#include "TFile.h"
#include "TCanvas.h"
#include "TStyle.h"
#include "TH1.h"
#include "TH2.h"
#include "TH3.h"
#include "TGaxis.h"
#include "TRandom.h"
#include "TLegend.h"
#include "TPaveStats.h"
#include "TGraph.h"
#include "TSystem.h"
#include "TTree.h"
#include "TTreePlayer.h"
#include "TF1.h"
#include "TCut.h"
#include "TPaletteAxis.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"



void background()
{
   double t; 
   int n=3;
   int i=0;
   int entry=1;
   	gStyle->SetOptStat(000000);
   	gStyle->SetOptFit(0); //no print stat
   TString myplot = TString::Format("background.png");
   FILE * infile=fopen("backgrounddata.txt", "r");
   TGaxis::SetMaxDigits(n);
   if(infile==NULL)
   {
      printf("Error opening file");
      exit(1);
   }
   TCanvas *c0 = new TCanvas("c0","",1280,1024);
   TH1F *graph1 = new TH1F("graph1","Hours",10,0,10);
   while( fscanf(infile,"%lf",&t)==1)
   { 
      std::cout << "entry = " << entry << "\t time = " << t  << std::endl;
      entry=entry+1;
       graph1->Fill(t);
   }
  	
  	 graph1->SetTitle("");
   graph1->GetXaxis()->SetTitle("Counts/s");
   TF1 *f = new TF1("f", "[0]*TMath::Power(([1]/[2]),(x/[2]))*(TMath::Exp(-([1]/[2])))/TMath::Gamma((x/[2])+1.)", 0, 10);
   f->SetParameters(1, 1, 1); // you MUST set non-zero initial values for parameters
   graph1->GetYaxis()->SetTitle("");
   graph1->GetYaxis()->SetTitleSize(40);
   graph1->GetYaxis()->SetTitleFont(43);
   graph1->GetYaxis()->SetLabelFont(43);
   graph1->GetYaxis()->SetLabelSize(40);
   graph1->GetXaxis()->SetTitleSize(40);
   graph1->GetXaxis()->SetTitleFont(43);
   graph1->GetXaxis()->SetLabelFont(43);
   graph1->GetXaxis()->SetLabelSize(40);
   graph1->SetFillColorAlpha(kBlue, 0.35);
   graph1->DrawNormalized();
   //graph1->Draw();
   gPad->Modified();
   gPad->Update(); // make sure it's really (re)drawn
   //graph1->Fit("gaus");
    graph1->Fit(f, "R"); // "R" = fit between "xmin" and "xmax" of the "f"
   gPad->Modified();
   gPad->Update(); // make sure it's really (re)drawn
   //TPaveStats *statsgraph1 = (TPaveStats*)graph1->GetListOfFunctions()->FindObject("stats");
  //statsgraph1->SetTextColor(kBlue);
   //statsgraph1->SetX1NDC(0.80); statsgraph1->SetX2NDC(0.98);
   //statsgraph1->SetY1NDC(0.77); statsgraph1->SetY2NDC(0.92);
   gPad->Update();
   c0->Print(myplot);
}