396 lines
9.4 KiB
Java
396 lines
9.4 KiB
Java
/* Point2D.java -- generic point in 2-D space
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Copyright (C) 1999, 2000, 2002 Free Software Foundation
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt.geom;
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/**
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* This class implements a generic point in 2D Cartesian space. The storage
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* representation is left up to the subclass. Point includes two useful
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* nested classes, for float and double storage respectively.
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*
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* @author Per Bothner <bothner@cygnus.com>
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* @author Eric Blake <ebb9@email.byu.edu>
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* @since 1.2
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* @status updated to 1.4
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*/
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public abstract class Point2D implements Cloneable
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{
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/**
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* The default constructor.
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*
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* @see Point
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* @see Point2D.Float
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* @see Point2D.Double
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*/
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protected Point2D()
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{
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}
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/**
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* Get the X coordinate, in double precision.
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*
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* @return the x coordinate
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*/
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public abstract double getX();
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/**
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* Get the Y coordinate, in double precision.
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*
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* @return the y coordinate
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*/
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public abstract double getY();
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/**
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* Set the location of this point to the new coordinates. There may be a
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* loss of precision.
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*
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* @param x the new x coordinate
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* @param y the new y coordinate
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*/
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public abstract void setLocation(double x, double y);
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/**
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* Set the location of this point to the new coordinates. There may be a
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* loss of precision.
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*
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* @param p the point to copy
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* @throws NullPointerException if p is null
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*/
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public void setLocation(Point2D p)
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{
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setLocation(p.getX(), p.getY());
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}
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/**
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* Return the square of the distance between two points.
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*
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* @param x1 the x coordinate of point 1
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* @param y1 the y coordinate of point 1
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* @param x2 the x coordinate of point 2
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* @param y2 the y coordinate of point 2
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* @return (x2 - x1)^2 + (y2 - y1)^2
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*/
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public static double distanceSq(double x1, double y1, double x2, double y2)
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{
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x2 -= x1;
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y2 -= y1;
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return x2 * x2 + y2 * y2;
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}
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/**
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* Return the distance between two points.
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*
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* @param x1 the x coordinate of point 1
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* @param y1 the y coordinate of point 1
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* @param x2 the x coordinate of point 2
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* @param y2 the y coordinate of point 2
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* @return the distance from (x1,y1) to (x2,y2)
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*/
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static public double distance(double x1, double y1, double x2, double y2)
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{
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return Math.sqrt(distanceSq(x1, y1, x2, y2));
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}
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/**
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* Return the square of the distance from this point to the given one.
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*
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* @param x the x coordinate of the other point
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* @param y the y coordinate of the other point
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* @return the square of the distance
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*/
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public double distanceSq(double x, double y)
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{
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return distanceSq(getX(), x, getY(), y);
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}
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/**
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* Return the square of the distance from this point to the given one.
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*
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* @param p the other point
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* @return the square of the distance
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* @throws NullPointerException if p is null
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*/
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public double distanceSq(Point2D p)
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{
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return distanceSq(getX(), p.getX(), getY(), p.getY());
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}
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/**
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* Return the distance from this point to the given one.
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*
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* @param x the x coordinate of the other point
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* @param y the y coordinate of the other point
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* @return the distance
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*/
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public double distance(double x, double y)
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{
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return distance(getX(), x, getY(), y);
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}
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/**
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* Return the distance from this point to the given one.
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*
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* @param p the other point
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* @return the distance
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* @throws NullPointerException if p is null
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*/
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public double distance(Point2D p)
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{
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return distance(getX(), p.getX(), getY(), p.getY());
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}
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/**
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* Create a new point of the same run-time type with the same contents as
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* this one.
