Logo ROOT  
Reference Guide
THStack Class Reference

The Histogram stack class.

A THStack is a collection of TH1 or TH2 histograms. Using THStack::Draw() the histogram collection is drawn in one go according to the drawing option.

THStack::Add() allows to add a new histogram to the list. The THStack does not own the objects in the list.

By default (if no option drawing option is specified), histograms will be paint stacked on top of each other. TH2 are stacked as lego plots.

If option "nostack" is specified the histograms are not drawn on top of each other but as they would if drawn using the option "same".

If option "nostackb" is specified the histograms are drawn next to each other as bar charts.

In all cases The axis range is computed automatically along the X and Y axis in order to show the complete histogram collection.

Example;

{
THStack *hs = new THStack("hs","");
TH1F *h1 = new TH1F("h1","test hstack",10,-4,4);
h1->FillRandom("gaus",20000);
hs->Add(h1);
TH1F *h2 = new TH1F("h2","test hstack",10,-4,4);
h2->FillRandom("gaus",15000);
hs->Add(h2);
TH1F *h3 = new TH1F("h3","test hstack",10,-4,4);
h3->FillRandom("gaus",10000);
hs->Add(h3);
TCanvas *cs = new TCanvas("cs","cs",10,10,700,900);
TText T; T.SetTextFont(42); T.SetTextAlign(21);
cs->Divide(2,2);
cs->cd(1); hs->Draw(); T.DrawTextNDC(.5,.95,"Default drawing option");
cs->cd(2); hs->Draw("nostack"); T.DrawTextNDC(.5,.95,"Option \"nostack\"");
cs->cd(3); hs->Draw("nostackb"); T.DrawTextNDC(.5,.95,"Option \"nostackb\"");
cs->cd(4); hs->Draw("lego1"); T.DrawTextNDC(.5,.95,"Option \"lego1\"");
return cs;
}
@ kRed
Definition: Rtypes.h:64
@ kGreen
Definition: Rtypes.h:64
@ kBlue
Definition: Rtypes.h:64
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37
The Canvas class.
Definition: TCanvas.h:27
TVirtualPad * cd(Int_t subpadnumber=0)
Set current canvas & pad.
Definition: TCanvas.cxx:701
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571
virtual void FillRandom(const char *fname, Int_t ntimes=5000)
Fill histogram following distribution in function fname.
Definition: TH1.cxx:3445
The Histogram stack class.
Definition: THStack.h:31
THStack()
THStack default constructor.
Definition: THStack.cxx:113
virtual void Draw(Option_t *chopt="")
Draw this multihist with its current attributes.
Definition: THStack.cxx:445
virtual void Add(TH1 *h, Option_t *option="")
add a new histogram to the list Only 1-d and 2-d histograms currently supported.
Definition: THStack.cxx:359
virtual void Divide(Int_t nx=1, Int_t ny=1, Float_t xmargin=0.01, Float_t ymargin=0.01, Int_t color=0)
Automatic pad generation by division.
Definition: TPad.cxx:1165
Base class for several text objects.
Definition: TText.h:23
TH1F * h1
Definition: legend1.C:5
double T(double x)
Definition: ChebyshevPol.h:34

A more complex example:

