vgl_line_segment_2d< Type > Class Template Reference

Represents a 2D line segment using two points. More...

#include <vgl_line_segment_2d.h>

List of all members.

Public Member Functions
	vgl_line_segment_2d ()
	Default constructor - does not initialise!.
	vgl_line_segment_2d (vgl_line_segment_2d< Type > const &l)
	Copy constructor.
	vgl_line_segment_2d (vgl_point_2d< Type > const &p1, vgl_point_2d< Type > const &p2)
	Construct from two end points.
	~vgl_line_segment_2d ()
	Destructor.
vgl_point_2d< Type >	point1 () const
	One end-point of the line segment.
vgl_point_2d< Type >	point2 () const
	The other end-point of the line segment.
bool	operator== (vgl_line_segment_2d< Type > const &l) const
	The equality comparison operator.
bool	operator!= (vgl_line_segment_2d< Type >const &other) const
	The inequality comparison operator.
Type	a () const
	Parameter a of line a*x + b*y + c = 0.
Type	b () const
	Parameter b of line a*x + b*y + c = 0.
Type	c () const
	Parameter c of line a*x + b*y + c = 0.
vgl_vector_2d< Type >	direction () const
	unit vector describing line direction.
vgl_vector_2d< Type >	normal () const
	unit vector orthogonal to line.
double	slope_radians () const
	angle with the oriented horizontal line y=0, measured in radians.
double	slope_degrees () const
	angle with the oriented horizontal line y=0, measured in 360-degrees.
void	set (vgl_point_2d< Type > const &p1, vgl_point_2d< Type > const &p2)
	Assignment.
vgl_point_2d< Type >	point_t (const double t) const
	Return a point on the line defined by a scalar parameter t.
Private Attributes
vgl_point_2d< Type >	point1_
	One end of line segment.
vgl_point_2d< Type >	point2_
	The other end of the line segment.
Related Functions
(Note that these are not member functions.)
template<class T >
vgl_point_2d< T >	vgl_closest_point (vgl_line_segment_2d< T > const &l, vgl_point_2d< T > const &p)
	Return the closest point on a line segment l to a point p in 2D.
template<class T >
double	vgl_distance (vgl_line_segment_2d< T > const &l, vgl_point_2d< T > const &p)
	Closest distance from a point p to a line segment l in 2D.
template<class T >
unsigned	vgl_intersection (vgl_box_2d< T > const &box, vgl_line_segment_2d< T > const &line, vgl_point_2d< T > &p0, vgl_point_2d< T > &p1)
	Returns the number of intersections of a line segment with a box, up to two are returned in p0 and p1.
template<class Type >
vcl_ostream &	operator<< (vcl_ostream &s, const vgl_line_segment_2d< Type > &p)
	Write to stream.
template<class Type >
vcl_istream &	operator>> (vcl_istream &is, vgl_line_segment_2d< Type > &p)
	Read from stream.
template<class T >
bool	vgl_lineseg_test_line (vgl_line_2d< T > const &l1, vgl_line_segment_2d< T > const &l2)
	true if the line meets the linesegment.
template<class T >
export bool	vgl_lineseg_test_point (vgl_point_2d< T > const &p, vgl_line_segment_2d< T > const &lseg)
	true if the point lies on the line segment and is between the endpoints.
template<class T >
bool	vgl_lineseg_test_lineseg (vgl_line_segment_2d< T > const &l1, vgl_line_segment_2d< T > const &l2)
	return true if the two linesegments meet.

---

Detailed Description

template<class Type>
class vgl_line_segment_2d< Type >

Represents a 2D line segment using two points.

Definition at line 23 of file vgl_line_segment_2d.h.

---

Constructor & Destructor Documentation

template<class Type>

vgl_line_segment_2d< Type >::vgl_line_segment_2d

(

)

[inline]

Default constructor - does not initialise!.

Definition at line 32 of file vgl_line_segment_2d.h.

template<class Type>

vgl_line_segment_2d< Type >::vgl_line_segment_2d

(

vgl_line_segment_2d< Type > const &

l

)

[inline]

Copy constructor.

Definition at line 35 of file vgl_line_segment_2d.h.

template<class Type>

vgl_line_segment_2d< Type >::vgl_line_segment_2d	(	vgl_point_2d< Type > const &	p1,
		vgl_point_2d< Type > const &	p2
	)		[inline]

Construct from two end points.

Definition at line 39 of file vgl_line_segment_2d.h.

template<class Type>

vgl_line_segment_2d< Type >::~vgl_line_segment_2d

(

)

[inline]

Destructor.

Definition at line 44 of file vgl_line_segment_2d.h.

---

Member Function Documentation

template<class Type >

Type vgl_line_segment_2d< Type >::a

(

)

const

Parameter a of line a*x + b*y + c = 0.

Definition at line 25 of file vgl_line_segment_2d.txx.

template<class Type >

Type vgl_line_segment_2d< Type >::b

(

)

const

Parameter b of line a*x + b*y + c = 0.

Definition at line 31 of file vgl_line_segment_2d.txx.

template<class Type >

Type vgl_line_segment_2d< Type >::c

(

)

const

Parameter c of line a*x + b*y + c = 0.

Definition at line 37 of file vgl_line_segment_2d.txx.

template<class Type >

vgl_vector_2d< Type > vgl_line_segment_2d< Type >::direction

(

)

const

unit vector describing line direction.

