VTK: vtkPolygon Class Reference

| VTK 9.3.1

Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
vtkPolygon Class Reference

a cell that represents an n-sided polygon More...

`#include <vtkPolygon.h>`

Inheritance diagram for vtkPolygon:
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Collaboration diagram for vtkPolygon:
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## Public Types
enum | EarCutMeasureTypes { PERIMETER2_TO_AREA_RATIO = 0 , DOT_PRODUCT = 1 , BEST_QUALITY = 2 }
typedef vtkCell | Superclass
Public Types inherited from vtkCell
typedef vtkObject | Superclass

## Public Member Functions
virtual vtkTypeBool | IsA (const char *type)
| Return 1 if this class is the same type of (or a subclass of) the named class. More...
vtkPolygon * | NewInstance () const
void | PrintSelf (ostream &os, vtkIndent indent) override
| Methods invoked by print to print information about the object including superclasses. More...
double | ComputeArea ()
| Compute the area of a polygon. More...
void | InterpolateFunctions (const double x[3], double *sf) override
| Compute the interpolation functions/derivatives. More...
bool | IsConvex ()
| Determine whether or not a polygon is convex. More...
int | ParameterizePolygon (double p0[3], double p10[3], double &l10, double p20[3], double &l20, double n[3])
| Create a local s-t coordinate system for a polygon. More...
int | Triangulate (vtkIdList *outTris)
| Triangulate this polygon. More...
int | NonDegenerateTriangulate (vtkIdList *outTris)
| Same as Triangulate(vtkIdList *outTris) but with a first pass to split the polygon into non-degenerate polygons. More...
int | BoundedTriangulate (vtkIdList *outTris, double tol)
| Triangulate polygon and enforce that the ratio of the smallest triangle area to the polygon area is greater than a user-defined tolerance. More...
int | GetCellType () override
| See the vtkCell API for descriptions of these methods. More...
int | GetCellDimension () override
| See the vtkCell API for descriptions of these methods. More...
int | GetNumberOfEdges () override
| See the vtkCell API for descriptions of these methods. More...
int | GetNumberOfFaces () override
| See the vtkCell API for descriptions of these methods. More...
vtkCell * | GetEdge (int edgeId) override
| See the vtkCell API for descriptions of these methods. More...
vtkCell * | GetFace (int) override
| See the vtkCell API for descriptions of these methods. More...
int | CellBoundary (int subId, const double pcoords[3], vtkIdList *pts) override
| See the vtkCell API for descriptions of these methods. More...
void | Contour (double value, vtkDataArray *cellScalars, vtkIncrementalPointLocator *locator, vtkCellArray *verts, vtkCellArray *lines, vtkCellArray *polys, vtkPointData *inPd, vtkPointData *outPd, vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd) override
| See the vtkCell API for descriptions of these methods. More...
void | Clip (double value, vtkDataArray *cellScalars, vtkIncrementalPointLocator *locator, vtkCellArray *tris, vtkPointData *inPd, vtkPointData *outPd, vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd, int insideOut) override
| See the vtkCell API for descriptions of these methods. More...
int | EvaluatePosition (const double x[3], double closestPoint[3], int &subId, double pcoords[3], double &dist2, double weights[]) override
| See the vtkCell API for descriptions of these methods. More...
void | EvaluateLocation (int &subId, const double pcoords[3], double x[3], double *weights) override
| See the vtkCell API for descriptions of these methods. More...
int | IntersectWithLine (const double p1[3], const double p2[3], double tol, double &t, double x[3], double pcoords[3], int &subId) override
| See the vtkCell API for descriptions of these methods. More...
int | Triangulate (int index, vtkIdList *ptIds, vtkPoints *pts) override
| See the vtkCell API for descriptions of these methods. More...
void | Derivatives (int subId, const double pcoords[3], const double *values, int dim, double *derivs) override
| See the vtkCell API for descriptions of these methods. More...
int | IsPrimaryCell () override
| See the vtkCell API for descriptions of these methods. More...
virtual bool | GetUseMVCInterpolation ()
| Set/Get the flag indicating whether to use Mean Value Coordinate for the interpolation. More...
virtual void | SetUseMVCInterpolation (bool)
| Set/Get the flag indicating whether to use Mean Value Coordinate for the interpolation. More...
virtual void | SetTolerance (double)
| Specify an internal tolerance for operations requiring polygon triangulation. More...
virtual double | GetTolerance ()
| Specify an internal tolerance for operations requiring polygon triangulation. More...
int | EarCutTriangulation (int measure=PERIMETER2_TO_AREA_RATIO)
| A fast triangulation method. More...
int | EarCutTriangulation (vtkIdList *outTris, int measure=PERIMETER2_TO_AREA_RATIO)
| A fast triangulation method. More...
int | UnbiasedEarCutTriangulation (int seed, int measure=PERIMETER2_TO_AREA_RATIO)
| A fast triangulation method. More...
int | UnbiasedEarCutTriangulation (int seed, vtkIdList *outTris, int measure=PERIMETER2_TO_AREA_RATIO)
| A fast triangulation method. More...
Public Member Functions inherited from vtkCell
vtkCell * | NewInstance () const
void | Initialize (int npts, const vtkIdType *pts, vtkPoints *p)
| Initialize cell from outside with point ids and point coordinates specified. More...
void | Initialize (int npts, vtkPoints *p)
| Initialize the cell with point coordinates specified. More...
virtual void | ShallowCopy (vtkCell *c)
| Copy this cell by reference counting the internal data structures. More...
virtual void | DeepCopy (vtkCell *c)
| Copy this cell by completely copying internal data structures. More...
virtual int | IsLinear ()
| Non-linear cells require special treatment beyond the usual cell type and connectivity list information. More...
virtual int | RequiresInitialization ()
| Some cells require initialization prior to access. More...
virtual void | Initialize ()
virtual int | IsExplicitCell ()
| Explicit cells require additional representational information beyond the usual cell type and connectivity list information. More...
virtual int | RequiresExplicitFaceRepresentation ()
| Determine whether the cell requires explicit face representation, and methods for setting and getting the faces (see vtkPolyhedron for example usage of these methods). More...
virtual void | SetFaces (vtkIdType *vtkNotUsed(faces))
