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`java.lang.Object`

`java.awt.geom.Line2D`

**Implemented Interfaces:**- Cloneable, Shape

**Known Direct Subclasses:**- Line2D.Double, Line2D.Float

Represents a directed line bewteen two points in (x,y) Cartesian space.
Remember, on-screen graphics have increasing x from left-to-right, and
increasing y from top-to-bottom. The storage is left to subclasses.

**Since:**- 1.2

## Nested Class Summary

`static class`

`Line2D.Double`

- This class defines a point in
`double`

precision.

`static class`

`Line2D.Float`

- This class defines a point in
`float`

precision.

## Constructor Summary

`Line2D()`

- The default constructor.

## Method Summary

`Object`

`clone()`

- Create a new line of the same run-time type with the same contents as this one.

`boolean`

`contains(double x, double y)`

- Test if a point is contained inside the line.

`boolean`

`contains(double x, double y, double w, double h)`

- Tests if the line contains a rectangle.

`boolean`

`boolean`

`contains(Rectangle2D r)`

- Tests if the line contains a rectangle.

`Rectangle`

`getBounds()`

- Gets a bounding box (not necessarily minimal) for this line.

`abstract Point2D`

`getP1()`

- Return the first point.

`abstract Point2D`

`getP2()`

- Return the second point.

`PathIterator`

`getPathIterator(AffineTransform at)`

- Return a path iterator, possibly applying a transform on the result.

`PathIterator`

`getPathIterator(AffineTransform at, double flatness)`

- Return a flat path iterator, possibly applying a transform on the result.

`abstract double`

`getX1()`

- Return the x coordinate of the first point.

`abstract double`

`getX2()`

- Return the x coordinate of the second point.

`abstract double`

`getY1()`

- Return the y coordinate of the first point.

`abstract double`

`getY2()`

- Return the y coordinate of the second point.

`boolean`

`intersects(double x, double y, double w, double h)`

- Tests if this line intersects the interior of the specified rectangle.

`boolean`

`intersects(Rectangle2D r)`

- Tests if this line intersects the interior of the specified rectangle.

`boolean`

`intersectsLine(double x1, double y1, double x2, double y2)`

- Test if this line intersects the line given by (x1,y1)->(x2,y2).

`boolean`

`intersectsLine(Line2D l)`

- Test if this line intersects the given line.

`static boolean`

`linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)`

- Test if the line segment (x1,y1)->(x2,y2) intersects the line segment (x3,y3)->(x4,y4).

`double`

`ptLineDist(double px, double py)`

- Measures the shortest distance from the reference point to a point on the infinite line extended from this segment.

`static double`

`ptLineDist(double x1, double y1, double x2, double y2, double px, double py)`

- Measures the shortest distance from the reference point to a point on the infinite line extended from the segment.

`double`

`ptLineDist(Point2D p)`

- Measures the shortest distance from the reference point to a point on the infinite line extended from this segment.

`double`

`ptLineDistSq(double px, double py)`

- Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment.

`static double`

`ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py)`

- Measures the square of the shortest distance from the reference point to a point on the infinite line extended from the segment.

`double`

`ptLineDistSq(Point2D p)`

- Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment.

`double`

`ptSegDist(double px, double py)`

- Measures the shortest distance from the reference point to a point on this line segment.

`static double`

`ptSegDist(double x1, double y1, double x2, double y2, double px, double py)`

- Measures the shortest distance from the reference point to a point on the line segment.

`double`

`double`

`ptSegDistSq(double px, double py)`

- Measures the square of the shortest distance from the reference point to a point on this line segment.

`static double`

`ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py)`

- Measures the square of the shortest distance from the reference point to a point on the line segment.

`double`

`ptSegDistSq(Point2D p)`

- Measures the square of the shortest distance from the reference point to a point on this line segment.

`int`

`relativeCCW(double px, double py)`

- Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p.

`static int`

`relativeCCW(double x1, double y1, double x2, double y2, double px, double py)`

- Computes the relative rotation direction needed to pivot the line about the first point in order to have the second point colinear with point p.

`int`

`relativeCCW(Point2D p)`

- Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p.

`abstract void`

`setLine(double x1, double y1, double x2, double y2)`

- Set the coordinates of the line to the given coordinates.

`void`

`void`

### Methods inherited from class java.lang.Object

`clone`

,`equals`

,`extends Object> getClass`

,`finalize`

,`hashCode`

,`notify`

,`notifyAll`

,`toString`

,`wait`

,`wait`

,`wait`

public Object clone()

Create a new line of the same run-time type with the same contents as this one.

