Line2 (CML Euclid 2.9 API)

java.lang.Object
- org.xmlcml.euclid.Line2

All Implemented Interfaces:

EuclidConstants
```
public class Line2
extends Object
implements EuclidConstants
```
line determined by one point (R) and a vector (V) this gives L = R + nV can assume that R and R+V are the two "ends of the line" the semantics of this are application-dependent

Author:

pm286

Field Summary

Fields
Modifier and Type Field and Description

static Line2 XAXIS

static Line2 YAXIS
- 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

Fields
Modifier and Type	Field and Description
`static Line2`	`XAXIS`
`static Line2`	`YAXIS`

Constructor Summary

Constructors
Constructor and Description

Line2(Real2 from, Real2 to)
generates vector

Line2(Real2 from, Vector2 v)
generates to

Constructors
Constructor and Description
`Line2(Real2 from, Real2 to)` generates vector
`Line2(Real2 from, Vector2 v)` generates to

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`Double`	`calculateUnsignedDistanceBetweenLines(Line2 line, Angle eps)` calculated unsigned distance between parallel lines.
`boolean`	`contains(Real2 point, double eps, boolean allowExtension)` does a line contain a point.
`Real2`	`createPointOnLine(Double dist)` creates point at (signed) distance dist from "from" point newPoint = from + (dist / line.length) * vector
`Real2`	`createPointOnLine(Double dist, int index)` creates point at (signed) distance dist from index point vector = xy(1-index) <- xy(index) newPoint = xy(index) + (dist / line.length) * vector
`void`	`flipCoordinates()` swaps to and from coordinates.
`Angle`	`getAngleMadeWith(Line2 line)` convenience method.
`double`	`getDistanceFromPoint(Real2 point)` Deprecated. use new name (unsignedDistanceFromPoint)
`Real2`	`getFrom()`
`Real2`	`getIntersection(Line2 line1)` get intersection of two lines see softSurfer algorithm
`double`	`getLambda(Real2 p)` gets multiplier of point from "from" finds nearest point (pp) on line (so avoids rounding errors) then finds pp = from + vector * lambda if pp is within segment , lambda is 0, 1
`double`	`getLength()` get length
`Real2`	`getMidPoint()` get mid point
`Real2`	`getNearestPointNew(Real2 point)` may be redundant...
`Real2`	`getNearestPointOnLine(Real2 point)` get nearest point on infinite line.
`int`	`getSerial(Real2 point, double eps)` gets serial number of point in line specification if point is within EPS of "from" returns 0 if point is within EPS of "to" returns 1 else returns -1
`double`	`getSignedDistanceFromPoint(Real2 point)` signed perpendicular distance from point to infinite line.
`double`	`getSlope()` get slope.
`Real2`	`getTo()`
`Vector2`	`getUnitVector()` get unit vector convenience
`double`	`getUnsignedDistanceFromPoint(Real2 point)` perpendicular distance from point to infinite line.
`Vector2`	`getVector()`
`double`	`getXIntercept()` "c" in y=m*x+c
`Real2`	`getXY(int i)` get point at either end.
`double`	`getYIntercept()` * "c" in y=m*x+c
`boolean`	`isAntiParallelTo(Line2 line, Angle eps)`
`boolean`	`isHorizontal(Angle eps)`
`Boolean`	`isParallelOrAntiParallelTo(Line2 line, Angle eps)` are unsigned lines parallel.
`Boolean`	`isParallelTo(Line2 line, Angle eps)` are two lines parallel within tolerance.
`Boolean`	`isPerpendicularTo(Line2 line, Angle angleEps)`
`boolean`	`isVertical(Angle eps)`
`void`	`setXY(Real2 xy, int i)` set point at either end.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - XAXIS
```
public static final Line2 XAXIS
```
  - YAXIS
```
public static final Line2 YAXIS
```
- Constructor Detail
  - Line2
```
public Line2(Real2 from,
             Real2 to)
```
    generates vector
    
    Parameters:
    
    from -
    
    to -
  - Line2
```
public Line2(Real2 from,
             Vector2 v)
```
    generates to
    
    Parameters:
    
    from -
    
    v -
- Method Detail
  - getSlope
```
public double getSlope()
```
    get slope. "m" in y=m*x+c if x component is zero returns Double.*_INFINITY;
    
    Returns:
    
    slope, Double.POSITIVE_INFINITY or Double.NEGATIVE_INFINITY;
  - getYIntercept
```
public double getYIntercept()
```
    * "c" in y=m*x+c
    
    Returns:
    
    intercept or Double.NaN if slope is infinite
  - getXIntercept
```
public double getXIntercept()
```
    "c" in y=m*x+c
    
    Returns:
    
    intercept or Double.NaN if slope is infinite
  - getIntersection
```
public Real2 getIntersection(Line2 line1)
```
    get intersection of two lines see softSurfer algorithm
    
    Parameters:
    
    line1 -
    
    Returns:
    
    null if parallel or antiparallel
  - contains
```
public boolean contains(Real2 point,
                        double eps,
                        boolean allowExtension)
```
    does a line contain a point. line is of zero thickness
    
    Parameters:
    
    point -
    
    eps - distance within which point muct approach line
    
    allowExtension - if true allow point to be "outside" line segment
    
    Returns:
    
    true if within eps of line
  - flipCoordinates
```
public void flipCoordinates()
```
    swaps to and from coordinates.
  - getUnitVector
```
public Vector2 getUnitVector()
```
    get unit vector convenience
    
    Returns:
    
    vector
  - getDistanceFromPoint
```
public double getDistanceFromPoint(Real2 point)
```
    Deprecated. use new name (unsignedDistanceFromPoint)
    
    signed perpendicular distance from point to infinite line.
    
