root/html608/spectrumpainter_8C.html

void spectrumpainter()
{
   TH2 *h2 = new TH2F("h2","h2",40,-8,8,40,-9,9);
   Float_t px, py;
   for (Int_t i = 0; i < 50000; i++) {
      gRandom->Rannor(px,py);
      h2->Fill(px,py);
      h2->Fill(px+4,py-4,0.5);
      h2->Fill(px+4,py+4,0.25);
      h2->Fill(px-3,py+4,0.125);
   }
   TCanvas *c1 = new TCanvas("c1","Illustration of 2D graphics",10,10,800,700);
   c1->Divide(2,2);
   c1->cd(1);
   h2->Draw("SPEC dm(2,10) zs(1)");
   c1->cd(2);
   h2->Draw("SPEC dm(1,10) pa(2,1,1) ci(1,4,8) a(15,45,0)");
   c1->cd(3);
   h2->Draw("SPEC dm(2,10) pa(1,1,1) ci(1,1,1) a(15,45,0) s(1,1)");
   c1->cd(4);
   h2->Draw("SPEC dm(1,10) pa(2,1,1) ci(1,4,8) a(15,45,0) cm(1,15,4,4,1) cg(1,2)");
}