如何使用 python 同时运行 matplotlib 和 PyQt5 Video

问题描述

我正在尝试同时运行 QVideoWidget 和 matplotlib 动画，

I'm trying to run QVideoWidget and matplotlib animation together,

但是当我运行这个 py 时，QVideoWidget 不起作用.

but when I run this py, QVideoWidget is not working.

我得到了 QVideoWidget 代码和 matplotlib 动画代码，然后将这些代码汇总到下面的代码中.

I got QVideoWidget code and matplotlib animation code then sum those code together in below code.

如果我关闭 matplotlib 动画窗口，则 QVideoWidget 正在工作.

If I close the matplotlib animation Window, then the QVideoWidget is working.

我想知道为什么会发生这种情况并解决这个问题

I wonder why this happen and solve this problem

谢谢

import matplotlib.pyplot as plt
import matplotlib.animation as animation
import random
from PyQt5.QtCore import QDir, Qt, QUrl
from PyQt5.QtMultimedia import QMediaContent, QMediaPlayer
from PyQt5.QtMultimediaWidgets import QVideoWidget
from PyQt5.QtWidgets import (QApplication, QFileDialog, QHBoxLayout, QLabel,
    QPushButton, QSizePolicy, QSlider, QStyle, QVBoxLayout, QWidget)
from PyQt5.QtWidgets import QMainWindow,QWidget, QPushButton, QAction
from PyQt5.QtGui import QIcon
import sys
from PyQt5.QtWidgets import (QApplication, QCheckBox, QGridLayout, QGroupBox,
    QMenu, QPushButton, QRadioButton, QVBoxLayout, QWidget)

# Parameters
x_len = 200         # Number of points to display
y_range = [10, 40]  # Range of possible Y values to display

# Create figure for plotting
fig = plt.figure(facecolor='white')
ax = fig.add_subplot(2, 1, 1)
bx = fig.add_subplot(2, 1, 2)
xs = list(range(0, 200))
ys = [0] * x_len
ax.set_ylim(y_range)
bx.set_ylim(y_range)
# Initialize communication with TMP102


# When everything done, release the capture


# Create a blank line. We will update the line in animate
line, = ax.plot(xs, ys)
line2, = bx.plot(xs, ys)
# Add labels
plt.title('TMP102 Temperature over Time')
plt.xlabel('Samples')
plt.ylabel('Temperature (deg C)')
class VideoWindow(QMainWindow):
    def __init__(self, parent=None):

        super(VideoWindow, self).__init__(parent)

        self.setWindowTitle("PyQt Video Player Widget Example - pythonprogramminglanguage.com")

        self.mediaPlayer = QMediaPlayer(None, QMediaPlayer.VideoSurface)

        videoWidget = QVideoWidget()

        self.playButton = QPushButton()
        self.playButton.setEnabled(False)
        self.playButton.setIcon(self.style().standardIcon(QStyle.SP_MediaPlay))
        self.playButton.clicked.connect(self.play)

        self.positionSlider = QSlider(Qt.Horizontal)
        self.positionSlider.setRange(0, 0)
        self.positionSlider.sliderMoved.connect(self.setPosition)

        self.errorLabel = QLabel()
        self.errorLabel.setSizePolicy(QSizePolicy.Preferred,
            QSizePolicy.Maximum)

        # Create new action
        openAction = QAction(QIcon('open.png'), '&Open', self)
        openAction.setShortcut('Ctrl+O')
        openAction.setStatusTip('Open movie')
        openAction.triggered.connect(self.openFile)

        # Create exit action
        exitAction = QAction(QIcon('exit.png'), '&Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.setStatusTip('Exit application')
        exitAction.triggered.connect(self.exitCall)

        # Create menu bar and add action
        menuBar = self.menuBar()
        fileMenu = menuBar.addMenu('&File')
        #fileMenu.addAction(newAction)
        fileMenu.addAction(openAction)
        fileMenu.addAction(exitAction)

        # Create a widget for window contents
        wid = QWidget(self)
        self.setCentralWidget(wid)

        # Create layouts to place inside widget
        controlLayout = QHBoxLayout()
        controlLayout.setContentsMargins(0, 0, 0, 0)
        controlLayout.addWidget(self.playButton)
        controlLayout.addWidget(self.positionSlider)
        layout = QVBoxLayout()
        layout.addWidget(videoWidget)
        layout.addLayout(controlLayout)
        layout.addWidget(self.errorLabel)
        # Set widget to contain window contents

        wid.setLayout(layout)

        self.mediaPlayer.setVideoOutput(videoWidget)
        self.mediaPlayer.stateChanged.connect(self.mediaStateChanged)
        self.mediaPlayer.positionChanged.connect(self.positionChanged)
        self.mediaPlayer.durationChanged.connect(self.durationChanged)
        self.mediaPlayer.error.connect(self.handleError)


