Source for org.jfree.util.ShapeUtilities

   1: /* ========================================================================
   2:  * JCommon : a free general purpose class library for the Java(tm) platform
   3:  * ========================================================================
   4:  *
   5:  * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
   6:  *
   7:  * Project Info:  http://www.jfree.org/jcommon/index.html
   8:  *
   9:  * This library is free software; you can redistribute it and/or modify it
  10:  * under the terms of the GNU Lesser General Public License as published by
  11:  * the Free Software Foundation; either version 2.1 of the License, or
  12:  * (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but
  15:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  16:  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
  17:  * License for more details.
  18:  *
  19:  * You should have received a copy of the GNU Lesser General Public
  20:  * License along with this library; if not, write to the Free Software
  21:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
  22:  * USA.
  23:  *
  24:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  25:  * in the United States and other countries.]
  26:  *
  27:  * -------------------
  28:  * ShapeUtilities.java
  29:  * -------------------
  30:  * (C)opyright 2003-2008, by Object Refinery Limited and Contributors.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: ShapeUtilities.java,v 1.18 2008/06/02 06:58:28 mungady Exp $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 13-Aug-2003 : Version 1 (DG);
  40:  * 16-Mar-2004 : Moved rotateShape() from RefineryUtilities.java to here (DG);
  41:  * 13-May-2004 : Added new shape creation methods (DG);
  42:  * 30-Sep-2004 : Added createLineRegion() method (DG);
  43:  *               Moved drawRotatedShape() method from RefineryUtilities class
  44:  *               to this class (DG);
  45:  * 04-Oct-2004 : Renamed ShapeUtils --> ShapeUtilities (DG);
  46:  * 26-Oct-2004 : Added a method to test the equality of two Line2D
  47:  *               instances (DG);
  48:  * 10-Nov-2004 : Added new translateShape() and equal(Ellipse2D, Ellipse2D)
  49:  *               methods (DG);
  50:  * 11-Nov-2004 : Renamed translateShape() --> createTranslatedShape() (DG);
  51:  * 07-Jan-2005 : Minor Javadoc fix (DG);
  52:  * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG);
  53:  * 21-Jan-2005 : Modified return type of RectangleAnchor.coordinates()
  54:  *               method (DG);
  55:  * 22-Feb-2005 : Added equality tests for Arc2D and GeneralPath (DG);
  56:  * 16-Mar-2005 : Fixed bug where equal(Shape, Shape) fails for two Polygon
  57:  *               instances (DG);
  58:  * 01-Jun-2008 : Fixed bug in equal(GeneralPath, GeneralPath) method (DG);
  59:  *
  60:  */
  61: 
  62: package org.jfree.util;
  63: 
  64: import java.awt.Graphics2D;
  65: import java.awt.Polygon;
  66: import java.awt.Shape;
  67: import java.awt.geom.AffineTransform;
  68: import java.awt.geom.Arc2D;
  69: import java.awt.geom.Ellipse2D;
  70: import java.awt.geom.GeneralPath;
  71: import java.awt.geom.Line2D;
  72: import java.awt.geom.PathIterator;
  73: import java.awt.geom.Point2D;
  74: import java.awt.geom.Rectangle2D;
  75: import java.util.Arrays;
  76: 
  77: import org.jfree.ui.RectangleAnchor;
  78: 
  79: /**
  80:  * Utility methods for {@link Shape} objects.
  81:  *
  82:  * @author David Gilbert
  83:  */
  84: public class ShapeUtilities {
  85: 
  86:     /**
  87:      * Prevents instantiation.
  88:      */
  89:     private ShapeUtilities() {
  90:     }
  91: 
  92:     /**
  93:      * Returns a clone of the specified shape, or <code>null</code>.  At the
  94:      * current time, this method supports cloning for instances of
  95:      * <code>Line2D</code>, <code>RectangularShape</code>, <code>Area</code>
  96:      * and <code>GeneralPath</code>.
