matplotlib 中的实时图形可防止 Python 关闭

【问题标题】：Live graph in matplotlib prevents Python to shutdownmatplotlib 中的实时图形可防止 Python 关闭
【发布时间】：2016-09-19 20:18:49
【问题描述】：

很久以前，我设计了一个绘制实时图表的小 PyQt Gui。传感器信号进入计算机，我的 Gui 会实时绘制该信号。

那时我与PyQt4 和matplotlib 1.5 一起工作。这是生成此类实时图表的代码（模拟传感器信号）。只需将此代码复制粘贴到 python 文件中即可。运行它，你会看到漂亮的跳舞图：

###################################################################
#                                                                 #
#                     PLOTTING A LIVE GRAPH                       #
#                  ----------------------------                   #
#            EMBED A MATPLOTLIB ANIMATION INSIDE YOUR             #
#            OWN GUI!                                             #
#            -> Python 3.5.x                                      #
#            -> matplotlib: 1.5                                   #
#            -> PyQt: 4                                           #
#                                                                 #
###################################################################


import sys
import os
from PyQt4 import QtGui
from PyQt4 import QtCore
import functools
import numpy as np
import random as rd
import matplotlib
matplotlib.use("Qt4Agg")
from matplotlib.figure import Figure
from matplotlib.animation import TimedAnimation
from matplotlib.lines import Line2D
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
import time
import threading



def setCustomSize(x, width, height):
    sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Fixed, QtGui.QSizePolicy.Fixed)
    sizePolicy.setHorizontalStretch(0)
    sizePolicy.setVerticalStretch(0)
    sizePolicy.setHeightForWidth(x.sizePolicy().hasHeightForWidth())
    x.setSizePolicy(sizePolicy)
    x.setMinimumSize(QtCore.QSize(width, height))
    x.setMaximumSize(QtCore.QSize(width, height))

''''''

class CustomMainWindow(QtGui.QMainWindow):

    def __init__(self):

        super(CustomMainWindow, self).__init__()

        # Define the geometry of the main window
        self.setGeometry(300, 300, 800, 400)
        self.setWindowTitle("my first window")

        # Create FRAME_A
        self.FRAME_A = QtGui.QFrame(self)
        self.FRAME_A.setStyleSheet("QWidget { background-color: %s }" % QtGui.QColor(210,210,235,255).name())
        self.LAYOUT_A = QtGui.QGridLayout()
        self.FRAME_A.setLayout(self.LAYOUT_A)
        self.setCentralWidget(self.FRAME_A)

        # Place the zoom button
        self.zoomBtn = QtGui.QPushButton(text = 'zoom')
        setCustomSize(self.zoomBtn, 100, 50)
        self.zoomBtn.clicked.connect(self.zoomBtnAction)
        self.LAYOUT_A.addWidget(self.zoomBtn, *(0,0))

        # Place the matplotlib figure
        self.myFig = CustomFigCanvas()
        self.LAYOUT_A.addWidget(self.myFig, *(0,1))

        # Add the callbackfunc to ..
        myDataLoop = threading.Thread(name = 'myDataLoop', target = dataSendLoop, args = (self.addData_callbackFunc,))
        myDataLoop.start()

        self.show()

    ''''''


    def zoomBtnAction(self):
        print("zoom in")
        self.myFig.zoomIn(5)

    ''''''

    def addData_callbackFunc(self, value):
        # print("Add data: " + str(value))
        self.myFig.addData(value)



''' End Class '''


class CustomFigCanvas(FigureCanvas, TimedAnimation):

    def __init__(self):

        self.addedData = []
        print(matplotlib.__version__)

        # The data
        self.xlim = 200
        self.n = np.linspace(0, self.xlim - 1, self.xlim)
        a = []
        b = []
        a.append(2.0)
        a.append(4.0)
        a.append(2.0)
        b.append(4.0)
        b.append(3.0)
        b.append(4.0)
        self.y = (self.n * 0.0) + 50

        # The window
        self.fig = Figure(figsize=(5,5), dpi=100)
        self.ax1 = self.fig.add_subplot(111)


        # self.ax1 settings
        self.ax1.set_xlabel('time')
        self.ax1.set_ylabel('raw data')
        self.line1 = Line2D([], [], color='blue')
        self.line1_tail = Line2D([], [], color='red', linewidth=2)
        self.line1_head = Line2D([], [], color='red', marker='o', markeredgecolor='r')
        self.ax1.add_line(self.line1)
        self.ax1.add_line(self.line1_tail)
        self.ax1.add_line(self.line1_head)
        self.ax1.set_xlim(0, self.xlim - 1)
        self.ax1.set_ylim(0, 100)


