multiple graphs with different axes..

From: Zoltan Szillasi <Zoltan.Szillasi_at_cern.ch>
Date: Sun, 13 Mar 2011 21:00:45 +0000

Dear All,

I would like to draw two graphs superimposed on the same canvas, but with different Y axes. I found a good example, but the ticks of the second graph appear despite that 'A' is not mentioned in the Draw options. Do You know how could I get rid of it? I'm running 5.28.00 under Windows Xp. This problem is also seen under 5.26 Win version.

Here is the example:

 void diffScales(){
   gROOT->Reset();
   c1 = new TCanvas("c1","gerrors2",200,10,700,500);    TPad *pad = new TPad("pad","",0,0,1,1);

   pad->SetFillColor(42);
   pad->SetGrid();
   pad->Draw();
   pad->cd();



      // draw a frame to define the range

   TH1F *hr = c1->DrawFrame(-0.4,0,1.2,12);

   hr->SetXTitle("X title");
   hr->SetYTitle("Y title");
   pad->GetFrame()->SetFillColor(21);
   pad->GetFrame()->SetBorderSize(12);



      // create first graph

   Int_t n1 = 10;

   Double_t x1[]  = {-0.22, 0.05, 0.25, 0.35, 0.5, 0.61,0.7,0.85,0.89,0.95};
   Double_t y1[]  = {1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1};
   Double_t ex1[] = {.05,.1,.07,.07,.04,.05,.06,.07,.08,.05};
   Double_t ey1[] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8};

   gr1 = new TGraphErrors(n1,x1,y1,ex1,ey1);

   gr1->SetMarkerColor(kBlue);
   gr1->SetMarkerStyle(21);
   gr1->Draw("LP");



      // create second graph

   Int_t n2 = 10;

   Float_t x2[]  = {-0.28, 0.005, 0.19, 0.29, 0.45, 0.56,0.65,0.80,0.90,1.01};
   Float_t y2[]  = {0.82,3.86,7,9,10,10.55,9.64,7.26,5.42,2};
   Float_t ex2[] = {.04,.12,.08,.06,.05,.04,.07,.06,.08,.04};
   Float_t ey2[] = {.6,.8,.7,.4,.3,.3,.4,.5,.6,.7};


   for (Int_t i=0;i<n2;i++) {
      y2[i] *= 100;
      ey2[i] *= 100;

   }
   //create a transparent pad drawn on top of the main pad    c1->cd();

   TPad *overlay = new TPad("overlay","",0,0,1,1);

   overlay->SetFillStyle(4000);
   overlay->SetFillColor(0);
   overlay->SetFrameFillStyle(4000);
   overlay->Draw();
   overlay->cd();

   gr2 = new TGraphErrors(n2,x2,y2,ex2,ey2);

   gr2->SetMarkerColor(kRed);
   gr2->SetMarkerStyle(20);
   gr2->SetName("gr2");
   Double_t xmin = pad->GetUxmin();
   Double_t ymin = 0;

   Double_t xmax = pad->GetUxmax();
   Double_t ymax = 1300;
   TH1F *hframe = overlay->DrawFrame(xmin,ymin,xmax,ymax);    hframe->GetXaxis()->SetLabelOffset(99);    hframe->GetYaxis()->SetLabelOffset(99);    gr2->Draw("LP");

   //Draw an axis on the right side
   TGaxis *axis = new TGaxis(xmax,ymin,xmax, ymax,ymin,ymax,510,"+L");

   axis->SetLineColor(kRed);
   axis->SetLabelColor(kRed);
   axis->Draw();

}

Thanks in advace!

Cheers,

                   Zoltan

Received on Sun Mar 13 2011 - 22:00:50 CET