Returns:- the clone

Since:- 1.2

public boolean contains(double x, double y)

Test if a point is contained inside the line. Since a line has no area, this returns false.

Parameters:`x`

- the x coordinate`y`

- the y coordinate

Returns:- false; the line does not contain points

public boolean contains(double x, double y, double w, double h)

Tests if the line contains a rectangle. Since lines have no area, this always returns false.

Parameters:`x`

- the x coordinate of the rectangle`y`

- the y coordinate of the rectangle`w`

- the width of the rectangle`h`

- the height of the rectangle

Returns:- false; the line does not contain points

public boolean contains(Point2D p)

Test if a point is contained inside the line. Since a line has no area, this returns false.

Parameters:`p`

- the point

Returns:- false; the line does not contain points

public boolean contains(Rectangle2D r)

Tests if the line contains a rectangle. Since lines have no area, this always returns false.

Parameters:`r`

- the rectangle

Returns:- false; the line does not contain points

public Rectangle getBounds()

Gets a bounding box (not necessarily minimal) for this line.

Returns:- the integer bounding box

See Also:`getBounds2D()`

public PathIterator getPathIterator(AffineTransform at)

Return a path iterator, possibly applying a transform on the result. This iterator is not threadsafe.

Specified by:- getPathIterator in interface Shape

Parameters:`at`

- the transform, or null

Returns:- a new path iterator

public PathIterator getPathIterator(AffineTransform at, double flatness)

Return a flat path iterator, possibly applying a transform on the result. This iterator is not threadsafe.

Specified by:- getPathIterator in interface Shape

Parameters:`at`

- the transform, or null`flatness`

- ignored, since lines are already flat

Returns:- a new path iterator

See Also:`getPathIterator(AffineTransform)`

public abstract double getX1()

Return the x coordinate of the first point.

Returns:- the starting x coordinate

public abstract double getX2()

Return the x coordinate of the second point.

Returns:- the ending x coordinate

public abstract double getY1()

Return the y coordinate of the first point.

Returns:- the starting y coordinate

public abstract double getY2()

Return the y coordinate of the second point.

Returns:- the ending y coordinate

public boolean intersects(double x, double y, double w, double h)

Tests if this line intersects the interior of the specified rectangle.

Specified by:- intersects in interface Shape

Parameters:`x`

- the x coordinate of the rectangle`y`

- the y coordinate of the rectangle`w`

- the width of the rectangle`h`

- the height of the rectangle

Returns:- true if the line intersects the rectangle

public boolean intersects(Rectangle2D r)

Tests if this line intersects the interior of the specified rectangle.

Specified by:- intersects in interface Shape

Parameters:`r`

- the rectangle

Returns:- true if the line intersects the rectangle

Throws:`NullPointerException`

- if r is null

public boolean intersectsLine(double x1, double y1, double x2, double y2)

Test if this line intersects the line given by (x1,y1)->(x2,y2).

Parameters:`x1`

- the first x coordinate of the other segment`y1`

- the first y coordinate of the other segment`x2`

- the second x coordinate of the other segment`y2`

- the second y coordinate of the other segment

Returns:- true if the segments intersect

public boolean intersectsLine(Line2D l)

Test if this line intersects the given line.

Parameters:`l`

- the other segment

Returns:- true if the segments intersect

Throws:`NullPointerException`

- if l is null

public static boolean linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)

Test if the line segment (x1,y1)->(x2,y2) intersects the line segment (x3,y3)->(x4,y4).

Parameters:`x1`

- the first x coordinate of the first segment`y1`

- the first y coordinate of the first segment`x2`

- the second x coordinate of the first segment`y2`

- the second y coordinate of the first segment`x3`

- the first x coordinate of the second segment`y3`

- the first y coordinate of the second segment`x4`

- the second x coordinate of the second segment`y4`

- the second y coordinate of the second segment

Returns:- true if the segments intersect

public double ptLineDist(double px, double py)

Measures the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the distance from the point to the extended line

public static double ptLineDist(double x1, double y1, double x2, double y2, double px, double py)

Measures the shortest distance from the reference point to a point on the infinite line extended from the segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`x1`

- the first x coordinate of the segment`y1`

- the first y coordinate of the segment`x2`

- the second x coordinate of the segment`y2`

- the second y coordinate of the segment`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the distance from the point to the extended line

public double ptLineDist(Point2D p)

Measures the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`p`

- the point

Returns:- the distance from the point to the extended line

Throws:`NullPointerException`

- if p is null

public double ptLineDistSq(double px, double py)

Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the square of the distance from the point to the extended line

public static double ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py)

Measures the square of the shortest distance from the reference point to a point on the infinite line extended from the segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`x1`

