001    /* ========================================================================
002     * JCommon : a free general purpose class library for the Java(tm) platform
003     * ========================================================================
004     *
005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006     * 
007     * Project Info:  http://www.jfree.org/jcommon/index.html
008     *
009     * This library is free software; you can redistribute it and/or modify it 
010     * under the terms of the GNU Lesser General Public License as published by 
011     * the Free Software Foundation; either version 2.1 of the License, or 
012     * (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but 
015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017     * License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this library; if not, write to the Free Software
021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022     * USA.  
023     *
024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025     * in the United States and other countries.]
026     * 
027     * -------------------
028     * ShapeUtilities.java
029     * -------------------
030     * (C)opyright 2003-2005, by Object Refinery Limited and Contributors.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: ShapeUtilities.java,v 1.17 2005/11/02 16:31:50 mungady Exp $
036     *
037     * Changes
038     * -------
039     * 13-Aug-2003 : Version 1 (DG);
040     * 16-Mar-2004 : Moved rotateShape() from RefineryUtilities.java to here (DG);
041     * 13-May-2004 : Added new shape creation methods (DG);
042     * 30-Sep-2004 : Added createLineRegion() method (DG);
043     *               Moved drawRotatedShape() method from RefineryUtilities class 
044     *               to this class (DG);
045     * 04-Oct-2004 : Renamed ShapeUtils --> ShapeUtilities (DG);
046     * 26-Oct-2004 : Added a method to test the equality of two Line2D 
047     *               instances (DG);
048     * 10-Nov-2004 : Added new translateShape() and equal(Ellipse2D, Ellipse2D)
049     *               methods (DG);
050     * 11-Nov-2004 : Renamed translateShape() --> createTranslatedShape() (DG);
051     * 07-Jan-2005 : Minor Javadoc fix (DG);
052     * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG);
053     * 21-Jan-2005 : Modified return type of RectangleAnchor.coordinates() 
054     *               method (DG);
055     * 22-Feb-2005 : Added equality tests for Arc2D and GeneralPath (DG);
056     * 16-Mar-2005 : Fixed bug where equal(Shape, Shape) fails for two Polygon
057     *               instances (DG);
058     *
059     */
060    
061    package org.jfree.util;
062    
063    import java.awt.Graphics2D;
064    import java.awt.Polygon;
065    import java.awt.Shape;
066    import java.awt.geom.AffineTransform;
067    import java.awt.geom.Arc2D;
068    import java.awt.geom.Ellipse2D;
069    import java.awt.geom.GeneralPath;
070    import java.awt.geom.Line2D;
071    import java.awt.geom.PathIterator;
072    import java.awt.geom.Point2D;
073    import java.awt.geom.Rectangle2D;
074    import java.util.Arrays;
075    
076    import org.jfree.ui.RectangleAnchor;
077    
078    /**
079     * Utility methods for {@link Shape} objects.
080     *
081     * @author David Gilbert
082     */
083    public class ShapeUtilities {
084    
085        /**
086         * Prevents instantiation.
087         */
088        private ShapeUtilities() {
089        }
090    
091        /**
092         * Returns a clone of the specified shape, or <code>null</code>.  At the 
093         * current time, this method supports cloning for instances of 
094         * <code>Line2D</code>, <code>RectangularShape</code>, <code>Area</code> 
095         * and <code>GeneralPath</code>.
096         * <p>
097         * <code>RectangularShape</code> includes <code>Arc2D</code>, 
098         * <code>Ellipse2D</code>, <code>Rectangle2D</code>, 
099         * <code>RoundRectangle2D</code>.
100         * 
101         * @param shape  the shape to clone (<code>null</code> permitted, 
102         *               returns <code>null</code>).
103         * 
104         * @return A clone or <code>null</code>.
105         */
106        public static Shape clone(final Shape shape) {
107    
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 = p1.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            );
321            return transform.createTransformedShape(shape);
322        }
323        
324        /**
325         * Translates a shape to a new location such that the anchor point 
326         * (relative to the rectangular bounds of the shape) aligns with the 
327         * specified (x, y) coordinate in Java2D space.
328         *  
329         * @param shape  the shape (<code>null</code> not permitted).
330         * @param anchor  the anchor (<code>null</code> not permitted).
331         * @param locationX  the x-coordinate (in Java2D space).
332         * @param locationY  the y-coordinate (in Java2D space).
333         * 
334         * @return A new and translated shape.
