Example of bar charts with 1-d histograms.
Author: Rene Brun
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Wednesday, April 17, 2024 at 11:12 AM.
Try to open first the file cernstaff.root in tutorials/tree directory
TString filedir = gROOT->GetTutorialDir();
filedir += TString("/tree/");
TString filename = "cernstaff.root";
bool fileNotFound = gSystem->AccessPathName(filename); // note opposite return code
If file is not found try to generate it using the macro tree/cernbuild.C
if (fileNotFound) {
TString macroName = filedir + "cernbuild.C";
if (!gInterpreter->IsLoaded(macroName)) gInterpreter->LoadMacro(macroName);
gROOT->ProcessLineFast("cernbuild()");
}
TFile * f = TFile::Open(filename);
if (!f) {
Error("hbars", "file cernstaff.root not found");
return nullptr;
}
TTree *T = (TTree*)f->Get("T");
if (!T) {
Error("hbars", "Tree T is not present in file %s", f->GetName());
return nullptr;
}
T->SetFillColor(45);
TCanvas *c1 = new TCanvas("c1","histograms with bars",700,800);
c1->SetFillColor(42);
c1->Divide(1,2);
Horizontal bar chart
c1->cd(1);
gPad->SetGrid();
gPad->SetLogx();
gPad->SetFrameFillColor(33);
T->Draw("Nation","","hbar2");
Vertical bar chart
c1->cd(2);
gPad->SetGrid();
gPad->SetFrameFillColor(33);
T->Draw("Division>>hDiv","","goff");
TH1F *hDiv = (TH1F*)gDirectory->Get("hDiv");
hDiv->SetStats(0);
TH1F *hDivFR = (TH1F*)hDiv->Clone("hDivFR");
T->Draw("Division>>hDivFR","Nation==\"FR\"","goff");
hDiv->SetBarWidth(0.45);
hDiv->SetBarOffset(0.1);
hDiv->SetFillColor(49);
TH1 *h1 = hDiv->DrawCopy("bar2");
hDivFR->SetBarWidth(0.4);
hDivFR->SetBarOffset(0.55);
hDivFR->SetFillColor(50);
TH1 *h2 = hDivFR->DrawCopy("bar2,same");
TLegend *legend = new TLegend(0.55,0.65,0.76,0.82);
legend->AddEntry(h1,"All nations","f");
legend->AddEntry(h2,"French only","f");
legend->Draw();
c1->cd();
delete f;
return c1;
Draw all canvases
gROOT->GetListOfCanvases()->Draw()