        FigureCanvas.__init__(self, self.fig)
        TimedAnimation.__init__(self, self.fig, interval = 50, blit = True)

    def new_frame_seq(self):
        return iter(range(self.n.size))

    def _init_draw(self):
        lines = [self.line1, self.line1_tail, self.line1_head]
        for l in lines:
            l.set_data([], [])

    def addData(self, value):
        self.addedData.append(value)

    def zoomIn(self, value):
        bottom = self.ax1.get_ylim()[0]
        top = self.ax1.get_ylim()[1]
        bottom += value
        top -= value
        self.ax1.set_ylim(bottom,top)
        self.draw()


    def _step(self, *args):
        # Extends the _step() method for the TimedAnimation class.
        try:
            TimedAnimation._step(self, *args)
        except Exception as e:
            self.abc += 1
            print(str(self.abc))
            TimedAnimation._stop(self)
            pass

    def _draw_frame(self, framedata):
        margin = 2
        while(len(self.addedData) > 0):
            self.y = np.roll(self.y, -1)
            self.y[-1] = self.addedData[0]
            del(self.addedData[0])


        self.line1.set_data(self.n[ 0 : self.n.size - margin ], self.y[ 0 : self.n.size - margin ])
        self.line1_tail.set_data(np.append(self.n[-10:-1 - margin], self.n[-1 - margin]), np.append(self.y[-10:-1 - margin], self.y[-1 - margin]))
        self.line1_head.set_data(self.n[-1 - margin], self.y[-1 - margin])
        self._drawn_artists = [self.line1, self.line1_tail, self.line1_head]



''' End Class '''


# You need to setup a signal slot mechanism, to 
# send data to your GUI in a thread-safe way.
# Believe me, if you don't do this right, things
# go very very wrong..
class Communicate(QtCore.QObject):
    data_signal = QtCore.pyqtSignal(float)

''' End Class '''



def dataSendLoop(addData_callbackFunc):
    # Setup the signal-slot mechanism.
    mySrc = Communicate()
    mySrc.data_signal.connect(addData_callbackFunc)

    # Simulate some data
    n = np.linspace(0, 499, 500)
    y = 50 + 25*(np.sin(n / 8.3)) + 10*(np.sin(n / 7.5)) - 5*(np.sin(n / 1.5))
    i = 0

    while(True):
        if(i > 499):
            i = 0
        time.sleep(0.1)
        mySrc.data_signal.emit(y[i]) # <- Here you emit a signal!
        i += 1
    ###
###




if __name__== '__main__':
    app = QtGui.QApplication(sys.argv)
    QtGui.QApplication.setStyle(QtGui.QStyleFactory.create('Plastique'))
    myGUI = CustomMainWindow()


    sys.exit(app.exec_())

''''''

最近我不得不切换到matplotlib 2.0.0b4。早期版本的 matplotlib 与 PyQt5 不兼容。我想将实时图表插入现有的 PyQt5 应用程序。所以我不得不切换到matplotlib 2.0.0b4。

这里是修改后的代码：

###################################################################
#                                                                 #
#                     PLOTTING A LIVE GRAPH                       #
#                  ----------------------------                   #
#            EMBED A MATPLOTLIB ANIMATION INSIDE YOUR             #
#            OWN GUI!                                             #
#            -> Python 3.5.2                                      #
#            -> matplotlib: 2.0.0b4                               #
#            -> PyQt: 5                                           #
#                                                                 #
###################################################################


import sys
import os
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *

import functools
import numpy as np
import random as rd
import matplotlib
matplotlib.use("Qt5Agg")
from matplotlib.figure import Figure
from matplotlib.animation import TimedAnimation
from matplotlib.lines import Line2D
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import time
import threading



def setCustomSize(x, width, height):
    sizePolicy = QSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
    sizePolicy.setHorizontalStretch(0)
    sizePolicy.setVerticalStretch(0)
    sizePolicy.setHeightForWidth(x.sizePolicy().hasHeightForWidth())
    x.setSizePolicy(sizePolicy)
    x.setMinimumSize(QSize(width, height))
    x.setMaximumSize(QSize(width, height))

