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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 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: */ 246: public String toString() 247: { 248: return getClass().getName() + "[x=" + x + ",y=" + y + ']'; 249: } 250: } // class Point