  97:      * <p>
  98:      * <code>RectangularShape</code> includes <code>Arc2D</code>,
  99:      * <code>Ellipse2D</code>, <code>Rectangle2D</code>,
 100:      * <code>RoundRectangle2D</code>.
 101:      *
 102:      * @param shape  the shape to clone (<code>null</code> permitted,
 103:      *               returns <code>null</code>).
 104:      *
 105:      * @return A clone or <code>null</code>.
 106:      */
 107:     public static Shape clone(final Shape shape) {
 108:         if (shape instanceof Cloneable) {
 109:             try {
 110:                 return (Shape) ObjectUtilities.clone(shape);
 111:             }
 112:             catch (CloneNotSupportedException cnse) {
 113:             }
 114:         }
 115:         final Shape result = null;
 116:         return result;
 117:     }
 118: 
 119:     /**
 120:      * Tests two shapes for equality.  If both shapes are <code>null</code>,
 121:      * this method will return <code>true</code>.
 122:      * <p>
 123:      * In the current implementation, the following shapes are supported:
 124:      * <code>Ellipse2D</code>, <code>Line2D</code> and <code>Rectangle2D</code>
 125:      * (implicit).
 126:      *
 127:      * @param s1  the first shape (<code>null</code> permitted).
 128:      * @param s2  the second shape (<code>null</code> permitted).
 129:      *
 130:      * @return A boolean.
 131:      */
 132:     public static boolean equal(final Shape s1, final Shape s2) {
 133:         if (s1 instanceof Line2D && s2 instanceof Line2D) {
 134:             return equal((Line2D) s1, (Line2D) s2);
 135:         }
 136:         else if (s1 instanceof Ellipse2D && s2 instanceof Ellipse2D) {
 137:             return equal((Ellipse2D) s1, (Ellipse2D) s2);
 138:         }
 139:         else if (s1 instanceof Arc2D && s2 instanceof Arc2D) {
 140:             return equal((Arc2D) s1, (Arc2D) s2);
 141:         }
 142:         else if (s1 instanceof Polygon && s2 instanceof Polygon) {
 143:             return equal((Polygon) s1, (Polygon) s2);
 144:         }
 145:         else if (s1 instanceof GeneralPath && s2 instanceof GeneralPath) {
 146:             return equal((GeneralPath) s1, (GeneralPath) s2);
 147:         }
 148:         else {
 149:             // this will handle Rectangle2D...
 150:             return ObjectUtilities.equal(s1, s2);
 151:         }
 152:     }
 153: 
 154:     /**
 155:      * Compares two lines are returns <code>true</code> if they are equal or
 156:      * both <code>null</code>.
 157:      *
 158:      * @param l1  the first line (<code>null</code> permitted).
 159:      * @param l2  the second line (<code>null</code> permitted).
 160:      *
 161:      * @return A boolean.
 162:      */
 163:     public static boolean equal(final Line2D l1, final Line2D l2) {
 164:         if (l1 == null) {
 165:             return (l2 == null);
 166:         }
 167:         if (l2 == null) {
 168:             return false;
 169:         }
 170:         if (!l1.getP1().equals(l2.getP1())) {
 171:             return false;
 172:         }
 173:         if (!l1.getP2().equals(l2.getP2())) {
 174:             return false;
 175:         }
 176:         return true;
 177:     }
 178: 
 179:     /**
 180:      * Compares two ellipses and returns <code>true</code> if they are equal or
 181:      * both <code>null</code>.
 182:      *
 183:      * @param e1  the first ellipse (<code>null</code> permitted).
 184:      * @param e2  the second ellipse (<code>null</code> permitted).
 185:      *
 186:      * @return A boolean.
 187:      */
 188:     public static boolean equal(final Ellipse2D e1, final Ellipse2D e2) {
 189:         if (e1 == null) {
 190:             return (e2 == null);
 191:         }
 192:         if (e2 == null) {
 193:             return false;
 194:         }
 195:         if (!e1.getFrame().equals(e2.getFrame())) {
 196:             return false;
 197:         }
 198:         return true;
 199:     }
 200: 
 201:     /**
 202:      * Compares two arcs and returns <code>true</code> if they are equal or
 203:      * both <code>null</code>.
