Grid in GraphicsView

Question

I want to implement grid in my graphicsView such that it fits to the graphicsView automatically and when I zoom in the graphicsView only the block size of grid should increase but not the line width of the grid. I tried the following but nothing happened.

void CadGraphicsScene::grid(QPainter *painter, const QRectF &rect)
{
    QPen pen;
    painter->setPen(pen);

    qreal left = int(rect.left()) - (int(rect.left()) % gridSize);
    qreal top = int(rect.top()) - (int(rect.top()) % gridSize);
    QVector<QPointF> points;
    for (qreal x = left; x < rect.right(); x += gridSize){
        for (qreal y = top; y < rect.bottom(); y += gridSize){
            points.append(QPointF(x,y));
        }
    }
    painter->drawPoints(points.data(), points.size());
}

Please help me out to make a grid.

Answer 1

1）使用化妆笔（宽度为零）2）通过QT习语，图形场景与视图无关（关于您在graphicsview中的缩放问题），但是您可以从传递的QPainter对象（QPainter * painter）-QPainter中提取视图的缩放系数:: worldTransform-> QTransform :: m11（horz_Scale）和QTransform :: m22（vert_Scale）-在这种情况下，您可以重新计算网格锚（对于100％缩放，QTransform :: m11 == QTransform :: m22 == 1） '飞'