making a RubberBand for selecting an area

[Alex22]

Hi,

I need to select an area with a RubberBand that returns QRectF::top, QRectF::bottom, QRectF::left, QRectF::right. For this I do this:

QwtPlotZoomer* zoomer = new QwtPlotZoomer( canvas );
    zoomer->setRubberBandPen( QColor( Qt::red ) );
    zoomer->setTrackerPen( QColor( Qt::green ) );
    zoomer->setMousePattern( QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlModifier );
    zoomer->setMousePattern( QwtEventPattern::MouseSelect3,
        Qt::RightButton );

QwtPlotZoomer* zoomer = new QwtPlotZoomer( canvas );
    zoomer->setRubberBandPen( QColor( Qt::red ) );
    zoomer->setTrackerPen( QColor( Qt::green ) );
    zoomer->setMousePattern( QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlModifier );
    zoomer->setMousePattern( QwtEventPattern::MouseSelect3,
        Qt::RightButton );

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and by using zoomed (const QRectF &rect) signal, rect can be obtain.

connect(zoomer, zoomed (QRectF), this, slot_pos(QRectF));
 
void MyClass::slot_pos(QRectF pos)
{
    qDebug() << pos.top << pos.bottom << pos.left << pos.right;
}

connect(zoomer, zoomed (QRectF), this, slot_pos(QRectF));

void MyClass::slot_pos(QRectF pos)
{
    qDebug() << pos.top << pos.bottom << pos.left << pos.right;
}

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now I have this problem:
Mouse LeftButton causes zooming. I want to to select an area with a RubberBand without zooming by for example LeftButton +ctrl.