如何获取图标大小以完全填充PushButton /在PyQt5 Python中可缩放

Question

我有一个名为TwoStateButton的类，该类继承QPushButton，以便在单击按钮时可以更改图标，因此在调整整个窗口的大小时，图标的大小与按钮的大小成比例。

运行此代码时，按钮占据整个窗口，并且图标大约占按钮的10％。我试图获取它，以使图标图像占据整个按钮，并且在调整窗口大小时，它们都被调整为相同的大小。

我应该对我的代码进行哪些修改以实现此目的？

import sys
from PyQt5 import QtCore, QtGui, QtWidgets


class TwoStateButton(QtWidgets.QPushButton):
    def __init__(self, on, hover, parent=None):
        super(TwoStateButton, self).__init__(parent)

        self.pad = 4  # padding between the icon and the button frame
        self.minSize = 8  # minimum size of the icon

        sizePolicy = QtWidgets.QSizePolicy(
            QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding
        )
        self.setSizePolicy(sizePolicy)
        self.setIcon(QtGui.QIcon(on))
        self.on = on
        self.hover = hover

    def mousePressEvent(self, event):
        super(TwoStateButton, self).mousePressEvent(event)
        self.setIcon(QtGui.QIcon(self.hover))

    def mouseReleaseEvent(self, event):
        super(TwoStateButton, self).mouseReleaseEvent(event)
        self.setIcon(QtGui.QIcon("%s" % (self.on)))

    def paintEvent(self, event):
        qp = QtGui.QPainter(self)
        opt = QtWidgets.QStyleOptionButton()
        self.initStyleOption(opt)
        r = opt.rect
        h = r.height()
        w = r.width()
        iconSize = max(min(h, w) - 2 * self.pad, self.minSize)
        opt.iconSize = QtCore.QSize(iconSize, iconSize)
        self.style().drawControl(QtWidgets.QStyle.CE_PushButton, opt, qp,self)


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(1090, 681)
        MainWindow.setStyleSheet("")
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.horizontalLayout = QtWidgets.QHBoxLayout(self.centralwidget)
        self.horizontalLayout.setObjectName("horizontalLayout")

        self.pushButton_2 = TwoStateButton(
            "images/Button5-3.png", "images/Button5-4.png", self.centralwidget
        )
        self.pushButton_2.setGeometry(QtCore.QRect(430, 310, 141, 81))
        self.pushButton_2.setText("")
        self.pushButton_2.setCheckable(False)
        self.pushButton_2.setObjectName("pushButton_2")
        self.horizontalLayout.addWidget(self.pushButton_2)

        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 1090, 22))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setStyleSheet(
            "border-image: url(:/images/Button5-3.png)"
        )
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())