virtual vtkIdType * | GetFaces ()
vtkPoints * | GetPoints ()
| Get the point coordinates for the cell. More...
vtkIdType | GetNumberOfPoints () const
| Return the number of points in the cell. More...
vtkIdList * | GetPointIds ()
| Return the list of point ids defining the cell. More...
vtkIdType | GetPointId (int ptId)
| For cell point i, return the actual point id. More...
virtual int | Inflate (double dist)
| Inflates the cell. More...
virtual double | ComputeBoundingSphere (double center[3]) const
| Computes the bounding sphere of the cell. More...
void | GetBounds (double bounds[6])
| Compute cell bounding box (xmin,xmax,ymin,ymax,zmin,zmax). More...
double * | GetBounds ()
| Compute cell bounding box (xmin,xmax,ymin,ymax,zmin,zmax). More...
double | GetLength2 ()
| Compute Length squared of cell (i.e., bounding box diagonal squared). More...
virtual int | GetParametricCenter (double pcoords[3])
| Return center of the cell in parametric coordinates. More...
virtual double | GetParametricDistance (const double pcoords[3])
| Return the distance of the parametric coordinate provided to the cell. More...
virtual double * | GetParametricCoords ()
| Return a contiguous array of parametric coordinates of the points defining this cell. More...
virtual void | InterpolateFunctions (const double vtkNotUsed(pcoords)[3], double *vtkNotUsed(weight))
| Compute the interpolation functions/derivatives (aka shape functions/derivatives) No-ops at this level. More...
virtual void | InterpolateDerivs (const double vtkNotUsed(pcoords)[3], double *vtkNotUsed(derivs))
virtual int | IntersectWithCell (vtkCell *other, double tol=0.0)
| Intersects with an other cell. More...
virtual int | IntersectWithCell (vtkCell *other, const vtkBoundingBox &boudingBox, const vtkBoundingBox &otherBoundingBox, double tol=0.0)
| Intersects with an other cell. More...
Public Member Functions inherited from vtkObject
| vtkBaseTypeMacro (vtkObject, vtkObjectBase)
virtual void | DebugOn ()
| Turn debugging output on. More...
virtual void | DebugOff ()
| Turn debugging output off. More...
bool | GetDebug ()
| Get the value of the debug flag. More...
void | SetDebug (bool debugFlag)
| Set the value of the debug flag. More...
virtual void | Modified ()
| Update the modification time for this object. More...
virtual vtkMTimeType | GetMTime ()
| Return this object's modified time. More...
void | RemoveObserver (unsigned long tag)
void | RemoveObservers (unsigned long event)
void | RemoveObservers (const char *event)
void | RemoveAllObservers ()
vtkTypeBool | HasObserver (unsigned long event)
vtkTypeBool | HasObserver (const char *event)
vtkTypeBool | InvokeEvent (unsigned long event)
vtkTypeBool | InvokeEvent (const char *event)
std::string | GetObjectDescription () const override
| The object description printed in messages and PrintSelf output. More...
unsigned long | AddObserver (unsigned long event, vtkCommand *, float priority=0.0f)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
unsigned long | AddObserver (const char *event, vtkCommand *, float priority=0.0f)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
vtkCommand * | GetCommand (unsigned long tag)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
void | RemoveObserver (vtkCommand *)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
void | RemoveObservers (unsigned long event, vtkCommand *)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
void | RemoveObservers (const char *event, vtkCommand *)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
vtkTypeBool | HasObserver (unsigned long event, vtkCommand *)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
vtkTypeBool | HasObserver (const char *event, vtkCommand *)
| Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...
template<class U , class T >
unsigned long | AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f)
| Overloads to AddObserver that allow developers to add class member functions as callbacks for events. More...
template<class U , class T >
unsigned long | AddObserver (unsigned long event, U observer, void(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
| Overloads to AddObserver that allow developers to add class member functions as callbacks for events. More...
template<class U , class T >
unsigned long | AddObserver (unsigned long event, U observer, bool(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
| Allow user to set the AbortFlagOn() with the return value of the callback method. More...
vtkTypeBool | InvokeEvent (unsigned long event, void *callData)
| This method invokes an event and return whether the event was aborted or not. More...
vtkTypeBool | InvokeEvent (const char *event, void *callData)
| This method invokes an event and return whether the event was aborted or not. More...
virtual void | SetObjectName (const std::string &objectName)
| Set/get the name of this object for reporting purposes. More...
virtual std::string | GetObjectName () const
| Set/get the name of this object for reporting purposes. More...
Public Member Functions inherited from vtkObjectBase
const char * | GetClassName () const
| Return the class name as a string. More...
virtual vtkIdType | GetNumberOfGenerationsFromBase (const char *name)
| Given the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class). More...
virtual void | Delete ()
| Delete a VTK object. More...
virtual void | FastDelete ()
| Delete a reference to this object. More...
void | InitializeObjectBase ()
void | Print (ostream &os)
| Print an object to an ostream. More...
virtual void | Register (vtkObjectBase *o)
| Increase the reference count (mark as used by another object). More...
virtual void | UnRegister (vtkObjectBase *o)
| Decrease the reference count (release by another object). More...
int | GetReferenceCount ()
| Return the current reference count of this object. More...
void | SetReferenceCount (int)
| Sets the reference count. More...
bool | GetIsInMemkind () const
| A local state flag that remembers whether this object lives in the normal or extended memory space. More...
virtual void | PrintHeader (ostream &os, vtkIndent indent)
| Methods invoked by print to print information about the object including superclasses. More...
virtual void | PrintTrailer (ostream &os, vtkIndent indent)
| Methods invoked by print to print information about the object including superclasses. More...
virtual bool | UsesGarbageCollector () const
| Indicate whether the class uses `vtkGarbageCollector` or not. More...