TCanvas *hstack() {
THStack *hs = new THStack("hs","Stacked 1D histograms");
//create three 1-d histograms
TH1F *h1st = new TH1F("h1st","test hstack",100,-4,4);
h1st->FillRandom("gaus",20000);
h1st->SetMarkerStyle(21);
hs->Add(h1st);
TH1F *h2st = new TH1F("h2st","test hstack",100,-4,4);
h2st->FillRandom("gaus",15000);
h2st->SetMarkerStyle(21);
hs->Add(h2st);
TH1F *h3st = new TH1F("h3st","test hstack",100,-4,4);
h3st->FillRandom("gaus",10000);
h3st->SetMarkerStyle(21);
hs->Add(h3st);
TCanvas *cst = new TCanvas("cst","stacked hists",10,10,700,700);
cst->Divide(2,2);
// in top left pad, draw the stack with defaults
cst->cd(1);
hs->Draw();
// in top right pad, draw the stack in non-stack mode
// and errors option
cst->cd(2);
gPad->SetGrid();
hs->Draw("nostack,e1p");
//in bottom left, draw in stack mode with "lego1" option
cst->cd(3);
gPad->SetFrameFillColor(17);
gPad->SetTheta(3.77);
gPad->SetPhi(2.9);
hs->Draw("lego1");
cst->cd(4);
//create two 2-D histograms and draw them in stack mode
gPad->SetFrameFillColor(17);
THStack *a = new THStack("a","Stacked 2D histograms");
TF2 *f1 = new TF2("f1",
"xygaus + xygaus(5) + xylandau(10)",-4,4,-4,4);
Double_t params1[] = {130,-1.4,1.8,1.5,1, 150,2,0.5,-2,0.5,
3600,-2,0.7,-3,0.3};
f1->SetParameters(params1);
TH2F *h2sta = new TH2F("h2sta","h2sta",20,-4,4,20,-4,4);
h2sta->SetFillColor(38);
h2sta->FillRandom("f1",4000);
TF2 *f2 = new TF2("f2","xygaus + xygaus(5)",-4,4,-4,4);
Double_t params2[] = {100,-1.4,1.9,1.1,2, 80,2,0.7,-2,0.5};
f2->SetParameters(params2);
TH2F *h2stb = new TH2F("h2stb","h2stb",20,-4,4,20,-4,4);
h2stb->SetFillColor(46);
h2stb->FillRandom("f2",3000);
a->Add(h2sta);
a->Add(h2stb);
a->Draw();
return cst;
}
double Double_t
Definition: RtypesCore.h:57
#define gPad
Definition: TVirtualPad.h:287
virtual void SetMarkerColor(Color_t mcolor=1)
Set the marker color.
Definition: TAttMarker.h:38
virtual void SetMarkerStyle(Style_t mstyle=1)
Set the marker style.
Definition: TAttMarker.h:40
virtual void SetParameters(const Double_t *params)
Definition: TF1.h:638
A 2-Dim function with parameters.
Definition: TF2.h:29
2-D histogram with a float per channel (see TH1 documentation)}
Definition: TH2.h:251
virtual void FillRandom(const char *fname, Int_t ntimes=5000)
Fill histogram following distribution in function fname.
Definition: TH2.cxx:599
TF1 * f1
Definition: legend1.C:11
auto * a
Definition: textangle.C:12

Note that picking is supported for all drawing modes.

