hlHisto3.C File Reference

Detailed Description

This tutorial demonstrates how the highlight mechanism can be used on a ntuple.

The ntuple in hsimple.root is drawn with three differents selection. Moving the mouse ove the two 1D representation display the on 2D plot the events contributing to the highlighted bin.

 
TList *list1 = 0;
TList *list2 = 0;
 
void InitGraphs(TNtuple *nt, TH1F *histo);
void Highlight3(TVirtualPad *pad, TObject *obj, Int_t xhb, Int_t yhb);
 
 
void hlHisto3()
{
   auto dir = gROOT->GetTutorialDir();
   dir.Append("/hsimple.C");
   dir.ReplaceAll("/./","/");
   if (!gInterpreter->IsLoaded(dir.Data())) gInterpreter->LoadMacro(dir.Data());
   auto file = (TFile*)gROOT->ProcessLineFast("hsimple(1)");
   if (!file) return;
 
   TNtuple *ntuple;
   file->GetObject("ntuple", ntuple);
   if (!ntuple) return;
   const char *cut = "pz > 3.0";
 
   TCanvas *Canvas1 = new TCanvas("Canvas1", "Canvas1", 0, 0, 700, 500);
   Canvas1->Divide(1, 2);
   TCanvas *Canvas2 = new TCanvas("Canvas2", "Canvas2", 705, 0, 500, 500);
 
   // Case1, histo1, pz distribution
   Canvas1->cd(1);
   ntuple->Draw("pz>>histo1(100, 2.0, 12.0)", cut);
   auto histo1 = (TH1F *)gPad->FindObject("histo1");
   auto info1  = new TText(7.0, histo1->GetMaximum()*0.6,
                            "please move the mouse over the frame");
   info1->SetTextColor(histo1->GetLineColor());
   info1->SetBit(kCannotPick);
   info1->Draw();
 
   // Case2, histo2, px*py*pz distribution
   Canvas1->cd(2);
   ntuple->Draw("(px*py*pz)>>histo2(100, -50.0, 50.0)", cut);
   auto histo2 = (TH1F *)gPad->FindObject("histo2");
   histo2->SetLineColor(kGreen+2);
   auto info2 = new TText(10.0, histo2->GetMaximum()*0.6, info1->GetTitle());
   info2->SetTextColor(histo2->GetLineColor());
   info2->SetBit(kCannotPick);
   info2->Draw();
   Canvas1->Update();
 
   histo1->SetHighlight();
   histo2->SetHighlight();
   Canvas1->HighlightConnect("Highlight3(TVirtualPad*,TObject*,Int_t,Int_t)");
 
   // Common graph (all entries, all histo bins)
   Canvas2->cd();
   ntuple->Draw("px:py", cut);
   auto gcommon = (TGraph *)gPad->FindObject("Graph");
   gcommon->SetBit(kCanDelete, kFALSE); // will be redraw
   auto htemp = (TH2F *)gPad->FindObject("htemp");
   gcommon->SetTitle(htemp->GetTitle());
   gcommon->GetXaxis()->SetTitle(htemp->GetXaxis()->GetTitle());
   gcommon->GetYaxis()->SetTitle(htemp->GetYaxis()->GetTitle());
   gcommon->Draw("AP");
 
   // Must be last
   ntuple->Draw("px:py:pz", cut, "goff");
   histo1->SetUniqueID(1); // mark as case1
   histo2->SetUniqueID(2); // mark as case2
   InitGraphs(ntuple, histo1);
   InitGraphs(ntuple, histo2);
}
 
 
void InitGraphs(TNtuple *nt, TH1F *histo)
{
   Long64_t nev = nt->GetSelectedRows();
   Double_t *px = nt->GetV1();
   Double_t *py = nt->GetV2();
   Double_t *pz = nt->GetV3();
 
   auto list = new TList();
   if      (histo->GetUniqueID() == 1) list1 = list;
   else if (histo->GetUniqueID() == 2) list2 = list;
   else  return;
 
   Int_t nbins = histo->GetNbinsX();
   Int_t bin;
   TGraph *g;
   for (bin = 0; bin < nbins; bin++) {
      g = new TGraph();
      g->SetName(TString::Format("g%sbin_%d", histo->GetName(), bin+1));
      g->SetBit(kCannotPick);
      g->SetMarkerStyle(25);
      g->SetMarkerColor(histo->GetLineColor());
      list->Add(g);
   }
 
   Double_t value = 0.0;
   for (Long64_t ie = 0; ie < nev; ie++) {
      if (histo->GetUniqueID() == 1) value = pz[ie];
      if (histo->GetUniqueID() == 2) value = px[ie]*py[ie]*pz[ie];
      bin = histo->FindBin(value) - 1;
      g = (TGraph *)list->At(bin);
      if (!g) continue; // under/overflow
      g->SetPoint(g->GetN(), py[ie], px[ie]); // reverse as px:py
   }
}
 
 
void Highlight3(TVirtualPad *pad, TObject *obj, Int_t xhb, Int_t yhb)
{
   auto histo = (TH1F *)obj;
   if(!histo) return;
 
   TCanvas *Canvas2 = (TCanvas *)gROOT->GetListOfCanvases()->FindObject("Canvas2");
   if (!Canvas2) return;
   TGraph *gcommon = (TGraph *)Canvas2->FindObject("Graph");
   if (!gcommon) return;
 
   TList *list = 0;
   if      (histo->GetUniqueID() == 1) list = list1; // case1
   else if (histo->GetUniqueID() == 2) list = list2; // case2
   if (!list) return;
   TGraph *g = (TGraph *)list->At(xhb);
   if (!g) return;
 
   TVirtualPad *savepad = gPad;
   Canvas2->cd();
   gcommon->Draw("AP");
   //gcommon->SetTitle(TString::Format("%d / %d", g->GetN(), gcommon->GetN()));
   if (histo->IsHighlight()) // don't draw g after highlight disabled
      if (g->GetN() > 0) g->Draw("P");
   Canvas2->Update();
   savepad->cd();
}

Date

March 2018

Author

Jan Musinsky

Definition in file hlHisto3.C.