Source for java.awt.geom.RectangularShape

   1: /* RectangularShape.java -- a rectangular frame for several generic shapes
   2:    Copyright (C) 2000, 2002 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.geom;
  40: 
  41: import java.awt.Rectangle;
  42: import java.awt.Shape;
  43: 
  44: /**
  45:  * This class provides a generic framework, and several helper methods, for
  46:  * subclasses which represent geometric objects inside a rectangular frame.
  47:  * This does not specify any geometry except for the bounding box.
  48:  *
  49:  * @author Tom Tromey (tromey@cygnus.com)
  50:  * @author Eric Blake (ebb9@email.byu.edu)
  51:  * @since 1.2
  52:  * @see Arc2D
  53:  * @see Ellipse2D
  54:  * @see Rectangle2D
  55:  * @see RoundRectangle2D
  56:  * @status updated to 1.4
  57:  */
  58: public abstract class RectangularShape implements Shape, Cloneable
  59: {
  60:   /**
  61:    * Default constructor.
  62:    */
  63:   protected RectangularShape()
  64:   {
  65:   }
  66: 
  67:   /**
  68:    * Get the x coordinate of the upper-left corner of the framing rectangle.
  69:    *
  70:    * @return the x coordinate
  71:    */
  72:   public abstract double getX();
  73: 
  74:   /**
  75:    * Get the y coordinate of the upper-left corner of the framing rectangle.
  76:    *
  77:    * @return the y coordinate
  78:    */
  79:   public abstract double getY();
  80: 
  81:   /**
  82:    * Get the width of the framing rectangle.
  83:    *
  84:    * @return the width
  85:    */
  86:   public abstract double getWidth();
  87: 
  88:   /**
  89:    * Get the height of the framing rectangle.
  90:    *
  91:    * @return the height
  92:    */
  93:   public abstract double getHeight();
  94: 
  95:   /**
  96:    * Get the minimum x coordinate in the frame. This is misnamed, or else
  97:    * Sun has a bug, because the implementation returns getX() even when
  98:    * getWidth() is negative.
  99:    *
 100:    * @return the minimum x coordinate
 101:    */
 102:   public double getMinX()
 103:   {
 104:     return getX();
 105:   }
 106: 
 107:   /**
 108:    * Get the minimum y coordinate in the frame. This is misnamed, or else
 109:    * Sun has a bug, because the implementation returns getY() even when
 110:    * getHeight() is negative.
 111:    *
 112:    * @return the minimum y coordinate
 113:    */
 114:   public double getMinY()
 115:   {
 116:     return getY();
 117:   }
 118: 
 119:   /**
 120:    * Get the maximum x coordinate in the frame. This is misnamed, or else
 121:    * Sun has a bug, because the implementation returns getX()+getWidth() even
 122:    * when getWidth() is negative.
 123:    *
 124:    * @return the maximum x coordinate
 125:    */
 126:   public double getMaxX()
 127:   {
 128:     return getX() + getWidth();
 129:   }
 130: 
 131:   /**
 132:    * Get the maximum y coordinate in the frame. This is misnamed, or else
 133:    * Sun has a bug, because the implementation returns getY()+getHeight() even
 134:    * when getHeight() is negative.
 135:    *
 136:    * @return the maximum y coordinate
 137:    */
 138:   public double getMaxY()
 139:   {
 140:     return getY() + getHeight();
 141:   }
 142: 
 143:   /**
 144:    * Return the x coordinate of the center point of the framing rectangle.
 145:    *
 146:    * @return the central x coordinate
 147:    */
 148:   public double getCenterX()
 149:   {
 150:     return getX() + getWidth() / 2;
 151:   }
 152: 
 153:   /**
 154:    * Return the y coordinate of the center point of the framing rectangle.
 155:    *
 156:    * @return the central y coordinate
 157:    */
 158:   public double getCenterY()
 159:   {
 160:     return getY() + getHeight() / 2;
 161:   }
 162: 
 163:   /**
 164:    * Return the frame around this object. Note that this may be a looser
 165:    * bounding box than getBounds2D.
