Qwt Legend

[maxpayne]

hello,

i was observing the cpu plot example. On executing the binary i noticed that the "user" and the "system" legend items were already checked and the corresponding curves were shown. However i would like only one curve to be shown when the widget starts.

1. How do i change this default behavior ?
2. Secondly, when a legend item is clicked..say "total" i would like the previous selection to be unchecked automatically. This does not happen in the example.

The code looks something like this:

connect(this, SIGNAL(legendChecked(QwtPlotItem *, bool)),
        SLOT(showCurve(QwtPlotItem *, bool)));

connect(this, SIGNAL(legendChecked(QwtPlotItem *, bool)),
        SLOT(showCurve(QwtPlotItem *, bool)));

To copy to clipboard, switch view to plain text mode 

and

void CpuPlot::showCurve(QwtPlotItem *item, bool on)
{
    item->setVisible(on);
    QWidget *w = legend()->find(item);
    if ( w && w->inherits("QwtLegendItem") )
        ((QwtLegendItem *)w)->setChecked(on);
 
    replot();
}

void CpuPlot::showCurve(QwtPlotItem *item, bool on)
{
    item->setVisible(on);
    QWidget *w = legend()->find(item);
    if ( w && w->inherits("QwtLegendItem") )
        ((QwtLegendItem *)w)->setChecked(on);
    
    replot();
}

To copy to clipboard, switch view to plain text mode 

[maxpayne]

any body??...this is kinda important...

[Uwe]

Change the implementation of showCurve:

When on is true iterate over all curves (plot->itemList( QwtPlotItem::Rtti_PlotCurve) and call showCurve(curve, false) for all other curves.

Uwe

[maxpayne]

thanks a lot for your reply,i know you must be busy.I followed your advice and:

showCurve(data[System].curve,true);
    showCurve(data[User].curve, false);
    showCurve(data[Total].curve, false);
    showCurve(data[Idle].curve, false);

showCurve(data[System].curve,true);
    showCurve(data[User].curve, false);
    showCurve(data[Total].curve, false);
    showCurve(data[Idle].curve, false);

To copy to clipboard, switch view to plain text mode 

this should ensure that i get only the system curve at the beginning.Next:

void CpuPlot::showCurve(QwtPlotItem *item, bool on)
{
    const QwtPlotItemList &list = this->itemList();
    for (QwtPlotItemIterator it = list.begin();it!=list.end();++it)
    {
    QwtPlotItem *item2 = *it;
    if (item2->rtti() == QwtPlotItem::Rtti_PlotCurve)
    item2->setVisible(false);
    }
    item->setVisible(on);
    QWidget *w = legend()->find(item);
    if ( w && w->inherits("QwtLegendItem") )
        ((QwtLegendItem *)w)->setChecked(on);
 
    replot();
}

void CpuPlot::showCurve(QwtPlotItem *item, bool on)
{
    const QwtPlotItemList &list = this->itemList();
    for (QwtPlotItemIterator it = list.begin();it!=list.end();++it)
    {
    QwtPlotItem *item2 = *it;
    if (item2->rtti() == QwtPlotItem::Rtti_PlotCurve)
    item2->setVisible(false);
    }
    item->setVisible(on);
    QWidget *w = legend()->find(item);
    if ( w && w->inherits("QwtLegendItem") )
        ((QwtLegendItem *)w)->setChecked(on);
    
    replot();
}

To copy to clipboard, switch view to plain text mode 

this removes a curve when the legend item is checked and displays the new curve.

however i don't see the system curve at the start of the application...even though its legend item is checked.

[Uwe]

Hide the curves only when "on" is true, otherwise a showCurve(..., false) hides all curves.

Uwe