Panner Zoomer Scroll synchronization

[Uwe]

Well this is one of the parts where the design of the Qwt classes is week. The main problem is, that there are local zoom stacks ( local for each zoomer object ) but not a general navigation stack recording the history of all navigation operations.

Probably the best you can do is to modify the zoom stack ( zoomStack/setZoomStack ) manually in a slot connected to the panned signal of your panner.

Uwe

[jklasdf]

The QwtPlotPanner class has a "panned" signal and a "moveCanvas" slot, so you can synchronize scrolling on two panners as follows:

QObject::connect(panner1,SIGNAL(panned(int,int)),panner2,SLOT(moveCanvas(int,int)));
QObject::connect(panner2,SIGNAL(panned(int,int)),panner1,SLOT(moveCanvas(int,int)));

QObject::connect(panner1,SIGNAL(panned(int,int)),panner2,SLOT(moveCanvas(int,int)));
QObject::connect(panner2,SIGNAL(panned(int,int)),panner1,SLOT(moveCanvas(int,int)));

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You could create a QwtLinkedPlotMagnifier class that derives from QwtPlotMagnifier to have similar slots and signals, and emit a resize_event() signal every time resize() is called:

class QwtLinkedPlotMagnifier : public QwtPlotMagnifier
{
    Q_OBJECT
public:
    explicit QwtLinkedPlotMagnifier(QwtPlotCanvas *canvas);
 
protected:
    virtual void rescale(double factor);
 
signals:
    void rescale_event(double factor);
 
public slots:
    void do_rescale(double factor);
 
};
 
QwtLinkedPlotMagnifier::QwtLinkedPlotMagnifier(QwtPlotCanvas *canvas) :
    QwtPlotMagnifier(canvas)
{
}
 
void QwtLinkedPlotMagnifier::rescale(double factor){
    QwtPlotMagnifier::rescale(factor);
    emit rescale_event(factor);
}
 
void QwtLinkedPlotMagnifier::do_rescale(double factor){
    QwtPlotMagnifier::rescale(factor);
}

class QwtLinkedPlotMagnifier : public QwtPlotMagnifier
{
    Q_OBJECT
public:
    explicit QwtLinkedPlotMagnifier(QwtPlotCanvas *canvas);

protected:
    virtual void rescale(double factor);

signals:
    void rescale_event(double factor);

public slots:
    void do_rescale(double factor);

};

QwtLinkedPlotMagnifier::QwtLinkedPlotMagnifier(QwtPlotCanvas *canvas) :
    QwtPlotMagnifier(canvas)
{
}

void QwtLinkedPlotMagnifier::rescale(double factor){
    QwtPlotMagnifier::rescale(factor);
    emit rescale_event(factor);
}

void QwtLinkedPlotMagnifier::do_rescale(double factor){
    QwtPlotMagnifier::rescale(factor);
}

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Not sure about getting the qwt zoomer class to do what you want, though.