org.xmlcml.euclid

Class Line3

java.lang.Object

org.xmlcml.euclid.Line3

All Implemented Interfaces:

EuclidConstants

public class Line3
extends Object
implements EuclidConstants

3-dimensional line class Line3 represents a 3-dimensional line It is one of a set of primitives which can be combined to create and manipulate complex 3-dimensional objects. Lines can be transformed with rotation matrices or rotation-translation matrices (Transform3), can be calculated from other primitives or can be used to generate other primitives. A line is a vector which is located in space. It is described by a unit vector (vector) and a point (p) on the line. Any point on the line can be used for p, and p could change during the existence of a calculation without affecting the integrity of the line, for example p = {1,1,1}, vector = {1,0,0} is the same line as p = {2,1,1}, vector = {1,0,0}. However the absolute direction of vector IS important, giving the line a direction. Default is a default Point3 (0.0, 0.0, 0.0) and default Vector3 (0.0, 0.0, 0.0). Operations on this line may lead to Exceptions such as ZeroLengthVector.

Author:

(C) P. Murray-Rust, 1996

Field Summary

Fields inherited from interface org.xmlcml.euclid.EuclidConstants

C_AMP, C_APOS, C_ATSIGN, C_BACKSLASH, C_BACKSPACE, C_CARET, C_COLON, C_COMMA, C_DEL, C_DOLLAR, C_EQUALS, C_FORMFEED, C_HASH, C_LANGLE, C_LBRAK, C_LCURLY, C_LSQUARE, C_MINUS, C_NBSP, C_NEWLINE, C_NL, C_PERCENT, C_PERIOD, C_PIPE, C_PLUS, C_POUND, C_QUERY, C_QUOT, C_RANGLE, C_RBRAK, C_RCURLY, C_RETURN, C_RSQUARE, C_SEMICOLON, C_SHRIEK, C_SLASH, C_SPACE, C_STAR, C_TAB, C_TILDE, C_UNDER, EPS, F_S, NONWHITEPUNC, NONWHITEPUNC0, NONWHITEPUNC0REGEX, ONE_THIRD, PUNC, S_AMP, S_APOS, S_ATSIGN, S_BACKSLASH, S_CARET, S_COLON, S_COMMA, S_DOLLAR, S_EMPTY, S_EQUALS, S_FORMFEED, S_HASH, S_LANGLE, S_LBRAK, S_LCURLY, S_LSQUARE, S_MINUS, S_NEWLINE, S_NL, S_PERCENT, S_PERIOD, S_PIPE, S_PLUS, S_POUND, S_QUERY, S_QUOT, S_RANGLE, S_RBRAK, S_RCURLY, S_RETURN, S_RSQUARE, S_SEMICOLON, S_SHRIEK, S_SLASH, S_SPACE, S_STAR, S_TAB, S_TILDE, S_UNDER, S_WHITEREGEX, TWO_THIRDS, U_S, WHITESPACE

Constructor Summary

Constructors

Constructor and Description
Line3() default consstructor.
Line3(Line3 l) copy constructor.
Line3(Point3 p1, Point3 p2) construct a line from two Point3s.
Line3(Point3 p, Vector3 v) construct from point and vector.

Method Summary

Modifier and Type	Method and Description
boolean	containsPoint(Point3 p) is a point on a line.
Point3	getClosestPointTo(Point3 p2) point on line closest to another point.
double	getDistanceFromPoint(Point3 p) distance of a point from a line
Point3	getIntersectionWith(Plane3 pl) point of intersection of line and plane calls Plane3.getIntersectionWith(Point3)
Point3	getPoint() get point from line.
Vector3	getVector() get vector from line.
boolean	isAntiparallelTo(Line3 l2) are two lines antiparallel.
boolean	isEqualTo(Line3 l2) are two lines identical.
boolean	isParallelTo(Line3 l2) are two lines parallel.
Line3	negative() form coincident antiparallel line.
String	toString() get string representation.
Line3	transform(Transform3 t) get transformed line.

Methods inherited from class java.lang.Object

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

Constructor Detail

Line3

public Line3()

default consstructor. no vector and point set

Line3

public Line3(Point3 p,
             Vector3 v)

construct from point and vector. the line will not necessarily retain the exact point and the vector need not be normalized p and vector are copied

Parameters:

p - a point on the line

v - non-zero vector through the point

Line3

public Line3(Point3 p1,
             Point3 p2)

construct a line from two Point3s. the line will not necessarily retain the exact points

Parameters:

p1 - a point on the line

p2 - another point on the line

Line3

public Line3(Line3 l)

copy constructor.

Parameters:

l - Line3 to copy

Method Detail

isEqualTo

public boolean isEqualTo(Line3 l2)

are two lines identical. must be coincident and parallel uses vect.equals() and containsPoint

Parameters:

l2 - Line3 to compare

Returns:

equals

negative

public Line3 negative()

form coincident antiparallel line.

Returns:

antiparallel line

getVector

public Vector3 getVector()

get vector from line.

Returns:

the vector (need not be normalized)

getPoint

public Point3 getPoint()

get point from line.

Returns:

any point on line

transform

public Line3 transform(Transform3 t)

get transformed line. does not alter this

Parameters:

t - transform

Returns:

transformed line

isParallelTo

public boolean isParallelTo(Line3 l2)

are two lines parallel. (not antiparallel) does not test coincidence

Parameters:

l2 - line to compare

Returns:

true if parallel

isAntiparallelTo

public boolean isAntiparallelTo(Line3 l2)

are two lines antiparallel. (not parallel) does not test coincidence

Parameters:

l2 - line to compare

Returns:

true if antiparallel

containsPoint

public boolean containsPoint(Point3 p)

is a point on a line. tests for Real.isZero() distance from line

Parameters:

p - point

Returns:

true if within Real.isZero()

getClosestPointTo

public Point3 getClosestPointTo(Point3 p2)

point on line closest to another point.

Parameters:

p2 - reference point

Returns:

point on line closest to p2

getDistanceFromPoint

public double getDistanceFromPoint(Point3 p)

distance of a point from a line

Parameters:

p - reference point

Returns:

distance from line

getIntersectionWith

public Point3 getIntersectionWith(Plane3 pl)

point of intersection of line and plane calls Plane3.getIntersectionWith(Point3)

Parameters:

pl - plane intersecting line

Returns:

point (null if line parallel to plane)

toString

public String toString()

get string representation.

Overrides:

toString in class Object

Returns:

string