001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/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 * XYAreaRenderer.java
029 * -------------------
030 * (C) Copyright 2002-2008, by Hari and Contributors.
031 *
032 * Original Author: Hari (ourhari@hotmail.com);
033 * Contributor(s): David Gilbert (for Object Refinery Limited);
034 * Richard Atkinson;
035 * Christian W. Zuckschwerdt;
036 *
037 * Changes:
038 * --------
039 * 03-Apr-2002 : Version 1, contributed by Hari. This class is based on the
040 * StandardXYItemRenderer class (DG);
041 * 09-Apr-2002 : Removed the translated zero from the drawItem method -
042 * overridden the initialise() method to calculate it (DG);
043 * 30-May-2002 : Added tool tip generator to constructor to match super
044 * class (DG);
045 * 25-Jun-2002 : Removed unnecessary local variable (DG);
046 * 05-Aug-2002 : Small modification to drawItem method to support URLs for HTML
047 * image maps (RA);
048 * 01-Oct-2002 : Fixed errors reported by Checkstyle (DG);
049 * 07-Nov-2002 : Renamed AreaXYItemRenderer --> XYAreaRenderer (DG);
050 * 25-Mar-2003 : Implemented Serializable (DG);
051 * 01-May-2003 : Modified drawItem() method signature (DG);
052 * 27-Jul-2003 : Made line and polygon properties protected rather than
053 * private (RA);
054 * 30-Jul-2003 : Modified entity constructor (CZ);
055 * 20-Aug-2003 : Implemented Cloneable and PublicCloneable (DG);
056 * 16-Sep-2003 : Changed ChartRenderingInfo --> PlotRenderingInfo (DG);
057 * 07-Oct-2003 : Added renderer state (DG);
058 * 08-Dec-2003 : Modified hotspot for chart entity (DG);
059 * 10-Feb-2004 : Changed the drawItem() method to make cut-and-paste overriding
060 * easier. Also moved state class into this class (DG);
061 * 25-Feb-2004 : Replaced CrosshairInfo with CrosshairState. Renamed
062 * XYToolTipGenerator --> XYItemLabelGenerator (DG);
063 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with
064 * getYValue() (DG);
065 * 11-Nov-2004 : Now uses ShapeUtilities to translate shapes (DG);
066 * 19-Jan-2005 : Now accesses primitives only from dataset (DG);
067 * 21-Mar-2005 : Override getLegendItem() and equals() methods (DG);
068 * 20-Apr-2005 : Use generators for legend tooltips and URLs (DG);
069 * ------------- JFREECHART 1.0.x ---------------------------------------------
070 * 06-Feb-2007 : Fixed bug 1086307, crosshairs with multiple axes (DG);
071 * 14-Feb-2007 : Fixed bug in clone() (DG);
072 * 20-Apr-2007 : Updated getLegendItem() for renderer change (DG);
073 * 04-May-2007 : Set processVisibleItemsOnly flag to false (DG);
074 * 17-May-2007 : Set datasetIndex and seriesIndex in getLegendItem() (DG);
075 * 18-May-2007 : Set dataset and seriesKey for LegendItem (DG);
076 * 17-Jun-2008 : Apply legend font and paint attributes (DG);
077 * 31-Dec-2008 : Fix for bug 2471906 - dashed outlines performance issue (DG);
078 *
079 */
080
081 package org.jfree.chart.renderer.xy;
082
083 import java.awt.BasicStroke;
084 import java.awt.Graphics2D;
085 import java.awt.Paint;
086 import java.awt.Polygon;
087 import java.awt.Shape;
088 import java.awt.Stroke;
089 import java.awt.geom.Area;
090 import java.awt.geom.GeneralPath;
091 import java.awt.geom.Line2D;
092 import java.awt.geom.Rectangle2D;
093 import java.io.IOException;
094 import java.io.ObjectInputStream;
095 import java.io.ObjectOutputStream;
096
097 import org.jfree.chart.LegendItem;
098 import org.jfree.chart.axis.ValueAxis;
099 import org.jfree.chart.entity.EntityCollection;
100 import org.jfree.chart.event.RendererChangeEvent;
101 import org.jfree.chart.labels.XYSeriesLabelGenerator;
102 import org.jfree.chart.labels.XYToolTipGenerator;
