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

// Example to illustrate the influence of the clipping window width on the
// estimated background.
//
// Authors: Miroslav Morhac, Olivier Couet


void Background_width2 ()
{
  Int_t i;
  Int_t nbins = 4096;
  Double_t xmin     = 0;
  Double_t xmax     = 4096;
  Double_t* source  = new Double_t [nbins];
  gROOT->ForceStyle ();

  TFile* f    = new TFile ("TSpectrum.root");
  TH1F* hdata = (TH1F*) f->Get ("back2");

  hdata->SetTitle ("Influence of clipping window width on the estimated background");
  hdata->SetAxisRange (0, 1000);
  hdata->SetMaximum (8000);
  hdata->Draw ("L");

  TSpectrum* Analyser1dim = new TSpectrum ();

  /*** Case for width of clipping window = 10 ***/

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

  Analyser1dim->Background (
                source, nbins, 10, TSpectrum::kBackDecreasingWindow,
                TSpectrum::kBackOrder2, kFALSE,
                TSpectrum::kBackSmoothing3, kFALSE );
/*
   const char* TSpectrum::Background (
     Double_t* spectrum,      pointer to the array of source spectrum
     Int_t ssize,             length of the spectrum vector
     Int_t numberIterations,  maximal width of clipping window,
     Int_t direction,         direction of change of clipping window.
                              Possible values: kBackIncreasingWindow, kBackDecreasingWindow
     Int_t filterOrder,       order of clipping filter. Possible values:
                              kBackOrder2, kBackOrder4, kBackOrder6, kBackOrder8
     bool  smoothing,         logical variable whether the smoothing operation in the
                              estimation of background will be included. (0/1)
     Int_t smoothWindow,      width of smoothing window. Possible values:
                              kBackSmoothing3, kBackSmoothing5, ..., kBackSmoothing15
     bool  compton            whether the estimation of Compton edge will be included. (0/1)
   )

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


  TH1F* hwindow10 = new TH1F ("hwindow10", "", nbins, xmin, xmax);
  for (i = 0; i < nbins; i++) hwindow10->SetBinContent (i+1, source[i]);
  hwindow10->SetLineColor (kRed);
  hwindow10->Draw ("SAME L");


  /*** Case for width of clipping window = 20 ***/

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

  Analyser1dim->Background (
                source, nbins, 20, TSpectrum::kBackDecreasingWindow,
                TSpectrum::kBackOrder2, kFALSE,
                TSpectrum::kBackSmoothing3, kFALSE );

  TH1F* hwindow20 = new TH1F ("hwindow20", "", nbins, xmin, xmax);
  for (i = 0; i < nbins; i++) hwindow20->SetBinContent (i+1, source[i]);
  hwindow20->SetLineColor (kBlue);
  hwindow20->Draw ("SAME L");


  /*** Case for width of clipping window = 30 ***/

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

  Analyser1dim->Background (
                source, nbins, 30, TSpectrum::kBackDecreasingWindow,
                TSpectrum::kBackOrder2, kFALSE,
                TSpectrum::kBackSmoothing3, kFALSE );

  TH1F* hwindow30 = new TH1F ("hwindow30", "", nbins, xmin, xmax);
  for (i = 0; i < nbins; i++) hwindow30->SetBinContent (i+1, source[i]);
  hwindow30->SetLineColor (kGreen);
  hwindow30->Draw ("SAME L");


  /*** Case for width of clipping window = 40 ***/

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

  Analyser1dim->Background ( 
                source, nbins, 40, TSpectrum::kBackDecreasingWindow,
                TSpectrum::kBackOrder2, kFALSE,
                TSpectrum::kBackSmoothing3, kFALSE );

  TH1F* hwindow40 = new TH1F ("hwindow40", "", nbins, xmin, xmax);
  for (i = 0; i < nbins; i++) hwindow40->SetBinContent (i+1, source[i]);
  hwindow40->SetLineColor (kMagenta);
  hwindow40->Draw ("SAME L");


  gStyle->SetOptStat (0);
  
  TLegend* legend = new TLegend (0.1, 0.7, 0.48, 0.9);
  legend->AddEntry (hdata    , "Data"     , "l");
  legend->AddEntry (hwindow10, "Width = 10", "l");
  legend->AddEntry (hwindow20, "Width = 20", "l");
  legend->AddEntry (hwindow30, "Width = 30", "l");
  legend->AddEntry (hwindow40, "Width = 40", "l");
  legend->Draw();
}