Package ucar.nc2.dt.ugrid.geom

Class Polygon2D

java.lang.Object
ucar.nc2.dt.ugrid.geom.Polygon2D
All Implemented Interfaces:
Shape, Serializable
Direct Known Subclasses:
Polygon2D.Double, Polygon2D.Float
public abstract class Polygon2D extends Object implements Shape, Serializable
NOTE: This class should NOT be used in situations involving geographic (lat, lon) data. In such cases, use LatLonPolygon2D instead.
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    Polygon2D.Double
    The concrete Polygon class that stores coordinates internally as doubles.
    static class 
    Polygon2D.Float
    The concrete Polygon class that stores coordinates internally as floats.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected boolean
    _closed
    The flag that says that the polygon has been closed
    protected int
    _coordCount
    The current number of coordinates

  • Constructor Summary

    Constructors
    Constructor
    Description
    Polygon2D()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    area(Polygon2D poly)
    Calculates the double area of the given polygon.
    void
    closePath()
    Close the polygon.
    boolean
    contains(double x, double y)
    Return true if the given point is inside the polygon.
    boolean
    contains(double x1, double y1, double w, double h)
    Return true if the given rectangle is entirely inside the polygon.
    boolean
    contains(Point2D p)
    Return true if the given point is inside the polygon.
    boolean
    contains(Rectangle2D r)
    Return true if the given rectangle is entirely inside the polygon.
    boolean
    contains(GeoRectangle r)
    Return true if the given rectangle is entirely inside the polygon.
    boolean
    contains(Polygon2D p)
    Determines if the given polygon is fully contained within this polygon.

    This method can be fooled by suppling a polygon whose points are completly contained in this polygon but has some intersecting lines.
    abstract Polygon2D
    copy()
    Creates a copy of this polygon with the same coordinates.
    double
    distance(Point2D p)
    Calculates the square of the distance from the point p to the nearest line segment specified by connecting the vertices of this Polygon2D
    double
    distanceSq(Point2D p)
    Calculates the square of the distance from the point p to the nearest line segment specified by connecting the vertices of this Polygon2D
    double
    getArea()
    Calculates the area of this Polygon2D
    Rectangle
    getBounds()
    Get the integer Rectangle bounds of the polygon.
    abstract Rectangle2D
    getBounds2D()
    Get the floating-point bounds of the polygon.
    abstract GeoRectangle
    getBoundsGeo()
    Get the bound box of this poly as a GeoRectangle2D
    abstract Point2D
    getCentroid()
    Calculates the center point of this Polygon2D
    double
    getMaxX()
    Determines the highest x value within the points of this polygon
    double
    getMaxY()
    Determines the highest x value within the points of this polygon
    double
    getMinX()
    Determines the lowest x value within the points of this polygon
    double
    getMinY()
    Determines the lowest y value within the points of this polygon
    PathIterator
    getPathIterator(AffineTransform at)
    Get a path iterator over the object.
    PathIterator
    getPathIterator(AffineTransform at, double flatness)
    Get a path iterator over the object.
    int
    getVertexCount()
    Get the number of vertices
    abstract List<Point2D>
    getVertices()
    Gets a list of Point2D vertices of this polygon.
    abstract double
    getX(int index)
    Get the given X-coordinate
    abstract double[]
    getXCoords()
    Gets a double array containing the X coordinates of the polygon.
    abstract double
    getY(int index)
    Get the given Y-coordinate
    abstract double[]
    getYCoords()
    Gets a double array containing the Y coordinates of the polygon.
    boolean
    intersects(double x1, double y1, double w, double h)
    Test if the polygon is intersected by the given rectangle.
    boolean
    intersects(Point2D p)
    Inclusively checks if the given point is contained within this polygon or intersected by any of its line-segments
    boolean
    intersects(Point2D e0, Point2D e1)
    Checks if the line segment given by the extremes e1 and e2 intersect this polygon, by checking segment to segment intersection for each vector of this polygon.
    boolean
    intersects(Rectangle2D r)
    Test if the polygon is intersected by the given rectangle.
    boolean
    intersects(GeoRectangle r)
    Test if the polygon is intersected by the given GeoRectangle.
    boolean
    intersects(Polygon2D poly)
    Checks if this polygon intersects the given polygon.
    static boolean
    lineIntersectsPoint(double e0x, double e0y, double e1x, double e1y, double p1x, double p1y)
    Checks if the point given by p1x, p1y is intersected by the line segment given by e0, e1
    static boolean
    linesIntersect(double p0x, double p0y, double p1x, double p1y, double p2x, double p2y, double p3x, double p3y)
    Checks if the line segment drawn from p0 to p1 intersects the line drawn from p2 to p3.
    abstract void
    lineTo(double x, double y)
    Add a new vertex to the end of the polygon.
    void
    lineTo(Point2D p)
     
    abstract void
    moveTo(double x, double y)
    Move the start point of the vertex to the given position.
    void
    moveTo(Point2D p)
     
    void
    reset()
    Reset the polygon back to empty.
    abstract void
    setX(int index, double x)
    Set the given X-coordinate.
    abstract void
    setY(int index, double y)
    Set the given Y-coordinate
    String
    toString()
    Return a string representation of the polygon.
    abstract void
    transform(AffineTransform at)
    Transform the polygon with the given transform.
    abstract void
    translate(double x, double y)
    Translate the polygon the given distance.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

