ImageScience 3.0.0

imagescience.shape
Class Polygon

java.lang.Object
  extended by imagescience.shape.Polygon
All Implemented Interfaces:
Shape

public class Polygon
extends java.lang.Object
implements Shape

A polygon in the x-y plane. Although higher-dimensional vertices are accepted, only the x- and y-coordinates of the vertices are actually considered by all methods.


Constructor Summary
Polygon()
          Default constructor.
Polygon(Polygon polygon)
          Copy constructor.
Polygon(java.util.Vector<Point> vertices)
          Constructs a polygon from the given vertices.
 
Method Summary
 double area()
          Returns the area spanned by the polygon.
 Image bitmap(boolean binary)
          Computes a bitmapped version of the shape.
 Bounds bounds()
          Computes the bounding box of the shape.
 boolean contains(double x, double y)
          Indicates the position of a point relative to the polygon.
 boolean contains(Point point)
          Indicates the position of a point relative to the polygon.
 java.awt.geom.GeneralPath contour()
          Returns the contour of the polygon.
 Shape duplicate()
          Duplicates the shape.
 boolean empty()
          Indicates whether the shape is empty.
 boolean equals(Shape shape)
          Indicates whether this object has the same shape as the given object.
 double perimeter()
          Returns the perimeter of the polygon.
 void set(java.util.Vector<Point> vertices)
          Sets the vertices of the polygon to the given vertices.
 void translate(double dx, double dy)
          Translates the polygon over the given distance.
 java.util.Vector<Point> vertices()
          Returns a new Vector object containing the handles of the vertices of the polygon.
 void vertices(java.util.Vector<Point> vertices)
          Sets the vertices of the polygon to the given vertices.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Polygon

public Polygon()
Default constructor. Results in a polygon with no vertices.


Polygon

public Polygon(java.util.Vector<Point> vertices)
Constructs a polygon from the given vertices.

Parameters:
vertices - The vertices that define the polygon. The handles of the Point objects are copied.
Throws:
java.lang.NullPointerException - If vertices or any of its elements is null.

Polygon

public Polygon(Polygon polygon)
Copy constructor.

Parameters:
polygon - The polygon to be copied. All information is copied and no memory is shared with this polygon.
Throws:
java.lang.NullPointerException - If polygon is null.
Method Detail

set

public void set(java.util.Vector<Point> vertices)
Sets the vertices of the polygon to the given vertices.

Parameters:
vertices - The vertices to be copied. The handles of the Point objects are copied.
Throws:
java.lang.NullPointerException - If vertices or any of its elements is null.

vertices

public void vertices(java.util.Vector<Point> vertices)
Sets the vertices of the polygon to the given vertices. Alias of method set(Vector).

Parameters:
vertices - The vertices to be copied. The handles of the Point objects are copied.
Throws:
java.lang.NullPointerException - If vertices or any of its elements is null.

vertices

public java.util.Vector<Point> vertices()
Returns a new Vector object containing the handles of the vertices of the polygon.

Returns:
A new Vector object containing the handles of the vertices of the polygon.

duplicate

public Shape duplicate()
Description copied from interface: Shape
Duplicates the shape.

Specified by:
duplicate in interface Shape
Returns:
A new Shape object that is an exact copy of this object. All information is copied and no memory is shared between this and the returned object.

translate

public void translate(double dx,
                      double dy)
Translates the polygon over the given distance. This is done by translating all the vertices over the given distance.

Parameters:
dx - The distance in the x-dimension over which to translate.
dy - The distance in the y-dimension over which to translate.

perimeter

public double perimeter()
Returns the perimeter of the polygon.

Returns:
The perimeter of the polygon. The perimeter is computed straightforwardly by adding the Euclidean distances between the subsequent vertices, including the distance between the last and the first vertex.

area

public double area()
Returns the area spanned by the polygon.

Returns:
The area of the polygon. The result is correct for all simple polygons, whether convex or concave, but may not be correct for self-intersecting polygons, except for special cases of self-overlapping polyons, where the overlap area is counted twice.

contains

public boolean contains(Point point)
Indicates the position of a point relative to the polygon.

Specified by:
contains in interface Shape
Parameters:
point - The point whose position relative to the polygon is to be tested. The point is treated as a 2D point. That is, only its x- and y-coordinate values are considered.
Returns:
The value contains(point.x,point.y).
Throws:
java.lang.NullPointerException - If point is null.

contains

public boolean contains(double x,
                        double y)
Indicates the position of a point relative to the polygon. The method is an implementation of Algorithm 7 described by K. Hormann and A. Agathos, "The Point in Polygon Problem for Arbitrary Polygons", Computational Geometry - Theory and Applications, vol. 20, no. 3, 2001, pp. 131-144. It is based on the non-zero winding rule.

Parameters:
x - The x-coordinate of the point.
y - The y-coordinate of the point.
Returns:
Value true if the point is on or inside the polygon, or false if it is outside the polygon.

contour

public java.awt.geom.GeneralPath contour()
Returns the contour of the polygon.

Returns:
A new GeneralPath object containing the contour of the polygon. The interior of the returned path is defined by the non-zero winding rule.

bitmap

public Image bitmap(boolean binary)
Description copied from interface: Shape
Computes a bitmapped version of the shape.

Specified by:
bitmap in interface Shape
Parameters:
binary - Determines whether the returned bitmap image is two-valued. If true, image elements whose center positions fall inside the shape are set to 255, and elements whose center positions fall outside the shape are set to 0. If false, additional processing is performed, by which each image element falling partly inside and partly outside the shape is set to 255 times its (approximate) inside-fraction.
Returns:
A new ByteImage object containing a bitmapped version of the shape. The origin of the integer coordinate system of the image corresponds to the position in the shape coordinate system obtained by taking the floor value of the lower bound of the shape in each dimension.

bounds

public Bounds bounds()
Description copied from interface: Shape
Computes the bounding box of the shape.

Specified by:
bounds in interface Shape
Returns:
A new Bounds object containing the bounding box of the shape.

equals

public boolean equals(Shape shape)
Description copied from interface: Shape
Indicates whether this object has the same shape as the given object.

Specified by:
equals in interface Shape
Parameters:
shape - The shape to compare this shape with.
Returns:
Value true if shape is not null, and an instance of the same class as this object, with the exact same shape, or false if this is not the case.

empty

public boolean empty()
Description copied from interface: Shape
Indicates whether the shape is empty.

Specified by:
empty in interface Shape
Returns:
Value true if the shape does not enclose any space, or false if it does.

ImageScience 3.0.0

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