    Parameters:
    
    point -
    
    Returns:
    
    distance
  - getSignedDistanceFromPoint
```
public double getSignedDistanceFromPoint(Real2 point)
```
    signed perpendicular distance from point to infinite line. will depend on direction of line.
    
    Parameters:
    
    point -
    
    Returns:
    
    distance
  - getUnsignedDistanceFromPoint
```
public double getUnsignedDistanceFromPoint(Real2 point)
```
    perpendicular distance from point to infinite line.
    
    Parameters:
    
    point -
    
    Returns:
    
    distance
  - getNearestPointNew
```
public Real2 getNearestPointNew(Real2 point)
```
    may be redundant...
    
    Parameters:
    
    point -
    
    Returns:
  - getNearestPointOnLine
```
public Real2 getNearestPointOnLine(Real2 point)
```
    get nearest point on infinite line.
    
    Parameters:
    
    point -
    
    Returns:
    
    distance
  - isParallelTo
```
public Boolean isParallelTo(Line2 line,
                            Angle eps)
```
    are two lines parallel within tolerance.
    
    Parameters:
    
    line -
    
    eps - maximum allowed angle between lines
    
    Returns:
    
    null if any arguments null
  - isAntiParallelTo
```
public boolean isAntiParallelTo(Line2 line,
                                Angle eps)
```
    Parameters:
    
    line -
    
    eps - maximum allowed angle between unsigned lines (i.e. << Math.PI/2)
    
    Returns:
    
    null if any arguments null
  - isParallelOrAntiParallelTo
```
public Boolean isParallelOrAntiParallelTo(Line2 line,
                                          Angle eps)
```
    are unsigned lines parallel.
    
    Parameters:
    
    line -
    
    eps -
    
    Returns:
    
    isParallel() or isAntiParallel; null if line or eps is null
  - calculateUnsignedDistanceBetweenLines
```
public Double calculateUnsignedDistanceBetweenLines(Line2 line,
                                                    Angle eps)
```
    calculated unsigned distance between parallel lines.
    uses distance from this.getXY(0) to nearest point on line.
    
    if lines are not exactly parallel the result has no absolute meaning but is heuristically useful.
    
    Parameters:
    
    line -
    
    eps -
    
    Returns:
    
    null if args are null or lines are not parallel
  - getAngleMadeWith
```
public Angle getAngleMadeWith(Line2 line)
```
    convenience method. gets angle formed between lines using Vector2.getAngleMadeWith(Vector2)
    
    Parameters:
    
    line -
    
    Returns:
    
    angle or null
  - isPerpendicularTo
```
public Boolean isPerpendicularTo(Line2 line,
                                 Angle angleEps)
```
  - getLambda
```
public double getLambda(Real2 p)
```
    gets multiplier of point from "from" finds nearest point (pp) on line (so avoids rounding errors) then finds pp = from + vector * lambda if pp is within segment , lambda is 0, 1
    
    Parameters:
    
    p -
    
    Returns:
    
    lambda
  - getMidPoint
```
public Real2 getMidPoint()
```
    get mid point
    
    Returns:
    
    mid point
  - getLength
```
public double getLength()
```
    get length
    
    Returns:
    
    length
  - getFrom
```
public Real2 getFrom()
```
    Returns:
    
    the from
  - getTo
```
public Real2 getTo()
```
    Returns:
    
    the to
  - getXY
```
public Real2 getXY(int i)
```
    get point at either end.
    
    Parameters:
    
    i - (0/from or 1/to)
    
    Returns:
  - setXY
```
public void setXY(Real2 xy,
                  int i)
```
    set point at either end.
    
    Parameters:
    
    i - (0/from or 1/to)
  - getVector
```
public Vector2 getVector()
```
    Returns:
    
    the vector
  - createPointOnLine
```
public Real2 createPointOnLine(Double dist)
```
    creates point at (signed) distance dist from "from" point newPoint = from + (dist / line.length) * vector
    
    Parameters:
    
    dist -
    
    Returns:
    
    new Point
  - createPointOnLine
```
public Real2 createPointOnLine(Double dist,
                               int index)
```
    creates point at (signed) distance dist from index point vector = xy(1-index) <- xy(index) newPoint = xy(index) + (dist / line.length) * vector
    
    Parameters:
    
    dist -
    
    index -
    
    Returns:
    
    new Point
  - getSerial
```
public int getSerial(Real2 point,
                     double eps)
```
    gets serial number of point in line specification if point is within EPS of "from" returns 0 if point is within EPS of "to" returns 1 else returns -1
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
    
    Returns:
    
    string
  - isHorizontal
```
public boolean isHorizontal(Angle eps)
```
  - isVertical
```
public boolean isVertical(Angle eps)
```

Class Line2

Field Summary

Fields inherited from interface org.xmlcml.euclid.EuclidConstants

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

XAXIS

YAXIS

Constructor Detail

Line2

Line2

Method Detail

getSlope

getYIntercept

getXIntercept

getIntersection

contains

flipCoordinates

getUnitVector

getDistanceFromPoint

getSignedDistanceFromPoint

getUnsignedDistanceFromPoint

getNearestPointNew

getNearestPointOnLine

isParallelTo

isAntiParallelTo

isParallelOrAntiParallelTo

calculateUnsignedDistanceBetweenLines

getAngleMadeWith

isPerpendicularTo

getLambda

getMidPoint

getLength

getFrom

getTo

getXY

setXY

getVector

createPointOnLine

createPointOnLine

getSerial

toString

isHorizontal

isVertical