Logo ROOT   6.21/01
Reference Guide
hbars.C
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1 /// \file
2 /// \ingroup tutorial_hist
3 /// \notebook
4 /// Example of bar charts with 1-d histograms.
5 ///
6 /// \macro_image
7 /// \macro_code
8 ///
9 /// \author Rene Brun
10 
11 TCanvas *hbars() {
12  // Try to open first the file cernstaff.root in tutorials/tree directory
13  TString filedir = gROOT->GetTutorialDir();
14  filedir += TString("/tree/");
15  TString filename = "cernstaff.root";
16  bool fileNotFound = gSystem->AccessPathName(filename); // note opposite return code
17 
18  // If file is not found try to generate it uing the macro tree/cernbuild.C
19  if (fileNotFound) {
20  TString macroName = filedir + "cernbuild.C";
21  if (!gInterpreter->IsLoaded(macroName)) gInterpreter->LoadMacro(macroName);
22  gROOT->ProcessLineFast("cernbuild()");
23  }
24  TFile * f = TFile::Open(filename);
25  if (!f) {
26  Error("hbars","file cernstaff.root not found");
27  return 0;
28  }
29  TTree *T = (TTree*)f->Get("T");
30  if (!T) {
31  Error("hbars","Tree T is not present in file %s",f->GetName() );
32  return 0;
33  }
34  T->SetFillColor(45);
35  TCanvas *c1 = new TCanvas("c1","histograms with bars",700,800);
36  c1->SetFillColor(42);
37  c1->Divide(1,2);
38 
39  // Horizontal bar chart
40  c1->cd(1); gPad->SetGrid(); gPad->SetLogx(); gPad->SetFrameFillColor(33);
41  T->Draw("Nation","","hbar2");
42 
43  // Vertical bar chart
44  c1->cd(2); gPad->SetGrid(); gPad->SetFrameFillColor(33);
45  T->Draw("Division>>hDiv","","goff");
46  TH1F *hDiv = (TH1F*)gDirectory->Get("hDiv");
47  hDiv->SetStats(0);
48  TH1F *hDivFR = (TH1F*)hDiv->Clone("hDivFR");
49  T->Draw("Division>>hDivFR","Nation==\"FR\"","goff");
50  hDiv->SetBarWidth(0.45);
51  hDiv->SetBarOffset(0.1);
52  hDiv->SetFillColor(49);
53  TH1 *h1 = hDiv->DrawCopy("bar2");
54  hDivFR->SetBarWidth(0.4);
55  hDivFR->SetBarOffset(0.55);
56  hDivFR->SetFillColor(50);
57  TH1 *h2 = hDivFR->DrawCopy("bar2,same");
58 
59  TLegend *legend = new TLegend(0.55,0.65,0.76,0.82);
60  legend->AddEntry(h1,"All nations","f");
61  legend->AddEntry(h2,"French only","f");
62  legend->Draw();
63 
64  c1->cd();
65  delete f;
66  return c1;
67 }
virtual Bool_t AccessPathName(const char *path, EAccessMode mode=kFileExists)
Returns FALSE if one can access a file using the specified access mode.
Definition: TSystem.cxx:1279
virtual void SetBarOffset(Float_t offset=0.25)
Definition: TH1.h:355
This class displays a legend box (TPaveText) containing several legend entries.
Definition: TLegend.h:23
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition: TFile.cxx:3925
return c1
Definition: legend1.C:41
double T(double x)
Definition: ChebyshevPol.h:34
virtual void Draw(Option_t *option="")
Draw this legend with its current attributes.
Definition: TLegend.cxx:423
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format...
Definition: TFile.h:48
#define gROOT
Definition: TROOT.h:415
Basic string class.
Definition: TString.h:131
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571
#define f(i)
Definition: RSha256.hxx:104
virtual TH1 * DrawCopy(Option_t *option="", const char *name_postfix="_copy") const
Copy this histogram and Draw in the current pad.
Definition: TH1.cxx:3028
#define gInterpreter
Definition: TInterpreter.h:555
virtual void SetBarWidth(Float_t width=0.5)
Definition: TH1.h:356
TH1F * h1
Definition: legend1.C:5
void Error(const char *location, const char *msgfmt,...)
R__EXTERN TSystem * gSystem
Definition: TSystem.h:557
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37
The Canvas class.
Definition: TCanvas.h:31
TLegendEntry * AddEntry(const TObject *obj, const char *label="", Option_t *option="lpf")
Add a new entry to this legend.
Definition: TLegend.cxx:330
The TH1 histogram class.
Definition: TH1.h:56
TObject * Clone(const char *newname=0) const
Make a complete copy of the underlying object.
Definition: TH1.cxx:2664
#define gPad
Definition: TVirtualPad.h:286
A TTree represents a columnar dataset.
Definition: TTree.h:72
#define gDirectory
Definition: TDirectory.h:223
virtual void SetStats(Bool_t stats=kTRUE)
Set statistics option on/off.
Definition: TH1.cxx:8412