 166:    *
 167:    * @return the frame, in double precision
 168:    * @see #setFrame(double, double, double, double)
 169:    */
 170:   public Rectangle2D getFrame()
 171:   {
 172:     return new Rectangle2D.Double(getX(), getY(), getWidth(), getHeight());
 173:   }
 174: 
 175:   /**
 176:    * Test if the shape is empty, meaning that no points are inside it.
 177:    *
 178:    * @return true if the shape is empty
 179:    */
 180:   public abstract boolean isEmpty();
 181: 
 182:   /**
 183:    * Set the framing rectangle of this shape to the given coordinate and size.
 184:    *
 185:    * @param x the new x coordinate
 186:    * @param y the new y coordinate
 187:    * @param w the new width
 188:    * @param h the new height
 189:    * @see #getFrame()
 190:    */
 191:   public abstract void setFrame(double x, double y, double w, double h);
 192: 
 193:   /**
 194:    * Set the framing rectangle of this shape to the given coordinate and size.
 195:    *
 196:    * @param p the new point
 197:    * @param d the new dimension
 198:    * @throws NullPointerException if p or d is null
 199:    * @see #getFrame()
 200:    */
 201:   public void setFrame(Point2D p, Dimension2D d)
 202:   {
 203:     setFrame(p.getX(), p.getY(), d.getWidth(), d.getHeight());
 204:   }
 205: 
 206:   /**
 207:    * Set the framing rectangle of this shape to the given rectangle.
 208:    *
 209:    * @param r the new framing rectangle
 210:    * @throws NullPointerException if r is null
 211:    * @see #getFrame()
 212:    */
 213:   public void setFrame(Rectangle2D r)
 214:   {
 215:     setFrame(r.getX(), r.getY(), r.getWidth(), r.getHeight());
 216:   }
 217: 
 218:   /**
 219:    * Set the framing rectangle of this shape using two points on a diagonal.
 220:    * The area will be positive.
 221:    *
 222:    * @param x1 the first x coordinate
 223:    * @param y1 the first y coordinate
 224:    * @param x2 the second x coordinate
 225:    * @param y2 the second y coordinate
 226:    */
 227:   public void setFrameFromDiagonal(double x1, double y1, double x2, double y2)
 228:   {
 229:     if (x1 > x2)
 230:       {
 231:     double t = x2;
 232:     x2 = x1;
 233:     x1 = t;
 234:       }
 235:     if (y1 > y2)
 236:       {
 237:     double t = y2;
 238:     y2 = y1;
 239:     y1 = t;
 240:       }
 241:     setFrame(x1, y1, x2 - x1, y2 - y1);
 242:   }
 243: 
 244:   /**
 245:    * Set the framing rectangle of this shape using two points on a diagonal.
 246:    * The area will be positive.
 247:    *
 248:    * @param p1 the first point
 249:    * @param p2 the second point
 250:    * @throws NullPointerException if either point is null
 251:    */
 252:   public void setFrameFromDiagonal(Point2D p1, Point2D p2)
 253:   {
 254:     setFrameFromDiagonal(p1.getX(), p1.getY(), p2.getX(), p2.getY());
 255:   }
 256: 
 257:   /**
 258:    * Set the framing rectangle of this shape using the center of the frame,
 259:    * and one of the four corners. The area will be positive.
 260:    *
 261:    * @param centerX the x coordinate at the center
 262:    * @param centerY the y coordinate at the center
 263:    * @param cornerX the x coordinate at a corner
 264:    * @param cornerY the y coordinate at a corner
 265:    */
 266:   public void setFrameFromCenter(double centerX, double centerY,
 267:                                  double cornerX, double cornerY)
 268:   {
 269:     double halfw = Math.abs(cornerX - centerX);
 270:     double halfh = Math.abs(cornerY - centerY);
 271:     setFrame(centerX - halfw, centerY - halfh, halfw + halfw, halfh + halfh);
 272:   }
 273: 
 274:   /**
 275:    * Set the framing rectangle of this shape using the center of the frame,
 276:    * and one of the four corners. The area will be positive.
