
Java™ Platform Standard Ed. 6 

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java.lang.Object java.awt.geom.Line2D
public abstract class Line2D
This Line2D
represents a line segment in (x,y)
coordinate space. This class, like all of the Java 2D API, uses a
default coordinate system called user space in which the yaxis
values increase downward and xaxis values increase to the right. For
more information on the user space coordinate system, see the
Coordinate Systems section of the Java 2D Programmer's Guide.
This class is only the abstract superclass for all objects that store a 2D line segment. The actual storage representation of the coordinates is left to the subclass.
Nested Class Summary  

static class 
Line2D.Double
A line segment specified with double coordinates. 
static class 
Line2D.Float
A line segment specified with float coordinates. 
Constructor Summary  

protected 
Line2D()
This is an abstract class that cannot be instantiated directly. 
Method Summary  

Object 
clone()
Creates a new object of the same class as this object. 
boolean 
contains(double x,
double y)
Tests if a specified coordinate is inside the boundary of this Line2D . 
boolean 
contains(double x,
double y,
double w,
double h)
Tests if the interior of this Line2D entirely contains
the specified set of rectangular coordinates. 
boolean 
contains(Point2D p)
Tests if a given Point2D is inside the boundary of
this Line2D . 
boolean 
contains(Rectangle2D r)
Tests if the interior of this Line2D entirely contains
the specified Rectangle2D . 
Rectangle 
getBounds()
Returns an integer Rectangle that completely encloses the
Shape . 
abstract Point2D 
getP1()
Returns the start Point2D of this Line2D . 
abstract Point2D 
getP2()
Returns the end Point2D of this Line2D . 
PathIterator 
getPathIterator(AffineTransform at)
Returns an iteration object that defines the boundary of this Line2D . 
PathIterator 
getPathIterator(AffineTransform at,
double flatness)
Returns an iteration object that defines the boundary of this flattened Line2D . 
abstract double 
getX1()
Returns the X coordinate of the start point in double precision. 
abstract double 
getX2()
Returns the X coordinate of the end point in double precision. 
abstract double 
getY1()
Returns the Y coordinate of the start point in double precision. 
abstract double 
getY2()
Returns the Y coordinate of the end point in double precision. 
boolean 
intersects(double x,
double y,
double w,
double h)
Tests if the interior of the Shape intersects the
interior of a specified rectangular area. 
boolean 
intersects(Rectangle2D r)
Tests if the interior of the Shape intersects the
interior of a specified Rectangle2D . 
boolean 
intersectsLine(double x1,
double y1,
double x2,
double y2)
Tests if the line segment from (x1,y1) to
(x2,y2) intersects this line segment. 
boolean 
intersectsLine(Line2D l)
Tests if the specified line segment intersects this line segment. 
static boolean 
linesIntersect(double x1,
double y1,
double x2,
double y2,
double x3,
double y3,
double x4,
double y4)
Tests if the line segment from (x1,y1) to
(x2,y2) intersects the line segment from (x3,y3)
to (x4,y4) . 
double 
ptLineDist(double px,
double py)
Returns the distance from a point to this line. 
static double 
ptLineDist(double x1,
double y1,
double x2,
double y2,
double px,
double py)
Returns the distance from a point to a line. 
double 
ptLineDist(Point2D pt)
Returns the distance from a Point2D to this line. 
double 
ptLineDistSq(double px,
double py)
Returns the square of the distance from a point to this line. 
static double 
ptLineDistSq(double x1,
double y1,
double x2,
double y2,
double px,
double py)
Returns the square of the distance from a point to a line. 
double 
ptLineDistSq(Point2D pt)
Returns the square of the distance from a specified Point2D to this line. 
double 
ptSegDist(double px,
double py)
Returns the distance from a point to this line segment. 
static double 
ptSegDist(double x1,
double y1,
double x2,
double y2,
double px,
double py)
Returns the distance from a point to a line segment. 
double 
ptSegDist(Point2D pt)
Returns the distance from a Point2D to this line
segment. 
double 
ptSegDistSq(double px,
double py)
Returns the square of the distance from a point to this line segment. 
static double 
ptSegDistSq(double x1,
double y1,
double x2,
double y2,
double px,
double py)
Returns the square of the distance from a point to a line segment. 
double 
ptSegDistSq(Point2D pt)
Returns the square of the distance from a Point2D to
this line segment. 
int 
relativeCCW(double px,
double py)
Returns an indicator of where the specified point (px,py) lies with respect to this line segment. 
static int 
relativeCCW(double x1,
double y1,
double x2,
double y2,
double px,
double py)
Returns an indicator of where the specified point (px,py) lies with respect to the line segment from
(x1,y1) to (x2,y2) . 
int 
relativeCCW(Point2D p)
Returns an indicator of where the specified Point2D
lies with respect to this line segment. 
abstract void 
setLine(double x1,
double y1,
double x2,
double y2)
Sets the location of the end points of this Line2D to
the specified double coordinates. 
void 
setLine(Line2D l)
Sets the location of the end points of this Line2D to
the same as those end points of the specified Line2D . 
void 
setLine(Point2D p1,
Point2D p2)
Sets the location of the end points of this Line2D to
the specified Point2D coordinates. 
Methods inherited from class java.lang.Object 