## Static Public Member Functions
static vtkPolygon * | New ()
static vtkTypeBool | IsTypeOf (const char *type)
static vtkPolygon * | SafeDownCast (vtkObjectBase *o)
static void | ComputeNormal (int numPts, double *pts, double n[3])
| Compute the polygon normal from an array of points. More...
static double | ComputeArea (vtkPoints *p, vtkIdType numPts, const vtkIdType *pts, double normal[3])
| Compute the area of a polygon in 3D. More...
static int | PointInPolygon (double x[3], int numPts, double *pts, double bounds[6], double n[3])
| Determine whether a point is inside the specified polygon. More...
static double | DistanceToPolygon (double x[3], int numPts, double *pts, double bounds[6], double closest[3])
| Compute the distance of a point to a polygon. More...
static int | IntersectPolygonWithPolygon (int npts, double *pts, double bounds[6], int npts2, double *pts2, double bounds2[6], double tol, double x[3])
| Method intersects two polygons. More...
static int | IntersectConvex2DCells (vtkCell *cell1, vtkCell *cell2, double tol, double p0[3], double p1[3])
| Intersect two convex 2D polygons to produce a line segment as output. More...
static void | ComputeNormal (vtkPoints *p, int numPts, const vtkIdType *pts, double n[3])
| Computes the unit normal to the polygon. More...
static void | ComputeNormal (vtkPoints *p, double n[3])
| Computes the unit normal to the polygon. More...
static void | ComputeNormal (vtkIdTypeArray *ids, vtkPoints *pts, double n[3])
| Computes the unit normal to the polygon. More...
static bool | IsConvex (vtkPoints *p, int numPts, const vtkIdType *pts)
| Determine whether or not a polygon is convex. More...
static bool | IsConvex (vtkIdTypeArray *ids, vtkPoints *p)
| Determine whether or not a polygon is convex. More...
static bool | IsConvex (vtkPoints *p)
| Determine whether or not a polygon is convex. More...
static bool | ComputeCentroid (vtkPoints *p, int numPts, const vtkIdType *pts, double centroid[3])
| Compute the centroid of a set of points. More...
static bool | ComputeCentroid (vtkIdTypeArray *ids, vtkPoints *pts, double centroid[3])
| Compute the centroid of a set of points. More...
Static Public Member Functions inherited from vtkCell
static vtkTypeBool | IsTypeOf (const char *type)
static vtkCell * | SafeDownCast (vtkObjectBase *o)
Static Public Member Functions inherited from vtkObject
static vtkObject * | New ()
| Create an object with Debug turned off, modified time initialized to zero, and reference counting on. More...
static void | BreakOnError ()
| This method is called when vtkErrorMacro executes. More...
static void | SetGlobalWarningDisplay (vtkTypeBool val)
| This is a global flag that controls whether any debug, warning or error messages are displayed. More...
static void | GlobalWarningDisplayOn ()
| This is a global flag that controls whether any debug, warning or error messages are displayed. More...
static void | GlobalWarningDisplayOff ()
| This is a global flag that controls whether any debug, warning or error messages are displayed. More...
static vtkTypeBool | GetGlobalWarningDisplay ()
| This is a global flag that controls whether any debug, warning or error messages are displayed. More...
Static Public Member Functions inherited from vtkObjectBase
static vtkTypeBool | IsTypeOf (const char *name)
| Return 1 if this class type is the same type of (or a subclass of) the named class. More...
static vtkIdType | GetNumberOfGenerationsFromBaseType (const char *name)
| Given a the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class). More...
static vtkObjectBase * | New ()
| Create an object with Debug turned off, modified time initialized to zero, and reference counting on. More...
static void | SetMemkindDirectory (const char *directoryname)
| The name of a directory, ideally mounted -o dax, to memory map an extended memory space within. More...
static bool | GetUsingMemkind ()
| A global state flag that controls whether vtkObjects are constructed in the usual way (the default) or within the extended memory space. More...