 277:    *
 278:    * @param center the center point
 279:    * @param corner a corner point
 280:    * @throws NullPointerException if either point is null
 281:    */
 282:   public void setFrameFromCenter(Point2D center, Point2D corner)
 283:   {
 284:     setFrameFromCenter(center.getX(), center.getY(),
 285:                        corner.getX(), corner.getY());
 286:   }
 287: 
 288:   /**
 289:    * Tests if a point is inside the boundary of the shape.
 290:    *
 291:    * @param p the point to test
 292:    * @return true if the point is inside the shape
 293:    * @throws NullPointerException if p is null
 294:    * @see #contains(double, double)
 295:    */
 296:   public boolean contains(Point2D p)
 297:   {
 298:     return contains(p.getX(), p.getY());
 299:   }
 300: 
 301:   /**
 302:    * Tests if a rectangle and this shape share common internal points.
 303:    *
 304:    * @param r the rectangle to test
 305:    * @return true if the rectangle intersects this shpae
 306:    * @throws NullPointerException if r is null
 307:    * @see #intersects(double, double, double, double)
 308:    */
 309:   public boolean intersects(Rectangle2D r)
 310:   {
 311:     return intersects(r.getX(), r.getY(), r.getWidth(), r.getHeight());
 312:   }
 313: 
 314:   /**
 315:    * Tests if the shape completely contains the given rectangle.
 316:    *
 317:    * @param r the rectangle to test
 318:    * @return true if r is contained in this shape
 319:    * @throws NullPointerException if r is null
 320:    * @see #contains(double, double, double, double)
 321:    */
 322:   public boolean contains(Rectangle2D r)
 323:   {
 324:     return contains(r.getX(), r.getY(), r.getWidth(), r.getHeight());
 325:   }
 326: 
 327:   /**
 328:    * Returns a bounding box for this shape, in integer format. Notice that you
 329:    * may get a tighter bound with getBounds2D.
 330:    *
 331:    * @return a bounding box
 332:    */
 333:   public Rectangle getBounds()
 334:   {
 335:     double x = getX();
 336:     double y = getY();
 337:     double maxx = Math.ceil(x + getWidth());
 338:     double maxy = Math.ceil(y + getHeight());
 339:     x = Math.floor(x);
 340:     y = Math.floor(y);
 341:     return new Rectangle((int) x, (int) y, (int) (maxx - x), (int) (maxy - y));
 342:   }
 343: 
 344:   /**
 345:    * Return an iterator along the shape boundary. If the optional transform
 346:    * is provided, the iterator is transformed accordingly. The path is
 347:    * flattened until all segments differ from the curve by at most the value
 348:    * of the flatness parameter, within the limits of the default interpolation
 349:    * recursion limit of 1024 segments between actual points. Each call
 350:    * returns a new object, independent from others in use. The result is
 351:    * threadsafe if and only if the iterator returned by
 352:    * {@link #getPathIterator(AffineTransform)} is as well.
 353:    *
 354:    * @param at an optional transform to apply to the iterator
 355:    * @param flatness the desired flatness
 356:    * @return a new iterator over the boundary
 357:    * @throws IllegalArgumentException if flatness is invalid
 358:    * @since 1.2
 359:    */
 360:   public PathIterator getPathIterator(AffineTransform at, double flatness)
 361:   {
 362:     return new FlatteningPathIterator(getPathIterator(at), flatness);
 363:   }
 364: 
 365:   /**
 366:    * Create a new shape of the same run-time type with the same contents as
 367:    * this one.
 368:    *
 369:    * @return the clone
 370:    */
 371:   public Object clone()
 372:   {
 373:     try
 374:       {
 375:         return super.clone();
 376:       }
 377:     catch (CloneNotSupportedException e)
 378:       {
 379:         throw (Error) new InternalError().initCause(e); // Impossible
 380:       }
 381:   }
 382: } // class RectangularShape