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
Methods inherited from interface java.awt.Shape 

getBounds2D 
Constructor Detail 

protected Line2D()
Line2D.Float
,
Line2D.Double
Method Detail 

public abstract double getX1()
Line2D
object.public abstract double getY1()
Line2D
object.public abstract Point2D getP1()
Point2D
of this Line2D
.
Point2D
of this Line2D
.public abstract double getX2()
Line2D
object.public abstract double getY2()
Line2D
object.public abstract Point2D getP2()
Point2D
of this Line2D
.
Point2D
of this Line2D
.public abstract void setLine(double x1, double y1, double x2, double y2)
Line2D
to
the specified double coordinates.
x1
 the X coordinate of the start pointy1
 the Y coordinate of the start pointx2
 the X coordinate of the end pointy2
 the Y coordinate of the end pointpublic void setLine(Point2D p1, Point2D p2)
Line2D
to
the specified Point2D
coordinates.
p1
 the start Point2D
of the line segmentp2
 the end Point2D
of the line segmentpublic void setLine(Line2D l)
Line2D
to
the same as those end points of the specified Line2D
.
l
 the specified Line2D
public static int relativeCCW(double x1, double y1, double x2, double y2, double px, double py)
(px,py)
lies with respect to the line segment from
(x1,y1)
to (x2,y2)
.
The return value can be either 1, 1, or 0 and indicates
in which direction the specified line must pivot around its
first end point, (x1,y1)
, in order to point at the
specified point (px,py)
.
A return value of 1 indicates that the line segment must turn in the direction that takes the positive X axis towards the negative Y axis. In the default coordinate system used by Java 2D, this direction is counterclockwise.
A return value of 1 indicates that the line segment must turn in the direction that takes the positive X axis towards the positive Y axis. In the default coordinate system, this direction is clockwise.
A return value of 0 indicates that the point lies exactly on the line segment. Note that an indicator value of 0 is rare and not useful for determining colinearity because of floating point rounding issues.
If the point is colinear with the line segment, but
not between the end points, then the value will be 1 if the point
lies "beyond (x1,y1)
" or 1 if the point lies
"beyond (x2,y2)
".
x1
 the X coordinate of the start point of the
specified line segmenty1
 the Y coordinate of the start point of the
specified line segmentx2
 the X coordinate of the end point of the
specified line segmenty2
 the Y coordinate of the end point of the
specified line segmentpx
 the X coordinate of the specified point to be
compared with the specified line segmentpy
 the Y coordinate of the specified point to be
compared with the specified line segment
public int relativeCCW(double px, double py)
(px,py)
lies with respect to this line segment.
See the method comments of
relativeCCW(double, double, double, double, double, double)
to interpret the return value.
px
 the X coordinate of the specified point
to be compared with this Line2D
py
 the Y coordinate of the specified point
to be compared with this Line2D
Line2D
relativeCCW(double, double, double, double, double, double)
public int relativeCCW(Point2D p)
Point2D
lies with respect to this line segment.
See the method comments of
relativeCCW(double, double, double, double, double, double)
to interpret the return value.
p
 the specified Point2D
to be compared
with this Line2D
Point2D
with respect to this Line2D
relativeCCW(double, double, double, double, double, double)
public static boolean linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)
(x1,y1)
to
(x2,y2)
intersects the line segment from (x3,y3)
to (x4,y4)
.
x1
 the X coordinate of the start point of the first
specified line segmenty1
 the Y coordinate of the start point of the first
specified line segmentx2
 the X coordinate of the end point of the first
specified line segmenty2
 the Y coordinate of the end point of the first
specified line segmentx3
 the X coordinate of the start point of the second
specified line segmenty3
 the Y coordinate of the start point of the second
specified line segmentx4
 the X coordinate of the end point of the second
specified line segmenty4
 the Y coordinate of the end point of the second
specified line segment
true
if the first specified line segment
and the second specified line segment intersect
each other; false
otherwise.public boolean intersectsLine(double x1, double y1, double x2, double y2)
(x1,y1)
to
(x2,y2)
intersects this line segment.
x1
 the X coordinate of the start point of the
specified line segmenty1
 the Y coordinate of the start point of the
specified line segmentx2
 the X coordinate of the end point of the
specified line segmenty2
 the Y coordinate of the end point of the
specified line segment
false
otherwise.public boolean intersectsLine(Line2D l)
l
 the specified Line2D
true
if this line segment and the specified line
segment intersect each other;
false
otherwise.public static double ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py)
x1
 the X coordinate of the start point of the
