library: libGraf #include "TCutG.h" |
TCutG
class description - source file - inheritance tree (.pdf)
public:
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)
protected:
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
TCutG
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.
Example:
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")
mycutg->SetName("mycutg");
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)
~TCutG()
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 1.16 2004/06/26 13:38:57 brun Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *
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