 204:      *
 205:      * @param a1  the first arc (<code>null</code> permitted).
 206:      * @param a2  the second arc (<code>null</code> permitted).
 207:      *
 208:      * @return A boolean.
 209:      */
 210:     public static boolean equal(final Arc2D a1, final Arc2D a2) {
 211:         if (a1 == null) {
 212:             return (a2 == null);
 213:         }
 214:         if (a2 == null) {
 215:             return false;
 216:         }
 217:         if (!a1.getFrame().equals(a2.getFrame())) {
 218:             return false;
 219:         }
 220:         if (a1.getAngleStart() != a2.getAngleStart()) {
 221:             return false;
 222:         }
 223:         if (a1.getAngleExtent() != a2.getAngleExtent()) {
 224:             return false;
 225:         }
 226:         if (a1.getArcType() != a2.getArcType()) {
 227:             return false;
 228:         }
 229:         return true;
 230:     }
 231: 
 232:     /**
 233:      * Tests two polygons for equality.  If both are <code>null</code> this
 234:      * method returns <code>true</code>.
 235:      *
 236:      * @param p1  polygon 1 (<code>null</code> permitted).
 237:      * @param p2  polygon 2 (<code>null</code> permitted).
 238:      *
 239:      * @return A boolean.
 240:      */
 241:     public static boolean equal(final Polygon p1, final Polygon p2) {
 242:         if (p1 == null) {
 243:             return (p2 == null);
 244:         }
 245:         if (p2 == null) {
 246:             return false;
 247:         }
 248:         if (p1.npoints != p2.npoints) {
 249:             return false;
 250:         }
 251:         if (!Arrays.equals(p1.xpoints, p2.xpoints)) {
 252:             return false;
 253:         }
 254:         if (!Arrays.equals(p1.ypoints, p2.ypoints)) {
 255:             return false;
 256:         }
 257:         return true;
 258:     }
 259: 
 260:     /**
 261:      * Tests two polygons for equality.  If both are <code>null</code> this
 262:      * method returns <code>true</code>.
 263:      *
 264:      * @param p1  path 1 (<code>null</code> permitted).
 265:      * @param p2  path 2 (<code>null</code> permitted).
 266:      *
 267:      * @return A boolean.
 268:      */
 269:     public static boolean equal(final GeneralPath p1, final GeneralPath p2) {
 270:         if (p1 == null) {
 271:             return (p2 == null);
 272:         }
 273:         if (p2 == null) {
 274:             return false;
 275:         }
 276:         if (p1.getWindingRule() != p2.getWindingRule()) {
 277:             return false;
 278:         }
 279:         PathIterator iterator1 = p1.getPathIterator(null);
 280:         PathIterator iterator2 = p2.getPathIterator(null);
 281:         double[] d1 = new double[6];
 282:         double[] d2 = new double[6];
 283:         boolean done = iterator1.isDone() && iterator2.isDone();
 284:         while (!done) {
 285:             if (iterator1.isDone() != iterator2.isDone()) {
 286:                 return false;
 287:             }
 288:             int seg1 = iterator1.currentSegment(d1);
 289:             int seg2 = iterator2.currentSegment(d2);
 290:             if (seg1 != seg2) {
 291:                 return false;
 292:             }
 293:             if (!Arrays.equals(d1, d2)) {
 294:                 return false;
 295:             }
 296:             iterator1.next();
 297:             iterator2.next();
 298:             done = iterator1.isDone() && iterator2.isDone();
 299:         }
 300:         return true;
 301:     }
 302: 
 303:     /**
 304:      * Creates and returns a translated shape.
 305:      *
 306:      * @param shape  the shape (<code>null</code> not permitted).
 307:      * @param transX  the x translation (in Java2D space).
 308:      * @param transY  the y translation (in Java2D space).
 309:      *
 310:      * @return The translated shape.
