如何使用QGraphicsPolygonItem获得圆顶大写？

from PyQt5.QtWidgets import QGraphicsPolygonItem, QApplication, QGraphicsScene, QGraphicsView
from PyQt5.QtCore import Qt, QPointF
from PyQt5.QtGui import QPolygonF, QPainter, QBrush, QColor

class CustomPolygonItem(QGraphicsPolygonItem):
    def __init__(self, polygon):
        super().__init__(polygon)

    def paint(self, painter, option, widget):
        painter.setRenderHint(QPainter.Antialiasing)
        painter.setPen(Qt.NoPen)
        painter.setBrush(QBrush(QColor(255, 0, 0)))  # 设置填充颜色为红色
        painter.drawPolygon(self.polygon())

scene = QGraphicsScene()
polygon = QPolygonF([
    QPointF(0, 0),
    QPointF(50, 0),
    QPointF(25, -50)
])
item = CustomPolygonItem(polygon)
scene.addItem(item)

view = QGraphicsView(scene)

view.show()