## Protected Member Functions
virtual vtkObjectBase * | NewInstanceInternal () const
| vtkPolygon ()
| ~vtkPolygon () override
void | InterpolateFunctionsUsingMVC (const double x[3], double *weights)
void | ComputeTolerance ()
Protected Member Functions inherited from vtkCell
| vtkCell ()
| ~vtkCell () override
Protected Member Functions inherited from vtkObject
| vtkObject ()
| ~vtkObject () override
void | RegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void | UnRegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void | InternalGrabFocus (vtkCommand *mouseEvents, vtkCommand *keypressEvents=nullptr)
| These methods allow a command to exclusively grab all events. More...
void | InternalReleaseFocus ()
| These methods allow a command to exclusively grab all events. More...
Protected Member Functions inherited from vtkObjectBase
| vtkObjectBase ()
virtual | ~vtkObjectBase ()
virtual void | ReportReferences (vtkGarbageCollector *)
| vtkObjectBase (const vtkObjectBase &)
void | operator= (const vtkObjectBase &)

## Protected Attributes
double | Tolerance
double | Tol
int | SuccessfulTriangulation
vtkIdList * | Tris
vtkTriangle * | Triangle
vtkQuad * | Quad
vtkDoubleArray * | TriScalars
vtkLine * | Line
bool | UseMVCInterpolation
Protected Attributes inherited from vtkCell
double | Bounds [6]
Protected Attributes inherited from vtkObject
bool | Debug
vtkTimeStamp | MTime
vtkSubjectHelper * | SubjectHelper
std::string | ObjectName
Protected Attributes inherited from vtkObjectBase
std::atomic< int32_t > | ReferenceCount
vtkWeakPointerBase ** | WeakPointers

## Additional Inherited Members
Public Attributes inherited from vtkCell
vtkPoints * | Points
vtkIdList * | PointIds
Static Protected Member Functions inherited from vtkObjectBase
static vtkMallocingFunction | GetCurrentMallocFunction ()
static vtkReallocingFunction | GetCurrentReallocFunction ()
static vtkFreeingFunction | GetCurrentFreeFunction ()
static vtkFreeingFunction | GetAlternateFreeFunction ()

## Detailed Description

a cell that represents an n-sided polygon

vtkPolygon is a concrete implementation of vtkCell to represent a 2D n-sided polygon. The polygons cannot have any internal holes, and cannot self-intersect. Define the polygon with n-points ordered in the counter- clockwise direction; do not repeat the last point.

Online Examples:

Tests:
  vtkPolygon (Tests)

Definition at line 40 of file vtkPolygon.h.

## Member Typedef Documentation

## ◆ Superclass

typedef vtkCell vtkPolygon::Superclass

Definition at line 44 of file vtkPolygon.h.

