PyQt5：如何制作透明覆盖物？

Question

我指的是@armatita中的答案 PySide/PyQt Overlay widget

@armatita的回答具有以下效果...

我想问一下，如何使覆盖层透明？ 确切地说：使用透明叠加层，仍可以单击其下方的按钮。

为方便起见，我将@armatita中的代码粘贴如下：

import sys
from PyQt5 import QtWidgets, QtCore, QtGui

class TranslucentWidgetSignals(QtCore.QObject):
    # SIGNALS
    CLOSE = QtCore.pyqtSignal()

class TranslucentWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(TranslucentWidget, self).__init__(parent)

        # make the window frameless
        self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground)

        self.fillColor = QtGui.QColor(30, 30, 30, 120)
        self.penColor = QtGui.QColor("#333333")

        self.popup_fillColor = QtGui.QColor(240, 240, 240, 255)
        self.popup_penColor = QtGui.QColor(200, 200, 200, 255)

        self.close_btn = QtWidgets.QPushButton(self)
        self.close_btn.setText("x")
        font = QtGui.QFont()
        font.setPixelSize(18)
        font.setBold(True)
        self.close_btn.setFont(font)
        self.close_btn.setStyleSheet("background-color: rgb(0, 0, 0, 0)")
        self.close_btn.setFixedSize(30, 30)
        self.close_btn.clicked.connect(self._onclose)

        self.SIGNALS = TranslucentWidgetSignals()

    def resizeEvent(self, event):
        s = self.size()
        popup_width = 300
        popup_height = 120
        ow = int(s.width() / 2 - popup_width / 2)
        oh = int(s.height() / 2 - popup_height / 2)
        self.close_btn.move(ow + 265, oh + 5)

    def paintEvent(self, event):
        # This method is, in practice, drawing the contents of
        # your window.

        # get current window size
        s = self.size()
        qp = QtGui.QPainter()
        qp.begin(self)
        qp.setRenderHint(QtGui.QPainter.Antialiasing, True)
        qp.setPen(self.penColor)
        qp.setBrush(self.fillColor)
        qp.drawRect(0, 0, s.width(), s.height())

        # drawpopup
        qp.setPen(self.popup_penColor)
        qp.setBrush(self.popup_fillColor)
        popup_width = 300
        popup_height = 120
        ow = int(s.width()/2-popup_width/2)
        oh = int(s.height()/2-popup_height/2)
        qp.drawRoundedRect(ow, oh, popup_width, popup_height, 5, 5)

        font = QtGui.QFont()
        font.setPixelSize(18)
        font.setBold(True)
        qp.setFont(font)
        qp.setPen(QtGui.QColor(70, 70, 70))
        tolw, tolh = 80, -5
        qp.drawText(ow + int(popup_width/2) - tolw, oh + int(popup_height/2) - tolh, "Yep, I'm a pop up.")

        qp.end()

    def _onclose(self):
        print("Close")
        self.SIGNALS.CLOSE.emit()


class ParentWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ParentWidget, self).__init__(parent)

        self._popup = QtWidgets.QPushButton("Gimme Popup!!!")
        self._popup.setFixedSize(150, 40)
        self._popup.clicked.connect(self._onpopup)

        self._other1 = QtWidgets.QPushButton("A button")
        self._other2 = QtWidgets.QPushButton("A button")
        self._other3 = QtWidgets.QPushButton("A button")
        self._other4 = QtWidgets.QPushButton("A button")

        hbox = QtWidgets.QHBoxLayout()
        hbox.addWidget(self._popup)
        hbox.addWidget(self._other1)
        hbox.addWidget(self._other2)
        hbox.addWidget(self._other3)
        hbox.addWidget(self._other4)
        self.setLayout(hbox)

        self._popframe = None
        self._popflag = False

    def resizeEvent(self, event):
        if self._popflag:
            self._popframe.move(0, 0)
            self._popframe.resize(self.width(), self.height())

    def _onpopup(self):
        self._popframe = TranslucentWidget(self)
        self._popframe.move(0, 0)
        self._popframe.resize(self.width(), self.height())
        self._popframe.SIGNALS.CLOSE.connect(self._closepopup)
        self._popflag = True
        self._popframe.show()

    def _closepopup(self):
        self._popframe.close()
        self._popflag = False


if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    main = ParentWidget()
    main.resize(500, 500)
    main.show()
    sys.exit(app.exec_())

根据我的初学者的知识，我可以想象下面的两行内容负责叠加层的透明度。但是我不知道该如何更改它们。

self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
self.setAttribute(QtCore.Qt.WA_TranslucentBackground)

感谢您的帮助！