103 import org.jfree.chart.plot.CrosshairState;
104 import org.jfree.chart.plot.PlotOrientation;
105 import org.jfree.chart.plot.PlotRenderingInfo;
106 import org.jfree.chart.plot.XYPlot;
107 import org.jfree.chart.urls.XYURLGenerator;
108 import org.jfree.data.xy.XYDataset;
109 import org.jfree.io.SerialUtilities;
110 import org.jfree.util.PublicCloneable;
111 import org.jfree.util.ShapeUtilities;
112
113 /**
114 * Area item renderer for an {@link XYPlot}. This class can draw (a) shapes at
115 * each point, or (b) lines between points, or (c) both shapes and lines,
116 * or (d) filled areas, or (e) filled areas and shapes. The example shown here
117 * is generated by the <code>XYAreaRendererDemo1.java</code> program included
118 * in the JFreeChart demo collection:
119 * <br><br>
120 * <img src="../../../../../images/XYAreaRendererSample.png"
121 * alt="XYAreaRendererSample.png" />
122 */
123 public class XYAreaRenderer extends AbstractXYItemRenderer
124 implements XYItemRenderer, PublicCloneable {
125
126 /** For serialization. */
127 private static final long serialVersionUID = -4481971353973876747L;
128
129 /**
130 * A state object used by this renderer.
131 */
132 static class XYAreaRendererState extends XYItemRendererState {
133
134 /** Working storage for the area under one series. */
135 public Polygon area;
136
137 /** Working line that can be recycled. */
138 public Line2D line;
139
140 /**
141 * Creates a new state.
142 *
143 * @param info the plot rendering info.
144 */
145 public XYAreaRendererState(PlotRenderingInfo info) {
146 super(info);
147 this.area = new Polygon();
148 this.line = new Line2D.Double();
149 }
150
151 }
152
153 /** Useful constant for specifying the type of rendering (shapes only). */
154 public static final int SHAPES = 1;
155
156 /** Useful constant for specifying the type of rendering (lines only). */
157 public static final int LINES = 2;
158
159 /**
160 * Useful constant for specifying the type of rendering (shapes and lines).
161 */
162 public static final int SHAPES_AND_LINES = 3;
163
164 /** Useful constant for specifying the type of rendering (area only). */
165 public static final int AREA = 4;
166
167 /**
168 * Useful constant for specifying the type of rendering (area and shapes).
169 */
170 public static final int AREA_AND_SHAPES = 5;
171
172 /** A flag indicating whether or not shapes are drawn at each XY point. */
173 private boolean plotShapes;
174
175 /** A flag indicating whether or not lines are drawn between XY points. */
176 private boolean plotLines;
177
178 /** A flag indicating whether or not Area are drawn at each XY point. */
179 private boolean plotArea;
180
181 /** A flag that controls whether or not the outline is shown. */
182 private boolean showOutline;
183
184 /**
185 * The shape used to represent an area in each legend item (this should
186 * never be <code>null</code>).
187 */
188 private transient Shape legendArea;
189
190 /**
191 * Constructs a new renderer.
192 */
193 public XYAreaRenderer() {
194 this(AREA);
195 }
196
197 /**
198 * Constructs a new renderer.
199 *
200 * @param type the type of the renderer.
201 */
202 public XYAreaRenderer(int type) {
203 this(type, null, null);
204 }
205
206 /**
207 * Constructs a new renderer. To specify the type of renderer, use one of
208 * the constants: <code>SHAPES</code>, <code>LINES</code>,
209 * <code>SHAPES_AND_LINES</code>, <code>AREA</code> or
210 * <code>AREA_AND_SHAPES</code>.
211 *
212 * @param type the type of renderer.
213 * @param toolTipGenerator the tool tip generator to use
214 * (<code>null</code> permitted).
215 * @param urlGenerator the URL generator (<code>null</code> permitted).