335         */
336        public static Shape createTranslatedShape(final Shape shape, 
337                                                  final RectangleAnchor anchor, 
338                                                  final double locationX,
339                                                  final double locationY) {
340            if (shape == null) {
341                throw new IllegalArgumentException("Null 'shape' argument.");
342            }        
343            if (anchor == null) {
344                throw new IllegalArgumentException("Null 'anchor' argument.");
345            }
346            Point2D anchorPoint = RectangleAnchor.coordinates(
347                shape.getBounds2D(), anchor
348            );
349            final AffineTransform transform = AffineTransform.getTranslateInstance(
350                locationX - anchorPoint.getX(), locationY - anchorPoint.getY()
351            );
352            return transform.createTransformedShape(shape);   
353        }
354    
355        /**
356         * Rotates a shape about the specified coordinates.
357         * 
358         * @param base  the shape (<code>null</code> permitted, returns 
359         *              <code>null</code>).
360         * @param angle  the angle (in radians).
361         * @param x  the x coordinate for the rotation point (in Java2D space).
362         * @param y  the y coordinate for the rotation point (in Java2D space).
363         * 
364         * @return the rotated shape.
365         */
366        public static Shape rotateShape(final Shape base, final double angle,
367                                        final float x, final float y) {
368            if (base == null) {
369                return null;
370            }
371            final AffineTransform rotate = AffineTransform.getRotateInstance(
372                angle, x, y
373            );
374            final Shape result = rotate.createTransformedShape(base);
375            return result;
376        }
377    
378        /**
379         * Draws a shape with the specified rotation about <code>(x, y)</code>.
380         *
381         * @param g2  the graphics device (<code>null</code> not permitted).
382         * @param shape  the shape (<code>null</code> not permitted).
383         * @param angle  the angle (in radians).
384         * @param x  the x coordinate for the rotation point.
385         * @param y  the y coordinate for the rotation point.
386         */
387        public static void drawRotatedShape(final Graphics2D g2, final Shape shape,
388                                            final double angle,
389                                            final float x, final float y) {
390    
391            final AffineTransform saved = g2.getTransform();
392            final AffineTransform rotate = AffineTransform.getRotateInstance(
393                angle, x, y
394            );
395            g2.transform(rotate);
396            g2.draw(shape);
397            g2.setTransform(saved);
398    
399        }
400    
401        /** A useful constant used internally. */
402        private static final float SQRT2 = (float) Math.pow(2.0, 0.5);
403    
404        /**
405         * Creates a diagonal cross shape.
406         * 
407         * @param l  the length of each 'arm'.
408         * @param t  the thickness.
409         * 
410         * @return A diagonal cross shape.
411         */
412        public static Shape createDiagonalCross(final float l, final float t) {
413            final GeneralPath p0 = new GeneralPath();
414            p0.moveTo(-l - t, -l + t);
415            p0.lineTo(-l + t, -l - t);
416            p0.lineTo(0.0f, -t * SQRT2);
417            p0.lineTo(l - t, -l - t);
418            p0.lineTo(l + t, -l + t);
419            p0.lineTo(t * SQRT2, 0.0f);
420            p0.lineTo(l + t, l - t);
421            p0.lineTo(l - t, l + t);
422            p0.lineTo(0.0f, t * SQRT2);
423            p0.lineTo(-l + t, l + t);
424            p0.lineTo(-l - t, l - t);
425            p0.lineTo(-t * SQRT2, 0.0f);
426            p0.closePath();
427            return p0;
428        }
429        
430        /**
431         * Creates a diagonal cross shape.
432         * 
433         * @param l  the length of each 'arm'.
434         * @param t  the thickness.
435         * 
436         * @return A diagonal cross shape.
437         */
438        public static Shape createRegularCross(final float l, final float t) {
439            final GeneralPath p0 = new GeneralPath();
440            p0.moveTo(-l, t);
441            p0.lineTo(-t, t);
442            p0.lineTo(-t, l);
443            p0.lineTo(t, l);
444            p0.lineTo(t, t);
445            p0.lineTo(l, t);
446            p0.lineTo(l, -t);
447            p0.lineTo(t, -t);
448            p0.lineTo(t, -l);
449            p0.lineTo(-t, -l);
450            p0.lineTo(-t, -t);
451            p0.lineTo(-l, -t);
452            p0.closePath();
453            return p0;
454        }
455        
456        /**
457         * Creates a diamond shape.
458         * 
459         * @param s  the size factor (equal to half the height of the diamond).
460         * 
461         * @return A diamond shape.
462         */
463        public static Shape createDiamond(final float s) {
464            final GeneralPath p0 = new GeneralPath();
465            p0.moveTo(0.0f, -s);
466            p0.lineTo(s, 0.0f);
467            p0.lineTo(0.0f, s);
468            p0.lineTo(-s, 0.0f);
469            p0.closePath();
470            return p0;
471        }
472        
473        /**
474         * Creates a triangle shape that points upwards.
475         * 
476         * @param s  the size factor (equal to half the height of the triangle).
477         * 
478         * @return A triangle shape.