specified line segmenty1
 the Y coordinate of the start point of the
specified line segmentx2
 the X coordinate of the end point of the
specified line segmenty2
 the Y coordinate of the end point of the
specified line segmentpx
 the X coordinate of the specified point being
measured against the specified line segmentpy
 the Y coordinate of the specified point being
measured against the specified line segment
ptLineDistSq(double, double, double, double, double, double)
public static double ptSegDist(double x1, double y1, double x2, double y2, double px, double py)
x1
 the X coordinate of the start point of the
specified line segmenty1
 the Y coordinate of the start point of the
specified line segmentx2
 the X coordinate of the end point of the
specified line segmenty2
 the Y coordinate of the end point of the
specified line segmentpx
 the X coordinate of the specified point being
measured against the specified line segmentpy
 the Y coordinate of the specified point being
measured against the specified line segment
ptLineDist(double, double, double, double, double, double)
public double ptSegDistSq(double px, double py)
px
 the X coordinate of the specified point being
measured against this line segmentpy
 the Y coordinate of the specified point being
measured against this line segment
ptLineDistSq(double, double)
public double ptSegDistSq(Point2D pt)
Point2D
to
this line segment.
The distance measured is the distance between the specified
point and the closest point between the current line's end points.
If the specified point intersects the line segment in between the
end points, this method returns 0.0.
pt
 the specified Point2D
being measured against
this line segment.
Point2D
to the current
line segment.ptLineDistSq(Point2D)
public double ptSegDist(double px, double py)
px
 the X coordinate of the specified point being
measured against this line segmentpy
 the Y coordinate of the specified point being
measured against this line segment
ptLineDist(double, double)
public double ptSegDist(Point2D pt)
Point2D
to this line
segment.
The distance measured is the distance between the specified
point and the closest point between the current line's end points.
If the specified point intersects the line segment in between the
end points, this method returns 0.0.
pt
 the specified Point2D
being measured
against this line segment
Point2D
to the current line
segment.ptLineDist(Point2D)
public static double ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py)
x1
 the X coordinate of the start point of the specified liney1
 the Y coordinate of the start point of the specified linex2
 the X coordinate of the end point of the specified liney2
 the Y coordinate of the end point of the specified linepx
 the X coordinate of the specified point being
measured against the specified linepy
 the Y coordinate of the specified point being
measured against the specified line
ptSegDistSq(double, double, double, double, double, double)
public static double ptLineDist(double x1, double y1, double x2, double y2, double px, double py)
x1
 the X coordinate of the start point of the specified liney1
 the Y coordinate of the start point of the specified linex2
 the X coordinate of the end point of the specified liney2
 the Y coordinate of the end point of the specified linepx
 the X coordinate of the specified point being
measured against the specified linepy
 the Y coordinate of the specified point being
measured against the specified line
ptSegDist(double, double, double, double, double, double)
public double ptLineDistSq(double px, double py)
Line2D
. If the specified point
intersects the line, this method returns 0.0.
px
 the X coordinate of the specified point being
measured against this linepy
 the Y coordinate of the specified point being
measured against this line
ptSegDistSq(double, double)
public double ptLineDistSq(Point2D pt)
Point2D
to this line.
The distance measured is the distance between the specified
point and the closest point on the infinitelyextended line
defined by this Line2D
. If the specified point
intersects the line, this method returns 0.0.
pt
 the specified Point2D
being measured
against this line
Point2D
to the current
line.ptSegDistSq(Point2D)
public double ptLineDist(double px, double py)
Line2D
. If the specified point
intersects the line, this method returns 0.0.
px
 the X coordinate of the specified point being
measured against this linepy
 the Y coordinate of the specified point being
measured against this line
ptSegDist(double, double)
public double ptLineDist(Point2D pt)
Point2D
to this line.
The distance measured is the distance between the specified
point and the closest point on the infinitelyextended line
defined by this Line2D
. If the specified point
intersects the line, this method returns 0.0.
pt
 the specified Point2D
being measured
Point2D
to the current line.ptSegDist(Point2D)
public boolean contains(double x, double y)
Line2D
. This method is required to implement the
Shape
interface, but in the case of Line2D
objects it always returns false
since a line contains