216 */
217 public XYAreaRenderer(int type, XYToolTipGenerator toolTipGenerator,
218 XYURLGenerator urlGenerator) {
219
220 super();
221 setBaseToolTipGenerator(toolTipGenerator);
222 setURLGenerator(urlGenerator);
223
224 if (type == SHAPES) {
225 this.plotShapes = true;
226 }
227 if (type == LINES) {
228 this.plotLines = true;
229 }
230 if (type == SHAPES_AND_LINES) {
231 this.plotShapes = true;
232 this.plotLines = true;
233 }
234 if (type == AREA) {
235 this.plotArea = true;
236 }
237 if (type == AREA_AND_SHAPES) {
238 this.plotArea = true;
239 this.plotShapes = true;
240 }
241 this.showOutline = false;
242 GeneralPath area = new GeneralPath();
243 area.moveTo(0.0f, -4.0f);
244 area.lineTo(3.0f, -2.0f);
245 area.lineTo(4.0f, 4.0f);
246 area.lineTo(-4.0f, 4.0f);
247 area.lineTo(-3.0f, -2.0f);
248 area.closePath();
249 this.legendArea = area;
250
251 }
252
253 /**
254 * Returns true if shapes are being plotted by the renderer.
255 *
256 * @return <code>true</code> if shapes are being plotted by the renderer.
257 */
258 public boolean getPlotShapes() {
259 return this.plotShapes;
260 }
261
262 /**
263 * Returns true if lines are being plotted by the renderer.
264 *
265 * @return <code>true</code> if lines are being plotted by the renderer.
266 */
267 public boolean getPlotLines() {
268 return this.plotLines;
269 }
270
271 /**
272 * Returns true if Area is being plotted by the renderer.
273 *
274 * @return <code>true</code> if Area is being plotted by the renderer.
275 */
276 public boolean getPlotArea() {
277 return this.plotArea;
278 }
279
280 /**
281 * Returns a flag that controls whether or not outlines of the areas are
282 * drawn.
283 *
284 * @return The flag.
285 *
286 * @see #setOutline(boolean)
287 */
288 public boolean isOutline() {
289 return this.showOutline;
290 }
291
292 /**
293 * Sets a flag that controls whether or not outlines of the areas are drawn
294 * and sends a {@link RendererChangeEvent} to all registered listeners.
295 *
296 * @param show the flag.
297 *
298 * @see #isOutline()
299 */
300 public void setOutline(boolean show) {
301 this.showOutline = show;
302 fireChangeEvent();
303 }
304
305 /**
306 * Returns the shape used to represent an area in the legend.
307 *
308 * @return The legend area (never <code>null</code>).
309 */
310 public Shape getLegendArea() {
311 return this.legendArea;
312 }
313
314 /**
315 * Sets the shape used as an area in each legend item and sends a
316 * {@link RendererChangeEvent} to all registered listeners.
317 *
318 * @param area the area (<code>null</code> not permitted).
319 */
320 public void setLegendArea(Shape area) {
321 if (area == null) {
322 throw new IllegalArgumentException("Null 'area' argument.");
323 }
324 this.legendArea = area;
325 fireChangeEvent();
326 }
327
328 /**
329 * Initialises the renderer and returns a state object that should be
330 * passed to all subsequent calls to the drawItem() method.
331 *
332 * @param g2 the graphics device.
333 * @param dataArea the area inside the axes.
334 * @param plot the plot.
335 * @param data the data.
336 * @param info an optional info collection object to return data back to
337 * the caller.
338 *
339 * @return A state object for use by the renderer.
340 */
341 public XYItemRendererState initialise(Graphics2D g2, Rectangle2D dataArea,
342 XYPlot plot, XYDataset data, PlotRenderingInfo info) {
343 XYAreaRendererState state = new XYAreaRendererState(info);
344
345 // in the rendering process, there is special handling for item
346 // zero, so we can't support processing of visible data items only
347 state.setProcessVisibleItemsOnly(false);
348 return state;
349 }
350
351 /**
352 * Returns a default legend item for the specified series. Subclasses
353 * should override this method to generate customised items.