## Member Enumeration Documentation

## ◆ EarCutMeasureTypes

enum vtkPolygon::EarCutMeasureTypes

Enumerator
PERIMETER2_TO_AREA_RATIO |
DOT_PRODUCT |
BEST_QUALITY |

Definition at line 284 of file vtkPolygon.h.

## Constructor & Destructor Documentation

## ◆ vtkPolygon()

vtkPolygon::vtkPolygon | ( |  | ) |
| protected

## ◆ ~vtkPolygon()

vtkPolygon::~vtkPolygon | ( |  | ) |
| overrideprotected

## Member Function Documentation

## ◆ New()

static vtkPolygon* vtkPolygon::New | ( |  | ) |
| static

## ◆ IsTypeOf()

static vtkTypeBool vtkPolygon::IsTypeOf | ( | const char * | type | ) |
| static

## ◆ IsA()

virtual vtkTypeBool vtkPolygon::IsA | ( | const char * | name | ) |
| virtual

Return 1 if this class is the same type of (or a subclass of) the named class.

Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkCell.

## ◆ SafeDownCast()

static vtkPolygon* vtkPolygon::SafeDownCast | ( | vtkObjectBase * | o | ) |
| static

## ◆ NewInstanceInternal()

virtual vtkObjectBase* vtkPolygon::NewInstanceInternal | ( |  | ) | const
| protectedvirtual

Reimplemented from vtkCell.

## ◆ NewInstance()

vtkPolygon* vtkPolygon::NewInstance | ( |  | ) | const

## ◆ PrintSelf()

void vtkPolygon::PrintSelf | ( | ostream & | os,
|  | vtkIndent | indent
| ) |  |
| overridevirtual

Methods invoked by print to print information about the object including superclasses.

Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkCell.

## ◆ GetCellType()

int vtkPolygon::GetCellType | ( |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

Definition at line 51 of file vtkPolygon.h.

## ◆ GetCellDimension()

int vtkPolygon::GetCellDimension | ( |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

Definition at line 52 of file vtkPolygon.h.

## ◆ GetNumberOfEdges()

int vtkPolygon::GetNumberOfEdges | ( |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

Definition at line 53 of file vtkPolygon.h.

## ◆ GetNumberOfFaces()

int vtkPolygon::GetNumberOfFaces | ( |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

Definition at line 54 of file vtkPolygon.h.

## ◆ GetEdge()

vtkCell* vtkPolygon::GetEdge | ( | int | edgeId | ) |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ GetFace()

vtkCell* vtkPolygon::GetFace | ( | int |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

Definition at line 56 of file vtkPolygon.h.

## ◆ CellBoundary()

int vtkPolygon::CellBoundary | ( | int | subId,
|  | const double | pcoords[3],
|  | vtkIdList * | pts
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ Contour()

void vtkPolygon::Contour | ( | double | value,
|  | vtkDataArray * | cellScalars,
|  | vtkIncrementalPointLocator * | locator,
|  | vtkCellArray * | verts,
|  | vtkCellArray * | lines,
|  | vtkCellArray * | polys,
|  | vtkPointData * | inPd,
|  | vtkPointData * | outPd,
|  | vtkCellData * | inCd,
|  | vtkIdType | cellId,
|  | vtkCellData * | outCd
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ Clip()

void vtkPolygon::Clip | ( | double | value,
|  | vtkDataArray * | cellScalars,
|  | vtkIncrementalPointLocator * | locator,
|  | vtkCellArray * | tris,
|  | vtkPointData * | inPd,
|  | vtkPointData * | outPd,
|  | vtkCellData * | inCd,
|  | vtkIdType | cellId,
|  | vtkCellData * | outCd,
|  | int | insideOut
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ EvaluatePosition()

int vtkPolygon::EvaluatePosition | ( | const double | x[3],
|  | double | closestPoint[3],
|  | int & | subId,
|  | double | pcoords[3],
|  | double & | dist2,
|  | double | weights[]
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ EvaluateLocation()

void vtkPolygon::EvaluateLocation | ( | int & | subId,
|  | const double | pcoords[3],
|  | double | x[3],
|  | double * | weights
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ IntersectWithLine()

int vtkPolygon::IntersectWithLine | ( | const double | p1[3],
|  | const double | p2[3],
|  | double | tol,
|  | double & | t,
|  | double | x[3],
|  | double | pcoords[3],
|  | int & | subId
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ Triangulate() [1/2]

int vtkPolygon::Triangulate | ( | int | index,
|  | vtkIdList * | ptIds,
|  | vtkPoints * | pts
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ Derivatives()

void vtkPolygon::Derivatives | ( | int | subId,
|  | const double | pcoords[3],
|  | const double * | values,
|  | int | dim,
|  | double * | derivs
| ) |  |
| overridevirtual

See the vtkCell API for descriptions of these methods.

Implements vtkCell.

