python - 在 PyQt5 GUI 中嵌入 matplotlib 时内存泄漏

Question

我基本上按照 this tutorial 使用 Qt Designer 构建了一个 Matplotlib GUI .我正在使用 python 3.5.2 和 pyqt 5.6.0 。您可以在下面看到的代码正在运行。但是，当更改绘图时，我的系统使用的内存会增加，至少根据 Windows 10 任务管理器是这样。为了更好地重现这一点，可以增加绘图命令中使用的随机值的数量。似乎 rmmppl 函数中的 self.canvas.close() 命令不足以实际释放已用内存。

如何防止内存使用量增加？

编辑:这是一个Screenshot图形用户界面

from PyQt5 import QtCore, QtGui, QtWidgets
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt5agg import (
FigureCanvasQTAgg as FigureCanvas,
NavigationToolbar2QT as NavigationToolbar)
import window
import numpy as np


class Plotter(QtWidgets.QMainWindow, window.Ui_MainWindow):
    def __init__(self):
        super(Plotter, self).__init__()
        self.setupUi(self)
        self.fig_dict = {}    
        self.mplfigs.itemClicked.connect(self.changefig)

    def addmpl(self, fig):
        self.canvas = FigureCanvas(fig)
        self.mplvl.addWidget(self.canvas)
        self.canvas.draw()
        self.toolbar = NavigationToolbar(self.canvas,self.mplwindow, coordinates = True)
        self.mplvl.addWidget(self.toolbar)

    def rmmppl(self):
        self.mplvl.removeWidget(self.canvas)
        self.canvas.close()
        self.mplvl.removeWidget(self.toolbar)
        self.toolbar.close()

    def addfig(self, name, fig):
        self.fig_dict[name]=fig
        self.mplfigs.addItem(name)

    def changefig(self,item):
        text = item.text()
        self.rmmppl()
        self.addmpl(self.fig_dict[text])



def main():
    import sys

    fig1 = Figure()
    ax1f1= fig1.add_subplot(111)
    ax1f1.plot(np.random.rand(5))

    fig2 = Figure()
    ax1f2 = fig2.add_subplot(121)
    ax1f2.plot(np.random.rand(5))
    ax1f2 = fig2.add_subplot(122)
    ax1f2.plot(np.random.rand(10))    

    app=QtWidgets.QApplication(sys.argv)
    main=Plotter()
    main.addmpl(fig1)
    main.addfig('Figure 1', fig1)
    main.addfig('Figure 2', fig2)
    main.show()

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

作为基本 GUI 结构的 window.py:

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(640, 432)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.horizontalLayout = QtWidgets.QHBoxLayout(self.centralwidget)
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.mplwindow = QtWidgets.QWidget(self.centralwidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.mplwindow.sizePolicy().hasHeightForWidth())
        self.mplwindow.setSizePolicy(sizePolicy)
        self.mplwindow.setObjectName("mplwindow")
        self.mplvl = QtWidgets.QVBoxLayout(self.mplwindow)
        self.mplvl.setContentsMargins(0, 0, 0, 0)
        self.mplvl.setObjectName("mplvl")
        self.horizontalLayout.addWidget(self.mplwindow)
        self.mplfigs = QtWidgets.QListWidget(self.centralwidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.mplfigs.sizePolicy().hasHeightForWidth())
        self.mplfigs.setSizePolicy(sizePolicy)
        self.mplfigs.setMaximumSize(QtCore.QSize(200, 16777215))
        self.mplfigs.setMinimumSize(QtCore.QSize(200, 0))
        self.mplfigs.setObjectName("mplfigs")
        self.horizontalLayout.addWidget(self.mplfigs)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 640, 31))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))

Answer 1

我在 Linux 上执行了您的代码，我观察到同样的内存泄漏。试试这个:

导入垃圾收集器:

import gc

然后修改你的rmmppl方法:

def rmmppl(self):
    self.canvas.close()
    self.canvas.deleteLater()
    self.toolbar.close()
    self.toolbar.deleteLater()
    gc.collect()

这是 deleteLater QObject Class Documentation 的文档