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h2proj.C File Reference

Detailed Description

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This example demonstrates how to display a histogram and its two projections.

A TExec allows to redraw automatically the projections when a zoom is performed on the 2D histogram.

TH2F *h2;
TH1D * projh2X;
TH1D * projh2Y;
TPad *right_pad, *top_pad;
void h2proj()
auto c1 = new TCanvas("c1", "c1",900,900);
TPad *center_pad = new TPad("center_pad", "center_pad",0.0,0.0,0.6,0.6);
right_pad = new TPad("right_pad", "right_pad",0.55,0.0,1.0,0.6);
top_pad = new TPad("top_pad", "top_pad",0.0,0.55,0.6,1.0);
h2 = new TH2F("h2","",40,-4,4,40,-20,20);
Float_t px, py;
for (Int_t i = 0; i < 25000; i++) {
projh2X = h2->ProjectionX();
projh2Y = h2->ProjectionY();
TLatex t;
t.DrawLatex(0.6,0.88,"This example demonstrates how to display");
t.DrawLatex(0.6,0.85,"a histogram and its two projections.");
auto ex = new TExec("zoom","ZoomExec()");
void ZoomExec()
int xfirst = h2->GetXaxis()->GetFirst();
int xlast = h2->GetXaxis()->GetLast();
double xmin = h2->GetXaxis()->GetBinLowEdge(xfirst);
double xmax = h2->GetXaxis()->GetBinUpEdge(xlast);
projh2X->GetXaxis()->SetRangeUser(xmin, xmax);
int yfirst = h2->GetYaxis()->GetFirst();
int ylast = h2->GetYaxis()->GetLast();
double ymin = h2->GetYaxis()->GetBinLowEdge(yfirst);
double ymax = h2->GetYaxis()->GetBinUpEdge(ylast);
projh2Y->GetXaxis()->SetRangeUser(ymin, ymax);
int Int_t
Definition RtypesCore.h:45
float Float_t
Definition RtypesCore.h:57
@ kBlue
Definition Rtypes.h:66
float xmin
float ymin
float xmax
float ymax
R__EXTERN TRandom * gRandom
Definition TRandom.h:62
R__EXTERN TStyle * gStyle
Definition TStyle.h:433
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition TAttFill.h:37
virtual void SetTextFont(Font_t tfont=62)
Set the text font.
Definition TAttText.h:46
virtual void SetTextSize(Float_t tsize=1)
Set the text size.
Definition TAttText.h:47
virtual Double_t GetBinLowEdge(Int_t bin) const
Return low edge of bin.
Definition TAxis.cxx:518
Int_t GetLast() const
Return last bin on the axis i.e.
Definition TAxis.cxx:469
virtual void SetRangeUser(Double_t ufirst, Double_t ulast)
Set the viewing range for the axis from ufirst to ulast (in user coordinates, that is,...
Definition TAxis.cxx:1077
virtual Double_t GetBinUpEdge(Int_t bin) const
Return up edge of bin.
Definition TAxis.cxx:528
Int_t GetFirst() const
Return first bin on the axis i.e.
Definition TAxis.cxx:458
The Canvas class.
Definition TCanvas.h:23
TExec is a utility class that can be used to execute a C++ command when some event happens in a pad.
Definition TExec.h:26
1-D histogram with a double per channel (see TH1 documentation)}
Definition TH1.h:621
TAxis * GetXaxis()
Definition TH1.h:323
TAxis * GetYaxis()
Definition TH1.h:324
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition TH1.cxx:3047
TList * GetListOfFunctions() const
Definition TH1.h:243
2-D histogram with a float per channel (see TH1 documentation)}
Definition TH2.h:258
TH1D * ProjectionY(const char *name="_py", Int_t firstxbin=0, Int_t lastxbin=-1, Option_t *option="") const
Project a 2-D histogram into a 1-D histogram along Y.
Definition TH2.cxx:2414
TH1D * ProjectionX(const char *name="_px", Int_t firstybin=0, Int_t lastybin=-1, Option_t *option="") const
Project a 2-D histogram into a 1-D histogram along X.
Definition TH2.cxx:2374
Int_t Fill(Double_t) override
Invalid Fill method.
Definition TH2.cxx:347
To draw Mathematical Formula.
Definition TLatex.h:18
TLatex * DrawLatex(Double_t x, Double_t y, const char *text)
Make a copy of this object with the new parameters And copy object attributes.
Definition TLatex.cxx:1943
void Add(TObject *obj) override
Definition TList.h:81
The most important graphics class in the ROOT system.
Definition TPad.h:28
void Modified(Bool_t flag=true) override
Definition TPad.h:420
TVirtualPad * cd(Int_t subpadnumber=0) override
Set Current pad.
Definition TPad.cxx:597
void Draw(Option_t *option="") override
Draw Pad in Current pad (re-parent pad if necessary).
Definition TPad.cxx:1268
virtual void Rannor(Float_t &a, Float_t &b)
Return 2 numbers distributed following a gaussian with mean=0 and sigma=1.
Definition TRandom.cxx:500
void SetOptStat(Int_t stat=1)
The type of information printed in the histogram statistics box can be selected via the parameter mod...
Definition TStyle.cxx:1636
void SetPalette(Int_t ncolors=kBird, Int_t *colors=nullptr, Float_t alpha=1.)
See TColor::SetPalette.
Definition TStyle.cxx:1884
return c1
Definition legend1.C:41
Double_t ex[n]
Definition legend1.C:17
Olivier Couet

Definition in file h2proj.C.