DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero > Class Template Reference

Aim: Small adapter to models of COrientationFunctor2. It is a model of concepts::CPointPredicate. It is also a ternary predicate on points, useful for basic geometric tasks such as convex hull computation. More...

#include <DGtal/geometry/tools/determinant/PredicateFromOrientationFunctor2.h>

Public Types
typedef TOrientationFunctor	Functor
typedef Functor::Point	Point
typedef functors::Thresholder< typename Functor::Value, acceptNeg, acceptZero >	MyThresholder

Public Member Functions
	BOOST_CONCEPT_ASSERT ((concepts::COrientationFunctor2< Functor >))
	PredicateFromOrientationFunctor2 (Alias< Functor > aFunctor)
void	init (const Point &aPoint1, const Point &aPoint2)
bool	operator() (const Point &aPoint) const
bool	operator() (const Point &aPoint1, const Point &aPoint2, const Point &aPoint3) const
void	selfDisplay (std::ostream &out) const
bool	isValid () const

Private Attributes
Functor *const	myFunctorPtr
const MyThresholder	myThresholder

Detailed Description

template<typename TOrientationFunctor, bool acceptNeg = false, bool acceptZero = false>
class DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >

Aim: Small adapter to models of COrientationFunctor2. It is a model of concepts::CPointPredicate. It is also a ternary predicate on points, useful for basic geometric tasks such as convex hull computation.

Description of template class 'PredicateFromOrientationFunctor2'

Once a orientation functor is defined, you can adapt it as follows:

  //geometric predicate
  PredicateFromOrientationFunctor2<OrientationFunctor> 
    pointPredicate( orientationFunctor ); 

The test can be done in one or two separate steps as follows:

  //initialization
  pointPredicate.init( P, Q ); 
  //which is equivalent to 
  //orientationFunctor.init( P, Q );
  //because the predicate stores a pointer to the functor

  //decision
  isCCW = pointPredicate( R ); 
  //which is equivalent to the following shortcut:
  //isCCW = pointPredicate( P, Q, R ); 

The default behavior is to return 'true' for strictly positive functor values. You can however custom this behavior with the last two template parameters.

Template Parameters

TOrientationFunctor	a model of COrientationFunctor2
acceptNeg	bool equal to 'true' to get a predicate returning 'true' for strictly negative values of the functor, but equal to 'false' to get a predicate returning 'true' for strictly positive values (default).
acceptZero	bool equal to 'true' to get a predicate returning 'true' for null values, but equal to 'false' for strictly positive or negative values (default).

Examples

geometry/tools/determinant/exampleInHalfPlane.cpp, geometry/tools/exampleAlphaShape.cpp, and geometry/tools/exampleConvexHull2D.cpp.

Definition at line 81 of file PredicateFromOrientationFunctor2.h.

Member Typedef Documentation

Functor

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

typedef TOrientationFunctor DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::Functor

Type of the adapter orientation functor

Definition at line 88 of file PredicateFromOrientationFunctor2.h.

MyThresholder

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

typedef functors::Thresholder<typename Functor::Value, acceptNeg, acceptZero> DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::MyThresholder

Type of the thresholder, which compares the result of the functor to zero

Definition at line 100 of file PredicateFromOrientationFunctor2.h.

Point

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

typedef Functor::Point DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::Point

Type of input points

Definition at line 94 of file PredicateFromOrientationFunctor2.h.

Constructor & Destructor Documentation

PredicateFromOrientationFunctor2()

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::PredicateFromOrientationFunctor2

(

Alias< Functor >

aFunctor

)

Constructor

Parameters

aFunctor

any orientation functor to alias

Member Function Documentation

BOOST_CONCEPT_ASSERT()

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::BOOST_CONCEPT_ASSERT

(

(concepts::COrientationFunctor2< Functor >)

)

init()

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

void DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::init	(	const Point &	aPoint1,
		const Point &	aPoint2
	)

Initialization of myFunctor

Parameters

aPoint1	a first point
aPoint2	a second point

Examples

geometry/tools/determinant/exampleInHalfPlane.cpp.

Referenced by basicUsage().

isValid()

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

bool DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::isValid

(

)

const

Checks the validity/consistency of the object.

Returns

'true' if the object is valid, 'false' otherwise.

operator()() [1/2]

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

bool DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::operator()

(

const Point &

aPoint

)

const

Unary parenthesis operator

Parameters

aPoint

any point

Returns

return value of the thresholder applied on the underlying unary functor

operator()() [2/2]

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

bool DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::operator()	(	const Point &	aPoint1,
		const Point &	aPoint2,
		const Point &	aPoint3
	)		const

Ternary parenthesis operator on three points

Parameters

aPoint1	first point
aPoint2	second point
aPoint3	third point

Returns

return value of the thresholder applied on the underlying orientation functor

selfDisplay()

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

void DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::selfDisplay

(

std::ostream &

out

)

const

Writes/Displays the object on an output stream.

Parameters

out	the output stream where the object is written.

Field Documentation

myFunctorPtr

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

Functor* const DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::myFunctorPtr

private

a pointer to an orientation functor

Definition at line 157 of file PredicateFromOrientationFunctor2.h.

myThresholder

template<typename TOrientationFunctor , bool acceptNeg = false, bool acceptZero = false>

const MyThresholder DGtal::PredicateFromOrientationFunctor2< TOrientationFunctor, acceptNeg, acceptZero >::myThresholder

private

object that thresholds the result of the functor

Definition at line 162 of file PredicateFromOrientationFunctor2.h.

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

• PredicateFromOrientationFunctor2.h