    def openFile(self):
        fileName, _ = QFileDialog.getOpenFileName(self, "Open Movie",
            QDir.homePath())

        if fileName != '':
            self.mediaPlayer.setMedia(
                QMediaContent(QUrl.fromLocalFile(fileName)))
            self.playButton.setEnabled(True)

    def exitCall(self):
        sys.exit(app.exec_())

    def play(self):
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.mediaPlayer.pause()
        else:
            self.mediaPlayer.play()

    def mediaStateChanged(self, state):
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.playButton.setIcon(
                self.style().standardIcon(QStyle.SP_MediaPause))
        else:
            self.playButton.setIcon(
                self.style().standardIcon(QStyle.SP_MediaPlay))

    def positionChanged(self, position):
        self.positionSlider.setValue(position)

    def durationChanged(self, duration):
        self.positionSlider.setRange(0, duration)

    def setPosition(self, position):
        self.mediaPlayer.setPosition(position)



    def handleError(self):
        self.playButton.setEnabled(False)
        self.errorLabel.setText("Error: " + self.mediaPlayer.errorString())

    def animate(i, ys):

        # Read temperature (Celsius) from TMP102
        temp_c = random.randint(15, 35)

        # Add y to list
        ys.append(temp_c)

        # Limit y list to set number of items
        ys = ys[-x_len:]

        # Update line with new Y values
        line.set_ydata(ys)
        line2.set_ydata(ys)
        return line, line2,

    ani = animation.FuncAnimation(fig, animate, fargs=(ys,),
                              interval=50,
                              blit=True)

# This function is called periodically from FuncAnimation


# Set up plot to call animate() function periodically



if __name__ == '__main__':
    app = QApplication(sys.argv)

    player = VideoWindow()
    player.resize(640, 480)
    player.show()
    plt.show()
    sys.exit(app.exec_())

推荐答案

每个 GUI 都需要一个事件循环来更新自身并参与用户事件、操作系统事件等.对于 matplotlib，它在使用时被调用plt.show() 以及调用 app.exec_() 时的 PyQt5.使用您当前的代码，matplotlib 的事件循环正在阻塞 PyQt，因此您无法与 PyQt5 创建的窗口进行交互.

Every GUI needs an event loop to be able to update itself and attend user events, OS events, etc. And in the case of matplotlib it is called when using plt.show() and in the case of PyQt5 when calling app.exec_(). With your current code the event loop of matplotlib is blocking PyQt, so you can not interact with the window created by PyQt5.

解决方法很简单，matplotlib支持包括PyQt5在内的多个后端，所以解决方法就是使用它，在下面链接你可以找到一个例子.

The solution is simple, matplotlib supports several backends including PyQt5, so the solution is to use it, in the following link you can find an example.

综合考虑，下面的代码实现了解决方案:

Considering the above, the following code implements the solution:

import random
import matplotlib
# Make sure that we are using QT5
matplotlib.use('Qt5Agg')
from PyQt5 import QtCore, QtGui, QtWidgets, QtMultimedia, QtMultimediaWidgets

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import matplotlib.animation as animation


class MyMplCanvas(FigureCanvas):
    def __init__(self, parent=None, width=5, height=4, dpi=100):
        fig = Figure(figsize=(width, height), dpi=dpi)

        # https://stackoverflow.com/a/6981055/6622587
        ax = fig.add_subplot(111)    # The big subplot
        self.ax = fig.add_subplot(211)
        self.bx = fig.add_subplot(212)

        FigureCanvas.__init__(self, fig)
        self.setParent(parent)

        FigureCanvas.setSizePolicy(self,
                                   QtWidgets.QSizePolicy.Expanding,
                                   QtWidgets.QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)

        ax.set_title('TMP102 Temperature over Time')
        ax.spines['top'].set_color('none')
        ax.spines['bottom'].set_color('none')
        ax.spines['left'].set_color('none')
        ax.spines['right'].set_color('none')
        ax.tick_params(labelcolor='w', top=False, bottom=False, left=False, right=False)
        ax.set_xlabel('Samples')
        ax.set_ylabel('Temperature (deg C)')

        self.x_len = 200         # Number of points to display
        self.y_range = [10, 40]  # Range of possible Y values to display
        self.xs = list(range(0, 200))

        self.ys = [0 for _ in range(self.x_len)]        
        self.anim = animation.FuncAnimation(fig, self.animate, init_func=self.init, interval=50,blit=True)

    def init(self):
        y_range = [10, 40]
        self.ax.set_ylim(*y_range)
        self.bx.set_ylim(*y_range)
        self.line, = self.ax.plot(self.xs, self.ys)
        self.line2, = self.bx.plot(self.xs, self.ys)
        return self.line, self.line2

