Class ApproximatePredicates_2

java.lang.Object

Jcg.geometry.kernel.ApproximatePredicates_2

All Implemented Interfaces:

GeometricPredicates_2

public class ApproximatePredicates_2
extends Object
implements GeometricPredicates_2

Approximate geometric predicates for plane objects (points, segments, rays)

Version:

dec 2012

Author:

Luca Castelli Aleardi and Steve Oudot (INF562, Ecole Polytechnique)

Constructor Summary

Constructors

Constructor	Description
ApproximatePredicates_2()

Method Summary

Modifier and Type	Method	Description
boolean	collinear(Point_2 a, Point_2 b, Point_2 c)	Returns true if a, b and c lie on a same line
boolean	doIntersect(Segment_2 s, Ray_2 r)	Returns true if segment s and ray r intersect
boolean	doIntersect(Segment_2 s, Segment_2 t)	Returns true if segments 's' and 't' intersect
boolean	inCircle(Point_2 p, Point_2 a, Point_2 b, Point_2 c)	Tests if point p lies inside the circumcircle of triangle a,b,c
boolean	isClockwise(Point_2 a, Point_2 b, Point_2 c)	Returns true if a, b and c turn in clockwise direction
boolean	isCounterClockwise(Point_2 a, Point_2 b, Point_2 c)	Returns true if a, b and c turn in counter-clockwise direction
boolean	liesOn(Point_2 p, Point_2 a, Point_2 b)	Returns true if point p lies on segment ab
int	orientation(Point_2 a, Point_2 b, Point_2 c)	Returns the orientation of a, b and c

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ApproximatePredicates_2

public ApproximatePredicates_2()

Method Details

orientation

public int orientation(Point_2 a,
 Point_2 b,
 Point_2 c)

Returns the orientation of a, b and c

Specified by:

orientation in interface GeometricPredicates_2

Parameters:

a - ,b,c the 3 points to test

Returns:

1 if sequence (a, b, c) turns in counter-clockwise direction, -1 if it turns in clockwise direction, 0 if the points are collinear

isCounterClockwise

public boolean isCounterClockwise(Point_2 a,
 Point_2 b,
 Point_2 c)

Returns true if a, b and c turn in counter-clockwise direction

Specified by:

isCounterClockwise in interface GeometricPredicates_2

Parameters:

a - ,b,c the 3 points to test

Returns:

true if a, b and c turn in counter-clockwise direction.
Warning: the result is false if the three points are collinear

isClockwise

public boolean isClockwise(Point_2 a,
 Point_2 b,
 Point_2 c)

Returns true if a, b and c turn in clockwise direction

Specified by:

isClockwise in interface GeometricPredicates_2

Parameters:

a - ,b,c the 3 points to test

Returns:

true if a, b and c turn in clockwise direction.
Warning: the result is false if the three points are collinear

collinear

public boolean collinear(Point_2 a,
 Point_2 b,
 Point_2 c)

Returns true if a, b and c lie on a same line

Specified by:

collinear in interface GeometricPredicates_2

Parameters:

a - ,b,c the 3 points to test

Returns:

true if a, b and c are collinear (lie on a same line)

inCircle

public boolean inCircle(Point_2 p,
 Point_2 a,
 Point_2 b,
 Point_2 c)

Tests if point p lies inside the circumcircle of triangle a,b,c

Specified by:

inCircle in interface GeometricPredicates_2

Parameters:

p - point to test

a - ,b,c triangle

Returns:

true/false

doIntersect

public boolean doIntersect(Segment_2 s,
 Segment_2 t)

Returns true if segments 's' and 't' intersect

Specified by:

doIntersect in interface GeometricPredicates_2

Parameters:

s - first segment

t - second segment

Returns:

true if s and t intersect each other

doIntersect

public boolean doIntersect(Segment_2 s,
 Ray_2 r)

Returns true if segment s and ray r intersect

Specified by:

doIntersect in interface GeometricPredicates_2

Parameters:

s - the segment

r - the ray

Returns:

true if s intersects r

liesOn

public boolean liesOn(Point_2 p,
 Point_2 a,
 Point_2 b)

Returns true if point p lies on segment ab

Specified by:

liesOn in interface GeometricPredicates_2

Parameters:

a - ,b,p the 3 points

Returns:

true if ab contains point p