Since
ROOT version 6.07/07: Stacks of 2D histograms can also be painted as candle plots:
ROOT version 6.09/02: Stacks of 2D histograms can also be painted as violin plots, combinations of candle and violin plots are possible as well:
void candleplotstack()
{
TRandom *rng = new TRandom();
TDatime *dateBegin = new TDatime(2010,1,1,0,0,0);
TDatime *dateEnd = new TDatime(2011,1,1,0,0,0);
int bins = 1000;
TH2I *h1 = new TH2I("h1","Machine A",6,dateBegin->Convert(),dateEnd->Convert(),bins,0,1000);
TH2I *h2 = new TH2I("h2","Machine B",6,dateBegin->Convert(),dateEnd->Convert(),bins,0,1000);
TH2I *hsum = new TH2I("h4","Sum",6,dateBegin->Convert(),dateEnd->Convert(),bins,0,1000);
float Rand;
for (int i = dateBegin->Convert(); i < dateEnd->Convert(); i+=86400*30) {
for (int j = 0; j < 1000; j++) {
Rand = rng->Gaus(500+sin(i/10000000.)*100,50); h1->Fill(i,Rand); hsum->Fill(i,Rand);
Rand = rng->Gaus(500+sin(i/12000000.)*100,50); h2->Fill(i,Rand); hsum->Fill(i,Rand);
}
}
hsum->SetFillColor(kGreen);
TCanvas *c1 = new TCanvas();
THStack *hs = new THStack("hs","Machine A+B");
hs->Add(h1);
hs->Add(h2,"candle2");
hs->Add(hsum, "violin1");
hs->Draw("candle3");
hs->GetXaxis()->SetNdivisions(410);
gPad->SetGrid(1,0);
hs->GetXaxis()->SetTimeFormat("%m/%y");
hs->GetXaxis()->SetTitle("Date [month/year]");
c1->Modified();
gPad->BuildLegend(0.75,0.75,0.95,0.95,"");
}
double sin(double)
R__EXTERN TStyle * gStyle
Definition: TStyle.h:410
virtual void SetNdivisions(Int_t n=510, Bool_t optim=kTRUE)
Set the number of divisions for this axis.
Definition: TAttAxis.cxx:229
virtual void SetLineColor(Color_t lcolor)
Set the line color.
Definition: TAttLine.h:40
virtual void SetTimeDisplay(Int_t value)
Definition: TAxis.h:161
virtual void SetTimeFormat(const char *format="")
Change the format used for time plotting.
Definition: TAxis.cxx:1013
This class stores the date and time with a precision of one second in an unsigned 32 bit word (950130...
Definition: TDatime.h:37
UInt_t Convert(Bool_t toGMT=kFALSE) const
Convert fDatime from TDatime format to the standard time_t format.
Definition: TDatime.cxx:181
virtual Int_t Fill(Double_t x)
Increment bin with abscissa X by 1.
Definition: TH1.cxx:3275
2-D histogram with an int per channel (see TH1 documentation)}
Definition: TH2.h:212
Int_t Fill(Double_t)
Invalid Fill method.
Definition: TH2.cxx:294
TAxis * GetXaxis() const
Get x axis of the histogram used to draw the stack.
Definition: THStack.cxx:601
virtual void SetTitle(const char *title="")
Set the title of the TNamed.
Definition: TNamed.cxx:164
This is the base class for the ROOT Random number generators.
Definition: TRandom.h:27
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:263
void SetTimeOffset(Double_t toffset)
Change the time offset for time plotting.
Definition: TStyle.cxx:1801
return c1
Definition: legend1.C:41
Definition: hsum.py:1

Automatic coloring according to the current palette is available as shown in the following example:

void thstackpalettecolor()
{
auto hs = new THStack("hs","Stacked 1D histograms colored using kOcean palette");
// Create three 1-d histograms and add them in the stack
auto h1st = new TH1F("h1st","test hstack",100,-4,4);
h1st->FillRandom("gaus",20000);
hs->Add(h1st);
auto h2st = new TH1F("h2st","test hstack",100,-4,4);
h2st->FillRandom("gaus",15000);
hs->Add(h2st);
auto h3st = new TH1F("h3st","test hstack",100,-4,4);
h3st->FillRandom("gaus",10000);
hs->Add(h3st);
// draw the stack
hs->Draw("pfc nostack");
}
@ kOcean
Definition: TColor.h:110
void SetPalette(Int_t ncolors=kBird, Int_t *colors=0, Float_t alpha=1.)
See TColor::SetPalette.
Definition: TStyle.cxx:1783

Definition at line 31 of file THStack.h.

Public Member Functions

 THStack ()
 THStack default constructor. More...
 
 THStack (const char *name, const char *title)
 constructor with name and title More...
 
 THStack (const THStack &hstack)
 THStack copy constructor. More...
 
 THStack (TH1 *hist, Option_t *axis="x", const char *name=0, const char *title=0, Int_t firstbin=1, Int_t lastbin=-1, Int_t firstbin2=1, Int_t lastbin2=-1, Option_t *proj_option="", Option_t *draw_option="")
 Creates a new THStack from a TH2 or TH3 It is filled with the 1D histograms from GetProjectionX or GetProjectionY for each bin of the histogram. More...
 
virtual ~THStack ()
 THStack destructor. More...
 
virtual void Add (TH1 *h, Option_t *option="")
 add a new histogram to the list Only 1-d and 2-d histograms currently supported. More...
 
TIter begin () const
 Get iterator over internal hists list. More...
 
virtual void Browse (TBrowser *b)
 Browse. More...
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Compute distance from point px,py to each graph. More...
 
virtual void Draw (Option_t *chopt="")
 Draw this multihist with its current attributes. More...
 