''''''

class CustomMainWindow(QMainWindow):

    def __init__(self):

        super(CustomMainWindow, self).__init__()


        # Define the geometry of the main window
        self.setGeometry(300, 300, 800, 400)
        self.setWindowTitle("my first window")

        # Create FRAME_A
        self.FRAME_A = QFrame(self)
        self.FRAME_A.setStyleSheet("QWidget { background-color: %s }" % QColor(210,210,235,255).name())
        self.LAYOUT_A = QGridLayout()
        self.FRAME_A.setLayout(self.LAYOUT_A)
        self.setCentralWidget(self.FRAME_A)

        # Place the zoom button
        self.zoomBtn = QPushButton(text = 'zoom')
        setCustomSize(self.zoomBtn, 100, 50)
        self.zoomBtn.clicked.connect(self.zoomBtnAction)
        self.LAYOUT_A.addWidget(self.zoomBtn, *(0,0))

        # Place the matplotlib figure
        self.myFig = CustomFigCanvas()
        self.LAYOUT_A.addWidget(self.myFig, *(0,1))

        # Add the callbackfunc to ..
        myDataLoop = threading.Thread(name = 'myDataLoop', target = dataSendLoop, args = (self.addData_callbackFunc,))
        myDataLoop.start()

        self.show()

    ''''''


    def zoomBtnAction(self):
        print("zoom in")
        self.myFig.zoomIn(5)

    ''''''

    def addData_callbackFunc(self, value):
        # print("Add data: " + str(value))
        self.myFig.addData(value)



''' End Class '''


class CustomFigCanvas(FigureCanvas, TimedAnimation):

    def __init__(self):
        self.addedData = []
        print(matplotlib.__version__)

        # The data
        self.xlim = 200
        self.n = np.linspace(0, self.xlim - 1, self.xlim)
        a = []
        b = []
        a.append(2.0)
        a.append(4.0)
        a.append(2.0)
        b.append(4.0)
        b.append(3.0)
        b.append(4.0)
        self.y = (self.n * 0.0) + 50

        # The window
        self.fig = Figure(figsize=(5,5), dpi=100)
        self.ax1 = self.fig.add_subplot(111)


        # self.ax1 settings
        self.ax1.set_xlabel('time')
        self.ax1.set_ylabel('raw data')
        self.line1 = Line2D([], [], color='blue')
        self.line1_tail = Line2D([], [], color='red', linewidth=2)
        self.line1_head = Line2D([], [], color='red', marker='o', markeredgecolor='r')
        self.ax1.add_line(self.line1)
        self.ax1.add_line(self.line1_tail)
        self.ax1.add_line(self.line1_head)
        self.ax1.set_xlim(0, self.xlim - 1)
        self.ax1.set_ylim(0, 100)


        FigureCanvas.__init__(self, self.fig)
        TimedAnimation.__init__(self, self.fig, interval = 50, blit = True)

    def new_frame_seq(self):
        return iter(range(self.n.size))

    def _init_draw(self):
        lines = [self.line1, self.line1_tail, self.line1_head]
        for l in lines:
            l.set_data([], [])

    def addData(self, value):
        self.addedData.append(value)

    def zoomIn(self, value):
        bottom = self.ax1.get_ylim()[0]
        top = self.ax1.get_ylim()[1]
        bottom += value
        top -= value
        self.ax1.set_ylim(bottom,top)
        self.draw()


    def _step(self, *args):
        # Extends the _step() method for the TimedAnimation class.
        try:
            TimedAnimation._step(self, *args)
        except Exception as e:
            self.abc += 1
            print(str(self.abc))
            TimedAnimation._stop(self)
            pass

    def _draw_frame(self, framedata):
        margin = 2
        while(len(self.addedData) > 0):
            self.y = np.roll(self.y, -1)
            self.y[-1] = self.addedData[0]
            del(self.addedData[0])


        self.line1.set_data(self.n[ 0 : self.n.size - margin ], self.y[ 0 : self.n.size - margin ])
        self.line1_tail.set_data(np.append(self.n[-10:-1 - margin], self.n[-1 - margin]), np.append(self.y[-10:-1 - margin], self.y[-1 - margin]))
        self.line1_head.set_data(self.n[-1 - margin], self.y[-1 - margin])
        self._drawn_artists = [self.line1, self.line1_tail, self.line1_head]