    • _coordCount

      protected int _coordCount
      The current number of coordinates

    • _closed

      protected boolean _closed
      The flag that says that the polygon has been closed

  • Constructor Details

    • Polygon2D

      public Polygon2D()

  • Method Details

    • area

      public static double area(Polygon2D poly)
      Calculates the double area of the given polygon.
      Parameters:
      poly - a Polygon2D object
      Returns:
      the double area

    • linesIntersect

      public static boolean linesIntersect(double p0x, double p0y, double p1x, double p1y, double p2x, double p2y, double p3x, double p3y)
      Checks if the line segment drawn from p0 to p1 intersects the line drawn from p2 to p3. This is an optimized variation of Line2D.linesIntersect(double, double, double, double, double, double, double, double)
      Parameters:
      p0x - the first points x value
      p0y - the first points y value
      p1x - the second points x value
      p1y - the second point's y value
      p2x - the third point's x value
      p2y - the third point's y value
      p3x - the fourth point's x value
      p3y - the fourth point's y value
      Returns:
      true if the lines created from the given points intersect, otherwise false

    • lineIntersectsPoint

      public static boolean lineIntersectsPoint(double e0x, double e0y, double e1x, double e1y, double p1x, double p1y)
      Checks if the point given by p1x, p1y is intersected by the line segment given by e0, e1
      Parameters:
      e0x - the line segment's first endpoint's x value
      e0y - the line segment's first endpoint's y value
      e1x - the line segment's second endpoint's x value
      e1y - the line segment's second endpoint's y value
      p1x - the point's x value
      p1y - the point's y value
      Returns:
      true if the point is intersected by the given line segment, otherwise false

    • closePath

      public void closePath()
      Close the polygon. No further segments can be added. If this method not called, then the path iterators will treat the polygon as thought it were closed, and implicitly join the most recently added vertex to the first one. However, this method should generally be called, as if the last vertex is the same as the first vertex, then it merges them.

    • contains

      public boolean contains(double x, double y)
      Return true if the given point is inside the polygon. This method uses a straight-forward algorithm, where a point is taken to be inside the polygon if a horizontal line extended from the point to infinity intersects an odd number of segments.
      Specified by:
      contains in interface Shape

    • contains

      public boolean contains(Point2D p)
      Return true if the given point is inside the polygon.
      Specified by:
      contains in interface Shape

    • contains

      public boolean contains(Rectangle2D r)
      Return true if the given rectangle is entirely inside the polygon. (Currently, this algorithm can be fooled by supplying a rectangle that has all four corners inside the polygon, but which intersects some edges.)
      Specified by:
      contains in interface Shape

    • contains

      public boolean contains(GeoRectangle r)
      Return true if the given rectangle is entirely inside the polygon. (Currently, this algorithm can be fooled by supplying a rectangle that has all four corners inside the polygon, but which intersects some edges.)

    • contains

      public boolean contains(Polygon2D p)
      Determines if the given polygon is fully contained within this polygon.

      This method can be fooled by suppling a polygon whose points are completly contained in this polygon but has some intersecting lines. In this instance, although the polygons intersect the given polygon is not "wholely" contained within this polygon. This method would still return true.
      Parameters:
      p - a Polygon2D object
      Returns:
      true if all the points of the given polygon are contained within this Polygon2D, otherwise false

    • copy

      public abstract Polygon2D copy()
      Creates a copy of this polygon with the same coordinates. The original polygon remains unchanged.
      Returns:
      a copy of the this polygon

    • contains

      public boolean contains(double x1, double y1, double w, double h)
      Return true if the given rectangle is entirely inside the polygon. (Currently, this algorithm can be fooled by supplying a rectangle that has all four corners inside the polygon, but which intersects some edges.)
      Specified by:
      contains in interface Shape

    • getArea

      public double getArea()
      Calculates the area of this Polygon2D
      Returns:
      the double area of this polygon

    • getBounds

      public Rectangle getBounds()
      Get the integer Rectangle bounds of the polygon.
      Specified by:
      getBounds in interface Shape

    • getBounds2D

      public abstract Rectangle2D getBounds2D()
      Get the floating-point bounds of the polygon.
      Specified by:
      getBounds2D in interface Shape

    • getBoundsGeo

      public abstract GeoRectangle getBoundsGeo()
      Get the bound box of this poly as a GeoRectangle2D