TIter end () const
 
TH1GetHistogram () const
 Returns a pointer to the histogram used to draw the axis Takes into account the two following cases. More...
 
TListGetHists () const
 
virtual Double_t GetMaximum (Option_t *option="")
 returns the maximum of all added histograms returns the maximum of all histograms if option "nostack". More...
 
virtual Double_t GetMinimum (Option_t *option="")
 returns the minimum of all added histograms returns the minimum of all histograms if option "nostack". More...
 
Int_t GetNhists () const
 Return the number of histograms in the stack. More...
 
TObjArrayGetStack ()
 Return pointer to Stack. Build it if not yet done. More...
 
TAxisGetXaxis () const
 Get x axis of the histogram used to draw the stack. More...
 
TAxisGetYaxis () const
 Get x axis of the histogram used to draw the stack. More...
 
virtual void ls (Option_t *option="") const
 List histograms in the stack. More...
 
virtual Long64_t Merge (TCollection *li, TFileMergeInfo *info)
 Merge the THStack in the TList into this stack. More...
 
virtual void Modified ()
 invalidate sum of histograms More...
 
virtual void Paint (Option_t *chopt="")
 Paint the list of histograms. More...
 
virtual void Print (Option_t *chopt="") const
 Print the list of histograms. More...
 
virtual void RecursiveRemove (TObject *obj)
 Recursively remove object from the list of histograms. More...
 
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save primitive as a C++ statement(s) on output stream out. More...
 
virtual void SetHistogram (TH1 *h)
 
virtual void SetMaximum (Double_t maximum=-1111)
 Set maximum. More...
 
virtual void SetMinimum (Double_t minimum=-1111)
 Set minimum. More...
 
- Public Member Functions inherited from TNamed
 TNamed ()
 
 TNamed (const char *name, const char *title)
 
 TNamed (const TNamed &named)
 TNamed copy ctor. More...
 
 TNamed (const TString &name, const TString &title)
 
virtual ~TNamed ()
 TNamed destructor. More...
 
virtual void Clear (Option_t *option="")
 Set name and title to empty strings (""). More...
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
 
virtual Int_t Compare (const TObject *obj) const
 Compare two TNamed objects. More...
 
virtual void Copy (TObject &named) const
 Copy this to obj. More...
 
virtual void FillBuffer (char *&buffer)
 Encode TNamed into output buffer. More...
 
virtual const char * GetName () const
 Returns name of object. More...
 
virtual const char * GetTitle () const
 Returns title of object. More...
 
virtual ULong_t Hash () const
 Return hash value for this object. More...
 
virtual Bool_t IsSortable () const
 
virtual void ls (Option_t *option="") const
 List TNamed name and title. More...
 
TNamedoperator= (const TNamed &rhs)
 TNamed assignment operator. More...
 
virtual void Print (Option_t *option="") const
 Print TNamed name and title. More...
 
virtual void SetName (const char *name)
 Set the name of the TNamed. More...
 
virtual void SetNameTitle (const char *name, const char *title)
 Set all the TNamed parameters (name and title). More...
 
virtual void SetTitle (const char *title="")
 Set the title of the TNamed. More...
 
virtual Int_t Sizeof () const
 Return size of the TNamed part of the TObject. More...
 
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 
 TObject (const TObject &object)
 TObject copy ctor. More...
 
virtual ~TObject ()
 TObject destructor. More...
 
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...
 
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad. More...
 
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action. More...
 
ULong_t CheckedHash ()
 Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object. More...
 
virtual const char * ClassName () const
 Returns name of class to which the object belongs. More...
 
virtual void Clear (Option_t *="")
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
 
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method. More...
 
virtual void Copy (TObject &object) const
 Copy this to obj. More...
 
virtual void Delete (Option_t *option="")
 Delete this object. More...
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Computes distance from point (px,py) to the object. More...
 
virtual void Draw (Option_t *option="")
 Default Draw method for all objects. More...
 
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs. More...
 
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
 
virtual void Dump () const
 Dump contents of object on stdout. More...
 
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. More...
 
virtual void Execute (const char *method, const char *params, Int_t *error=0)
 Execute method on this object with the given parameter string, e.g. More...
 
