How to clear QwtPlot curves before replotting?

Question

In the earlier versions of Qwt we add QwtPlot::clear() but now, I can't find it.

Any ideas? I have a real time plot, so when replotting, the info before xmin is not really important and with time it crashes as the replot is replotting all the information before xmin.

Answer 1

The method Qwtplot::clear() has been deprecated. Use QwtPlotDict::detachItems instead.

void QwtPlotDict::detachItems(int rtti = QwtPlotItem::Rtti_PlotItem, 
                              bool autoDelete = true 
                             )

Parameters:

rtti: In case of QwtPlotItem::Rtti_PlotItem detach all items otherwise only those items of the type rtti. autoDelete: If true, delete all detached items

Answer 2

one of the way to clear plot is to set your data points to empty: for example: (m_vctTime,m_vctValue -vector) (curve=new QwtPlotCurve()) (plot=new QwtPlot(parent))

m_vctTime.clear();
m_vctValue.clear();
curve->setSamples(m_vctTime,m_vctValue);
plot->replot();    

that clears your plot