th2polyBoxes.C File Reference

This tutorial illustrates how to create an histogram with polygonal bins (TH2Poly). More...

Go to the source code of this file.

Detailed Description

This tutorial illustrates how to create an histogram with polygonal bins (TH2Poly).

The bins are boxes.

{
   TCanvas *ch2p2 = new TCanvas("ch2p2","ch2p2",600,400);
   gStyle->SetPalette(57);
   TH2Poly *h2p = new TH2Poly();
   h2p->SetName("Boxes");
   h2p->SetTitle("Boxes");

   Int_t i,j;
   Int_t nx = 40;
   Int_t ny = 40;
   Double_t x1,y1,x2,y2;
   Double_t dx=0.2, dy=0.1;
   x1 = 0.;
   x2 = dx;

   for (i = 0; i<nx; i++) {
      y1 = 0.;
      y2 = dy;
      for (j = 0; j<ny; j++) {
         h2p->AddBin(x1, y1, x2, y2);
         y1 = y2;
         y2 = y2+y2*dy;
      }
      x1 = x2;
      x2 = x2+x2*dx;
   }

   TRandom ran;
   for (i = 0; i<300000; i++) {
      h2p->Fill(50*ran.Gaus(2.,1), ran.Gaus(2.,1));
   }

   h2p->Draw("COLZ");
   return ch2p2;
}

Author

Olivier Couet

Definition in file th2polyBoxes.C.