[ROOT] Re: your mail

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sat Feb 24 2001 - 23:13:11 MET


Hi Claire,
Option "same" does not exist for TGraph. The paint function
will take options "a" and "p". Option "a" recompute the range
and draw a new frame. Do something like:
 - create canvas
 - Draw a frame (with DrawFrame or an empty histogram)
 - Draw the box
 - Draw the graph with gr->Draw("p")

Rene Brun

On Sat, 24 Feb 2001, Claire Gwenlan wrote:

> Hi Rene,
> 
> I've kind of sorted out the problem but not quite. What I want is a shaded
> band stretching right across the graph in the x-direction and from -1 to 1
> in the y direction. So, I've created a TBox and drawn it, but what
> happens, obviously, is that it draws over my points. Then when I try and
> redraw the TGraph over the top to get my points back I can only do it if I
> set no marker style. If I set no marker stylr and then go
> 
> gr->Draw("same")
> 
> It is OK, and the shaded box remains.
> 
> However, if I try
> 
> gr->Draw("samep")
> 
> then everything is completely wiped out and I no longer see the shaded box
> (although of course the points are redrawn correctly but completely anew).
> 
> Why is this?
> 
> Cheers,
> 
> Claire
> 
> 
> __________________________________
>  Claire Gwenlan
>  Department of Physics & Astronomy
>  University College London
>  Gower Street
>  LONDON
>  WC1E 6BT
> 
>  Tel: 020 7679 3454
> _________________________________
> 
> On Sat, 24 Feb 2001, Rene Brun wrote:
> 
> > Hi Claire,
> > It is not clear what you want to shade exactly.
> > Here is an example from which you can get some inspiration.
> > 
> > Rene Brun
> > 
> > 
> > {
> >    gROOT->Reset();
> >    Int_t nbins = 100;
> >    TH1F *h1 = new TH1F("h1","h1",nbins,-3,3);
> >    h1->FillRandom("gaus",10000);
> >    h1->Draw();
> >    TH1F *h2 = (TH1F*)h1->Clone();
> >    Double_t mean = h1->GetMean();
> >    Double_t rms  = h1->GetRMS();
> >    for (Int_t i=1;i<=nbins;i++) {
> >       Double_t x = h1->GetXaxis()->GetBinCenter(i);
> >       if (x <mean-rms || x > mean+rms) h2->SetBinContent(i,0);
> >    }
> >    h2->SetFillColor(kRed);
> >    h2->SetFillStyle(3013);
> >    h2->Draw("same");
> > }
> > 
> > On Sat, 24 Feb 2001, Claire Gwenlan wrote:
> > 
> > > 
> > > Hi everybody,
> > > 
> > > Just wondering how to create a nice shaded band on a TGraph, for example a
> > > band stretching from -1 to +1 to represent 1 standard deviation on a
> > > graph.
> > > 
> > > Cheers,
> > > 
> > > Claire
> > > 
> > > __________________________________
> > >  Claire Gwenlan
> > >  Department of Physics & Astronomy
> > >  University College London
> > >  Gower Street
> > >  LONDON
> > >  WC1E 6BT
> > > 
> > >  Tel: 020 7679 3454
> > > _________________________________
> > > 
> > > 
> > 
> > 
> 



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