''' End Class '''


# You need to setup a signal slot mechanism, to
# send data to your GUI in a thread-safe way.
# Believe me, if you don't do this right, things
# go very very wrong..
class Communicate(QObject):
    data_signal = pyqtSignal(float)

''' End Class '''



def dataSendLoop(addData_callbackFunc):
    # Setup the signal-slot mechanism.
    mySrc = Communicate()
    mySrc.data_signal.connect(addData_callbackFunc)

    # Simulate some data
    n = np.linspace(0, 499, 500)
    y = 50 + 25*(np.sin(n / 8.3)) + 10*(np.sin(n / 7.5)) - 5*(np.sin(n / 1.5))
    i = 0

    while(True):
        if(i > 499):
            i = 0
        time.sleep(0.1)
        mySrc.data_signal.emit(y[i]) # <- Here you emit a signal!
        i += 1
    ###
###




if __name__== '__main__':

    app = QApplication(sys.argv)
    QApplication.setStyle(QStyleFactory.create('Plastique'))
    myGUI = CustomMainWindow()
    sys.exit(app.exec_())



''''''

代码运行良好。动画图显示在我的屏幕上，运行流畅。但是当我关闭 GUI 时，python 不会退出。它只是挂起。因为我总是从 Windows cmd shell 启动我的 python 程序，所以我点击了Ctrl-C 按钮来终止该进程。但这也无济于事。我必须完全关闭 cmd shell 才能杀死 Python 进程。

编辑：

显然 matplotlib 1.5 与 PyQt5 兼容（感谢 Tacaswell 先生指出这一点）。我坚持使用 matplotlib v2 的主要原因是使用 PyQt5。这个论点不再成立，所以我决定将 matplotlib 降级到 1.5。我重新安装了 anaconda 以返回 matplotlib 1.5.3，并清除了 matplotlib 2.0.0b 中的所有痕迹。我的系统现在如下：

  • 操作系统：Windows 10 64 位
  • python: 3.5.2 |Anaconda 自定义（64 位）|
  • pyqt4:
    • Qt 版本：4.8.7
    • SIP 版本：4.18.1
    • PyQt 版本：4.11.4
  • pyqt5:
    • Qt 版本：5.7.0
    • SIP 版本：4.18.1
    • PyQt 版本：5.7
  • matplotlib：1.5.3

测试 1：使用 matplotlib 1.5.3 和 PyQt4 的实时图表

我只是运行上面给出的代码 - 基于 PyQt4。实时图表绘制流畅。但是关闭 GUI 并不足以完全停止 python 进程。仍然有一些僵尸进程在后台运行。我必须潜入 Windows 任务管理器才能杀死它。只有在这样做之后，cmd shell 才会再次提示输入新的输入。所以，问题还是一样的。我有点困惑，因为我记得这段代码在 matplotlib 1.5 和 PyQt4 上运行得很好。

测试 2：使用 matplotlib 1.5.3 和 PyQt5 的实时图表

我遇到了完全相同的问题。

【问题讨论】：

  • 这确实不是 beta 功能明智的。我们只是在更改默认样式时要小心。另外，mpl 1.5 应该支持 qt5...
  • 你能用一个更短的例子重现这个吗？
  • 嗨@tacaswell。我想借此机会非常感谢您在 matplotlib 上的志愿工作。你的工作对像我这样买不起 Matlab 的人来说意义重大。我真的很感谢你的辛勤工作。我也感谢您在 StackOverflow 上为帮助人们所做的努力。我在我的问题中添加了一个 EDIT 部分，其中包含更多详细信息。我希望我们能弄清楚如何让 matplotlib 进程正确关闭。再次感谢:-)
  • 我怀疑将 python 线程与 qt 应用程序混合使用（我只使用QThreads 这样做过）。如果您删除线程工作（而是通过按下按钮或通过QTimer 添加新数据）您是否有同样的问题？您可能需要在退出时明确终止您的线程循环？

标签： python python-3.x matplotlib


【解决方案1】：

显然问题出在后台线程的创建上：

myDataLoop = threading.Thread(name = ..., target = ..., args = ...)

要确保这样的后台线程会在 MainThread 结束时终止，您必须将其定义为 daemon:

myDataLoop = threading.Thread(name = ..., daemon = True, target = ..., args = ...)

现在它可以正常关闭了:-)

【讨论】：

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