// root.cern.ch/root/htmldoc/guides/spectrum/Spectrum.html#dimensional-spectra
// root.cern.ch/doc/master/Background__compton_8C.html

// See: M.Morhac et al., Nucl. Instr. Meth. A 401, 113 (1997)

// Example to illustrate the background estimator (class TSpectrum) including
// Compton edges.
//
// Authors: Miroslav Morhac, Olivier Couet


void Background_compton () 
{
   Int_t i;
   Int_t nbins = 512;
   Double_t xmin     = 0;
   Double_t xmax     = nbins;
   Double_t* source = new Double_t [nbins];
   gROOT->ForceStyle ();

   TFile* f    = new TFile ("TSpectrum.root");
   TH1F* hdata = (TH1F*) f->Get("back3");
   hdata->SetTitle ("Estimation of background with Compton edges under peaks");
   hdata->GetXaxis()->SetRange (1, nbins);
   hdata->Draw ("L");

   TSpectrum* Analyser1dim = new TSpectrum ();

   for (i = 0; i < nbins; i++) source[i] = hdata->GetBinContent (i+1);

   Analyser1dim->Background (
          source, nbins, 10, TSpectrum::kBackDecreasingWindow,
          TSpectrum::kBackOrder8, kTRUE,
          TSpectrum::kBackSmoothing5, kTRUE);

/*
   const char* TSpectrum::Background ( ..., bool compton );

   bool compton:    whether the estimation of Compton edge will be included. (0/1)

   See: root.cern.ch/doc/v608/classTSpectrum.html#a7830480612d1ee301964e6c79319f444 
*/

   TH1F *hbkgnd1 = new TH1F ("hbkgnd1", "", nbins, xmin, xmax);
   for (i = 0; i < nbins; i++) hbkgnd1->SetBinContent (i+1, source[i]);
   hbkgnd1->SetLineColor (kRed);
   hbkgnd1->Draw ("SAME L");
}