math.geom2d.polygon
Class SimplePolygon2D

java.lang.Object
  math.geom2d.polygon.SimplePolygon2D

All Implemented Interfaces:

Serializable, CirculinearDomain2D, CirculinearShape2D, Domain2D, Polygon2D, Shape2D

public class SimplePolygon2D
extends Object
implements Polygon2D

Represent a polygonal domain whose boundary is a single closed polyline.

See Also:

Serialized Form

Field Summary

protected ArrayList<Point2D>

points The inner ordered list of vertices.

Fields inherited from interface math.geom2d.Shape2D

ACCURACY

Constructor Summary

SimplePolygon2D()
Empty constructor: no vertex.

SimplePolygon2D(Collection<? extends Point2D> points)

SimplePolygon2D(double[] xcoords, double[] ycoords)
Constructor from two arrays, one for each coordinate.

SimplePolygon2D(Point2D[] tab)
Constructor from an array of points

Method Summary

void	addPoint(Point2D point) Deprecated. replaced by addVertex() (0.7.1)
void	addVertex(Point2D point) Adds a point as the last vertex.
void	clearPoints() Deprecated. use clearVertices instead
void	clearVertices() Removes all the vertices of the polygon.
Domain2D	clip(Box2D box) Returns the shape formed by the polygon clipped by the given box.
SimplePolygon2D	clone()
SimplePolygon2D	complement() Returns the polygon created by reversing the order of the vertices.
boolean	contains(double x, double y) Returns true if the point (x, y) lies inside the polygon, with precision given by Shape2D.ACCURACY.
boolean	contains(Point2D p) Return true if the point p lies inside the polygon, with precision given by Shape2D.ACCURACY.
static SimplePolygon2D	create(Collection<? extends Point2D> points) Static factory for creating a new SimplePolygon2D from a collection of points.
static SimplePolygon2D	create(Point2D[] points) Static factory for creating a new SimplePolygon2D from an array of points.
void	draw(Graphics2D g2) Draw the shape on the given graphics.
boolean	equals(Object obj) Tests if the two polygons are equal.
void	fill(Graphics2D g) Fills the interior of the domain, using the Graphics current Paint.
double	getArea() Computes area of the polygon, by returning the absolute value of the signed area.
CirculinearBoundarySet2D<LinearRing2D>	getBoundary() Returns a set of one LinearRing2D, which encloses the polygon.
Box2D	getBoundingBox() Returns the bounding box of the polygon.
CirculinearDomain2D	getBuffer(double dist) Computes the buffer of the shape, formed by the set of points located at a distance from the shape that is lower or equal to d.
Point2D	getCentroid() Computes the centroid (center of mass) of the polygon.
double	getDistance(double x, double y) Returns the distance of the point to the polygon.
double	getDistance(Point2D p) Returns the distance of the point to the polygon.
int	getEdgeNumber() Returns the number of edges.
Collection<LineSegment2D>	getEdges() Returns the set of edges, as a collection of LineSegment2D.
GeneralPath	getGeneralPath() Returns a general path iterator.
Collection<LinearRing2D>	getRings() Returns the set of rings comprising the boundary of this polygon.
double	getSignedArea() Computes the signed area of the polygon.
double	getSignedDistance(double x, double y) Returns the signed distance of the shape to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape.
double	getSignedDistance(Point2D p) Returns the signed distance of the shape to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape.
Point2D	getVertex(int i) Returns the i-th vertex of the polygon.
int	getVertexNumber() Returns the number of vertices of the polygon.
Collection<Point2D>	getVertices() Returns the points of the polygon.
int	getWindingNumber(double x, double y) Computes the winding number of the polygon.
boolean	isBounded() Returns true if polygon is oriented counter-clockwise, false otherwise.
boolean	isEmpty() Returns true if the shape does not contain any point.
void	removePoint(Point2D point) Deprecated. replaced by removeVertex() (0.7.1)
void	removeVertex(Point2D point) Removes a vertex of the polygon.
void	setVertex(int index, Point2D position) Changes the position of the i-th vertex.
SimplePolygon2D	transform(AffineTransform2D trans) Returns the new Polygon created by an affine transform of this polygon.
CirculinearDomain2D	transform(CircleInversion2D inv) Transforms the shape by a circle inversion.

Methods inherited from class java.lang.Object

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

Field Detail

points

protected ArrayList<Point2D> points

The inner ordered list of vertices. The last point is connected to the first one.

