THStack

class THStack : public TNamed

    protected:

      void BuildStack()

    public:

                       THStack()
                       THStack(const char* name, const char* title)
                       THStack(const 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 = "")
                       THStack(const THStack& hstack)
               virtual ~THStack()
          virtual void Add(TH1* h, Option_t* option = "")
          virtual void Browse(TBrowser* b)
        static TClass* Class()
         virtual Int_t DistancetoPrimitive(Int_t px, Int_t py)
          virtual void Draw(Option_t* chopt = "")
                  TH1* GetHistogram() const
                TList* GetHists() const
      virtual Double_t GetMaximum(Option_t* option = "")
      virtual Double_t GetMinimum(Option_t* option = "")
            TObjArray* GetStack()
                TAxis* GetXaxis() const
                TAxis* GetYaxis() const
       virtual TClass* IsA() const
          virtual void ls(Option_t* option = "") const
          virtual void Modified()
              THStack& operator=(const THStack&)
          virtual void Paint(Option_t* chopt = "")
          virtual void Print(Option_t* chopt = "") const
          virtual void RecursiveRemove(TObject* obj)
          virtual void SavePrimitive(ofstream& out, Option_t* option)
          virtual void SetMaximum(Double_t maximum = -1111)
          virtual void SetMinimum(Double_t minimum = -1111)
          virtual void ShowMembers(TMemberInspector& insp, char* parent)
          virtual void Streamer(TBuffer& b)
                  void StreamerNVirtual(TBuffer& b)

Data Members

    protected:

          TList* fHists      Pointer to array of TH1
      TObjArray* fStack      !Pointer to array of sums of TH1
            TH1* fHistogram  !Pointer to histogram used for drawing axis
        Double_t fMaximum    Maximum value for plotting along y
        Double_t fMinimum    Minimum value for plotting along y

Class Description

   A THStack is a collection of TH1 (or derived) objects
   Use THStack::Add to add a new histogram to the list.
   The THStack owns the objects in the list.
   By default (if option "nostack" is not specified), histograms will be paint
   stacked on top of each other.
   Example;
      THStack hs("hs","test stacked histograms");
      TH1F *h1 = new TH1F("h1","test hstack",100,-4,4);
      h1->FillRandom("gaus",20000);
      h1->SetFillColor(kRed);
      hs.Add(h1);
      TH1F *h2 = new TH1F("h2","test hstack",100,-4,4);
      h2->FillRandom("gaus",15000);
      h2->SetFillColor(kBlue);
      hs.Add(h2);
      TH1F *h3 = new TH1F("h3","test hstack",100,-4,4);
      h3->FillRandom("gaus",10000);
      h3->SetFillColor(kGreen);
      hs.Add(h3);
      TCanvas c1("c1","stacked hists",10,10,700,900);
      c1.Divide(1,2);
      c1.cd(1);
      hs.Draw();
      c1.cd(2);
      hs->Draw("nostack");

  See a more complex example in $ROOTSYS/tutorials/hstack.C

  Note that picking is supported for all drawing modes.

 THStack default constructor

 constructor with name and title

 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"
 - firstbin2, lastbin2:
          Other axis range for TH3::Project3D, defaults to "all bins".
          Ignored for TH2s
 - proj_option:
          option passed to TH2::ProjectionX/Y and TH3::Project3D (along
          with axis)
 - draw_option:
          option passed to THStack::Add.

 THStack destructor

 THStack copy constructor

 add a new histogram to the list
 Only 1-d and 2-d histograms currently supported.
 A drawing option may be specified

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

 Compute distance from point px,py to each graph

*-*-*-*-*-*-*-*-*-*-*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.

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

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

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

 Return pointer to Stack. Build it if not yet done

 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.

 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.

 List histograms in the stack

 invalidate sum of histograms

 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 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.

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

 Print the list of histograms

 Recursively remove object from the list of histograms

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

Inline Functions

             TList* GetHists() const
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void Streamer(TBuffer& b)
               void StreamerNVirtual(TBuffer& b)
           THStack& operator=(const THStack&)