jdk/src/share/classes/java/awt/Point.java

/*
 * Copyright 1995-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package java.awt;

import java.awt.geom.Point2D;

/**
 * A point representing a location in {@code (x,y)} coordinate space,
 * specified in integer precision.
 *
 * @author      Sami Shaio
 * @since       1.0
 */
public class Point extends Point2D implements java.io.Serializable {
    /**
     * The X coordinate of this <code>Point</code>.
     * If no X coordinate is set it will default to 0.
     *
     * @serial
     * @see #getLocation()
     * @see #move(int, int)
     * @since 1.0
     */
    public int x;

    /**
     * The Y coordinate of this <code>Point</code>.
     * If no Y coordinate is set it will default to 0.
     *
     * @serial
     * @see #getLocation()
     * @see #move(int, int)
     * @since 1.0
     */
    public int y;

    /*
     * JDK 1.1 serialVersionUID
     */
    private static final long serialVersionUID = -5276940640259749850L;

    /**
     * Constructs and initializes a point at the origin
     * (0,&nbsp;0) of the coordinate space.
     * @since       1.1
     */
    public Point() {
        this(0, 0);
    }

    /**
     * Constructs and initializes a point with the same location as
     * the specified <code>Point</code> object.
     * @param       p a point
     * @since       1.1
     */
    public Point(Point p) {
        this(p.x, p.y);
    }

    /**
     * Constructs and initializes a point at the specified
     * {@code (x,y)} location in the coordinate space.
     * @param x the X coordinate of the newly constructed <code>Point</code>
     * @param y the Y coordinate of the newly constructed <code>Point</code>
     * @since 1.0
     */
    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

    /**
     * {@inheritDoc}
     * @since 1.2
     */
    public double getX() {
        return x;
    }

    /**
     * {@inheritDoc}
     * @since 1.2
     */
    public double getY() {
        return y;
    }

    /**
     * Returns the location of this point.
     * This method is included for completeness, to parallel the
     * <code>getLocation</code> method of <code>Component</code>.
     * @return      a copy of this point, at the same location
     * @see         java.awt.Component#getLocation
     * @see         java.awt.Point#setLocation(java.awt.Point)
     * @see         java.awt.Point#setLocation(int, int)
     * @since       1.1
     */
    public Point getLocation() {
        return new Point(x, y);
    }

    /**
     * Sets the location of the point to the specified location.
     * This method is included for completeness, to parallel the
     * <code>setLocation</code> method of <code>Component</code>.
     * @param       p  a point, the new location for this point
     * @see         java.awt.Component#setLocation(java.awt.Point)
     * @see         java.awt.Point#getLocation
     * @since       1.1
     */
    public void setLocation(Point p) {
        setLocation(p.x, p.y);
    }

    /**
     * Changes the point to have the specified location.
     * <p>
     * This method is included for completeness, to parallel the
     * <code>setLocation</code> method of <code>Component</code>.
     * Its behavior is identical with <code>move(int,&nbsp;int)</code>.
     * @param       x the X coordinate of the new location
     * @param       y the Y coordinate of the new location
     * @see         java.awt.Component#setLocation(int, int)
     * @see         java.awt.Point#getLocation
     * @see         java.awt.Point#move(int, int)
     * @since       1.1
     */
    public void setLocation(int x, int y) {
        move(x, y);
    }

    /**
     * Sets the location of this point to the specified double coordinates.
     * The double values will be rounded to integer values.
     * Any number smaller than <code>Integer.MIN_VALUE</code>
     * will be reset to <code>MIN_VALUE</code>, and any number
     * larger than <code>Integer.MAX_VALUE</code> will be
     * reset to <code>MAX_VALUE</code>.
     *
     * @param x the X coordinate of the new location
     * @param y the Y coordinate of the new location
     * @see #getLocation
     */
    public void setLocation(double x, double y) {
        this.x = (int) Math.floor(x+0.5);
        this.y = (int) Math.floor(y+0.5);
    }

    /**
     * Moves this point to the specified location in the
     * {@code (x,y)} coordinate plane. This method
     * is identical with <code>setLocation(int,&nbsp;int)</code>.
     * @param       x the X coordinate of the new location
     * @param       y the Y coordinate of the new location
     * @see         java.awt.Component#setLocation(int, int)
     */
    public void move(int x, int y) {
        this.x = x;
        this.y = y;
    }

    /**
     * Translates this point, at location {@code (x,y)},
     * by {@code dx} along the {@code x} axis and {@code dy}
     * along the {@code y} axis so that it now represents the point
     * {@code (x+dx,y+dy)}.
     *
     * @param       dx   the distance to move this point
     *                            along the X axis
     * @param       dy    the distance to move this point
     *                            along the Y axis
     */
    public void translate(int dx, int dy) {
        this.x += dx;
        this.y += dy;
    }

    /**
     * Determines whether or not two points are equal. Two instances of
     * <code>Point2D</code> are equal if the values of their
     * <code>x</code> and <code>y</code> member fields, representing
     * their position in the coordinate space, are the same.
     * @param obj an object to be compared with this <code>Point2D</code>
     * @return <code>true</code> if the object to be compared is
     *         an instance of <code>Point2D</code> and has
     *         the same values; <code>false</code> otherwise.
     */
    public boolean equals(Object obj) {
        if (obj instanceof Point) {
            Point pt = (Point)obj;
            return (x == pt.x) && (y == pt.y);
        }
        return super.equals(obj);
    }

    /**
     * Returns a string representation of this point and its location
     * in the {@code (x,y)} coordinate space. This method is
     * intended to be used only for debugging purposes, and the content
     * and format of the returned string may vary between implementations.
     * The returned string may be empty but may not be <code>null</code>.
     *
     * @return  a string representation of this point
     */
    public String toString() {
        return getClass().getName() + "[x=" + x + ",y=" + y + "]";
    }
}