## ◆ IsPrimaryCell()

int vtkPolygon::IsPrimaryCell | ( |  | ) |
| inlineoverridevirtual

See the vtkCell API for descriptions of these methods.

Reimplemented from vtkCell.

Definition at line 72 of file vtkPolygon.h.

## ◆ ComputeArea() [1/2]

double vtkPolygon::ComputeArea | ( |  | ) |

Compute the area of a polygon.

This is a convenience function which simply calls static double ComputeArea(vtkPoints *p, vtkIdType numPts, vtkIdType *pts, double normal[3]); with the appropriate parameters from the instantiated vtkPolygon.

## ◆ InterpolateFunctions()

void vtkPolygon::InterpolateFunctions | ( | const double | x[3],
|  | double * | sf
| ) |  |
| override

Compute the interpolation functions/derivatives.

(aka shape functions/derivatives) Two interpolation algorithms are available: 1/r^2 and Mean Value Coordinate. The former is used by default. To use the second algorithm, set UseMVCInterpolation to be true. The function assumes the input point lies on the polygon plane without checking that.

## ◆ ComputeNormal() [1/4]

static void vtkPolygon::ComputeNormal | ( | vtkPoints * | p,
|  | int | numPts,
|  | const vtkIdType * | pts,
|  | double | n[3]
| ) |  |
| static

Computes the unit normal to the polygon.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ ComputeNormal() [2/4]

static void vtkPolygon::ComputeNormal | ( | vtkPoints * | p,
|  | double | n[3]
| ) |  |
| static

Computes the unit normal to the polygon.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ ComputeNormal() [3/4]

static void vtkPolygon::ComputeNormal | ( | vtkIdTypeArray * | ids,
|  | vtkPoints * | pts,
|  | double | n[3]
| ) |  |
| static

Computes the unit normal to the polygon.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ ComputeNormal() [4/4]

static void vtkPolygon::ComputeNormal | ( | int | numPts,
|  | double * | pts,
|  | double | n[3]
| ) |  |
| static

Compute the polygon normal from an array of points.

This version assumes that the polygon is convex, and looks for the first valid normal.

## ◆ IsConvex() [1/4]

bool vtkPolygon::IsConvex | ( |  | ) |

Determine whether or not a polygon is convex.

This is a convenience function that simply calls static bool IsConvex(int numPts, vtkIdType *pts, vtkPoints *p) with the appropriate parameters from the instantiated vtkPolygon.

## ◆ IsConvex() [2/4]

static bool vtkPolygon::IsConvex | ( | vtkPoints * | p,
|  | int | numPts,
|  | const vtkIdType * | pts
| ) |  |
| static

Determine whether or not a polygon is convex.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ IsConvex() [3/4]

static bool vtkPolygon::IsConvex | ( | vtkIdTypeArray * | ids,
|  | vtkPoints * | p
| ) |  |
| static

Determine whether or not a polygon is convex.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ IsConvex() [4/4]

static bool vtkPolygon::IsConvex | ( | vtkPoints * | p | ) |
| static

Determine whether or not a polygon is convex.

If pts=nullptr, point indexing is assumed to be {0, 1, ..., numPts-1}.

## ◆ ComputeCentroid() [1/2]

static bool vtkPolygon::ComputeCentroid | ( | vtkPoints * | p,
|  | int | numPts,
|  | const vtkIdType * | pts,
|  | double | centroid[3]
| ) |  |
| static

Compute the centroid of a set of points.

Returns false if the computation is invalid (this occurs when numPts=0 or when ids is empty).

## ◆ ComputeCentroid() [2/2]

static bool vtkPolygon::ComputeCentroid | ( | vtkIdTypeArray * | ids,
|  | vtkPoints * | pts,
|  | double | centroid[3]
| ) |  |
| static

Compute the centroid of a set of points.

Returns false if the computation is invalid (this occurs when numPts=0 or when ids is empty).

## ◆ ComputeArea() [2/2]

static double vtkPolygon::ComputeArea | ( | vtkPoints * | p,
|  | vtkIdType | numPts,
|  | const vtkIdType * | pts,
|  | double | normal[3]
| ) |  |
| static

Compute the area of a polygon in 3D.

The area is returned, as well as the normal (a side effect of using this method). If you desire to compute the area of a triangle, use vtkTriangleArea which is faster. If pts==nullptr, point indexing is supposed to be {0, 1, ..., numPts-1}. If you already have a vtkPolygon instantiated, a convenience function, ComputeArea() is provided.

## ◆ ParameterizePolygon()

int vtkPolygon::ParameterizePolygon | ( | double | p0[3],
|  | double | p10[3],
|  | double & | l10,
|  | double | p20[3],
|  | double & | l20,
|  | double | n[3]
| ) |  |

Create a local s-t coordinate system for a polygon.