 311:      */
 312:     public static Shape createTranslatedShape(final Shape shape,
 313:                                               final double transX,
 314:                                               final double transY) {
 315:         if (shape == null) {
 316:             throw new IllegalArgumentException("Null 'shape' argument.");
 317:         }
 318:         final AffineTransform transform = AffineTransform.getTranslateInstance(
 319:                 transX, transY);
 320:         return transform.createTransformedShape(shape);
 321:     }
 322: 
 323:     /**
 324:      * Translates a shape to a new location such that the anchor point
 325:      * (relative to the rectangular bounds of the shape) aligns with the
 326:      * specified (x, y) coordinate in Java2D space.
 327:      *
 328:      * @param shape  the shape (<code>null</code> not permitted).
 329:      * @param anchor  the anchor (<code>null</code> not permitted).
 330:      * @param locationX  the x-coordinate (in Java2D space).
 331:      * @param locationY  the y-coordinate (in Java2D space).
 332:      *
 333:      * @return A new and translated shape.
 334:      */
 335:     public static Shape createTranslatedShape(final Shape shape,
 336:                                               final RectangleAnchor anchor,
 337:                                               final double locationX,
 338:                                               final double locationY) {
 339:         if (shape == null) {
 340:             throw new IllegalArgumentException("Null 'shape' argument.");
 341:         }
 342:         if (anchor == null) {
 343:             throw new IllegalArgumentException("Null 'anchor' argument.");
 344:         }
 345:         Point2D anchorPoint = RectangleAnchor.coordinates(
 346:                 shape.getBounds2D(), anchor);
 347:         final AffineTransform transform = AffineTransform.getTranslateInstance(
 348:                 locationX - anchorPoint.getX(), locationY - anchorPoint.getY());
 349:         return transform.createTransformedShape(shape);
 350:     }
 351: 
 352:     /**
 353:      * Rotates a shape about the specified coordinates.
 354:      *
 355:      * @param base  the shape (<code>null</code> permitted, returns
 356:      *              <code>null</code>).
 357:      * @param angle  the angle (in radians).
 358:      * @param x  the x coordinate for the rotation point (in Java2D space).
 359:      * @param y  the y coordinate for the rotation point (in Java2D space).
 360:      *
 361:      * @return the rotated shape.
 362:      */
 363:     public static Shape rotateShape(final Shape base, final double angle,
 364:                                     final float x, final float y) {
 365:         if (base == null) {
 366:             return null;
 367:         }
 368:         final AffineTransform rotate = AffineTransform.getRotateInstance(
 369:                 angle, x, y);
 370:         final Shape result = rotate.createTransformedShape(base);
 371:         return result;
 372:     }
 373: 
 374:     /**
 375:      * Draws a shape with the specified rotation about <code>(x, y)</code>.
 376:      *
 377:      * @param g2  the graphics device (<code>null</code> not permitted).
 378:      * @param shape  the shape (<code>null</code> not permitted).
 379:      * @param angle  the angle (in radians).
 380:      * @param x  the x coordinate for the rotation point.
 381:      * @param y  the y coordinate for the rotation point.
 382:      */
 383:     public static void drawRotatedShape(final Graphics2D g2, final Shape shape,
 384:                                         final double angle,
 385:                                         final float x, final float y) {
 386: 
 387:         final AffineTransform saved = g2.getTransform();
 388:         final AffineTransform rotate = AffineTransform.getRotateInstance(
 389:                 angle, x, y);
 390:         g2.transform(rotate);
 391:         g2.draw(shape);
 392:         g2.setTransform(saved);
 393: 
 394:     }
 395: 
 396:     /** A useful constant used internally. */
 397:     private static final float SQRT2 = (float) Math.pow(2.0, 0.5);
 398: 
 399:     /**
 400:      * Creates a diagonal cross shape.
 401:      *
 402:      * @param l  the length of each 'arm'.
 403:      * @param t  the thickness.
 404:      *
 405:      * @return A diagonal cross shape.