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray. More...
 
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to an event at (px,py). More...
 
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
 
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
 
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
 
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
 
virtual const char * GetIconName () const
 Returns mime type name of object. More...
 
virtual const char * GetName () const
 Returns name of object. More...
 
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
 
virtual Option_tGetOption () const
 
virtual const char * GetTitle () const
 Returns title of object. More...
 
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
 
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
 
virtual ULong_t Hash () const
 Return hash value for this object. More...
 
Bool_t HasInconsistentHash () const
 Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e. More...
 
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. More...
 
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname". More...
 
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl. More...
 
virtual void Inspect () const
 Dump contents of this object in a graphics canvas. More...
 
void InvertBit (UInt_t f)
 
virtual Bool_t IsEqual (const TObject *obj) const
 Default equal comparison (objects are equal if they have the same address in memory). More...
 
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
 
R__ALWAYS_INLINE Bool_t IsOnHeap () const
 
virtual Bool_t IsSortable () const
 
R__ALWAYS_INLINE Bool_t IsZombie () const
 
virtual void ls (Option_t *option="") const
 The ls function lists the contents of a class on stdout. More...
 
void MayNotUse (const char *method) const
 Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...
 
virtual Bool_t Notify ()
 This method must be overridden to handle object notification. More...
 
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete. More...
 
void operator delete (void *ptr)
 Operator delete. More...
 
void operator delete[] (void *ptr)
 Operator delete []. More...
 
voidoperator new (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator new[] (size_t sz)
 
voidoperator new[] (size_t sz, void *vp)
 
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
 
virtual void Paint (Option_t *option="")
 This method must be overridden if a class wants to paint itself. More...
 
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
 
virtual void Print (Option_t *option="") const
 This method must be overridden when a class wants to print itself. More...
 
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
 
virtual void RecursiveRemove (TObject *obj)
 Recursively remove this object from a list. More...
 
void ResetBit (UInt_t f)
 
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename. More...
 
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save a primitive as a C++ statement(s) on output stream "out". More...
 
void SetBit (UInt_t f)
 
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f. More...
 
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object. More...
 
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id. More...
 
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
 
R__ALWAYS_INLINE Bool_t TestBit (UInt_t f) const
 
Int_t TestBits (UInt_t f) const
 
virtual void UseCurrentStyle ()
 Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...
 
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...
 

Protected Member Functions

void BuildStack ()
 build sum of all histograms Build a separate list fStack containing the running sum of all histograms More...
 
- Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
 Interface to ErrorHandler (protected). More...
 
void MakeZombie ()
 

Protected Attributes

TH1fHistogram
 Pointer to array of sums of TH1. More...
 
TListfHists
 
Double_t fMaximum
 
Double_t fMinimum
 
TObjArrayfStack
 
- Protected Attributes inherited from TNamed
TString fName
 
TString fTitle
 

Private Member Functions

THStackoperator= (const THStack &)
 

Additional Inherited Members

- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
  kBitMask = 0x00ffffff
}
 
enum  { kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }
 
enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }
 
enum  EStatusBits {
  kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) ,
  kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13)
}
 
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag. More...
 
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
 
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
 
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...
 
- Protected Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }
 

#include <THStack.h>

Inheritance diagram for THStack:
[legend]

Constructor & Destructor Documentation

◆ THStack() [1/4]

THStack::THStack ( )

THStack default constructor.

Definition at line 113 of file THStack.cxx.

◆ THStack() [2/4]

THStack::THStack ( const char *  name,
const char *  title 
)

constructor with name and title

Definition at line 125 of file THStack.cxx.

◆ THStack() [3/4]

THStack::THStack ( TH1 hist,
Option_t axis = "x",
const char *  name = 0,
const char *  title = 0,
Int_t  firstbin = 1,
Int_t  lastbin = -1,
Int_t  firstbin2 = 1,
Int_t  lastbin2 = -1,
Option_t proj_option = "",
Option_t draw_option = "" 
)

Creates a new THStack from a TH2 or TH3 It is filled with the 1D histograms from GetProjectionX or GetProjectionY for each bin of the histogram.

