Question

I plot complex data using QwtPlot, so, I reimplement QwtSeriesData for converting my data into QPointF. The “sample(int)” converts MyObject to QPointf. My QwtSeriesData data manages a

myVector=vector<MyObject>;

Now, I need to select point drawn into my plot. I try to use QwtPlotPicker but it only returns a QPointF.

How to get the index “idx” of the selected point in order to get myObject=myVector[idx]?

Answer 1

Use the closestPoint() method in the curve.

int QwtPlotCurve::closestPoint  (   const QPoint &      pos,
    double *    dist = NULL 
) 

It will return the id of the closest point in the curve!

Hope this helps you.