354 *
355 * @param datasetIndex the dataset index (zero-based).
356 * @param series the series index (zero-based).
357 *
358 * @return A legend item for the series.
359 */
360 public LegendItem getLegendItem(int datasetIndex, int series) {
361 LegendItem result = null;
362 XYPlot xyplot = getPlot();
363 if (xyplot != null) {
364 XYDataset dataset = xyplot.getDataset(datasetIndex);
365 if (dataset != null) {
366 XYSeriesLabelGenerator lg = getLegendItemLabelGenerator();
367 String label = lg.generateLabel(dataset, series);
368 String description = label;
369 String toolTipText = null;
370 if (getLegendItemToolTipGenerator() != null) {
371 toolTipText = getLegendItemToolTipGenerator().generateLabel(
372 dataset, series);
373 }
374 String urlText = null;
375 if (getLegendItemURLGenerator() != null) {
376 urlText = getLegendItemURLGenerator().generateLabel(
377 dataset, series);
378 }
379 Paint paint = lookupSeriesPaint(series);
380 result = new LegendItem(label, description, toolTipText,
381 urlText, this.legendArea, paint);
382 result.setLabelFont(lookupLegendTextFont(series));
383 Paint labelPaint = lookupLegendTextPaint(series);
384 if (labelPaint != null) {
385 result.setLabelPaint(labelPaint);
386 }
387 result.setDataset(dataset);
388 result.setDatasetIndex(datasetIndex);
389 result.setSeriesKey(dataset.getSeriesKey(series));
390 result.setSeriesIndex(series);
391 }
392 }
393 return result;
394 }
395
396 /**
397 * Draws the visual representation of a single data item.
398 *
399 * @param g2 the graphics device.
400 * @param state the renderer state.
401 * @param dataArea the area within which the data is being drawn.
402 * @param info collects information about the drawing.
403 * @param plot the plot (can be used to obtain standard color information
404 * etc).
405 * @param domainAxis the domain axis.
406 * @param rangeAxis the range axis.
407 * @param dataset the dataset.
408 * @param series the series index (zero-based).
409 * @param item the item index (zero-based).
410 * @param crosshairState crosshair information for the plot
411 * (<code>null</code> permitted).
412 * @param pass the pass index.
413 */
414 public void drawItem(Graphics2D g2, XYItemRendererState state,
415 Rectangle2D dataArea, PlotRenderingInfo info, XYPlot plot,
416 ValueAxis domainAxis, ValueAxis rangeAxis, XYDataset dataset,
417 int series, int item, CrosshairState crosshairState, int pass) {
418
419 if (!getItemVisible(series, item)) {
420 return;
421 }
422 XYAreaRendererState areaState = (XYAreaRendererState) state;
423
424 // get the data point...
425 double x1 = dataset.getXValue(series, item);
426 double y1 = dataset.getYValue(series, item);
427 if (Double.isNaN(y1)) {
428 y1 = 0.0;
429 }
430 double transX1 = domainAxis.valueToJava2D(x1, dataArea,
431 plot.getDomainAxisEdge());
432 double transY1 = rangeAxis.valueToJava2D(y1, dataArea,
433 plot.getRangeAxisEdge());
434
435 // get the previous point and the next point so we can calculate a
436 // "hot spot" for the area (used by the chart entity)...
