QCustomPlot: How to update data of a graph?

Question

I use QCustomPlot to display histograms of pictures. The function I use to set the a curve is the following:

void SingleHistogram::setHist(const QVector<double> &x,
                              const QVector<double> &y)
{
    //clearGraphs();
    graph(0)->setData(x, y);
    graph(0)->rescaleAxes(true);
    replot();
}

It works great for the first picture I open:

But when I set a new histogram using the same function, the first curve is not removed (even if setData() calls clearData() method of the graph) :

As you can seen the second curve (the peak) is added to the graph.

I'd like not to delete and reconstruct a new QCPGraph for efficiency since I feel like it is useless.

Could someone tell me what I am doing wrong here?

Thanks!

Mandar · Answer 1 · 2016-04-03T15:01:46.560

0

Just out of curiosity, are you clearing your vectors x,y? if not you should clear them before loading new graph.

code will look somewhat like

// Graph 1    
setHist(x,y);  // set graph

//
// ..Some code
//

//before loading new values
x.clear();
y.clear();

// Graph 2 
// Fill up new values
// x=[],y=[]

// set NEW graph
setHist(x,y);

edited Apr 03 '16 at 15:01

answered Apr 03 '16 at 04:24

Mandar

1,006
11
28

Failed: `error: 'class QCPGraph' has no member named 'replot'` :(! – Plouff Apr 03 '16 at 08:20
may be you should add a function like `clearValues()` – Mandar Apr 03 '16 at 15:02
It didn't work either. My input data was "corrupted"! – Plouff Apr 08 '16 at 19:32

score 0 · Accepted Answer · answered Apr 08 '16 at 19:31

0

Actually, I found that the input data I provided the graph contained 2 sets of values. So each x coordinate had 2 y values.

It's interesting to know that QCustom plot will produce this kind of graph in this case!

answered Apr 08 '16 at 19:31

Plouff

3,290
2
27
45

QCustomPlot: How to update data of a graph?

2 Answers2