PyQt -是否有将QGraphicsItem移动限制在特定线路路径上的实现？

from PyQt5.QtWidgets import QGraphicsPathItem, QGraphicsScene, QGraphicsView, QApplication
from PyQt5.QtGui import QPainterPath
from PyQt5.QtCore import Qt

class CustomPathItem(QGraphicsPathItem):
    def __init__(self, path):
        super().__init__()
        self.setPath(path)
        self.setFlag(self.ItemIsMovable)

    def itemChange(self, change, value):
        if change == self.ItemPositionChange:
            # 获取当前移动位置
            newPos = value
            # 限制移动位置在路径上
            path = self.path()
            if not path.contains(newPos):
                # 如果不在路径上，则将移动位置修正为路径上的最近点
                point = path.pointAtPercent(path.percentAtLength(path.closestSubpathPositionToPoint(newPos)))
                newPos.setX(point.x())
                newPos.setY(point.y())
                return newPos

        return super().itemChange(change, value)

if __name__ == '__main__':
    app = QApplication([])
    scene = QGraphicsScene()
    view = QGraphicsView(scene)

    # 创建自定义路径
    path = QPainterPath()
    path.moveTo(0, 0)
    path.lineTo(100, 0)
    path.lineTo(100, 100)
    path.lineTo(0, 100)
    path.lineTo(0, 0)
    
    # 创建自定义路径项
    customItem = CustomPathItem(path)
    scene.addItem(customItem)

    view.show()
    app.exec()