core/vgl/vgl_homg_line_2d.h File Reference

line in projective 2D space More...

#include <vcl_iosfwd.h>
#include <vgl/vgl_fwd.h>
#include <vcl_cassert.h>
#include <vgl/vgl_vector_2d.h>

Go to the source code of this file.

Classes
class	vgl_homg_line_2d< T >
	Represents a homogeneous 2D line. More...
Defines
#define	vgl_Abs(x)   (x<0?-x:x)
#define	l   vgl_homg_line_2d<T>
#define	VGL_HOMG_LINE_2D_INSTANTIATE(T)   extern "please include vgl/vgl_homg_line_2d.txx first"
Functions
template<class T >
bool	is_ideal (l const &line, T tol=(T) 0)
	Return true iff line is the line at infinity.
template<class T >
bool	concurrent (l const &l1, l const &l2, l const &l3)
	Are three lines concurrent, i.e., do they pass through a common point?.
template<class T >
vcl_ostream &	operator<< (vcl_ostream &s, l const &line)
	Print line equation to stream.
template<class T >
vcl_istream &	operator>> (vcl_istream &s, l &line)
	Load in line parameters from stream.

---

Detailed Description

line in projective 2D space

Author:

Don Hamilton, Peter Tu

    Modifications
     Peter Vanroose -  6 July 2001 - Added normal(), direction() and concurrent()
     Peter Vanroose -  4 July 2001 - Added assertions and cstr from non-homg line
     Peter Vanroose - 27 June 2001 - Added operator==
   

Definition in file vgl_homg_line_2d.h.

---

Define Documentation

#define l   vgl_homg_line_2d<T>

Definition at line 119 of file vgl_homg_line_2d.h.

#define vgl_Abs

(

x

)

(x<0?-x:x)

#define VGL_HOMG_LINE_2D_INSTANTIATE

(

T

)

extern "please include vgl/vgl_homg_line_2d.txx first"

Definition at line 149 of file vgl_homg_line_2d.h.

---

Function Documentation

template<class T >

bool concurrent	(	l const &	l1,
		l const &	l2,
		l const &	l3
	)		[inline]

Are three lines concurrent, i.e., do they pass through a common point?.

Definition at line 130 of file vgl_homg_line_2d.h.

template<class T >

bool is_ideal	(	l const &	line,
		T	tol = (T)0
	)		[inline]

Return true iff line is the line at infinity.

This version checks (max(|a|,|b|) <= tol * |c|

Definition at line 125 of file vgl_homg_line_2d.h.

template<class T >

vcl_ostream & operator<<	(	vcl_ostream &	s,
		l const &	line
	)

Print line equation to stream.

Write line description to stream: "<vgl_line_2d ax+by+c>".

Write to stream (verbose).

template<class T >

vcl_istream & operator>>	(	vcl_istream &	s,
		l &	line
	)

Load in line parameters from stream.

Read in three line parameters from stream.

Read parameters from stream.

Either just reads three blank-separated numbers, or reads three comma-separated numbers, or reads three numbers in parenthesized form "(123, 321, -456)" or reads a formatted line equation "123x+321y-456=0"