QwtWheel, How to update the values related to axis xBottom that continuously changes

[HappyCoder]

Hi,

i have a little problem with QwtWheel and how to update it's values related to a x-Axis that continuously changes.

Subclass MasterWheel from QwtWheel

When scaleDivChanged() signal was triggered, i apply the changes to the MasterWheel.
When valueChanged(double) signal was triggered, i apply the new values from MasterWheel to the axis

The problem:
-> when scaleDivChanged() i apply the new values to the MasterWheel (only if it is not in use)
-> i set also the value to the lowerBound() of the QwtScaleDiv
-> BUT, when the value is changed i got the signal to change the axis
-> if i apply the new value to axis, i trigger the signal scaleDivChanged() and so on...

now i have a circle of signals and slots

How to set the values of a QwtWheel if the xBottom changes continuously?

Thx
Stefan

Here is my code:

connect( pPlotPressure->axisWidget( QwtPlot::xBottom ), SIGNAL(scaleDivChanged()), SLOT(setMasterWheelValues()));
connect( pMasterWheel, SIGNAL(valueChanged(double)), SLOT(setAxisScaleByMasterWheel(double)));

connect( pPlotPressure->axisWidget( QwtPlot::xBottom ), SIGNAL(scaleDivChanged()), SLOT(setMasterWheelValues()));
connect( pMasterWheel, SIGNAL(valueChanged(double)), SLOT(setAxisScaleByMasterWheel(double)));

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void PlotManager::setMasterWheelValues()
{
    // wheelPressed() set isActive() to true
    // wheelReleased() set isActive() to false
    if( !(pMasterWheel->isActive()) )
    {
        const QwtScaleDiv scaleDiv = pPlotPressure->axisScaleDiv( QwtPlot::xBottom );
        const double minValue = scaleDiv.lowerBound();
        const double maxValue = scaleDiv.upperBound();
 
        if( maxValue > pMasterWheel->maximum() )
            pMasterWheel->setMaximum( maxValue );
        if( minValue < pMasterWheel->minimum() )
            pMasterWheel->setMinimum( minValue );
 
//        pMasterWheel->setValue( minValue );   // THIS LINE IS THE PROBLEM
 
        d_data->dxMasterWheel = scaleDiv.range();
    }
}
 
void PlotManager::setAxisScaleByMasterWheel(double value)
{
    pPlotPressure->setAxisScale( QwtPlot::xBottom, value, value + d_data->dxMasterWheel );
    pPlotPressure->replot();
}

void PlotManager::setMasterWheelValues()
{
    // wheelPressed() set isActive() to true
    // wheelReleased() set isActive() to false
    if( !(pMasterWheel->isActive()) )
    {
        const QwtScaleDiv scaleDiv = pPlotPressure->axisScaleDiv( QwtPlot::xBottom );
        const double minValue = scaleDiv.lowerBound();
        const double maxValue = scaleDiv.upperBound();

        if( maxValue > pMasterWheel->maximum() )
            pMasterWheel->setMaximum( maxValue );
        if( minValue < pMasterWheel->minimum() )
            pMasterWheel->setMinimum( minValue );

//        pMasterWheel->setValue( minValue );   // THIS LINE IS THE PROBLEM

        d_data->dxMasterWheel = scaleDiv.range();
    }
}

void PlotManager::setAxisScaleByMasterWheel(double value)
{
    pPlotPressure->setAxisScale( QwtPlot::xBottom, value, value + d_data->dxMasterWheel );
    pPlotPressure->replot();
}

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