library: libGraf
#include "TCutG.h"


class description - source file - inheritance tree (.pdf)

class TCutG : public TGraph

Inheritance Chart:

TCutG() TCutG(const TCutG& cutg) TCutG(const char* name, Int_t n) TCutG(const char* name, Int_t n, const Float_t* x, const Float_t* y) TCutG(const char* name, Int_t n, const Double_t* x, const Double_t* y) virtual ~TCutG() static TClass* Class() TObject* GetObjectX() const TObject* GetObjectY() const const char* GetVarX() const const char* GetVarY() const Double_t Integral(TH2* h, Option_t* option = "") const virtual TClass* IsA() const virtual Int_t IsInside(Double_t x, Double_t y) const TCutG& operator=(const TCutG&) virtual void SavePrimitive(ofstream& out, Option_t* option) virtual void SetObjectX(TObject* obj) virtual void SetObjectY(TObject* obj) virtual void SetVarX(const char* varx) virtual void SetVarY(const char* vary) virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)

Data Members

TString fVarX X variable TString fVarY Y variable TObject* fObjectX !pointer to an object corresponding to X TObject* fObjectY !pointer to an object corresponding to Y

Class Description

  A Graphical cut.                                                    
  A TCutG object defines a closed polygon in a x,y plot.              
  It can be created via the graphics editor option "CutG"             
  or directly by invoking its constructor.                            
  To create a TCutG via the graphics editor, use the left button      
  to select the points building the contour of the cut. Click on      
  the right button to close the TCutG.                                
  When it is created via the graphics editor, the TCutG object        
  is named "CUTG". It is recommended to immediatly change the name    
  by using the context menu item "SetName".                           //                                                                      
   When the graphics editor is used, the names of the variables X,Y   
   are automatically taken from the current pad title.                
  Assume a TTree object T and:                                        
     Root > T.Draw("abs(fMomemtum)%fEtot")                            
  the TCutG members fVarX, fVary will be set to:                      
     fVarx = fEtot                                                    
     fVary = abs(fMomemtum)                                           
  A graphical cut can be used in a TTree selection expression:        
    Root > T.Draw("fEtot","cutg1")                                    
    where "cutg1" is the name of an existing graphical cut.           
  Note that, as shown in the example above, a graphical cut may be    
  used in a selection expression when drawing TTrees expressions      
  of 1-d, 2-d or 3-dimensions.                                        
  The expressions used in TTree::Draw can reference the variables     
  in the fVarX, fVarY of the graphical cut plus other variables.      
  When the TCutG object is created, it is added to the list of special
  objects in the main TROOT object pointed by gROOT. To retrieve a    
  pointer to this object from the code or command line, do:           
      TCutG *mycutg;                                                  
      mycutg = (TCutG*)gROOT->GetListOfSpecials()->FindObject("CUTG") 
  Example of use of a TCutG in TTree::Draw:                           
       tree.Draw("x:y","mycutg && z>0 %% sqrt(x)>1")                  
  A Graphical cut may be drawn via TGraph::Draw.                      
  It can be edited like a normal TGraph.                              
  A Graphical cut may be saved to a file via TCutG::Write.            //                                                                     

TCutG() : TGraph()

TCutG(const TCutG &cutg) :TGraph(cutg)
 TCutG copy constructor

TCutG(const char *name, Int_t n) :TGraph(n)

TCutG(const char *name, Int_t n, const Float_t *x, const Float_t *y) :TGraph(n,x,y)

TCutG(const char *name, Int_t n, const Double_t *x, const Double_t *y) :TGraph(n,x,y)


Double_t Integral(TH2 *h, Option_t *option) const
 Compute the integral of 2-d histogram h for all bins inside the cut
 if option "width" is specified, the integral is the sum of
 the bin contents multiplied by the bin width in x and in y.

Int_t IsInside(Double_t x, Double_t y) const
*.         Function which returns 1 if point x,y lies inside the
*.              polygon defined by the graph points
*.                                0 otherwise
*.     The loop is executed with the end-point coordinates of a
*.     line segment (X1,Y1)-(X2,Y2) and the Y-coordinate of a
*.     horizontal line.
*.     The counter inter is incremented if the line (X1,Y1)-(X2,Y2)
*.     intersects the horizontal line.
*.     In this case XINT is set to the X-coordinate of the
*.     intersection point.
*.     If inter is an odd number, then the point x,y is within
*.     the polygon.
*.         This routine is based on an original algorithm
*.         developed by R.Nierhaus.

void SavePrimitive(ofstream &out, Option_t *option)
 Save primitive as a C++ statement(s) on output stream out

void SetVarX(const char *varx)

void SetVarY(const char *vary)

void Streamer(TBuffer &R__b)
 Stream an object of class TCutG.

Inline Functions

           TObject* GetObjectX() const
           TObject* GetObjectY() const
        const char* GetVarX() const
        const char* GetVarY() const
               void SetObjectX(TObject* obj)
               void SetObjectY(TObject* obj)
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void StreamerNVirtual(TBuffer& b)
             TCutG& operator=(const TCutG&)

Author: Rene Brun 16/05/97
Last update: root/graf:$Name: $:$Id: TCutG.cxx,v 1.17 2005/09/05 07:25:22 brun Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *

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