- the first x coordinate of the segment`y1`

- the first y coordinate of the segment`x2`

- the second x coordinate of the segment`y2`

- the second y coordinate of the segment`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the square of the distance from the point to the extended line

public double ptLineDistSq(Point2D p)

Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters:`p`

- the point

Returns:- the square of the distance from the point to the extended line

Throws:`NullPointerException`

- if p is null

public double ptSegDist(double px, double py)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the distance from the point to the segment

public static double ptSegDist(double x1, double y1, double x2, double y2, double px, double py)

Measures the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Parameters:`x1`

- the first x coordinate of the segment`y1`

- the first y coordinate of the segment`x2`

- the second x coordinate of the segment`y2`

- the second y coordinate of the segment`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the distance from the point to the segment

public double ptSegDist(Point2D p)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:`p`

- the point

Returns:- the distance from the point to the segment

Throws:`NullPointerException`

- if p is null

public double ptSegDistSq(double px, double py)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the square of the distance from the point to the segment

public static double ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py)

Measures the square of the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Parameters:`x1`

- the first x coordinate of the segment`y1`

- the first y coordinate of the segment`x2`

- the second x coordinate of the segment`y2`

- the second y coordinate of the segment`px`

- the x coordinate of the point`py`

- the y coordinate of the point

Returns:- the square of the distance from the point to the segment

public double ptSegDistSq(Point2D p)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters:`p`

- the point

Returns:- the square of the distance from the point to the segment

Throws:`NullPointerException`

- if p is null

public int relativeCCW(double px, double py)

Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p. Because of floating point rounding, don't expect this to be a perfect measure of colinearity. The answer is 1 if the line has a shorter rotation in the direction of the positive X axis to the negative Y axis (counter-clockwise in the default Java coordinate system), or -1 if the shortest rotation is in the opposite direction (clockwise). If p is already colinear, the return value is -1 if it lies beyond the first point, 0 if it lies in the segment, or 1 if it lies beyond the second point. If the first and second point are coincident, this returns 0.

Parameters:`px`

- the reference x coordinate`py`

- the reference y coordinate

Returns:- the relative rotation direction

public static int relativeCCW(double x1, double y1, double x2, double y2, double px, double py)

Computes the relative rotation direction needed to pivot the line about the first point in order to have the second point colinear with point p. Because of floating point rounding, don't expect this to be a perfect measure of colinearity. The answer is 1 if the line has a shorter rotation in the direction of the positive X axis to the negative Y axis (counter-clockwise in the default Java coordinate system), or -1 if the shortest rotation is in the opposite direction (clockwise). If p is already colinear, the return value is -1 if it lies beyond the first point, 0 if it lies in the segment, or 1 if it lies beyond the second point. If the first and second point are coincident, this returns 0.

Parameters:`x1`

- the first x coordinate`y1`

- the first y coordinate`x2`

- the second x coordinate`y2`

- the second y coordinate`px`

- the reference x coordinate`py`

- the reference y coordinate

Returns:- the relative rotation direction

public int relativeCCW(Point2D p)

Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p. Because of floating point rounding, don't expect this to be a perfect measure of colinearity. The answer is 1 if the line has a shorter rotation in the direction of the positive X axis to the negative Y axis (counter-clockwise in the default Java coordinate system), or -1 if the shortest rotation is in the opposite direction (clockwise). If p is already colinear, the return value is -1 if it lies beyond the first point, 0 if it lies in the segment, or 1 if it lies beyond the second point. If the first and second point are coincident, this returns 0.

Parameters:`p`

- the reference point

Returns:- the relative rotation direction

Throws:`NullPointerException`

- if p is null

public abstract void setLine(double x1, double y1, double x2, double y2)

Set the coordinates of the line to the given coordinates. Loss of precision may occur due to rounding issues.

Parameters:`x1`

- the first x coordinate`y1`

- the first y coordinate`x2`

- the second x coordinate`y2`

- the second y coordinate

public void setLine(Line2D l)

Set the coordinates to those of the given line.

Parameters:`l`

- the line to copy

Throws:`NullPointerException`

- if l is null

public void setLine(Point2D p1, Point2D p2)

Set the coordinates to the given points.

Parameters:`p1`

- the first point`p2`

- the second point

Throws:`NullPointerException`

- if either point is null

Line2D.java -- represents a line in 2-D space, plus operations on a line
Copyright (C) 2000, 2001, 2002 Free Software Foundation
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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terms of your choice, provided that you also meet, for each linked
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or based on this library. If you modify this library, you may extend
this exception to your version of the library, but you are not
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exception statement from your version.

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