Constructor Detail

SimplePolygon2D

public SimplePolygon2D()

Empty constructor: no vertex.

SimplePolygon2D

public SimplePolygon2D(Point2D[] tab)

Constructor from an array of points

Parameters:

tab - the vertices stored in an array of Point2D

SimplePolygon2D

public SimplePolygon2D(double[] xcoords,
                       double[] ycoords)

Constructor from two arrays, one for each coordinate.

Parameters:

xcoords - the x coordinate of each vertex

ycoords - the y coordinate of each vertex

SimplePolygon2D

public SimplePolygon2D(Collection<? extends Point2D> points)

Method Detail

create

public static SimplePolygon2D create(Collection<? extends Point2D> points)

Static factory for creating a new SimplePolygon2D from a collection of points.

Since:

0.8.1

create

public static SimplePolygon2D create(Point2D[] points)

Static factory for creating a new SimplePolygon2D from an array of points.

Since:

0.8.1

addVertex

public void addVertex(Point2D point)

Adds a point as the last vertex.

removeVertex

public void removeVertex(Point2D point)

Removes a vertex of the polygon.

Parameters:

point - the vertex to be removed.

addPoint

@Deprecated
public void addPoint(Point2D point)

Deprecated. replaced by addVertex() (0.7.1)

Adds a point as the last vertex.

removePoint

@Deprecated
public void removePoint(Point2D point)

Deprecated. replaced by removeVertex() (0.7.1)

Removes a vertex of the polygon.

Parameters:

point - the vertex to be removed.

getArea

public double getArea()

Computes area of the polygon, by returning the absolute value of the signed area.

getSignedArea

public double getSignedArea()

Computes the signed area of the polygon. Algorithm is taken from page: http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/. Signed are is positive if polygon is oriented counter-clockwise, and negative otherwise. Result is wrong if polygon is self-intersecting.

Returns:

the signed area of the polygon.

getCentroid

public Point2D getCentroid()

Computes the centroid (center of mass) of the polygon. Algorithm is taken from page: http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/.

Returns:

the centroid of the polygon

getWindingNumber

public int getWindingNumber(double x,
                            double y)

Computes the winding number of the polygon. Algorithm adapted from http://www.geometryalgorithms.com/Archive/algorithm_0103/algorithm_0103.htm

Parameters:

x - the x-coordinate of the point

y - the y-coordinate of the point

Returns:

the number of windings of the curve around the point

clearPoints

@Deprecated
public void clearPoints()

Deprecated. use clearVertices instead

Removes all the vertices of the polygon.

clearVertices

public void clearVertices()

Removes all the vertices of the polygon.

setVertex

public void setVertex(int index,
                      Point2D position)

Changes the position of the i-th vertex.

getVertices

public Collection<Point2D> getVertices()

Returns the points of the polygon. The result is a pointer to the inner collection of vertices.

Specified by:

getVertices in interface Polygon2D

getVertex

public Point2D getVertex(int i)

Returns the i-th vertex of the polygon.

Specified by:

getVertex in interface Polygon2D

Parameters:

i - index of the vertex, between 0 and the number of vertices

getVertexNumber

public int getVertexNumber()

Returns the number of vertices of the polygon.

Specified by:

getVertexNumber in interface Polygon2D

Since:

0.6.3

getEdges

public Collection<LineSegment2D> getEdges()

Returns the set of edges, as a collection of LineSegment2D.

Specified by:

getEdges in interface Polygon2D

getEdgeNumber

public int getEdgeNumber()

Returns the number of edges. For a simple polygon, this equals the number of vertices.

Specified by:

getEdgeNumber in interface Polygon2D

getRings

public Collection<LinearRing2D> getRings()

Description copied from interface: Polygon2D

Returns the set of rings comprising the boundary of this polygon.

Specified by:

getRings in interface Polygon2D

Returns:

the set of boundary rings.

transform

public CirculinearDomain2D transform(CircleInversion2D inv)

Description copied from interface: CirculinearShape2D

Transforms the shape by a circle inversion. The result is still an instance a CirculinearShape2D.

Specified by:

transform in interface CirculinearDomain2D

Specified by:

transform in interface CirculinearShape2D

Parameters:

inv - the circle inversion

Returns:

the transformed shape

getBuffer

public CirculinearDomain2D getBuffer(double dist)

Description copied from interface: CirculinearShape2D

Computes the buffer of the shape, formed by the set of points located at a distance from the shape that is lower or equal to d.