437 int itemCount = dataset.getItemCount(series);
438 double x0 = dataset.getXValue(series, Math.max(item - 1, 0));
439 double y0 = dataset.getYValue(series, Math.max(item - 1, 0));
440 if (Double.isNaN(y0)) {
441 y0 = 0.0;
442 }
443 double transX0 = domainAxis.valueToJava2D(x0, dataArea,
444 plot.getDomainAxisEdge());
445 double transY0 = rangeAxis.valueToJava2D(y0, dataArea,
446 plot.getRangeAxisEdge());
447
448 double x2 = dataset.getXValue(series, Math.min(item + 1,
449 itemCount - 1));
450 double y2 = dataset.getYValue(series, Math.min(item + 1,
451 itemCount - 1));
452 if (Double.isNaN(y2)) {
453 y2 = 0.0;
454 }
455 double transX2 = domainAxis.valueToJava2D(x2, dataArea,
456 plot.getDomainAxisEdge());
457 double transY2 = rangeAxis.valueToJava2D(y2, dataArea,
458 plot.getRangeAxisEdge());
459
460 double transZero = rangeAxis.valueToJava2D(0.0, dataArea,
461 plot.getRangeAxisEdge());
462 Polygon hotspot = null;
463 if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
464 hotspot = new Polygon();
465 hotspot.addPoint((int) transZero,
466 (int) ((transX0 + transX1) / 2.0));
467 hotspot.addPoint((int) ((transY0 + transY1) / 2.0),
468 (int) ((transX0 + transX1) / 2.0));
469 hotspot.addPoint((int) transY1, (int) transX1);
470 hotspot.addPoint((int) ((transY1 + transY2) / 2.0),
471 (int) ((transX1 + transX2) / 2.0));
472 hotspot.addPoint((int) transZero,
473 (int) ((transX1 + transX2) / 2.0));
474 }
475 else { // vertical orientation
476 hotspot = new Polygon();
477 hotspot.addPoint((int) ((transX0 + transX1) / 2.0),
478 (int) transZero);
479 hotspot.addPoint((int) ((transX0 + transX1) / 2.0),
480 (int) ((transY0 + transY1) / 2.0));
481 hotspot.addPoint((int) transX1, (int) transY1);
482 hotspot.addPoint((int) ((transX1 + transX2) / 2.0),
483 (int) ((transY1 + transY2) / 2.0));
484 hotspot.addPoint((int) ((transX1 + transX2) / 2.0),
485 (int) transZero);
486 }
487
488 if (item == 0) { // create a new area polygon for the series
489 areaState.area = new Polygon();
490 // the first point is (x, 0)
491 double zero = rangeAxis.valueToJava2D(0.0, dataArea,
492 plot.getRangeAxisEdge());
493 if (plot.getOrientation() == PlotOrientation.VERTICAL) {
494 areaState.area.addPoint((int) transX1, (int) zero);
495 }
496 else if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
497 areaState.area.addPoint((int) zero, (int) transX1);
498 }
499 }
500
501 // Add each point to Area (x, y)
502 if (plot.getOrientation() == PlotOrientation.VERTICAL) {
503 areaState.area.addPoint((int) transX1, (int) transY1);
504 }
505 else if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
506 areaState.area.addPoint((int) transY1, (int) transX1);
507 }
508
509 PlotOrientation orientation = plot.getOrientation();
510 Paint paint = getItemPaint(series, item);
511 Stroke stroke = getItemStroke(series, item);
512 g2.setPaint(paint);
513 g2.setStroke(stroke);
514
515 Shape shape = null;
516 if (getPlotShapes()) {
517 shape = getItemShape(series, item);
518 if (orientation == PlotOrientation.VERTICAL) {
519 shape = ShapeUtilities.createTranslatedShape(shape, transX1,
520 transY1);
521 }
522 else if (orientation == PlotOrientation.HORIZONTAL) {
523 shape = ShapeUtilities.createTranslatedShape(shape, transY1,
524 transX1);
525 }
526 g2.draw(shape);
527 }
528
529 if (getPlotLines()) {
530 if (item > 0) {
531 if (plot.getOrientation() == PlotOrientation.VERTICAL) {
532 areaState.line.setLine(transX0, transY0, transX1, transY1);
533 }
534 else if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
535 areaState.line.setLine(transY0, transX0, transY1, transX1);
536 }
537 g2.draw(areaState.line);
538 }
539 }
540
541 // Check if the item is the last item for the series.
542 // and number of items > 0. We can't draw an area for a single point.