The point p0 is the origin of the local system, p10 is s-axis vector, and p20 is the t-axis vector. (These are expressed in the modeling coordinate system and are vectors of dimension [3].) The values l20 and l20 are the lengths of the vectors p10 and p20, and n is the polygon normal.

## ◆ PointInPolygon()

static int vtkPolygon::PointInPolygon | ( | double | x[3],
|  | int | numPts,
|  | double * | pts,
|  | double | bounds[6],
|  | double | n[3]
| ) |  |
| static

Determine whether a point is inside the specified polygon.

The function computes the winding number to assess inclusion. It works for arbitrary polygon shapes (e.g., non-convex) oriented arbitrarily in 3D space. Returns 0 if the point is not in the polygon; 1 if it is. Can also return -1 to indicate a degenerate polygon. Parameters passed into the method include the point in question x[3]; the polygon defined by (npts,pts); the bounds of the polygon bounds[6]; and the normal n[3] to the polygon. (The implementation was inspired by Dan Sunday's book Practical Geometry Algorithms.) This method is thread safe.

## ◆ Triangulate() [2/2]

int vtkPolygon::Triangulate | ( | vtkIdList * | outTris | ) |

Triangulate this polygon.

The user must provide the vtkIdList outTris. On output, the outTris list contains the ids of the points defining the triangulation (i.e., not the associated polygon->PointIds, rather the index into the polygon->Points array). The ids are ordered into groups of three: each three-group defines one triangle. The method returns non-zero if the triangulation is successful.

## ◆ NonDegenerateTriangulate()

int vtkPolygon::NonDegenerateTriangulate | ( | vtkIdList * | outTris | ) |

Same as Triangulate(vtkIdList *outTris) but with a first pass to split the polygon into non-degenerate polygons.

## ◆ BoundedTriangulate()

int vtkPolygon::BoundedTriangulate | ( | vtkIdList * | outTris,
|  | double | tol
| ) |  |

Triangulate polygon and enforce that the ratio of the smallest triangle area to the polygon area is greater than a user-defined tolerance.

The user must provide the vtkIdList outTris. On output, the outTris list contains the ids of the points defining the triangulation. The ids are ordered into groups of three: each three-group defines one triangle.

## ◆ DistanceToPolygon()

static double vtkPolygon::DistanceToPolygon | ( | double | x[3],
|  | int | numPts,
|  | double * | pts,
|  | double | bounds[6],
|  | double | closest[3]
| ) |  |
| static

Compute the distance of a point to a polygon.

The closest point on the polygon is also returned. The bounds should be provided to accelerate the computation.

## ◆ IntersectPolygonWithPolygon()

static int vtkPolygon::IntersectPolygonWithPolygon | ( | int | npts,
|  | double * | pts,
|  | double | bounds[6],
|  | int | npts2,
|  | double * | pts2,
|  | double | bounds2[6],
|  | double | tol,
|  | double | x[3]
| ) |  |
| static

Method intersects two polygons.

You must supply the number of points and point coordinates (npts, *pts) and the bounding box (bounds) of the two polygons. Also supply a tolerance squared for controlling error. The method returns 1 if there is an intersection, and 0 if not. A single point of intersection x[3] is also returned if there is an intersection.

## ◆ IntersectConvex2DCells()

static int vtkPolygon::IntersectConvex2DCells | ( | vtkCell * | cell1,
|  | vtkCell * | cell2,
|  | double | tol,
|  | double | p0[3],
|  | double | p1[3]
| ) |  |
| static

Intersect two convex 2D polygons to produce a line segment as output.

The return status of the methods indicated no intersection (returns 0); a single point of intersection (returns 1); or a line segment (i.e., two points of intersection, returns 2). The points of intersection are returned in the arrays p0 and p1. If less than two points of intersection are generated then p1 and/or p0 may be indeterminiate. Finally, if the two convex polygons are parallel, then "0" is returned (i.e., no intersection) even if the triangles lie on one another.

## ◆ GetUseMVCInterpolation()

virtual bool vtkPolygon::GetUseMVCInterpolation | ( |  | ) |
| virtual

Set/Get the flag indicating whether to use Mean Value Coordinate for the interpolation.

If true, InterpolateFunctions() uses the Mean Value Coordinate to compute weights. Otherwise, the conventional 1/r^2 method is used. The UseMVCInterpolation parameter is set to false by default.

## ◆ SetUseMVCInterpolation()

virtual void vtkPolygon::SetUseMVCInterpolation | ( | bool |  | ) |
| virtual

Set/Get the flag indicating whether to use Mean Value Coordinate for the interpolation.