It illustrates the differences and total sum along an axis.

Parameters:

  • hist: the histogram used for the projections. Can be an object deriving from TH2 or TH3.
  • axis: for TH2: "x" for ProjectionX, "y" for ProjectionY. for TH3: see TH3::Project3D.
  • name: fName is set to name if given, otherwise to histo's name with "_stack_<axis>" appended, where <axis> is the value of the parameter axis.
  • title: fTitle is set to title if given, otherwise to histo's title with ", stack of <axis> projections" appended.
  • firstbin, lastbin: for each bin within [firstbin,lastbin] a stack entry is created. See TH2::ProjectionX/Y for use overflow bins. Defaults to "all bins but under- / overflow"
  • firstbin2, lastbin2: Other axis range for TH3::Project3D, defaults to "all bins but under- / overflow". Ignored for TH2s
  • proj_option: option passed to TH2::ProjectionX/Y and TH3::Project3D (along with axis)
  • draw_option: option passed to THStack::Add.

Definition at line 167 of file THStack.cxx.

◆ THStack() [4/4]

THStack::THStack ( const THStack hstack)

THStack copy constructor.

Definition at line 339 of file THStack.cxx.

◆ ~THStack()

THStack::~THStack ( )
virtual

THStack destructor.

Definition at line 320 of file THStack.cxx.

Member Function Documentation

◆ Add()

void THStack::Add ( TH1 h1,
Option_t option = "" 
)
virtual

add a new histogram to the list Only 1-d and 2-d histograms currently supported.

A drawing option may be specified

Definition at line 359 of file THStack.cxx.

◆ begin()

TIter THStack::begin ( ) const

Get iterator over internal hists list.

Definition at line 1076 of file THStack.cxx.

◆ Browse()

void THStack::Browse ( TBrowser b)
virtual

Browse.

Reimplemented from TObject.

Definition at line 374 of file THStack.cxx.

◆ BuildStack()

void THStack::BuildStack ( )
protected

build sum of all histograms Build a separate list fStack containing the running sum of all histograms

Definition at line 384 of file THStack.cxx.

◆ DistancetoPrimitive()

Int_t THStack::DistancetoPrimitive ( Int_t  px,
Int_t  py 
)
virtual

Compute distance from point px,py to each graph.

Reimplemented from TObject.

Definition at line 407 of file THStack.cxx.

◆ Draw()

void THStack::Draw ( Option_t option = "")
virtual

Draw this multihist with its current attributes.

Options to draw histograms are described in THistPainter::Paint By default (if option "nostack" is not specified), histograms will be paint stacked on top of each other.

Reimplemented from TObject.

Definition at line 445 of file THStack.cxx.

◆ end()

TIter THStack::end ( ) const
inline

Definition at line 62 of file THStack.h.

◆ GetHistogram()

TH1 * THStack::GetHistogram ( ) const

Returns a pointer to the histogram used to draw the axis Takes into account the two following cases.

1- option 'A' was specified in THStack::Draw. Return fHistogram 2- user had called TPad::DrawFrame. return pointer to hframe histogram

IMPORTANT NOTES

  • You must call Draw before calling this function. The returned histogram depends on the selected Draw options.
  • This function returns a pointer to an intermediate fixed bin size histogram used to set the range and for picking. You cannot use this histogram to return the bin information. You must get a pointer to one of the histograms in the stack, the first one, for example.

Definition at line 476 of file THStack.cxx.

◆ GetHists()

TList * THStack::GetHists ( ) const
inline

Definition at line 60 of file THStack.h.

◆ GetMaximum()

Double_t THStack::GetMaximum ( Option_t option = "")
virtual

returns the maximum of all added histograms returns the maximum of all histograms if option "nostack".

Definition at line 491 of file THStack.cxx.

◆ GetMinimum()

Double_t THStack::GetMinimum ( Option_t option = "")
virtual

returns the minimum of all added histograms returns the minimum of all histograms if option "nostack".

Definition at line 535 of file THStack.cxx.

◆ GetNhists()

Int_t THStack::GetNhists ( ) const

Return the number of histograms in the stack.

