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.

	TGeoPolygon (Int_t nvert)
	Default constructor.

virtual	~TGeoPolygon ()
	Destructor.

Double_t	Area () const
	Computes area of the polygon in [length^2].

Bool_t	Contains (const Double_t *point) const
	Check if a point given by X = point[0], Y = point[1] is inside the polygon.

virtual void	Draw (Option_t *option="")
	Draw the polygon.

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.

void	GetConvexVertices (Double_t x, Double_t y) const
	Fill list of vertices of the convex outscribed polygon into provided arrays.

Int_t	GetNconvex () const

Int_t	GetNvert () const

void	GetVertices (Double_t x, Double_t y) const
	Fill list of vertices into provided arrays.

Double_t *	GetX ()

Double_t *	GetY ()

Bool_t	IsClockwise () const

Bool_t	IsConvex () const

Bool_t	IsFinished () const

Bool_t	IsIllegalCheck () const
	Check for illegal crossings between non-consecutive segments.

Double_t	Safety (const Double_t *point, Int_t &isegment) const
	Compute minimum distance from POINT to any segment. Returns segment index.

void	SetConvex (Bool_t flag=kTRUE)

void	SetNextIndex (Int_t index=-1)
	Sets the next polygone index.

void	SetXY (Double_t x, Double_t y)
	Set X/Y array pointer for the polygon and daughters.

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor.

	TObject (const TObject &object)
	TObject copy ctor.

virtual	~TObject ()
	TObject destructor.

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract.

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad.

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action.

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.

virtual const char *	ClassName () const
	Returns name of class to which the object belongs.

virtual void	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility.

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method.

virtual void	Copy (TObject &object) const
	Copy this to obj.

virtual void	Delete (Option_t *option="")
	Delete this object.

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object.

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs.

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad for instance with: `gROOT->SetSelectedPad(gPad)`.

virtual void	Dump () const
	Dump contents of object on stdout.

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message.

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.

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray.

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py).

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message.

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes.

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object.

virtual const char *	GetIconName () const
	Returns mime type name of object.

virtual const char *	GetName () const
	Returns name of object.

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py).

virtual Option_t *	GetOption () const

virtual const char *	GetTitle () const
	Returns title of object.

virtual UInt_t	GetUniqueID () const
	Return the unique object id.

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out.

virtual ULong_t	Hash () const
	Return hash value for this object.

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.

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message.

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname".

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl.

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas.

void	InvertBit (UInt_t f)

Bool_t	IsDestructed () const
	IsDestructed.

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory).

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

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.

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).

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification.

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete.

void	operator delete (void *ptr)
	Operator delete.

void	operator delete[] (void *ptr)
	Operator delete [].

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator.

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself.

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list.

virtual void	Print (Option_t *option="") const
	This method must be overridden when a class wants to print itself.

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory.

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list.

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename.

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out".

void	SetBit (UInt_t f)

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f.

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object.

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id.

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message.

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.

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory.

Protected Attributes
TObjArray *	fDaughters {nullptr}
	pointer to list of current Y coordinates of vertices

Int_t *	fInd {nullptr}

Int_t *	fIndc {nullptr}

Int_t	fNconvex {0}

Int_t	fNvert {0}

Double_t *	fX {nullptr}

Double_t *	fY {nullptr}
	pointer to list of current X coordinates of vertices

Private Member Functions
	TGeoPolygon (const TGeoPolygon &)=delete

void	ConvexCheck ()
	Check polygon convexity.

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.

Bool_t	IsSegConvex (Int_t i1, Int_t i2=-1) const
	Check if a segment [0..fNvert-1] belongs to the outscribed convex pgon.

TGeoPolygon &	operator= (const TGeoPolygon &)=delete

void	OutscribedConvex ()
	Compute indices for the outscribed convex polygon.

Additional Inherited Members
Static Public Member Functions inherited from TObject
static Longptr_t	GetDtorOnly ()
	Return destructor only flag.

static Bool_t	GetObjectStat ()
	Get status of object stat flag.

static void	SetDtorOnly (void *obj)
	Set destructor only flag.

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable.

Protected Types inherited from TObject
enum	{ kOnlyPrepStep = BIT(3) }

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).

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:

[legend]

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

geom/geom/inc/TGeoPolygon.h
geom/geom/src/TGeoPolygon.cxx

Public Types

Public Member Functions

Protected Attributes

Private Member Functions

Additional Inherited Members

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ TGeoPolygon() [1/3]

◆ TGeoPolygon() [2/3]

◆ TGeoPolygon() [3/3]

◆ ~TGeoPolygon()

Member Function Documentation

◆ Area()

◆ Contains()

◆ ConvexCheck()

◆ Draw()

◆ FinishPolygon()

◆ GetConvexVertices()

◆ GetNconvex()

◆ GetNvert()

◆ GetVertices()

◆ GetX()

◆ GetY()

◆ IsClockwise()

◆ IsConvex()

◆ IsFinished()

◆ IsIllegalCheck()

◆ IsRightSided()

◆ IsSegConvex()

◆ operator=()

◆ OutscribedConvex()

◆ Safety()

◆ SetConvex()

◆ SetNextIndex()

◆ SetXY()

Member Data Documentation

◆ fDaughters

◆ fInd

◆ fIndc

◆ fNconvex

◆ fNvert

◆ fX

◆ fY