmentation fault  python testcode.py

The segfault came after closing the MatPlotLib.

Interestingly, if I uncomment the line matplotlib.use('TkAgg'), the GUI does not crash after closing MatPlotLib (even if the MatPlotLib window does look a bit different than usual).

MacOSX
TkAgg
Mac OS Version is 13.4.1 and patch enabled so applying the patch

(with the grey bottom looking a bit broken)

(normal)

Just for the sake of testing, commenting out the line plt.rcParams['keymap.quit'] = '' # It may help or not. does not change anything: it still crashes without TkAgg on, and works with it on.

For now, I'll use the fix with TkAgg, but it would still be cool to understand what's causing the problem and for it to be fixed for everyone else using the PySimpleGUI library.

[jason990420]

Maybe it is the issue for matplotlib, not PySimpleGUI.
Refer Issue matplotlib/matplotlib#18953