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*
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* @return the clone
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*/
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public Object clone()
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{
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try
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{
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return super.clone();
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}
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catch (CloneNotSupportedException e)
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{
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throw (Error) new InternalError().initCause(e); // Impossible
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}
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}
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/**
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* Return the hashcode for this point. The formula is not documented, but
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* appears to be the same as:
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* <pre>
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* long l = Double.doubleToLongBits(getY());
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* l = l * 31 ^ Double.doubleToLongBits(getX());
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* return (int) ((l >> 32) ^ l);
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* </pre>
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*
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* @return the hashcode
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*/
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public int hashCode()
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{
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// Talk about a fun time reverse engineering this one!
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long l = java.lang.Double.doubleToLongBits(getY());
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l = l * 31 ^ java.lang.Double.doubleToLongBits(getX());
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return (int) ((l >> 32) ^ l);
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}
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/**
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* Compares two points for equality. This returns true if they have the
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* same coordinates.
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*
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* @param o the point to compare
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* @return true if it is equal
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*/
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public boolean equals(Object o)
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{
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if (! (o instanceof Point2D))
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return false;
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Point2D p = (Point2D) o;
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return getX() == p.getX() && getY() == p.getY();
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}
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/**
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* This class defines a point in <code>double</code> precision.
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*
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* @author Eric Blake <ebb9@email.byu.edu>
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* @since 1.2
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* @status updated to 1.4
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*/
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public static class Double extends Point2D
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{
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/** The X coordinate. */
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public double x;
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/** The Y coordinate. */
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public double y;
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/**
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* Create a new point at (0,0).
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*/
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public Double()
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{
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}
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/**
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* Create a new point at (x,y).
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*
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* @param x the x coordinate
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* @param y the y coordinate
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*/
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public Double(double x, double y)
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{
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this.x = x;
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this.y = y;
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}
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/**
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* Return the x coordinate.
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*
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* @return the x coordinate
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*/
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public double getX()
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{
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return x;
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}
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/**
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* Return the y coordinate.
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*
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* @return the y coordinate
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*/
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public double getY()
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{
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return y;
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}
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/**
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* Sets the location of this point.
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*
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* @param x the new x coordinate
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* @param y the new y coordinate
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*/
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public void setLocation(double x, double y)
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{
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this.x = x;
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this.y = y;
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}
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/**
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* Returns a string representation of this object. The format is:
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* <code>"Point2D.Double[" + x + ", " + y + ']'</code>.
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*
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* @return a string representation of this object
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*/
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public String toString()
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{
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return "Point2D.Double[" + x + ", " + y + ']';
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}
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} // class Double
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/**
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* This class defines a point in <code>float</code> precision.
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*
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* @author Eric Blake <ebb9@email.byu.edu>
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* @since 1.2
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* @status updated to 1.4
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*/
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public static class Float extends Point2D
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{
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/** The X coordinate. */
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public float x;
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/** The Y coordinate. */
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public float y;
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/**
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* Create a new point at (0,0).
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*/
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public Float()
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{
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}
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/**
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* Create a new point at (x,y).
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*
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* @param x the x coordinate
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* @param y the y coordinate
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*/
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public Float(float x, float y)
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{
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this.x = x;
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this.y = y;
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}
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/**
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* Return the x coordinate.
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*
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* @return the x coordinate
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*/
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public double getX()
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{
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return x;
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}
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/**
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* Return the y coordinate.
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*
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* @return the y coordinate
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*/
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public double getY()
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{
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return y;
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}
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/**
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* Sets the location of this point.
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*
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* @param x the new x coordinate
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* @param y the new y coordinate
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*/
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public void setLocation(double x, double y)
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{
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this.x = (float) x;
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this.y = (float) y;
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}
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/**
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* Sets the location of this point.
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*
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* @param x the new x coordinate
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* @param y the new y coordinate
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*/
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public void setLocation(float x, float y)
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{
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this.x = x;
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this.y = y;
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}
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/**
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* Returns a string representation of this object. The format is:
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* <code>"Point2D.Float[" + x + ", " + y + ']'</code>.
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*
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* @return a string representation of this object
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*/
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public String toString()
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{
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return "Point2D.Float[" + x + ", " + y + ']';
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}
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} // class Float
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} // class Point2D
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