 406:      */
 407:     public static Shape createDiagonalCross(final float l, final float t) {
 408:         final GeneralPath p0 = new GeneralPath();
 409:         p0.moveTo(-l - t, -l + t);
 410:         p0.lineTo(-l + t, -l - t);
 411:         p0.lineTo(0.0f, -t * SQRT2);
 412:         p0.lineTo(l - t, -l - t);
 413:         p0.lineTo(l + t, -l + t);
 414:         p0.lineTo(t * SQRT2, 0.0f);
 415:         p0.lineTo(l + t, l - t);
 416:         p0.lineTo(l - t, l + t);
 417:         p0.lineTo(0.0f, t * SQRT2);
 418:         p0.lineTo(-l + t, l + t);
 419:         p0.lineTo(-l - t, l - t);
 420:         p0.lineTo(-t * SQRT2, 0.0f);
 421:         p0.closePath();
 422:         return p0;
 423:     }
 424: 
 425:     /**
 426:      * Creates a diagonal cross shape.
 427:      *
 428:      * @param l  the length of each 'arm'.
 429:      * @param t  the thickness.
 430:      *
 431:      * @return A diagonal cross shape.
 432:      */
 433:     public static Shape createRegularCross(final float l, final float t) {
 434:         final GeneralPath p0 = new GeneralPath();
 435:         p0.moveTo(-l, t);
 436:         p0.lineTo(-t, t);
 437:         p0.lineTo(-t, l);
 438:         p0.lineTo(t, l);
 439:         p0.lineTo(t, t);
 440:         p0.lineTo(l, t);
 441:         p0.lineTo(l, -t);
 442:         p0.lineTo(t, -t);
 443:         p0.lineTo(t, -l);
 444:         p0.lineTo(-t, -l);
 445:         p0.lineTo(-t, -t);
 446:         p0.lineTo(-l, -t);
 447:         p0.closePath();
 448:         return p0;
 449:     }
 450: 
 451:     /**
 452:      * Creates a diamond shape.
 453:      *
 454:      * @param s  the size factor (equal to half the height of the diamond).
 455:      *
 456:      * @return A diamond shape.
 457:      */
 458:     public static Shape createDiamond(final float s) {
 459:         final GeneralPath p0 = new GeneralPath();
 460:         p0.moveTo(0.0f, -s);
 461:         p0.lineTo(s, 0.0f);
 462:         p0.lineTo(0.0f, s);
 463:         p0.lineTo(-s, 0.0f);
 464:         p0.closePath();
 465:         return p0;
 466:     }
 467: 
 468:     /**
 469:      * Creates a triangle shape that points upwards.
 470:      *
 471:      * @param s  the size factor (equal to half the height of the triangle).
 472:      *
 473:      * @return A triangle shape.
 474:      */
 475:     public static Shape createUpTriangle(final float s) {
 476:         final GeneralPath p0 = new GeneralPath();
 477:         p0.moveTo(0.0f, -s);
 478:         p0.lineTo(s, s);
 479:         p0.lineTo(-s, s);
 480:         p0.closePath();
 481:         return p0;
 482:     }
 483: 
 484:     /**
 485:      * Creates a triangle shape that points downwards.
 486:      *
 487:      * @param s  the size factor (equal to half the height of the triangle).
 488:      *
 489:      * @return A triangle shape.
 490:      */
 491:     public static Shape createDownTriangle(final float s) {
 492:         final GeneralPath p0 = new GeneralPath();
 493:         p0.moveTo(0.0f, s);
 494:         p0.lineTo(s, -s);
 495:         p0.lineTo(-s, -s);
 496:         p0.closePath();
 497:         return p0;
 498:     }
 499: 
 500:     /**
 501:      * Creates a region surrounding a line segment by 'widening' the line
 502:      * segment.  A typical use for this method is the creation of a
 503:      * 'clickable' region for a line that is displayed on-screen.
 504:      *
 505:      * @param line  the line (<code>null</code> not permitted).
 506:      * @param width  the width of the region.
 507:      *
 508:      * @return A region that surrounds the line.
