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Reference Guide
TGeoPolygon Class Reference

An arbitrary polygon defined by vertices.

The vertices have to be defined CLOCKWISE in the XY plane, making either a convex or concave polygon. No test for malformed polygons is performed.

A polygon is a 2D shape defined by vertices in the XY plane. It is used by TGeoXtru class for computing Contains() and Safety(). Only the pointers to the actual lists of XY values are used - these are not owned by the class.

To check if a point in XY plane is contained by a polygon, this is split into an outscribed convex polygon and the remaining polygons of its subtraction from the outscribed one. A point is INSIDE if it is contained by the outscribed polygon but NOT by the remaining ones. Since these can also be arbitrary polygons at their turn, a tree structure is formed:

P = Pconvex - (Pconvex-P) where (-) means 'subtraction'
Pconvex-P = P1 + P2 + ... where (+) means 'union'

Note that P1, P2, ... do not intersect each other and they are defined by subsets of the list of vertices of P. They can be split in the same way as P*

Therefore, if C(P) represents the Boolean : 'does P contains a given point?', then:

C(P) = C(Pconvex) .and. not(C(P1) | C(P2) | ...)

For creating a polygon without TGeoXtru class, one has to call the constructor TGeoPolygon(nvert) and then SetXY(Double_t *x, Double_t *y) providing the arrays of X and Y vertex positions (defined clockwise) that have to 'live' longer than the polygon they will describe. This complication is due to efficiency reasons. At the end one has to call the FinishPolygon() method.

Definition at line 19 of file TGeoPolygon.h.

Public Types

enum  { kGeoConvex = BIT(9), kGeoFinishPolygon = BIT(10), kGeoACW = BIT(11) }
 
- 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)
}
 

Public Member Functions

 TGeoPolygon ()
 Dummy constructor. More...
 
 TGeoPolygon (Int_t nvert)
 Default constructor. More...
 
virtual ~TGeoPolygon ()
 Destructor. More...
 
Double_t Area () const
 Computes area of the polygon in [length^2]. More...
 
Bool_t Contains (const Double_t *point) const
 Check if a point given by X = point[0], Y = point[1] is inside the polygon. More...
 
virtual void Draw (Option_t *option="")
 Draw the polygon. More...
 
void FinishPolygon ()
 Decompose polygon in a convex outscribed part and a list of daughter polygons that have to be subtracted to get the actual one. More...
 
void GetConvexVertices (Double_t *x, Double_t *y) const
 Fill list of vertices of the convex outscribed polygon into provided arrays. More...
 
Int_t GetNconvex () const
 
Int_t GetNvert () const
 
void GetVertices (Double_t *x, Double_t *y) const
 Fill list of vertices into provided arrays. More...
 
Double_tGetX ()
 
Double_tGetY ()
 
Bool_t IsClockwise () const
 
Bool_t IsConvex () const
 
Bool_t IsFinished () const
 
Bool_t IsIllegalCheck () const
 Check for illegal crossings between non-consecutive segments. More...
 
Double_t Safety (const Double_t *point, Int_t &isegment) const
 Compute minimum distance from POINT to any segment. Returns segment index. More...
 
void SetConvex (Bool_t flag=kTRUE)
 
void SetNextIndex (Int_t index=-1)
 Sets the next polygone index. More...
 
void SetXY (Double_t *x, Double_t *y)
 Set X/Y array pointer for the polygon and daughters. 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 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, Bool_t set)
 Set or unset the user status bits as specified in f. More...
 
void SetBit (UInt_t f)
 
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 Attributes

TObjArrayfDaughters {nullptr}
 pointer to list of current Y coordinates of vertices More...
 
Int_tfInd {nullptr}
 
Int_tfIndc {nullptr}
 
Int_t fNconvex {0}
 
Int_t fNvert {0}
 
Double_tfX {nullptr}
 
Double_tfY {nullptr}
 pointer to list of current X coordinates of vertices More...
 

Private Member Functions

 TGeoPolygon (const TGeoPolygon &)=delete
 
void ConvexCheck ()
 Check polygon convexity. More...
 
Bool_t IsRightSided (const Double_t *point, Int_t ind1, Int_t ind2) const
 Check if POINT is right-sided with respect to the segment defined by IND1 and IND2. More...
 
Bool_t IsSegConvex (Int_t i1, Int_t i2=-1) const
 Check if a segment [0..fNvert-1] belongs to the outscribed convex pgon. More...
 
TGeoPolygonoperator= (const TGeoPolygon &)=delete
 
void OutscribedConvex ()
 Compute indices for the outscribed convex polygon. More...
 

Additional Inherited Members

- 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 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 ()
 

#include <TGeoPolygon.h>

Inheritance diagram for TGeoPolygon:
[legend]

Member Enumeration Documentation

◆ anonymous enum

anonymous enum
Enumerator
kGeoConvex 
kGeoFinishPolygon 
kGeoACW 

Definition at line 22 of file TGeoPolygon.h.

Constructor & Destructor Documentation

◆ TGeoPolygon() [1/3]

TGeoPolygon::TGeoPolygon ( const TGeoPolygon )
privatedelete

◆ TGeoPolygon() [2/3]

TGeoPolygon::TGeoPolygon ( )

Dummy constructor.

Definition at line 65 of file TGeoPolygon.cxx.

◆ TGeoPolygon() [3/3]

TGeoPolygon::TGeoPolygon ( Int_t  nvert)

Default constructor.

Definition at line 81 of file TGeoPolygon.cxx.

◆ ~TGeoPolygon()

TGeoPolygon::~TGeoPolygon ( )
virtual

Destructor.