479         */
480        public static Shape createUpTriangle(final float s) {
481            final GeneralPath p0 = new GeneralPath();
482            p0.moveTo(0.0f, -s);
483            p0.lineTo(s, s);
484            p0.lineTo(-s, s);
485            p0.closePath();
486            return p0;
487        }
488    
489        /**
490         * Creates a triangle shape that points downwards.
491         * 
492         * @param s  the size factor (equal to half the height of the triangle).
493         * 
494         * @return A triangle shape.
495         */
496        public static Shape createDownTriangle(final float s) {
497            final GeneralPath p0 = new GeneralPath();
498            p0.moveTo(0.0f, s);
499            p0.lineTo(s, -s);
500            p0.lineTo(-s, -s);
501            p0.closePath();
502            return p0;
503        }
504    
505        /**
506         * Creates a region surrounding a line segment by 'widening' the line 
507         * segment.  A typical use for this method is the creation of a 
508         * 'clickable' region for a line that is displayed on-screen.
509         * 
510         * @param line  the line (<code>null</code> not permitted).
511         * @param width  the width of the region.
512         * 
513         * @return A region that surrounds the line.
514         */
515        public static Shape createLineRegion(final Line2D line, final float width) {
516            final GeneralPath result = new GeneralPath();
517            final float x1 = (float) line.getX1();
518            final float x2 = (float) line.getX2();
519            final float y1 = (float) line.getY1();
520            final float y2 = (float) line.getY2();
521            if ((x2 - x1) != 0.0) {
522                final double theta = Math.atan((y2 - y1) / (x2 - x1));
523                final float dx = (float) Math.sin(theta) * width;
524                final float dy = (float) Math.cos(theta) * width;
525                result.moveTo(x1 - dx, y1 + dy);
526                result.lineTo(x1 + dx, y1 - dy);
527                result.lineTo(x2 + dx, y2 - dy);
528                result.lineTo(x2 - dx, y2 + dy);
529                result.closePath();
530            }
531            else {
532                // special case, vertical line
533                result.moveTo(x1 - width / 2.0f, y1);
534                result.lineTo(x1 + width / 2.0f, y1);
535                result.lineTo(x2 + width / 2.0f, y2);
536                result.lineTo(x2 - width / 2.0f, y2);
537                result.closePath();
538            }
539            return result;    
540        }
541            
542        /**
543         * Returns a point based on (x, y) but constrained to be within the bounds 
544         * of a given rectangle.
545         *
546         * @param x  the x-coordinate.
547         * @param y  the y-coordinate.
548         * @param area  the constraining rectangle (<code>null</code> not 
549         *              permitted).
550         *
551         * @return A point within the rectangle.
552         * 
553         * @throws NullPointerException if <code>area</code> is <code>null</code>.
554         */
555        public static Point2D getPointInRectangle(double x, double y, 
556                                                  final Rectangle2D area) {
557    
558            x = Math.max(area.getMinX(), Math.min(x, area.getMaxX()));
559            y = Math.max(area.getMinY(), Math.min(y, area.getMaxY()));
560            return new Point2D.Double(x, y);
561    
562        }
563    
564        /**
565         * Checks, whether the given rectangle1 fully contains rectangle 2
566         * (even if rectangle 2 has a height or width of zero!).
567         *
568         * @param rect1  the first rectangle.
569         * @param rect2  the second rectangle.
570         * 
571         * @return A boolean.
572         */
573        public static boolean contains(final Rectangle2D rect1, 
574                                       final Rectangle2D rect2) {
575            
576            final double x0 = rect1.getX();
577            final double y0 = rect1.getY();
578            final double x = rect2.getX();
579            final double y = rect2.getY();
580            final double w = rect2.getWidth();
581            final double h = rect2.getHeight();
582    
583            return ((x >= x0) && (y >= y0) 
584                    && ((x + w) <= (x0 + rect1.getWidth())) 
585                    && ((y + h) <= (y0 + rect1.getHeight())));
586        
587        }
588        
589    
590        /**
591         * Checks, whether the given rectangle1 fully contains rectangle 2
592         * (even if rectangle 2 has a height or width of zero!).
593         *
594         * @param rect1  the first rectangle.
595         * @param rect2  the second rectangle.
596         *
597         * @return A boolean.
598         */
599        public static boolean intersects (final Rectangle2D rect1, 
600                                          final Rectangle2D rect2) {
601    
602          final double x0 = rect1.getX();
603          final double y0 = rect1.getY();
604    
605          final double x = rect2.getX();
606          final double width = rect2.getWidth();
607          final double y = rect2.getY();
608          final double height = rect2.getHeight();
609          return (x + width >= x0 && y + height >= y0 && x <= x0 + rect1.getWidth()
610                  && y <= y0 + rect1.getHeight());
611        }
612    }