 509:      */
 510:     public static Shape createLineRegion(final Line2D line, final float width) {
 511:         final GeneralPath result = new GeneralPath();
 512:         final float x1 = (float) line.getX1();
 513:         final float x2 = (float) line.getX2();
 514:         final float y1 = (float) line.getY1();
 515:         final float y2 = (float) line.getY2();
 516:         if ((x2 - x1) != 0.0) {
 517:             final double theta = Math.atan((y2 - y1) / (x2 - x1));
 518:             final float dx = (float) Math.sin(theta) * width;
 519:             final float dy = (float) Math.cos(theta) * width;
 520:             result.moveTo(x1 - dx, y1 + dy);
 521:             result.lineTo(x1 + dx, y1 - dy);
 522:             result.lineTo(x2 + dx, y2 - dy);
 523:             result.lineTo(x2 - dx, y2 + dy);
 524:             result.closePath();
 525:         }
 526:         else {
 527:             // special case, vertical line
 528:             result.moveTo(x1 - width / 2.0f, y1);
 529:             result.lineTo(x1 + width / 2.0f, y1);
 530:             result.lineTo(x2 + width / 2.0f, y2);
 531:             result.lineTo(x2 - width / 2.0f, y2);
 532:             result.closePath();
 533:         }
 534:         return result;
 535:     }
 536: 
 537:     /**
 538:      * Returns a point based on (x, y) but constrained to be within the bounds
 539:      * of a given rectangle.
 540:      *
 541:      * @param x  the x-coordinate.
 542:      * @param y  the y-coordinate.
 543:      * @param area  the constraining rectangle (<code>null</code> not
 544:      *              permitted).
 545:      *
 546:      * @return A point within the rectangle.
 547:      *
 548:      * @throws NullPointerException if <code>area</code> is <code>null</code>.
 549:      */
 550:     public static Point2D getPointInRectangle(double x, double y,
 551:                                               final Rectangle2D area) {
 552: 
 553:         x = Math.max(area.getMinX(), Math.min(x, area.getMaxX()));
 554:         y = Math.max(area.getMinY(), Math.min(y, area.getMaxY()));
 555:         return new Point2D.Double(x, y);
 556: 
 557:     }
 558: 
 559:     /**
 560:      * Checks, whether the given rectangle1 fully contains rectangle 2
 561:      * (even if rectangle 2 has a height or width of zero!).
 562:      *
 563:      * @param rect1  the first rectangle.
 564:      * @param rect2  the second rectangle.
 565:      *
 566:      * @return A boolean.
 567:      */
 568:     public static boolean contains(final Rectangle2D rect1,
 569:                                    final Rectangle2D rect2) {
 570: 
 571:         final double x0 = rect1.getX();
 572:         final double y0 = rect1.getY();
 573:         final double x = rect2.getX();
 574:         final double y = rect2.getY();
 575:         final double w = rect2.getWidth();
 576:         final double h = rect2.getHeight();
 577: 
 578:         return ((x >= x0) && (y >= y0)
 579:                 && ((x + w) <= (x0 + rect1.getWidth()))
 580:                 && ((y + h) <= (y0 + rect1.getHeight())));
 581: 
 582:     }
 583: 
 584: 
 585:     /**
 586:      * Checks, whether the given rectangle1 fully contains rectangle 2
 587:      * (even if rectangle 2 has a height or width of zero!).
 588:      *
 589:      * @param rect1  the first rectangle.
 590:      * @param rect2  the second rectangle.
 591:      *
 592:      * @return A boolean.
 593:      */
 594:     public static boolean intersects (final Rectangle2D rect1,
 595:                                       final Rectangle2D rect2) {
 596: 
 597:       final double x0 = rect1.getX();
 598:       final double y0 = rect1.getY();
 599: 
 600:       final double x = rect2.getX();
 601:       final double width = rect2.getWidth();
 602:       final double y = rect2.getY();
 603:       final double height = rect2.getHeight();
 604:       return (x + width >= x0 && y + height >= y0 && x <= x0 + rect1.getWidth()
 605:               && y <= y0 + rect1.getHeight());
 606:     }
 607: 
 608: }