Embedding in Qt

Simple Qt application embedding Matplotlib canvases. This program will work equally well using Qt4 and Qt5. Either version of Qt can be selected (for example) by setting the MPLBACKEND environment variable to “Qt4Agg” or “Qt5Agg”, or by first importing the desired version of PyQt.

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(ApplicationWindow, self).__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):
        self._dynamic_ax.clear()
        t = np.linspace(0, 10, 101)
        # Shift the sinusoid as a function of time.
        self._dynamic_ax.plot(t, np.sin(t + time.time()))
        self._dynamic_ax.figure.canvas.draw()


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