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

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
>
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