Definition at line 102 of file TGeoPolygon.cxx.

Member Function Documentation

◆ Area()

Double_t TGeoPolygon::Area ( ) const

Computes area of the polygon in [length^2].

Definition at line 114 of file TGeoPolygon.cxx.

◆ Contains()

Bool_t TGeoPolygon::Contains ( const Double_t point) const

Check if a point given by X = point[0], Y = point[1] is inside the polygon.

Definition at line 130 of file TGeoPolygon.cxx.

◆ ConvexCheck()

void TGeoPolygon::ConvexCheck ( )
private

Check polygon convexity.

Definition at line 148 of file TGeoPolygon.cxx.

◆ Draw()

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

Draw the polygon.

Reimplemented from TObject.

Definition at line 169 of file TGeoPolygon.cxx.

◆ FinishPolygon()

void TGeoPolygon::FinishPolygon ( )

Decompose polygon in a convex outscribed part and a list of daughter polygons that have to be subtracted to get the actual one.

Definition at line 179 of file TGeoPolygon.cxx.

◆ GetConvexVertices()

void TGeoPolygon::GetConvexVertices ( Double_t x,
Double_t y 
) const

Fill list of vertices of the convex outscribed polygon into provided arrays.

Definition at line 239 of file TGeoPolygon.cxx.

◆ GetNconvex()

Int_t TGeoPolygon::GetNconvex ( ) const
inline

Definition at line 56 of file TGeoPolygon.h.

◆ GetNvert()

Int_t TGeoPolygon::GetNvert ( ) const
inline

Definition at line 55 of file TGeoPolygon.h.

◆ GetVertices()

void TGeoPolygon::GetVertices ( Double_t x,
Double_t y 
) const

Fill list of vertices into provided arrays.

Definition at line 230 of file TGeoPolygon.cxx.

◆ GetX()

Double_t* TGeoPolygon::GetX ( )
inline

Definition at line 57 of file TGeoPolygon.h.

◆ GetY()

Double_t* TGeoPolygon::GetY ( )
inline

Definition at line 58 of file TGeoPolygon.h.

◆ IsClockwise()

Bool_t TGeoPolygon::IsClockwise ( ) const
inline

Definition at line 61 of file TGeoPolygon.h.

◆ IsConvex()

Bool_t TGeoPolygon::IsConvex ( ) const
inline

Definition at line 62 of file TGeoPolygon.h.

◆ IsFinished()

Bool_t TGeoPolygon::IsFinished ( ) const
inline

Definition at line 63 of file TGeoPolygon.h.

◆ IsIllegalCheck()

Bool_t TGeoPolygon::IsIllegalCheck ( ) const

Check for illegal crossings between non-consecutive segments.

Definition at line 278 of file TGeoPolygon.cxx.

◆ IsRightSided()

Bool_t TGeoPolygon::IsRightSided ( const Double_t point,
Int_t  ind1,
Int_t  ind2 
) const
private

Check if POINT is right-sided with respect to the segment defined by IND1 and IND2.

Definition at line 250 of file TGeoPolygon.cxx.

◆ IsSegConvex()

Bool_t TGeoPolygon::IsSegConvex ( Int_t  i1,
Int_t  i2 = -1 
) const
private

Check if a segment [0..fNvert-1] belongs to the outscribed convex pgon.

Definition at line 262 of file TGeoPolygon.cxx.

◆ operator=()

TGeoPolygon& TGeoPolygon::operator= ( const TGeoPolygon )
privatedelete

◆ OutscribedConvex()

void TGeoPolygon::OutscribedConvex ( )
private

Compute indices for the outscribed convex polygon.

Definition at line 308 of file TGeoPolygon.cxx.

◆ Safety()

Double_t TGeoPolygon::Safety ( const Double_t point,
Int_t isegment 
) const

Compute minimum distance from POINT to any segment. Returns segment index.

Definition at line 357 of file TGeoPolygon.cxx.

◆ SetConvex()

void TGeoPolygon::SetConvex ( Bool_t  flag = kTRUE)
inline

Definition at line 66 of file TGeoPolygon.h.

◆ SetNextIndex()

void TGeoPolygon::SetNextIndex ( Int_t  index = -1)

Sets the next polygone index.

If index<0 sets all indices consecutive in increasing order.

Definition at line 415 of file TGeoPolygon.cxx.

◆ SetXY()

void TGeoPolygon::SetXY ( Double_t x,
Double_t y 
)

Set X/Y array pointer for the polygon and daughters.

Definition at line 439 of file TGeoPolygon.cxx.

Member Data Documentation

◆ fDaughters

TObjArray* TGeoPolygon::fDaughters {nullptr}
protected

pointer to list of current Y coordinates of vertices

Definition at line 35 of file TGeoPolygon.h.

◆ fInd

Int_t* TGeoPolygon::fInd {nullptr}
protected

Definition at line 31 of file TGeoPolygon.h.

◆ fIndc

Int_t* TGeoPolygon::fIndc {nullptr}
protected

Definition at line 32 of file TGeoPolygon.h.

◆ fNconvex

Int_t TGeoPolygon::fNconvex {0}
protected

Definition at line 30 of file TGeoPolygon.h.

◆ fNvert

Int_t TGeoPolygon::fNvert {0}
protected

Definition at line 29 of file TGeoPolygon.h.

◆ fX

Double_t* TGeoPolygon::fX {nullptr}
protected

Definition at line 33 of file TGeoPolygon.h.

◆ fY

Double_t* TGeoPolygon::fY {nullptr}
protected

pointer to list of current X coordinates of vertices

Definition at line 34 of file TGeoPolygon.h.

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