// Use a THStack to show a 2-D hist with cells with different colors
// run this example with the two options
//  root > .x multicolor.C
//  root > .x multicolor.C(1)
//Author: Rene Brun
         
#include "TCanvas.h"
#include "TH2.h"
#include "THStack.h"
#include "TRandom.h"
   
void multicolor(Int_t stack=0) {
   TCanvas *c1 = new TCanvas;
   Int_t nbins = 20;
   TH2F *h1 = new TH2F("h1","h1",nbins,-4,4,nbins,-4,4);
   h1->SetFillColor(kGreen);
   TH2F *h2 = new TH2F("h2","h2",nbins,-4,4,nbins,-4,4);
   h2->SetFillColor(kYellow);
   TH2F *h3 = new TH2F("h3","h3",nbins,-4,4,nbins,-4,4);
   h3->SetFillColor(kRed);
   THStack *hs = new THStack("hs","three plots");
   hs->Add(h1);
   hs->Add(h2);
   hs->Add(h3);
   TRandom r;
   Int_t i;
   for (i=0;i<20000;i++) h1->Fill(r.Gaus(),r.Gaus());

   for(int i = 0 ; i < nbins ; i++) {
     for (int j = 0 ; j < nbins ; j++) {
       Int_t bin = h1->GetBin(i,j);
       Double_t content = h1->GetBinContent(bin);
       if (content > 150 && content < 300) {
	 h1->SetBinContent(bin,0);
	 h2->SetBinContent(bin,content);
	 h3->SetBinContent(bin,0);
       } else if (content >= 300) {
	 h1->SetBinContent(bin,0);
	 h2->SetBinContent(bin,0);
	 h3->SetBinContent(bin,content);
       }
     }
   }

   hs->Draw("lego1");
   hs->GetXaxis()->LabelsOption("v");
   hs->GetXaxis()->SetLabelSize(0.03);

   h1->GetXaxis()->SetBinLabel(1, "new");
   // attempt 1
   h2->GetYaxis()->SetBinLabel(1, "new");
   // attempt 2 (who knows...)
   //h2->GetYaxis()->SetBinLabel(5, "new");

   gPad->Modified();

   TCanvas *c2 = new TCanvas;
   c2->cd();
   h2->Draw();
   c2->Modified();
}