Transparent QMainWindow

qtransparentmainwindow.py

from typing import *

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

class QTransparentMainWindow(QMainWindow):
    closing = pyqtSignal()

    _movable = False
    _move_offset = 0

    _backgroundOpacity = 1.0
    _backgroundColor = Qt.gray

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.setAttribute(Qt.WA_TranslucentBackground)
        self.setAttribute(Qt.WA_NoSystemBackground)

    def paintEvent(self, event: QPaintEvent):
        painter = QPainter(self)
        painter.setOpacity(self._backgroundOpacity)
        painter.setBrush(self._backgroundColor)
        painter.setPen(QPen(self._backgroundColor))
        painter.drawRect(self.rect())

    def mouseMoveEvent(self, event: QMouseEvent):
        if self._movable:
            self.move(event.globalX() - self._move_offset.x(), event.globalY() - self._move_offset.y())

    def mousePressEvent(self, event: QMouseEvent):
        if self._movable:
            self._move_offset = event.pos()

    def closeEvent(self, event: QCloseEvent):
        super().closeEvent(event)
        self.closing.emit()

    def setBackgroundOpacity(self, opacity: float):
        self._backgroundOpacity = opacity

    def backgroundOpacity(self) -> float:
        return self._backgroundOpacity

    def setBackgroundColor(self, color: Union[QBrush, QColor, Qt.GlobalColor, QGradient, Qt.BrushStyle]):
        self._backgroundColor = color

    def backgroundColor(self) -> Union[QBrush, QColor, Qt.GlobalColor, QGradient, Qt.BrushStyle]:
        return self._backgroundColor

    def setMovable(self, movable: bool):
        self._movable = movable

    def movable(self) -> bool:
        return self._movable