Qwt move marker with mouse between interpolated points

[Eligijus]

Hello,

Let's say i have curve with coordinates (x, y)(1, 1) (2, 1) (3, 1) and a marker. I want to get more x points for my marker to snap on when i move it with mouse. In other words i want my marker to snap to 1.1 , 1.2 , 1.3 x coordinates( now it only snaps to 1, 2 ,3).

Code snippet of how i move my marker:

    marker->setLineStyle(QwtPlotMarker::VLine);
    marker->attach(tracePlot);

    picker = new QwtPlotPicker(tracePlot->xBottom, tracePlot->yLeft, QwtPicker::NoRubberBand,
QwtPicker::AlwaysOff, tracePlot->canvas());
    pickerMachine = new QwtPickerDragPointMachine();
    picker->setStateMachine(pickerMachine);

connect(picker, &QwtPicker::moved, this, &Widget::moveMarker);

void Widget::moveMarker(QPoint actualMousePosition)
{
    if(!flagZoom)
    {
        QwtText label;
        QString temp;
        int x = curve->closestPoint(actualMousePosition, NULL);
        QPointF position = curve->sample(x);
        marker->setValue(position);
        temp = QString::number(marker->xValue());
        label.setText(temp);
        marker->setLabel(label);
    }
    tracePlot->replot();
}

I figured i get limited by

closestPoint(actualMousePosition, NULL);
sample(x);

returning ints but can't find any other solution.

[SGaist]

Hi,

That's a question you should bring to the Qwt mailing list. Qwt's author is very active there.