// Builds a polar graph in a square Canvas.
void macro3(){
TCanvas *CPol = new TCanvas("CPol","TGraphPolar Examples",600,600);
Double_t rmin=0;
Double_t rmax=TMath::Pi()*2;
Double_t r[1000];
Double_t theta[1000];
TF1 * fp1 = new TF1("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]);
}
TGraphPolar * grP1 = new TGraphPolar(1000,r,theta);
grP1->SetLineColor(2);
grP1->Draw("AOL");
}