[FIXED] Matplotlib in Tkinter segmentation fault on Ubuntu Mate

Issue

I'm using matplotlib inside a tkinter window on python3. The program works fine on my coding machine (ubuntu18.04 running in windows WSL). Unfortunately, I need this program to run on my Raspberry Pi 4 which has Ubuntu20.04 64bit installed with the distro Ubuntu Mate 1.24.0. When I run my program on the RPi I get segmentation fault as soon as I call

FigureCanvasTkAgg.draw()

Nevertheless, I use matplotlib in other programs (using pyplot) and they work fine.

Details:

• these are my imports:

import tkinter as tk
import numpy as np
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure

• This is a brief summary of what my program does:
  • I have a class that implements the tkinter window; in the constructor, I instantiate the following plot variables:

        self.figure = Figure(figsize=(5, 5), dpi=100)
        self.subplot = self.figure.add_subplot(111)
        self.canvas = FigureCanvasTkAgg(
            self.figure, master=self.tkWindow)

• Then, the class has this method to update the plot:

    def updatePlot(self, x, y, title, xlabel, ylabel):
        self.subplot.clear()
        self.subplot.set_title(title)
        self.subplot.set_xlabel(xlabel)
        self.subplot.set_ylabel(ylabel)
        self.subplot.plot(x, y, color='red', label='unfiltered')
        self.subplot.legend(loc='upper right')
        self.canvas.draw() # <- this is the line that causes the crash
        self.canvas.get_tk_widget().grid(row=4, columnspan=5)

• Versions on my windows machine:

  • Ubuntu 18.04.5
  • Python3 3.6.9
  • Matplotlib 2.1.1
  • Tkinter 0.1.0

• Versions on my RPi:

  • Ubuntu 20.04.3
  • Python3 3.8.10
  • Matplotlib 3.3.4
  • Tkinter 0.1.0

Solution

I've had the same problem on my Raspberry Pi 3 B+ with Raspbian running on it.

Try changing FigureCanvasTkAgg.draw() with FigureCanvasTkAgg.draw_idle()

Answered By - Clown Down