Segment Class Reference

2D segment lines More...

#include <geometry.hpp>

Collaboration diagram for Segment:

List of all members.

Public Member Functions
	Segment ()
	Default constructor.
	Segment (const Segment &seg)
	Copy constructor.
	Segment (const Point &a, const Point &b)
	Assign constructor.
	Segment (const rat &xa, const rat &ya, const rat &xb, const rat &yb)
	Assign constructor.
Point	get_left () const
	Reads private memeber left.
Point	get_right () const
	Reads private member right.
rat	high (const Point &) const
	Computes the high of a segment line.
bool	less (const Segment &, const Point &) const
	Order of the segment relatively to a point.
bool	intersect (const Segment &, Point &) const
	Search for intersections.
bool	is_rend (const Point &) const
	Checks if a point is the right endpoint of the segment line.
bool	is_lend (const Point &) const
	Checks if a point is the left endpoint of the segment line.
bool	is_in (const Point &) const
	Checks if a point is in the interior of the segment line.
Private Attributes
Point	left
	Left endpoint.
Point	right
	Right endpoint.
Slope	slope
	Slope.

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Detailed Description

2D segment lines

Using class Point for the endpoints of the segment line, and struct Slope to indicate the direction of the segment line.

For a couple of point, one is said to be the left one and the other the right one regarding to the lexographic order on the (x,y)-coordinates.

Definition at line 110 of file geometry.hpp.

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Constructor & Destructor Documentation

Segment::Segment

(

const Segment &

seg

)

[inline]

Copy constructor.

Parameters:

seg	Segment to copy

Definition at line 127 of file geometry.hpp.

Segment::Segment	(	const Point &	a,
		const Point &	b
	)		[inline]

Assign constructor.

Parameters:

a,b	Points to be left and right ones of the segment line

Definition at line 137 of file geometry.hpp.

Segment::Segment	(	const rat &	xa,
		const rat &	ya,
		const rat &	xb,
		const rat &	yb
	)		[inline]

Assign constructor.

Parameters:

xa,ya	Coordinates of the left endpoint
xb,yb	Coordinates of the right endpoint

Definition at line 146 of file geometry.hpp.

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Member Function Documentation

Point Segment::get_left

(

)

const

Reads private memeber left.

Returns:

Left endpoint

Definition at line 72 of file geometry.cpp.

Point Segment::get_right

(

)

const

Reads private member right.

Returns:

Right endpoint

Definition at line 80 of file geometry.cpp.

rat Segment::high

(

const Point &

p_sweep

)

const

Computes the high of a segment line.

Parameters:

p_sweep

Sweeping point to use in the comparison.

Returns:

High of the segment line

We define the high of a segment line regarding to a point as :

• not defined if the segment line does not cross the vertical line with abscissa the abscissa of the point.
• if the segment line is vertical
  • the y-coordinate of the point if the segment line contains the point.
  • the y-coordinate of the left endpoint if the point is laying below the segment line.
  • the y-coordinate of the right endpoint if the point is laying above the segment line.
• the y-coordinate of the crossing point of the segment and the vertical line with abscissa the abscissa of the point else.

Definition at line 141 of file geometry.cpp.

bool Segment::intersect	(	const Segment &	seg,
		Point &	inter
	)		const

Search for intersections.

Parameters:

seg	Segment to check if it is crossing the current one.
inter	If there is an intersection, used to report it.

Returns:

True if and only if there is an intersection.

The searching is done by computing the determinant of the classic system induced by the segment lines.

Definition at line 93 of file geometry.cpp.

bool Segment::is_in

(

const Point &

p

)

const

Checks if a point is in the interior of the segment line.

Parameters:

p	Point to test.

Returns:

True if and only if p is in the interior.

Definition at line 207 of file geometry.cpp.

bool Segment::is_lend

(

const Point &

p

)

const

Checks if a point is the left endpoint of the segment line.

Parameters:

p	Point to test.

Returns:

True if and only if p is the left endpoint.

Definition at line 197 of file geometry.cpp.

bool Segment::is_rend

(

const Point &

p

)

const

Checks if a point is the right endpoint of the segment line.

Parameters:

p	Point to test.

Returns:

True if and only if p is the right endpoint.

Definition at line 187 of file geometry.cpp.

bool Segment::less	(	const Segment &	s,
		const Point &	p_sweep
	)		const

Order of the segment relatively to a point.

Parameters:

s	Segment to compare with.
p_sweep	Sweeping point.

Returns:

True if and only if the current segment is less than s

A segment is less than an other if its high is less than the other's high or if its high is equal to the other's high and its slope is less than the other's slope.

Definition at line 172 of file geometry.cpp.

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

• geometry.hpp
• geometry.cpp