Embedding matplotlib graph into pyqt5

Question

I've tried using example pieces of code to embed my animated graph of mars and earth orbiting the sun using an _update_plot from pyplot from matplotlib into a PyQt5 GUI. There are no examples that use pyplot and I'm really struggling. What have I dont wrong here: (?)

Attempt:

import sys
import time

import numpy as np

from matplotlib.backends.qt_compat import QtCore, QtWidgets, is_pyqt5
if is_pyqt5():
    from matplotlib.backends.backend_qt5agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
else:
    from matplotlib.backends.backend_qt4agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
from matplotlib.figure import Figure


class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self._main = QtWidgets.QWidget()
        self.setCentralWidget(self._main)
        layout = QtWidgets.QVBoxLayout(self._main)

        static_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(static_canvas)
        self.addToolBar(NavigationToolbar(static_canvas, self))

        dynamic_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(dynamic_canvas)
        self.addToolBar(QtCore.Qt.BottomToolBarArea,
                        NavigationToolbar(dynamic_canvas, self))

        self._static_ax = static_canvas.figure.subplots()
        t = np.linspace(0, 10, 501)
        self._static_ax.plot(t, np.tan(t), ".")

        self._dynamic_ax = dynamic_canvas.figure.subplots()
        self._timer = dynamic_canvas.new_timer(
            100, [(self._update_canvas, (), {})])
        self._timer.start()

    def _update_canvas(self):
        scat = scat.set_offsets(([math.cos(math.radians(i))*7.5, math.sin(math.radians(i))*7.5], [math.cos(math.radians(i/2))*9, math.sin(math.radians(i/2))*9], [0, 0]))
        anim = self.animation.FuncAnimation(fig, scat, fargs = (fig, scat, l,l2),
                               frames = 720, interval = 10)



if __name__ == "__main__":
    qapp = QtWidgets.QApplication(sys.argv)
    app = ApplicationWindow()
    app.show()
    qapp.exec_()

the Original code I'm trying to embed is this:

import math
import matplotlib.pyplot as plt
import matplotlib.animation as animation
import numpy as np

def _update_plot(i, fig, scat): 
        M = ((math.sin(math.radians(i))*7.5)-(math.sin(math.radians(i/2))*9))/((math.cos(math.radians(i))*7.5)-(math.cos(math.radians(i/2))*9))
        g = M*(15-(math.cos(math.radians(i/2))*9))+(math.sin(math.radians(i/2))*9)

        scat.set_offsets(([math.cos(math.radians(i))*7.5, math.sin(math.radians(i))*7.5], [math.cos(math.radians(i/2))*9, math.sin(math.radians(i/2))*9], [0, 0]))
        return [scat]

fig = plt.figure()
x = [0]
y = [0]

ax = fig.add_subplot(111)
ax.set_aspect('equal')
ax.grid(True, linestyle = '-', color = '0.10')
ax.set_xlim([-15, 15])
ax.set_ylim([-15, 15])

scat = plt.scatter(x, y, c = x, zorder=3)
scat.set_alpha(0.8)

anim = animation.FuncAnimation(fig, _update_plot, fargs = (fig, scat),
                               frames = 720, interval = 10)

plt.show()

Any help/advice is greatly appreciated.

Answer 1

The idea is indeed to not use pyplot in case you embedd in a custom GUI. Else your figure would be managed by pyplot as well as the GUI.

The adaption of your example could look like this:

import sys
import numpy as np

from matplotlib.backends.qt_compat import QtWidgets
from matplotlib.backends.backend_qt5agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)

from matplotlib.figure import Figure
from matplotlib import animation


class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self._main = QtWidgets.QWidget()
        self.setCentralWidget(self._main)
        layout = QtWidgets.QVBoxLayout(self._main)

        self.fig = Figure(figsize=(5, 3))
        self.canvas = FigureCanvas(self.fig)
        layout.addWidget(self.canvas)
        self.addToolBar(NavigationToolbar(self.canvas, self))

        self.setup()

    def setup(self):
        self.ax = self.fig.subplots()
        self.ax.set_aspect('equal')
        self.ax.grid(True, linestyle = '-', color = '0.10')
        self.ax.set_xlim([-15, 15])
        self.ax.set_ylim([-15, 15])

        self.scat = self.ax.scatter([], [],  zorder=3)
        self.scat.set_alpha(0.8)

        self.anim = animation.FuncAnimation(self.fig, self.update,
                                                 frames = 720, interval = 10)


    def update(self, i):
        self.scat.set_offsets(([np.cos(np.radians(i))*7.5, np.sin(np.radians(i))*7.5], 
                                  [np.cos(np.radians(i/2))*9, np.sin(np.radians(i/2))*9]))



if __name__ == "__main__":
    qapp = QtWidgets.QApplication(sys.argv)
    app = ApplicationWindow()
    app.show()
    qapp.exec_()