If true, InterpolateFunctions() uses the Mean Value Coordinate to compute weights. Otherwise, the conventional 1/r^2 method is used. The UseMVCInterpolation parameter is set to false by default.

## ◆ SetTolerance()

virtual void vtkPolygon::SetTolerance | ( | double |  | ) |
| virtual

Specify an internal tolerance for operations requiring polygon triangulation.

(For example, clipping and contouring operations proceed by first triangulating the polygon, and then clipping/contouring the resulting triangles.) This is a normalized tolerance value multiplied by the diagonal length of the polygon bounding box. Is it used to determine whether potential triangulation edges intersect one another.

## ◆ GetTolerance()

virtual double vtkPolygon::GetTolerance | ( |  | ) |
| virtual

Specify an internal tolerance for operations requiring polygon triangulation.

(For example, clipping and contouring operations proceed by first triangulating the polygon, and then clipping/contouring the resulting triangles.) This is a normalized tolerance value multiplied by the diagonal length of the polygon bounding box. Is it used to determine whether potential triangulation edges intersect one another.

## ◆ InterpolateFunctionsUsingMVC()

void vtkPolygon::InterpolateFunctionsUsingMVC | ( | const double | x[3],
|  | double * | weights
| ) |  |
| protected

## ◆ ComputeTolerance()

void vtkPolygon::ComputeTolerance | ( |  | ) |
| protected

## ◆ EarCutTriangulation() [1/2]

int vtkPolygon::EarCutTriangulation | ( | int | measure = `PERIMETER2_TO_AREA_RATIO` | ) |

A fast triangulation method.

Uses recursive divide and conquer based on plane splitting to reduce loop into triangles. The cell (e.g., triangle) is presumed properly initialized (i.e., Points and PointIds). Ears can be removed using different measures (the measures indicate convexity plus characterize the local geometry around each vertex).

## ◆ EarCutTriangulation() [2/2]

int vtkPolygon::EarCutTriangulation | ( | vtkIdList * | outTris,
|  | int | measure = `PERIMETER2_TO_AREA_RATIO`
| ) |  |

A fast triangulation method.

Uses recursive divide and conquer based on plane splitting to reduce loop into triangles. The cell (e.g., triangle) is presumed properly initialized (i.e., Points and PointIds). Ears can be removed using different measures (the measures indicate convexity plus characterize the local geometry around each vertex).

## ◆ UnbiasedEarCutTriangulation() [1/2]

int vtkPolygon::UnbiasedEarCutTriangulation | ( | int | seed,
|  | int | measure = `PERIMETER2_TO_AREA_RATIO`
| ) |  |

A fast triangulation method.

Uses recursive divide and conquer based on plane splitting to reduce loop into triangles. The cell (e.g., triangle) is presumed properly initialized (i.e., Points and PointIds). Unlike EarCutTriangulation(), vertices are visited sequentially without preference to angle.

## ◆ UnbiasedEarCutTriangulation() [2/2]

int vtkPolygon::UnbiasedEarCutTriangulation | ( | int | seed,
|  | vtkIdList * | outTris,
|  | int | measure = `PERIMETER2_TO_AREA_RATIO`
| ) |  |

A fast triangulation method.

Uses recursive divide and conquer based on plane splitting to reduce loop into triangles. The cell (e.g., triangle) is presumed properly initialized (i.e., Points and PointIds). Unlike EarCutTriangulation(), vertices are visited sequentially without preference to angle.

## Member Data Documentation

## ◆ Tolerance

double vtkPolygon::Tolerance
| protected

Definition at line 260 of file vtkPolygon.h.

## ◆ Tol

double vtkPolygon::Tol
| protected

Definition at line 261 of file vtkPolygon.h.

## ◆ SuccessfulTriangulation

int vtkPolygon::SuccessfulTriangulation
| protected

Definition at line 264 of file vtkPolygon.h.

## ◆ Tris

vtkIdList* vtkPolygon::Tris
| protected

Definition at line 265 of file vtkPolygon.h.

## ◆ Triangle

vtkTriangle* vtkPolygon::Triangle
| protected

Definition at line 268 of file vtkPolygon.h.

## ◆ Quad

vtkQuad* vtkPolygon::Quad
| protected

Definition at line 269 of file vtkPolygon.h.

## ◆ TriScalars

vtkDoubleArray* vtkPolygon::TriScalars
| protected

Definition at line 270 of file vtkPolygon.h.

## ◆ Line

vtkLine* vtkPolygon::Line
| protected

Definition at line 271 of file vtkPolygon.h.

## ◆ UseMVCInterpolation

bool vtkPolygon::UseMVCInterpolation
| protected

Definition at line 275 of file vtkPolygon.h.

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

- Common/DataModel/vtkPolygon.h