Definition at line 579 of file THStack.cxx.

◆ GetStack()

TObjArray * THStack::GetStack ( )

Return pointer to Stack. Build it if not yet done.

Definition at line 588 of file THStack.cxx.

◆ GetXaxis()

TAxis * THStack::GetXaxis ( ) const

Get x axis of the histogram used to draw the stack.

IMPORTANT NOTE You must call Draw before calling this function. The returned histogram depends on the selected Draw options.

Definition at line 601 of file THStack.cxx.

◆ GetYaxis()

TAxis * THStack::GetYaxis ( ) const

Get x axis of the histogram used to draw the stack.

IMPORTANT NOTE You must call Draw before calling this function. The returned histogram depends on the selected Draw options.

Definition at line 616 of file THStack.cxx.

◆ ls()

void THStack::ls ( Option_t option = "") const
virtual

List histograms in the stack.

Reimplemented from TNamed.

Definition at line 627 of file THStack.cxx.

◆ Merge()

Long64_t THStack::Merge ( TCollection li,
TFileMergeInfo info 
)
virtual

Merge the THStack in the TList into this stack.

Returns the total number of histograms in the result or -1 in case of an error.

Definition at line 640 of file THStack.cxx.

◆ Modified()

void THStack::Modified ( )
virtual

invalidate sum of histograms

Definition at line 663 of file THStack.cxx.

◆ operator=()

THStack & THStack::operator= ( const THStack )
private

◆ Paint()

void THStack::Paint ( Option_t choptin = "")
virtual

Paint the list of histograms.

By default, histograms are shown stacked.

  • the first histogram is paint
  • then the sum of the first and second, etc

If option "nostack" is specified, histograms are all paint in the same pad as if the option "same" had been specified.

If the option nostackb is specified histograms are all paint in the same pad next to each other as bar plots.

if option "pads" is specified, the current pad/canvas is subdivided into a number of pads equal to the number of histograms and each histogram is paint into a separate pad.

By default the background of the histograms is erased before drawing the histograms. The option "noclear" avoid this behaviour. This is useful when drawing a THStack on top of an other plot. If the patterns used to draw the histograms in the stack are transparents, then the plot behind will be visible.

See THistPainter::Paint for a list of valid options.

Reimplemented from TObject.

Definition at line 697 of file THStack.cxx.

◆ Print()

void THStack::Print ( Option_t chopt = "") const
virtual

Print the list of histograms.

Reimplemented from TNamed.

Definition at line 981 of file THStack.cxx.

◆ RecursiveRemove()

void THStack::RecursiveRemove ( TObject obj)
virtual

Recursively remove object from the list of histograms.

Reimplemented from TObject.

Definition at line 995 of file THStack.cxx.

◆ SavePrimitive()

void THStack::SavePrimitive ( std::ostream &  out,
Option_t option = "" 
)
virtual

Save primitive as a C++ statement(s) on output stream out.

Reimplemented from TObject.

Definition at line 1005 of file THStack.cxx.

◆ SetHistogram()

virtual void THStack::SetHistogram ( TH1 h)
inlinevirtual

Definition at line 76 of file THStack.h.

◆ SetMaximum()

void THStack::SetMaximum ( Double_t  maximum = -1111)
virtual

Set maximum.

Definition at line 1058 of file THStack.cxx.

◆ SetMinimum()

void THStack::SetMinimum ( Double_t  minimum = -1111)
virtual

Set minimum.

Definition at line 1067 of file THStack.cxx.

Member Data Documentation

◆ fHistogram

TH1* THStack::fHistogram
protected

Pointer to array of sums of TH1.

Definition at line 38 of file THStack.h.

◆ fHists

TList* THStack::fHists
protected

Definition at line 36 of file THStack.h.

◆ fMaximum

Double_t THStack::fMaximum
protected

Definition at line 39 of file THStack.h.

◆ fMinimum

Double_t THStack::fMinimum
protected

Definition at line 40 of file THStack.h.

◆ fStack

TObjArray* THStack::fStack
protected

Definition at line 37 of file THStack.h.

Libraries for THStack:
[legend]

The documentation for this class was generated from the following files: