DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger > Class Template Reference

Aim: Class that implements an orientation functor, ie. it provides a way to compute the orientation of three given 2d points. More precisely, it returns: More...

#include <DGtal/geometry/tools/determinant/InHalfPlaneBySimple3x3Matrix.h>

Inheritance diagram for DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >:

Public Types
typedef TPoint	Point
typedef std::array< Point, 2 >	PointArray
typedef PointArray::size_type	SizeArray
typedef TInteger	Integer
typedef SimpleMatrix< Integer, 3, 3 >	Matrix
typedef Integer	Value

Public Member Functions
	BOOST_CONCEPT_ASSERT ((concepts::CEuclideanRing< Integer >))
void	init (const Point &aP, const Point &aQ)
void	init (const PointArray &aA)
Value	operator() (const Point &aR) const
void	selfDisplay (std::ostream &out) const
bool	isValid () const

Static Public Attributes
static const SizeArray	size = 2

Private Attributes
Matrix	myMatrix

Detailed Description

template<typename TPoint, typename TInteger>
class DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >

Aim: Class that implements an orientation functor, ie. it provides a way to compute the orientation of three given 2d points. More precisely, it returns:

• zero if the three points belong to the same line
• strictly positive if the three points are counter-clockwise oriented
• striclty negative if the three points are clockwise oriented. The orientation test is performed by the evaluation of the determinant of a 3x3 matrix stored into an instance of SimpleMatrix.

Basic usage:

...
typedef Z2i::Point Point; 
typedef InHalfPlaneBySimple3x3Matrix<Point, Z2i::Integer> MyType; 
 
MyType orientationTest; 
orientationTest.init( Point(0,0), Point(5,2) ); 
return orientationTest( Point(2,1) ); 
//a strictly positive value is returned because (0,0) (5,2) (2,1) are CCW oriented

Template Parameters

TPoint	a model of point
TInteger	a model of integer for the 3x3 matrix entries and the result, at least a model of CEuclideanRing

NB. In order to be sure that the result will be exact, you should be sure that TInteger can represent integers with 2b+3 bits if the points coordinates are coded with b bits.

See also

SimpleMatrix

InHalfPlaneBy2x2DetComputer

Examples

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

Definition at line 91 of file InHalfPlaneBySimple3x3Matrix.h.

Member Typedef Documentation

Integer

template<typename TPoint , typename TInteger >

typedef TInteger DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::Integer

Type of matrix integral entries

NB: the type of the points coordinates are casted into Integer before being stored into the matrix.

Definition at line 120 of file InHalfPlaneBySimple3x3Matrix.h.

Matrix

template<typename TPoint , typename TInteger >

typedef SimpleMatrix<Integer, 3, 3> DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::Matrix

Type of matrix

Definition at line 126 of file InHalfPlaneBySimple3x3Matrix.h.

Point

template<typename TPoint , typename TInteger >

typedef TPoint DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::Point

Type of points

Definition at line 99 of file InHalfPlaneBySimple3x3Matrix.h.

PointArray

template<typename TPoint , typename TInteger >

typedef std::array<Point,2> DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::PointArray

Type of point array

Definition at line 104 of file InHalfPlaneBySimple3x3Matrix.h.

SizeArray

template<typename TPoint , typename TInteger >

typedef PointArray::size_type DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::SizeArray

Type used to represent the size of the array

Definition at line 108 of file InHalfPlaneBySimple3x3Matrix.h.

Value

template<typename TPoint , typename TInteger >

typedef Integer DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::Value

Type of integer for the result

Definition at line 131 of file InHalfPlaneBySimple3x3Matrix.h.

Member Function Documentation

BOOST_CONCEPT_ASSERT()

template<typename TPoint , typename TInteger >

DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::BOOST_CONCEPT_ASSERT

(

(concepts::CEuclideanRing< Integer >)

)

init() [1/2]

template<typename TPoint , typename TInteger >

void DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::init	(	const Point &	aP,
		const Point &	aQ )

Initialisation. The first two column vectors are stored into myMatrix

Parameters

aP	first point
aQ	second point

init() [2/2]

template<typename TPoint , typename TInteger >

void DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::init

(

const PointArray &

aA

)

Initialisation. The first two column vectors are stored into myMatrix

Parameters

aA	array of two points

isValid()

template<typename TPoint , typename TInteger >

bool DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::isValid

(

)

const

Checks the validity/consistency of the object.

Returns

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

operator()()

template<typename TPoint , typename TInteger >

Value DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::operator()

(

const Point &

aR

)

const

Main operator.

Warning

InHalfPlaneBy2x2DetComputer::init() should be called before

Parameters

aR	any point to test

Returns

orientation of the three points aP aQ aR :

• zero if the three points belong to the same line
• strictly positive if the three points are counter-clockwise oriented
• striclty negative if the three points are clockwise oriented

See also

InHalfPlaneBy2x2DetComputer::init()

selfDisplay()

template<typename TPoint , typename TInteger >

void DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::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

myMatrix

template<typename TPoint , typename TInteger >

Matrix DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::myMatrix

mutableprivate

3x3 matrix whose determinant provides the expected result

Definition at line 179 of file InHalfPlaneBySimple3x3Matrix.h.

size

template<typename TPoint , typename TInteger >

const SizeArray DGtal::InHalfPlaneBySimple3x3Matrix< TPoint, TInteger >::size = 2

static

static size of the array, ie. 2

Definition at line 112 of file InHalfPlaneBySimple3x3Matrix.h.

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

• InHalfPlaneBySimple3x3Matrix.h