QGraphicsView与QGraphicsScene

class CanvasView(QGraphicsView):
    def __init__(self, scene, parent=None):
        super().__init__(scene, parent)
        # 设置样式，不然会有滚动条
        self.setStyleSheet("padding:0px;border:0px")
        self.setAlignment(Qt.AlignLeft | Qt.AlignTop)


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

        self.scene = QGraphicsScene(self)
        self.m_view = CanvasView(self.scene, self)
        self.m_view.setGeometry(0, 0, 800, 600)
        self.scene.setSceneRect(0, 0, self.m_view.width(), self.m_view.height())

        pen = QPen()
        pen.setColor(Qt.blue)
        pen.setWidth(1)
        brush = QBrush(Qt.SolidPattern)
        brush.setColor(Qt.yellow)
        self.scene.addRect(0, 0, 800, 600, pen, brush)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    wid = MyWidget()
    wid.setGeometry(100, 100, 800, 600)
    wid.show()
    app.exec_()