Using QwtSeriesData as data bridge for large datasets

[Uwe]

class YourData: public QwtSeriesData<QPointF>
{
    ....
    virtual size_t size() const
    {
        return 1000000;
    }
 
    virtual QPointF sample( size_t i ) const
    {
        return QPointF( i * delta, m_values[i] );
    }
 
    // optional
    virtual QRectF boundingRect() const
    {
        return QRect( 0.0, yMin, size() * delta, ymax - yMin );       
    }
 
private:
    double *m_values;
};

class YourData: public QwtSeriesData<QPointF>
{
    ....
    virtual size_t size() const
    {
        return 1000000;
    }

    virtual QPointF sample( size_t i ) const
    {
        return QPointF( i * delta, m_values[i] );
    }

    // optional
    virtual QRectF boundingRect() const
    {
        return QRect( 0.0, yMin, size() * delta, ymax - yMin );       
    }

private:
    double *m_values;
};

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When workin with huge datasets you might want to have a look at the QwtPlotCurve::FilterPointsAggressive from svn trunk.

Uwe