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hlHisto1.C File Reference

Detailed Description

This tutorial demonstrates how the highlight mechanism can be used on an histogram.

A 2D histogram is booked an filled with a random gaussian distribution. Then an highlight method is connected to the histogram. Moving the mouse on the histogram will update the histogram title in real time according to the highlighted bin.

TText *info = nullptr;
void HighlightTitle(TVirtualPad *pad, TObject *obj, Int_t xhb, Int_t yhb)
auto h2 = dynamic_cast<TH2F*>(obj);
if (!h2) return;
if (!h2->IsHighlight()) { // after highlight disabled
h2->SetTitle("Disable highlight");
if (info) info->SetTitle("");
t.Form("bin[%02d, %02d] (%5.2f, %5.2f) content %g", xhb, yhb,
h2->GetXaxis()->GetBinCenter(xhb), h2->GetYaxis()->GetBinCenter(yhb),
h2->GetBinContent(xhb, yhb));
void hlHisto1()
auto c1 = new TCanvas();
auto h2 = new TH2F("h2", "", 50, -5.0, 5.0, 50, -5.0, 5.0);
for (Int_t i = 0; i < 10000; i++) h2->Fill(gRandom->Gaus(), gRandom->Gaus());
info = new TText(0.0, -4.0, "please move the mouse over the frame");
// call after update to apply changes in the histogram painter
int Int_t
Definition RtypesCore.h:45
@ kRed
Definition Rtypes.h:66
@ kCannotPick
Definition TObject.h:374
R__EXTERN TRandom * gRandom
Definition TRandom.h:62
virtual void SetTextAlign(Short_t align=11)
Set the text alignment.
Definition TAttText.h:42
virtual void SetTextColor(Color_t tcolor=1)
Set the text color.
Definition TAttText.h:44
The Canvas class.
Definition TCanvas.h:23
void SetTitle(const char *title) override
Change/set the title.
Definition TH1.cxx:6667
2-D histogram with a float per channel (see TH1 documentation)}
Definition TH2.h:258
virtual void SetTitle(const char *title="")
Set the title of the TNamed.
Definition TNamed.cxx:164
Mother of all ROOT objects.
Definition TObject.h:41
void SetBit(UInt_t f, Bool_t set)
Set or unset the user status bits as specified in f.
Definition TObject.cxx:780
virtual void Draw(Option_t *option="")
Default Draw method for all objects.
Definition TObject.cxx:274
virtual Double_t Gaus(Double_t mean=0, Double_t sigma=1)
Samples a random number from the standard Normal (Gaussian) Distribution with the given mean and sigm...
Definition TRandom.cxx:274
Basic string class.
Definition TString.h:139
const char * Data() const
Definition TString.h:377
void Form(const char *fmt,...)
Formats a string using a printf style format descriptor.
Definition TString.cxx:2335
Base class for several text objects.
Definition TText.h:22
TVirtualPad is an abstract base class for the Pad and Canvas classes.
Definition TVirtualPad.h:51
virtual void Update()=0
return c1
Definition legend1.C:41
March 2018
Jan Musinsky

Definition in file hlHisto1.C.