Point.java   [plain text]


/* Copyright (C) 1999, 2002  Free Software Foundation

This file is part of GNU Classpath.

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permission to link this library with independent modules to produce an
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package java.awt;
import java.awt.geom.Point2D;

/* Written using "Java Class Libraries", 2nd edition, plus online
 * API docs for JDK 1.2 beta from http://www.javasoft.com.
 * Status:  Believed complete and correct, except that neither toString
 * nor hashCode have been compared with JDK output.
 */

/**
 * This class represents a point on the screen using cartesian coordinates.
 *
 * @author Per Bothner <bothner@cygnus.com>
 * @author Aaron M. Renn (arenn@urbanophile.com)
 * @date February 8, 1999.
 */
public class Point extends Point2D implements java.io.Serializable
{
  /**
   * @serial The X coordinate of the point.
   */
  public int x;

  /**
   * @serial The Y coordinate of the point.
   */
  public int y;

  /**
   * Initializes a new instance of <code>Point</code> representing the
   * coordiates (0,0).
   */
  public Point () { }

  /**
   * Initializes a new instance of <code>Point</code> with coordinates
   * identical to the coordinates of the specified points.
   *
   * @param point The point to copy the coordinates from.
   */
  public Point (Point p) { this.x = p.x;  this.y = p.y; }

  /**
   * Initializes a new instance of <code>Point</code> with the specified
   * coordinates.
   *
   * @param x The X coordinate of this point.
   * @param y The Y coordinate of this point.
   */
  public Point (int x, int y) { this.x = x;  this.y = y; }

  /**
   * Tests whether or not this object is equal to the specified object.
   * This will be true if and only if the specified objectj:
   * <p>
   * <ul>
   * <li>Is not <code>null</code>.
   * <li>Is an instance of <code>Point</code>.
   * <li>Has X and Y coordinates equal to this object's.
   * </ul>
   *
   * @param obj The object to test against for equality.
   *
   * @return <code>true</code> if the specified object is equal to this
   * object, <code>false</code> otherwise.
  */
  public boolean equals (Object obj)
  {
    if (! (obj instanceof Point))
      return false;
    Point p = (Point) obj;
    return this.x == p.x && this.y == p.y;
  }

  /**
   * Returns a hash value for this point.
   *
   * @param A hash value for this point.
   */
  public int hashCode () { return x ^ y; }

  /**
   * Returns the location of this object as a point.  A pretty useless
   * method.  It is included to mimic the <code>getLocation</code> method
   * in component.
   *
   * @return This point.
   */
  public Point getLocation () { return new Point(this); }

  /**
   * Sets this object's coordinates to the specified values.  This method
   * is identical to the <code>setLocation(int, int)</code> method.
   *
   * @param x The new X coordinate.
   * @param y The new Y coordinate.
   */
  public void move (int x, int y) { this.x = x;  this.y = y; }

  /**
   * Sets this object's coordinates to the specified values.  This method
   * is identical to the <code>move()</code> method.
   *
   * @param x The new X coordinate.
   * @param y The new Y coordinate.
   */
  public void setLocation (int x, int y) { this.x = x;  this.y = y; }

  /**
   * Sets this object's coordinates to match those of the specified point.
   *
   * @param point The point to copy the coordinates from.
   */
  public void setLocation (Point pt) { this.x = pt.x;  this.y = pt.y; }

  /**
   * Changes the coordinates of this point such that the specified 
   * <code>dx</code> parameter is added to the existing X coordinate and
   * <code>dy</code> is added to the existing Y coordinate.
   *
   * @param dx The amount to add to the X coordinate.
   * @param dy The amount to add to the Y coordinate.
   */
  public void translate (int x, int y) { this.x += x;  this.y += y; }

  /**
   * Returns a string representation of this object.
   *
   * @return A string representation of this object.
   */
  public String toString ()
  {
    return getClass().getName() + "[x:"+x+",y:"+y+']';
  }

  public double getX() { return x; }
  public double getY() { return y; }

  public void setLocation (double x, double y)
  { this.x = (int) x;  this.y = (int) y; }

}