no area.
contains
in interface Shape
x
 the X coordinate of the specified point to be testedy
 the Y coordinate of the specified point to be tested
false
because a Line2D
contains
no area.public boolean contains(Point2D p)
Point2D
is inside the boundary of
this Line2D
.
This method is required to implement the Shape
interface,
but in the case of Line2D
objects it always returns
false
since a line contains no area.
contains
in interface Shape
p
 the specified Point2D
to be tested
false
because a Line2D
contains
no area.public boolean intersects(double x, double y, double w, double h)
Shape
intersects the
interior of a specified rectangular area.
The rectangular area is considered to intersect the Shape
if any point is contained in both the interior of the
Shape
and the specified rectangular area.
The Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Shape
intersect, but
Shapes
this method might
return true
even though the rectangular area does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.
intersects
in interface Shape
x
 the X coordinate of the upperleft corner
of the specified rectangular areay
 the Y coordinate of the upperleft corner
of the specified rectangular areaw
 the width of the specified rectangular areah
 the height of the specified rectangular area
true
if the interior of the Shape
and
the interior of the rectangular area intersect, or are
both highly likely to intersect and intersection calculations
would be too expensive to perform; false
otherwise.Area
public boolean intersects(Rectangle2D r)
Shape
intersects the
interior of a specified Rectangle2D
.
The Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Rectangle2D
and the
Shape
intersect, but
Shapes
this method might
return true
even though the Rectangle2D
does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.
intersects
in interface Shape
r
 the specified Rectangle2D
true
if the interior of the Shape
and
the interior of the specified Rectangle2D
intersect, or are both highly likely to intersect and intersection
calculations would be too expensive to perform; false
otherwise.Shape.intersects(double, double, double, double)
public boolean contains(double x, double y, double w, double h)
Line2D
entirely contains
the specified set of rectangular coordinates.
This method is required to implement the Shape
interface,
but in the case of Line2D
objects it always returns
false since a line contains no area.
contains
in interface Shape
x
 the X coordinate of the upperleft corner of the
specified rectangular areay
 the Y coordinate of the upperleft corner of the
specified rectangular areaw
 the width of the specified rectangular areah
 the height of the specified rectangular area
false
because a Line2D
contains
no area.Area
,
Shape.intersects(double, double, double, double)
public boolean contains(Rectangle2D r)
Line2D
entirely contains
the specified Rectangle2D
.
This method is required to implement the Shape
interface,
but in the case of Line2D
objects it always returns
false
since a line contains no area.
contains
in interface Shape
r
 the specified Rectangle2D
to be tested
false
because a Line2D
contains
no area.Shape.contains(double, double, double, double)
public Rectangle getBounds()
Rectangle
that completely encloses the
Shape
. Note that there is no guarantee that the
returned Rectangle
is the smallest bounding box that
encloses the Shape
, only that the Shape
lies entirely within the indicated Rectangle
. The
returned Rectangle
might also fail to completely
enclose the Shape
if the Shape
overflows
the limited range of the integer data type. The
getBounds2D
method generally returns a
tighter bounding box due to its greater flexibility in
representation.
getBounds
in interface Shape
Rectangle
that completely encloses
the Shape
.Shape.getBounds2D()
public PathIterator getPathIterator(AffineTransform at)
Line2D
.
The iterator for this class is not multithreaded safe,
which means that this Line2D
class does not
guarantee that modifications to the geometry of this
Line2D
object do not affect any iterations of that
geometry that are already in process.
getPathIterator
in interface Shape
at
 the specified AffineTransform
PathIterator
that defines the boundary of this
Line2D
.public PathIterator getPathIterator(AffineTransform at, double flatness)
Line2D
.
The iterator for this class is not multithreaded safe,
which means that this Line2D
class does not
guarantee that modifications to the geometry of this
Line2D
object do not affect any iterations of that
geometry that are already in process.
getPathIterator
in interface Shape
at
 the specified AffineTransform
flatness
 the maximum amount that the control points for a
given curve can vary from colinear before a subdivided
curve is replaced by a straight line connecting the
end points. Since a Line2D
object is
always flat, this parameter is ignored.
PathIterator
that defines the boundary of the
flattened Line2D
public Object clone()
clone
in class Object
OutOfMemoryError
 if there is not enough memory.Cloneable

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