Re: Access to TGraph from Tree->Draw 2D

Well, to change the line color just use SetLineColor on the ntuple. I cannot run your example as many things are missing, but here is a very simple one based on the ntuple you can find in hsimple.root:

{

   c1 = new TCanvas("c1","ntuple",200,10,700,500);    TFile f("hsimple.root");
   ntuple->SetLineColor(3);
   ntuple->Draw("px:py","","L");
}

in this example the lines are green.

Cheers, O.C.

On Mon, 23 May 2005, Jean-Eric Campagne wrote:

> Sorry Olivier I was a little bit too short.
>
> 1) When I do only
> T1.Draw("numum:log10enm","log10enm>-1 && log10enm<2","LSAME");
> The drawing is Ok but the color of the line is red and I do not manage to
> change it.
>
> 2) When I am trying to access the TGraph
> T1.Draw("numum:log10enm","log10enm>-1 && log10enm<2");
> TGraph *graph = (TGraph*)gPad->GetPrimitive("graph");
> Then graph=0.
> I was looking for this data access to change color of the line...
>
> At the end of the day I would like to superpose other graphs on top of each
> other.
>
> Best
> J.E
>
>
>
>
> --On lundi 23 mai 2005 16:01 +0200 Olivier Couet <couet_at_mail.cern.ch> wrote:
>
> >
> > Hello,
> >
> > I am a bit confused with your email. You 1st said:
> >
> > "graph seems to be 0."
> >
> > But nevertheless it seems you get the graph because later on you said:
> >
> > "when I only Draw with LSAME option it is Ok"
> >
> > So where is the problem ? you can draw the graph, don't you ? is your
> > problem "only" with the graph color definition ?
> >
> > Cheers, O.Couet
> >
> > On Mon, 23 May 2005, Jean-Eric Campagne wrote:
> >
> > > Hello,
> > > I would like to access the TGraph created by a TTree->Draw(x1:x2) as in
> > > the folowing:
> > >
> > > T1.Draw("numum:log10enm","log10enm>-1 && log10enm<2");
> > > TGraph *graph = (TGraph*)gPad->GetPrimitive("graph");
> > >
> > > But graph seems to be 0. My complete C macro is:
> > >
> > > {
> > > TGaxis::SetMaxDigits(2);
> > > //gStyle->SetOptStat(1); //stat
> > > TCanvas* c1 = new TCanvas("c1","SPL Flux",100,100,600,600);
> > > c1->SetGridx();
> > > c1->SetGridy();
> > > c1->SetLogx();
> > >
> > > //draw a dummy frame
> > > TH2D* hdum = new TH2D("hdum","Lipari Xcc",10,1e-1,1e2,10,0,1.6);
> > > hdum->SetXTitle("E_{#nu} (GeV)");
> > > hdum->SetYTitle("#sigma/E (10^{-38}cm^{2})/GeV");
> > > hdum->Draw();
> > >
> > > TPad *overlay = new TPad("overlay","",
> > > gStyle->GetPadLeftMargin(),
> > > gStyle->GetPadBottomMargin(),
> > > 1-gStyle->GetPadRightMargin(),
> > > 1-gStyle->GetPadTopMargin());
> > > overlay->SetFillStyle(4000);
> > > overlay->Draw();
> > > overlay->Range(-1.,0.,2.,1.6); //set the range in linear scale
> > >
> > >
> > > TTree T1("t1","Xsection CC");
> > > //Globes x-section
> > >
> > > T1.ReadFile("./LipSezUrtoMauro.txt","log10enm/F:nuem/F:numum/F:nutaum/F:
> > > anuem/F: anumum/F:anutaum/F");
> > > overlay->cd();
> > > T1.Draw("numum:log10enm","log10enm>-1 && log10enm<2");
> > > TGraph *graph = (TGraph*)gPad->GetPrimitive("graph");
> > > graph->SetLineColor(4);
> > > graph->Draw("LSAME");
> > > }
> > >
> > > Of course when I only Draw with LSAME option it is Ok, but I do not
> > > manage to change the color of the line...
> > >
> > > An idea?
> > > J.E
> > >
> > > ........................................................................
> > > ... .LAL - IN2P3 - CNRS
> > > .LAL - B.P 34 - 91898 Orsay Cedex - France
> > > .Piece 108
> > > .Tel +33 (0)1 64 46 84 29
> > > .Fax +33 (0)1 64 46 83 97
> > > ........................................................................
> > > ...
> > >
> > >
> > >
> >
> > --
> > Org: CERN - European Laboratory for Particle Physics.
> > Mail: 1211 Geneve 23 - Switzerland Mailbox: J25910
> > E-Mail: Olivier.Couet_at_cern.ch Phone: +41 22
> > 7676522 WWW: http://cern.ch/Olivier.Couet/ Fax:
> > +41 22 7670300
>
>
>
> ...........................................................................
> .LAL - IN2P3 - CNRS
> .LAL - B.P 34 - 91898 Orsay Cedex - France
> .Piece 108
> .Tel +33 (0)1 64 46 84 29
> .Fax +33 (0)1 64 46 83 97
> ...........................................................................
>
>
>

-- 
Org:    CERN - European Laboratory for Particle Physics.
Mail:   1211 Geneve 23 - Switzerland                     Mailbox: J25910      
E-Mail: Olivier.Couet_at_cern.ch                            Phone:   +41 22 7676522
WWW:    http://cern.ch/Olivier.Couet/                    Fax:     +41 22 7670300