1 /* Point.java -- represents a point in 2-D space 2 Copyright (C) 1999, 2002, 2006 Free Software Foundation 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package java.awt; 40 41 import java.awt.geom.Point2D; 42 import java.io.Serializable; 43 44 /** 45 * This class represents a point on the screen using cartesian coordinates. 46 * Remember that in screen coordinates, increasing x values go from left to 47 * right, and increasing y values go from top to bottom. 48 * 49 * <p>There are some public fields; if you mess with them in an inconsistent 50 * manner, it is your own fault when you get invalid results. Also, this 51 * class is not threadsafe. 52 * 53 * @author Per Bothner (bothner@cygnus.com) 54 * @author Aaron M. Renn (arenn@urbanophile.com) 55 * @author Eric Blake (ebb9@email.byu.edu) 56 * @since 1.0 57 * @status updated to 1.4 58 */ 59 public class Point extends Point2D implements Serializable 60 { 61 /** 62 * Compatible with JDK 1.0+. 63 */ 64 private static final long serialVersionUID = -5276940640259749850L; 65 66 /** 67 * The x coordinate. 68 * 69 * @see #getLocation() 70 * @see #move(int, int) 71 * @serial the X coordinate of the point 72 */ 73 public int x; 74 75 /** 76 * The y coordinate. 77 * 78 * @see #getLocation() 79 * @see #move(int, int) 80 * @serial The Y coordinate of the point 81 */ 82 public int y; 83 84 /** 85 * Initializes a new instance of <code>Point</code> representing the 86 * coordinates (0, 0). 87 * 88 * @since 1.1 89 */ Point()90 public Point() 91 { 92 } 93 94 /** 95 * Initializes a new instance of <code>Point</code> with coordinates 96 * identical to the coordinates of the specified point. 97 * 98 * @param p the point to copy the coordinates from 99 * @throws NullPointerException if p is null 100 */ Point(Point p)101 public Point(Point p) 102 { 103 x = p.x; 104 y = p.y; 105 } 106 107 /** 108 * Initializes a new instance of <code>Point</code> with the specified 109 * coordinates. 110 * 111 * @param x the X coordinate 112 * @param y the Y coordinate 113 */ Point(int x, int y)114 public Point(int x, int y) 115 { 116 this.x = x; 117 this.y = y; 118 } 119 120 /** 121 * Get the x coordinate. 122 * 123 * @return the value of x, as a double 124 */ getX()125 public double getX() 126 { 127 return x; 128 } 129 130 /** 131 * Get the y coordinate. 132 * 133 * @return the value of y, as a double 134 */ getY()135 public double getY() 136 { 137 return y; 138 } 139 140 /** 141 * Returns the location of this point. A pretty useless method, as this 142 * is already a point. 143 * 144 * @return a copy of this point 145 * @see #setLocation(Point) 146 * @since 1.1 147 */ getLocation()148 public Point getLocation() 149 { 150 return new Point(x, y); 151 } 152 153 /** 154 * Sets this object's coordinates to match those of the specified point. 155 * 156 * @param p the point to copy the coordinates from 157 * @throws NullPointerException if p is null 158 * @since 1.1 159 */ setLocation(Point p)160 public void setLocation(Point p) 161 { 162 x = p.x; 163 y = p.y; 164 } 165 166 /** 167 * Sets this object's coordinates to the specified values. This method 168 * is identical to the <code>move()</code> method. 169 * 170 * @param x the new X coordinate 171 * @param y the new Y coordinate 172 */ setLocation(int x, int y)173 public void setLocation(int x, int y) 174 { 175 this.x = x; 176 this.y = y; 177 } 178 179 /** 180 * Sets this object's coordinates to the specified values. This method 181 * rounds to the nearest integer coordinates by adding 0.5 and calling 182 * {@link Math#floor(double)}. 183 * 184 * @param x the new X coordinate 185 * @param y the new Y coordinate 186 */ setLocation(double x, double y)187 public void setLocation(double x, double y) 188 { 189 this.x = (int) Math.floor(x + 0.5); 190 this.y = (int) Math.floor(y + 0.5); 191 } 192 193 /** 194 * Sets this object's coordinates to the specified values. This method 195 * is identical to the <code>setLocation(int, int)</code> method. 196 * 197 * @param x the new X coordinate 198 * @param y the new Y coordinate 199 */ move(int x, int y)200 public void move(int x, int y) 201 { 202 this.x = x; 203 this.y = y; 204 } 205 206 /** 207 * Changes the coordinates of this point such that the specified 208 * <code>dx</code> parameter is added to the existing X coordinate and 209 * <code>dy</code> is added to the existing Y coordinate. 210 * 211 * @param dx the amount to add to the X coordinate 212 * @param dy the amount to add to the Y coordinate 213 */ translate(int dx, int dy)214 public void translate(int dx, int dy) 215 { 216 x += dx; 217 y += dy; 218 } 219 220 /** 221 * Tests whether or not this object is equal to the specified object. 222 * This will be true if and only if the specified object is an instance 223 * of Point2D and has the same X and Y coordinates. 224 * 225 * @param obj the object to test against for equality 226 * @return true if the specified object is equal 227 */ equals(Object obj)228 public boolean equals(Object obj) 229 { 230 // NOTE: No special hashCode() method is required for this class, 231 // as this equals() implementation is functionally equivalent to 232 // super.equals(), which does define a proper hashCode(). 233 234 if (! (obj instanceof Point2D)) 235 return false; 236 Point2D p = (Point2D) obj; 237 return x == p.getX() && y == p.getY(); 238 } 239 240 /** 241 * Returns a string representation of this object. The format is: 242 * <code>getClass().getName() + "[x=" + x + ",y=" + y + ']'</code>. 243 * 244 * @return a string representation of this object 245 */ toString()246 public String toString() 247 { 248 return getClass().getName() + "[x=" + x + ",y=" + y + ']'; 249 } 250 } // class Point 251