DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer > 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/InHalfPlaneBy2x2DetComputer.h>

Public Types
typedef TPoint	Point
typedef std::array< Point, 2 >	PointArray
typedef PointArray::size_type	SizeArray
typedef TDetComputer	DetComputer
typedef TDetComputer::ArgumentInteger	ArgumentInteger
typedef TDetComputer::ResultInteger	Value

Public Member Functions
	BOOST_CONCEPT_ASSERT ((C2x2DetComputer< DetComputer >))
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
ArgumentInteger	myA
ArgumentInteger	myB
DetComputer	myDetComputer

Detailed Description

template<typename TPoint, typename TDetComputer>
class DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >

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 reduced to the computation of the determinant of a 2x2 matrix, the implementation of which is delegated to a determinant computer.

Basic usage:

...
typedef Z2i::Point Point; 
typedef Simple2x2DetComputer<Z2i::Integer> DeterminantComputer; 
typedef InHalfPlaneBy2x2DetComputer<Point, DeterminantComputer> 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
TDetComputer	a model of C2x2DetComputer

NB: The robustness of the computation depends on the robustness of the determinant computer. However, in order to be sure that the result will be exact, you should be sure that the chosen determinant computer can safely deal with integers coded with b+1 bits if the points coordinates are coded with b bits.

See also

Simple2x2DetComputer SimpleIncremental2x2DetComputer AvnaimEtAl2x2DetComputer FilteredDetComputer

Examples

geometry/tools/determinant/exampleInHalfPlane.cpp.

Definition at line 92 of file InHalfPlaneBy2x2DetComputer.h.

Member Typedef Documentation

ArgumentInteger

template<typename TPoint , typename TDetComputer >

typedef TDetComputer::ArgumentInteger DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::ArgumentInteger

Type of input integers for the determinant computer

NB: the type of the points coordinates are casted into ArgumentInteger before being passed to the determinant computer.

Definition at line 127 of file InHalfPlaneBy2x2DetComputer.h.

DetComputer

template<typename TPoint , typename TDetComputer >

typedef TDetComputer DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::DetComputer

Type of determinant computer

Definition at line 118 of file InHalfPlaneBy2x2DetComputer.h.

Point

template<typename TPoint , typename TDetComputer >

typedef TPoint DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::Point

Type of points

Definition at line 100 of file InHalfPlaneBy2x2DetComputer.h.

PointArray

template<typename TPoint , typename TDetComputer >

typedef std::array<Point,2> DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::PointArray

Type of point array

Definition at line 105 of file InHalfPlaneBy2x2DetComputer.h.

SizeArray

template<typename TPoint , typename TDetComputer >

typedef PointArray::size_type DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::SizeArray

Type used to represent the size of the array

Definition at line 109 of file InHalfPlaneBy2x2DetComputer.h.

Value

template<typename TPoint , typename TDetComputer >

typedef TDetComputer::ResultInteger DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::Value

Type of integer for the result

Definition at line 132 of file InHalfPlaneBy2x2DetComputer.h.

Member Function Documentation

BOOST_CONCEPT_ASSERT()

template<typename TPoint , typename TDetComputer >

DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::BOOST_CONCEPT_ASSERT

(

(C2x2DetComputer< DetComputer >)

)

init() [1/2]

template<typename TPoint , typename TDetComputer >

void DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::init	(	const Point &	aP,
		const Point &	aQ )

Initialisation.

Parameters

aP	first point
aQ	second point

init() [2/2]

template<typename TPoint , typename TDetComputer >

void DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::init

(

const PointArray &

aA

)

Initialisation.

Parameters

aA	array of two points

isValid()

template<typename TPoint , typename TDetComputer >

bool DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::isValid

(

)

const

Checks the validity/consistency of the object.

Returns

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

operator()()

template<typename TPoint , typename TDetComputer >

Value DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::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 TDetComputer >

void DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::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

myA

template<typename TPoint , typename TDetComputer >

ArgumentInteger DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::myA

private

Coordinates of the first point.

Definition at line 189 of file InHalfPlaneBy2x2DetComputer.h.

myB

template<typename TPoint , typename TDetComputer >

ArgumentInteger DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::myB

private

Definition at line 189 of file InHalfPlaneBy2x2DetComputer.h.

myDetComputer

template<typename TPoint , typename TDetComputer >

DetComputer DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::myDetComputer

mutableprivate

A 2x2 determinant computer

Definition at line 193 of file InHalfPlaneBy2x2DetComputer.h.

size

template<typename TPoint , typename TDetComputer >

const SizeArray DGtal::InHalfPlaneBy2x2DetComputer< TPoint, TDetComputer >::size = 2

static

static size of the array, ie. 2

Definition at line 113 of file InHalfPlaneBy2x2DetComputer.h.

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

• InHalfPlaneBy2x2DetComputer.h