如何在PYQT中使用Cross Cursor实现SNAP网格？

Question

我想像波纹管一样绘制一个像图片一样的快照网格，我可以绘制背景点，但是我不知道如何在鼠标移动时捕捉网格点，在这里有人知道该怎么做吗？谢谢。

我的示例代码
它开始很慢，有时卡住了。

import cv2 as cv
import numpy as np

import math

from qtpy.QtWidgets import *
from qtpy.QtCore import *
from qtpy.QtGui import *

class Point(QGraphicsItem):
    def boundingRect(self) -> QRectF:
        return QRectF(-3, -3, 6, 6)

    def paint(self, painter: QPainter, option: 'QStyleOptionGraphicsItem', widget) -> None:
        painter.setPen(Qt.NoPen)
        painter.setBrush(Qt.red)
        painter.drawEllipse(self.boundingRect())

class Scene(QGraphicsScene):
    def __init__(self):
        super().__init__()
        self.setItemIndexMethod(QGraphicsScene.BspTreeIndex)
        self.setBackgroundBrush(Qt.lightGray)
        self.initScene()

    def initScene(self):
        y = x =  np.arange(1000*100, step=50)
        xx, yy = np.meshgrid(x, y)
        for px, py in zip(xx.flatten(), yy.flatten()):
            point = Point()
            point.setPos(px, py)
            self.addItem(point)

    def wheelEvent(self, event: 'QGraphicsSceneWheelEvent') -> None:
        factor = math.pow(2.718, event.delta()/360)
        factorRatio = self.views()[0].transform().scale(factor, factor).mapRect(QRectF(0, 0, 1, 1)).width()
        if factorRatio < 0.3 or factorRatio > 5:
            return

        self.views()[0].scale(factor, factor)
        return super().wheelEvent(event)

app  = QApplication([])
view = QGraphicsView()
view.setRenderHints(QPainter.Antialiasing)
view.setScene(Scene())
view.resize(500, 500)
view.show()
app.exec()

想要快照网格