    • getCentroid

      public abstract Point2D getCentroid()
      Calculates the center point of this Polygon2D
      Returns:
      the center point of this Polygon2D

    • distanceSq

      public double distanceSq(Point2D p)
      Calculates the square of the distance from the point p to the nearest line segment specified by connecting the vertices of this Polygon2D
      Parameters:
      p - a Point2D
      Returns:
      the square of the distance from the given point to this Polygon2D

    • distance

      public double distance(Point2D p)
      Calculates the square of the distance from the point p to the nearest line segment specified by connecting the vertices of this Polygon2D
      Parameters:
      p - a Point2D
      Returns:
      the square of the distance from the given point to this Polygon2D

    • getXCoords

      public abstract double[] getXCoords()
      Gets a double array containing the X coordinates of the polygon.
      Returns:
      the X coordinates

    • getYCoords

      public abstract double[] getYCoords()
      Gets a double array containing the Y coordinates of the polygon.
      Returns:
      the Y coordinates

    • getVertices

      public abstract List<Point2D> getVertices()
      Gets a list of Point2D vertices of this polygon.
      Returns:
      a List{Point2D} of vertices

    • getMinX

      public double getMinX()
      Determines the lowest x value within the points of this polygon
      Returns:
      the lowest x value

    • getMinY

      public double getMinY()
      Determines the lowest y value within the points of this polygon
      Returns:
      the lowest y value

    • getMaxX

      public double getMaxX()
      Determines the highest x value within the points of this polygon
      Returns:
      the highest x value

    • getMaxY

      public double getMaxY()
      Determines the highest x value within the points of this polygon
      Returns:
      the highest x value

    • getPathIterator

      public PathIterator getPathIterator(AffineTransform at, double flatness)
      Get a path iterator over the object.
      Specified by:
      getPathIterator in interface Shape

    • getPathIterator

      public PathIterator getPathIterator(AffineTransform at)
      Get a path iterator over the object.
      Specified by:
      getPathIterator in interface Shape

    • getVertexCount

      public int getVertexCount()
      Get the number of vertices

    • getX

      public abstract double getX(int index)
      Get the given X-coordinate
      Throws:
      IndexOutOfBoundsException - The index is out of bounds.

    • getY

      public abstract double getY(int index)
      Get the given Y-coordinate
      Throws:
      IndexOutOfBoundsException - The index is out of bounds.

    • intersects

      public boolean intersects(Point2D e0, Point2D e1)
      Checks if the line segment given by the extremes e1 and e2 intersect this polygon, by checking segment to segment intersection for each vector of this polygon. [TPL]

    • intersects

      public boolean intersects(Polygon2D poly)
      Checks if this polygon intersects the given polygon. This algorithm uses the 2D Polygon-Polygon Intersection test as proposed in the webaddress below
      Returns:
      true if there is an intersection, otherwise false
      See Also:

    • intersects

      public boolean intersects(Rectangle2D r)
      Test if the polygon is intersected by the given rectangle. (Currently, this algorithm can be fooled by supplying a rectangle that has no corners inside the polygon, and does not contain any vertex of the polygon, but which intersects some edges.)
      Specified by:
      intersects in interface Shape

    • intersects

      public boolean intersects(GeoRectangle r)
      Test if the polygon is intersected by the given GeoRectangle. (Currently, this algorithm can be fooled by supplying a rectangle that has no corners inside the polygon, and does not contain any vertex of the polygon, but which intersects some edges.)

    • intersects

      public boolean intersects(double x1, double y1, double w, double h)
      Test if the polygon is intersected by the given rectangle.
      Specified by:
      intersects in interface Shape

    • intersects

      public boolean intersects(Point2D p)
      Inclusively checks if the given point is contained within this polygon or intersected by any of its line-segments
      Parameters:
      p - a Point2D
      Returns:
      true if the given point is intersected by this Polygon2D, otherwise false

    • lineTo

      public void lineTo(Point2D p)

    • lineTo

      public abstract void lineTo(double x, double y)
      Add a new vertex to the end of the polygon. Throw an exception of the polygon has already been closed.

    • moveTo

      public void moveTo(Point2D p)

    • moveTo

      public abstract void moveTo(double x, double y)
      Move the start point of the vertex to the given position. Throw an exception if the line already contains any vertices.

    • reset

      public void reset()
      Reset the polygon back to empty.

    • setX

      public abstract void setX(int index, double x)
      Set the given X-coordinate.
      Throws:
      IndexOutOfBoundsException - The index is out of bounds.

    • setY

      public abstract void setY(int index, double y)
      Set the given Y-coordinate
      Throws:
      IndexOutOfBoundsException - The index is out of bounds.

    • transform

      public abstract void transform(AffineTransform at)
      Transform the polygon with the given transform.

    • translate

      public abstract void translate(double x, double y)
      Translate the polygon the given distance.

    • toString

      public String toString()
      Return a string representation of the polygon.
      Overrides:
      toString in class Object