Question

我刚刚在背景中的QGraphicsView中绘制了网格线

  drawbackground(QPainter *painter, const QRectF &rect)
    {
    QVarLengthArray<QLineF, 100> linesX;
    for (qreal x = left; x < sceneRect.right(); x += gridInterval )
    {

    linesX.append(QLineF(x, sceneRect.top(), x, sceneRect.bottom()));
    }

    QVarLengthArray<QLineF, 100> linesY;
    for (qreal y = top; y < sceneRect.bottom(); y += gridInterval ){

    linesY.append(QLineF(sceneRect.left(), y, sceneRect.right(), y));
    }

    painter->drawLines(linesX.data(), linesX.size());
    painter->drawLines(linesY.data(), linesY.size());
    }

并通过

缩放视图

void
ViewPort::zoomIn()
{
    zoom(qreal(1.2));
}

void
ViewPort::zoomOut()
{
    zoom(1 / qreal(1.2));
}

void
ViewPort::zoom(qreal scaleFactor)
{

    qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();

    if (factor < 1 || factor > 100)
        return;

    scale(scaleFactor, scaleFactor);

}

现在场景有很多项目我必须缩放但我需要忽略我在graphicsView drawBackground上绘制的网格线。我怎么能忽略gridLines的规模转换。？

我尝试过QPainter :: resetTransform（）但是徒劳无功..

Answer 1

如果将行聚合到从QGraphicsItem派生的对象并将该项添加到场景中，则可以设置标志QGraphicsItem :: ItemIgnoresTransformations，以阻止它响应缩放和其他转换。

graphicsView缩放忽略在defectground中

1 个答案: