graphpolar3.C

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/// \file
/// \ingroup tutorial_graphs
/// \notebook
/// Create and draw a polar graph with PI axis using a TF1.
///
/// \macro_image
/// \macro_code
///
/// \author Olivier Couet
 
void graphpolar3()
{
   TCanvas *CPol = new TCanvas("CPol", "TGraphPolar Examples", 500, 500);
 
   Double_t rmin = 0;
   Double_t rmax = TMath::Pi() * 2;
   Double_t r[1000];
   Double_t theta[1000];
 
   TF1 fp1("fplot", "cos(x)", rmin, rmax);
   for (Int_t ipt = 0; ipt < 1000; ipt++) {
      r[ipt] = ipt * (rmax - rmin) / 1000 + rmin;
      theta[ipt] = fp1.Eval(r[ipt]);
   }
 
   auto grP1 = new TGraphPolar(1000, r, theta);
   grP1->SetTitle("");
   grP1->SetLineColor(2);
   grP1->Draw("AOL");
}