Plotting with matplotlib in threads

Question

I know there are quite some questions on matplotlib and threading, also that pyplot is not threadsave. I couldn\'t find anything on this particular problem however. What I w

Answer 1

Use a Qt signal to call your plotting function in the main thread

import matplotlib
matplotlib.use("qt4agg")
import matplotlib.pyplot as plt
import threading
import time

from PyQt4 import QtCore

class Call_in_QT_main_loop(QtCore.QObject):
    signal = QtCore.pyqtSignal()

    def __init__(self, func):
        super().__init__()
        self.func = func
        self.args = list()
        self.kwargs = dict()
        self.signal.connect(self._target)

    def _target(self):
        self.func(*self.args, **self.kwargs)

    def __call__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs
        self.signal.emit()

@Call_in_QT_main_loop
def plot_a_graph():
    f,a = plt.subplots(1)
    line = plt.plot(range(10))
    plt.show()
    print("plotted graph")
    print(threading.current_thread())  # print the thread that runs this code

def worker():
    plot_a_graph()
    print(threading.current_thread())  # print the thread that runs this code
    time.sleep(4)

testthread = threading.Thread(target=worker)

testthread.start()