Specified by:

getBuffer in interface CirculinearShape2D

Parameters:

dist - the maximal distance between a point of the buffer and the shape

Returns:

the buffer of the shape

getBoundary

public CirculinearBoundarySet2D<LinearRing2D> getBoundary()

Returns a set of one LinearRing2D, which encloses the polygon.

Specified by:

getBoundary in interface CirculinearDomain2D

Specified by:

getBoundary in interface Domain2D

Specified by:

getBoundary in interface Polygon2D

Returns:

the boundary of the domain

complement

public SimplePolygon2D complement()

Returns the polygon created by reversing the order of the vertices.

Specified by:

complement in interface Domain2D

Specified by:

complement in interface Polygon2D

Returns:

the polygon complementary to this

getDistance

public double getDistance(Point2D p)

Returns the distance of the point to the polygon. This is actually the minimal distance computed for each edge if the polygon, or ZERO if the point belong to the polygon.

Specified by:

getDistance in interface Shape2D

getDistance

public double getDistance(double x,
                          double y)

Returns the distance of the point to the polygon. This is actually the minimal distance computed for each edge if the polygon, or ZERO if the point belong to the polygon.

Specified by:

getDistance in interface Shape2D

getSignedDistance

public double getSignedDistance(Point2D p)

Returns the signed distance of the shape to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape. In this case, absolute value of distance is equals to the distance to the border of the shape.

getSignedDistance

public double getSignedDistance(double x,
                                double y)

Returns the signed distance of the shape to the given point: this distance is positive if the point lies outside the shape, and is negative if the point lies inside the shape. In this case, absolute value of distance is equals to the distance to the border of the shape.

clip

public Domain2D clip(Box2D box)

Returns the shape formed by the polygon clipped by the given box.

Specified by:

clip in interface Domain2D

Specified by:

clip in interface Shape2D

Parameters:

box - the clipping box

Returns:

the clipped shape

getBoundingBox

public Box2D getBoundingBox()

Returns the bounding box of the polygon.

Specified by:

getBoundingBox in interface Shape2D

Returns:

the bounding box of the shape.

isBounded

public boolean isBounded()

Returns true if polygon is oriented counter-clockwise, false otherwise.

Specified by:

isBounded in interface Shape2D

isEmpty

public boolean isEmpty()

Description copied from interface: Shape2D

Returns true if the shape does not contain any point. This is the case for example for PointSet2D without any point.

Specified by:

isEmpty in interface Shape2D

Returns:

true if the shape does not contain any point.

transform

public SimplePolygon2D transform(AffineTransform2D trans)

Returns the new Polygon created by an affine transform of this polygon. If the transform is not direct, the order of vertices is reversed.

Specified by:

transform in interface Domain2D

Specified by:

transform in interface Polygon2D

Specified by:

transform in interface Shape2D

Parameters:

trans - an affine transform

Returns:

the transformed shape

contains

public boolean contains(Point2D p)

Return true if the point p lies inside the polygon, with precision given by Shape2D.ACCURACY.

Specified by:

contains in interface Shape2D

contains

public boolean contains(double x,
                        double y)

Returns true if the point (x, y) lies inside the polygon, with precision given by Shape2D.ACCURACY.

Specified by:

contains in interface Shape2D

getGeneralPath

public GeneralPath getGeneralPath()

Returns a general path iterator.

draw

public void draw(Graphics2D g2)

Description copied from interface: Shape2D

Draw the shape on the given graphics. If the shape is empty, nothing is drawn. If the shape is unbounded, an exception is thrown.

Specified by:

draw in interface Domain2D

Specified by:

draw in interface Shape2D

Parameters:

g2 - the Graphics to draw on

fill

public void fill(Graphics2D g)

Description copied from interface: Domain2D

Fills the interior of the domain, using the Graphics current Paint.

Specified by:

fill in interface Domain2D

Parameters:

g - the Graphics to fill on

equals

public boolean equals(Object obj)

Tests if the two polygons are equal. Test first the number of vertices, then the bounding boxes, then if each vertex of the polygon is contained in the vertices array of this polygon.

Overrides:

equals in class Object

clone

public SimplePolygon2D clone()

Overrides:

clone in class Object