Pyqt5 drawing

1 Use QPainterPath and QPainterPath::arcTo functions

void QPainterPath::arcTo(const QRectF & rectangle, qreal startAngle, qreal sweepLength)

Create an arc that occupies the specified rectangle to specify the startAngle angle (0-360). Start rotating sweepLength degrees.
When sweepLength is a positive number, it rotates counterclockwise, and when it is a negative number, it rotates clockwise.

class Example(QFrame):
    def __init__(self):
        super().__init__()
        self.setFixedSize(600,800)
        self.arcRadius=45
        self.startPos=(100,100)

    def paintEvent(self,event):
        painter = QPainter(self)
        painter.setBrush(Qt.green)
        painter.setRenderHint(QPainter.Antialiasing)
        #绘制第一段
        path1 = QPainterPath()
        path1.moveTo(*self.startPos)
        path1.arcTo(QRectF(self.startPos[0],self.startPos[1]-self.arcRadius,self.arcRadius*2,self.arcRadius*2),180,-90)
        print(path1.currentPosition())
        path1.lineTo(145+100,55)
        path1.lineTo(self.startPos[0],self.startPos[1])
          
if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    app.exit(app.exec_())