Definition at line 43 of file vgl_line_segment_2d.txx.

template<class Type >

vgl_vector_2d< Type > vgl_line_segment_2d< Type >::normal

(

)

const

unit vector orthogonal to line.

Definition at line 50 of file vgl_line_segment_2d.txx.

template<class Type>

bool vgl_line_segment_2d< Type >::operator!=

(

vgl_line_segment_2d< Type >const &

other

)

const [inline]

The inequality comparison operator.

Definition at line 58 of file vgl_line_segment_2d.h.

template<class Type>

bool vgl_line_segment_2d< Type >::operator==

(

vgl_line_segment_2d< Type > const &

l

)

const [inline]

The equality comparison operator.

Definition at line 53 of file vgl_line_segment_2d.h.

template<class Type>

vgl_point_2d<Type> vgl_line_segment_2d< Type >::point1

(

)

const [inline]

One end-point of the line segment.

Definition at line 47 of file vgl_line_segment_2d.h.

template<class Type>

vgl_point_2d<Type> vgl_line_segment_2d< Type >::point2

(

)

const [inline]

The other end-point of the line segment.

Definition at line 50 of file vgl_line_segment_2d.h.

template<class Type>

vgl_point_2d<Type> vgl_line_segment_2d< Type >::point_t

(

const double

t

)

const [inline]

Return a point on the line defined by a scalar parameter t.

t=0.0 corresponds to point1 and t=1.0 to point2. 0<t<1 for points on the segment between point1 and point2. t<0 for points on the (infinite) line, outside the segment, and closer to point1 than to point2. t>1 for points on the (infinite) line, outside the segment, and closer to point2 than to point1.

Definition at line 94 of file vgl_line_segment_2d.h.

template<class Type>

void vgl_line_segment_2d< Type >::set	(	vgl_point_2d< Type > const &	p1,
		vgl_point_2d< Type > const &	p2
	)		[inline]

Assignment.

Definition at line 86 of file vgl_line_segment_2d.h.

template<class Type >

double vgl_line_segment_2d< Type >::slope_degrees

(

)

const

angle with the oriented horizontal line y=0, measured in 360-degrees.

Returns values between -180 and 180.

Definition at line 57 of file vgl_line_segment_2d.txx.

template<class Type >

double vgl_line_segment_2d< Type >::slope_radians

(

)

const

angle with the oriented horizontal line y=0, measured in radians.

Returns values between -pi and pi.

Definition at line 72 of file vgl_line_segment_2d.txx.

---

Friends And Related Function Documentation

template<class Type >

vcl_ostream & operator<<	(	vcl_ostream &	s,
		const vgl_line_segment_2d< Type > &	p
	)		[related]

Write to stream.

template<class Type >

vcl_istream & operator>>	(	vcl_istream &	is,
		vgl_line_segment_2d< Type > &	p
	)		[related]

Read from stream.

template<class T >

vgl_point_2d< T > vgl_closest_point	(	vgl_line_segment_2d< T > const &	l,
		vgl_point_2d< T > const &	p
	)		[related]

Return the closest point on a line segment l to a point p in 2D.

See also:

vgl_distance_to_linesegment()

template<class T >

double vgl_distance	(	vgl_line_segment_2d< T > const &	l,
		vgl_point_2d< T > const &	p
	)		[related]

Closest distance from a point p to a line segment l in 2D.

See also:

vgl_distance_to_linesegment()

vgl_distance2_to_linesegment()

template<class T >

unsigned vgl_intersection	(	vgl_box_2d< T > const &	box,
		vgl_line_segment_2d< T > const &	line,
		vgl_point_2d< T > &	p0,
		vgl_point_2d< T > &	p1
	)		[related]

Returns the number of intersections of a line segment with a box, up to two are returned in p0 and p1.

template<class T >

bool vgl_lineseg_test_line	(	vgl_line_2d< T > const &	l1,
		vgl_line_segment_2d< T > const &	l2
	)		[related]

true if the line meets the linesegment.

End points are considered to belong to a line segment.

Definition at line 39 of file vgl_lineseg_test.h.

template<class T >

bool vgl_lineseg_test_lineseg	(	vgl_line_segment_2d< T > const &	l1,
		vgl_line_segment_2d< T > const &	l2
	)		[related]

return true if the two linesegments meet.

End points are considered to belong to a line segment.

Definition at line 61 of file vgl_lineseg_test.h.

template<class T >

bool vgl_lineseg_test_point	(	vgl_point_2d< T > const &	p,
		vgl_line_segment_2d< T > const &	lseg
	)		[related]

true if the point lies on the line segment and is between the endpoints.

Definition at line 88 of file vgl_lineseg_test.txx.

---

Member Data Documentation

template<class Type>

vgl_point_2d<Type> vgl_line_segment_2d< Type >::point1_ [private]

One end of line segment.

Definition at line 26 of file vgl_line_segment_2d.h.

template<class Type>

vgl_point_2d<Type> vgl_line_segment_2d< Type >::point2_ [private]

The other end of the line segment.

Definition at line 28 of file vgl_line_segment_2d.h.

---

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

• core/vgl/vgl_line_segment_2d.h
• core/vgl/vgl_closest_point.h
• core/vgl/vgl_distance.h
• core/vgl/vgl_intersection.h
• core/vgl/vgl_line_segment_2d.txx
• core/vgl/vgl_lineseg_test.h
• core/vgl/vgl_lineseg_test.txx