#include"Riostream.h"
#include"TFile.h"
#include"TH1.h"
#include"TNtuple.h"
#include"TStyle.h"
#include"TSpectrum.h"
#include"TCanvas.h"
#include"TVirtualFitter.h"

void background()
{

   Int_t i;
   Double_t nbins = 256;
   Double_t xmin  = 0;
   Double_t xmax  = nbins;
   Double_t *source = new Double_t[nbins];
   TH1F *back = new TH1F("back","",nbins,xmin,xmax);
   TH1F *d = new TH1F("d","",nbins,xmin,xmax);
   TFile *f = new TFile("/home/mydanguyen/Documents/khongbia_7200s_03042016.root","recreate");
   back=(TH1F*)f->Get("back1;1");
   TCanvas *Background = gROOT->GetListOfCanvases()->FindObject("Background");
   if (!Background) Background =
     new TCanvas("Background",
                 "Estimation of background with increasing window",
                 10,10,1000,700);
   back->Draw();
   TSpectrum *s = new TSpectrum();
   for (i = 0; i < nbins; i++) source[i]=back->GetBinContent(i + 1);
   s->Background(source,nbins,6,kBackIncreasingWindow,kBackOrder2,kFALSE,
                 kBackSmoothing3,kFALSE);
   for (i = 0; i < nbins; i++) d->SetBinContent(i + 1,source[i]);
   d->SetLineColor(kRed);
   d->Draw("SAME L");
}