    def animate(self, i):
        temp_c = random.randint(15, 35)
        self.ys.append(temp_c)
        self.ys = self.ys[-self.x_len:]
        self.line.set_ydata(self.ys)
        self.line2.set_ydata(self.ys)
        return self.line, self.line2


class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(ApplicationWindow, self).__init__(parent)
        main_widget = QtWidgets.QWidget()
        l = QtWidgets.QVBoxLayout(main_widget)
        sc = MyMplCanvas(main_widget, width=5, height=4, dpi=100)
        l.addWidget(sc)
        self.setCentralWidget(main_widget)


class VideoWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):

        super(VideoWindow, self).__init__(parent)

        self.setWindowTitle("PyQt Video Player Widget Example - pythonprogramminglanguage.com")

        self.mediaPlayer = QtMultimedia.QMediaPlayer(self, QtMultimedia.QMediaPlayer.VideoSurface)

        videoWidget = QtMultimediaWidgets.QVideoWidget()

        self.playButton = QtWidgets.QPushButton()
        self.playButton.setEnabled(False)
        self.playButton.setIcon(self.style().standardIcon(QtWidgets.QStyle.SP_MediaPlay))
        self.playButton.clicked.connect(self.play)

        self.positionSlider = QtWidgets.QSlider(QtCore.Qt.Horizontal)
        self.positionSlider.setRange(0, 0)
        self.positionSlider.sliderMoved.connect(self.setPosition)

        self.errorLabel =QtWidgets.QLabel()
        self.errorLabel.setSizePolicy(QtWidgets.QSizePolicy.Preferred, QtWidgets.QSizePolicy.Maximum)

        # Create new action
        openAction = QtWidgets.QAction(QtGui.QIcon('open.png'), '&Open', self)
        openAction.setShortcut('Ctrl+O')
        openAction.setStatusTip('Open movie')
        openAction.triggered.connect(self.openFile)

        # Create exit action
        exitAction = QtWidgets.QAction(QtGui.QIcon('exit.png'), '&Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.setStatusTip('Exit application')
        exitAction.triggered.connect(self.exitCall)

        # Create menu bar and add action
        menuBar = self.menuBar()
        fileMenu = menuBar.addMenu('&File')
        #fileMenu.addAction(newAction)
        fileMenu.addAction(openAction)
        fileMenu.addAction(exitAction)

        # Create a widget for window contents
        wid = QtWidgets.QWidget()
        self.setCentralWidget(wid)

        # Create layouts to place inside widget
        controlLayout = QtWidgets.QHBoxLayout()
        controlLayout.setContentsMargins(0, 0, 0, 0)
        controlLayout.addWidget(self.playButton)
        controlLayout.addWidget(self.positionSlider)
        layout = QtWidgets.QVBoxLayout()
        layout.addWidget(videoWidget)
        layout.addLayout(controlLayout)
        layout.addWidget(self.errorLabel)
        # Set widget to contain window contents

        wid.setLayout(layout)

        self.mediaPlayer.setVideoOutput(videoWidget)
        self.mediaPlayer.stateChanged.connect(self.mediaStateChanged)
        self.mediaPlayer.positionChanged.connect(self.positionChanged)
        self.mediaPlayer.durationChanged.connect(self.durationChanged)
        self.mediaPlayer.error.connect(self.handleError)


    def openFile(self):
        fileName, _ = QtWidgets.QFileDialog.getOpenFileName(self, "Open Movie", QtCore.QDir.homePath())

        if fileName:
            media = QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(fileName))
            self.mediaPlayer.setMedia(media)
            self.playButton.setEnabled(True)

    def exitCall(self):
        QtWidgets.QApplication.quit()

    def play(self):
        if self.mediaPlayer.state() == QtMultimedia.QMediaPlayer.PlayingState:
            self.mediaPlayer.pause()
        else:
            self.mediaPlayer.play()

    def mediaStateChanged(self, state):
        if self.mediaPlayer.state() == QtMultimedia.QMediaPlayer.PlayingState:
            self.playButton.setIcon(
                self.style().standardIcon(QtWidgets.QStyle.SP_MediaPause))
        else:
            self.playButton.setIcon(
                self.style().standardIcon(QtWidgets.QStyle.SP_MediaPlay))

    def positionChanged(self, position):
        self.positionSlider.setValue(position)

    def durationChanged(self, duration):
        self.positionSlider.setRange(0, duration)

    def setPosition(self, position):
        self.mediaPlayer.setPosition(position)

    def handleError(self):
        self.playButton.setEnabled(False)
        self.errorLabel.setText("Error: " + self.mediaPlayer.errorString())


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)

    player = VideoWindow()
    player.resize(640, 480)
    player.show()

    w = ApplicationWindow()
    w.show()
    sys.exit(app.exec_())

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