543 if (getPlotArea() && item > 0 && item == (itemCount - 1)) {
544
545 if (orientation == PlotOrientation.VERTICAL) {
546 // Add the last point (x,0)
547 areaState.area.addPoint((int) transX1, (int) transZero);
548 }
549 else if (orientation == PlotOrientation.HORIZONTAL) {
550 // Add the last point (x,0)
551 areaState.area.addPoint((int) transZero, (int) transX1);
552 }
553
554 g2.fill(areaState.area);
555
556 // draw an outline around the Area.
557 if (isOutline()) {
558 Shape area = areaState.area;
559
560 // Java2D has some issues drawing dashed lines around "large"
561 // geometrical shapes - for example, see bug 6620013 in the
562 // Java bug database. So, we'll check if the outline is
563 // dashed and, if it is, do our own clipping before drawing
564 // the outline...
565 Stroke outlineStroke = lookupSeriesOutlineStroke(series);
566 if (outlineStroke instanceof BasicStroke) {
567 BasicStroke bs = (BasicStroke) outlineStroke;
568 if (bs.getDashArray() != null) {
569 Area poly = new Area(areaState.area);
570 // we make the clip region slightly larger than the
571 // dataArea so that the clipped edges don't show lines
572 // on the chart
573 Area clip = new Area(new Rectangle2D.Double(
574 dataArea.getX() - 5.0, dataArea.getY() - 5.0,
575 dataArea.getWidth() + 10.0,
576 dataArea.getHeight() + 10.0));
577 poly.intersect(clip);
578 area = poly;
579 }
580 } // end of workaround
581
582 g2.setStroke(outlineStroke);
583 g2.setPaint(lookupSeriesOutlinePaint(series));
584 g2.draw(area);
585 }
586 }
587
588 int domainAxisIndex = plot.getDomainAxisIndex(domainAxis);
589 int rangeAxisIndex = plot.getRangeAxisIndex(rangeAxis);
590 updateCrosshairValues(crosshairState, x1, y1, domainAxisIndex,
591 rangeAxisIndex, transX1, transY1, orientation);
592
593 // collect entity and tool tip information...
594 EntityCollection entities = state.getEntityCollection();
595 if (entities != null && hotspot != null) {
596 addEntity(entities, hotspot, dataset, series, item, 0.0, 0.0);
597 }
598
599 }
600
601 /**
602 * Returns a clone of the renderer.
603 *
604 * @return A clone.
605 *
606 * @throws CloneNotSupportedException if the renderer cannot be cloned.
607 */
608 public Object clone() throws CloneNotSupportedException {
609 XYAreaRenderer clone = (XYAreaRenderer) super.clone();
610 clone.legendArea = ShapeUtilities.clone(this.legendArea);
611 return clone;
612 }
613
614 /**
615 * Tests this renderer for equality with an arbitrary object.
616 *
617 * @param obj the object (<code>null</code> permitted).
618 *
619 * @return A boolean.
620 */
621 public boolean equals(Object obj) {
622 if (obj == this) {
623 return true;
624 }
625 if (!(obj instanceof XYAreaRenderer)) {
626 return false;
627 }
628 XYAreaRenderer that = (XYAreaRenderer) obj;
629 if (this.plotArea != that.plotArea) {
630 return false;
631 }
632 if (this.plotLines != that.plotLines) {
633 return false;
634 }
635 if (this.plotShapes != that.plotShapes) {
636 return false;
637 }
638 if (this.showOutline != that.showOutline) {
639 return false;
640 }
641 if (!ShapeUtilities.equal(this.legendArea, that.legendArea)) {
642 return false;
643 }
644 return true;
645 }
646
647 /**
648 * Provides serialization support.
649 *
650 * @param stream the input stream.
651 *
652 * @throws IOException if there is an I/O error.
653 * @throws ClassNotFoundException if there is a classpath problem.
654 */
655 private void readObject(ObjectInputStream stream)
656 throws IOException, ClassNotFoundException {
657 stream.defaultReadObject();
658 this.legendArea = SerialUtilities.readShape(stream);
659 }
660
661 /**
662 * Provides serialization support.
663 *
664 * @param stream the output stream.
665 *
666 * @throws IOException if there is an I/O error.
667 */
668 private void writeObject(ObjectOutputStream stream) throws IOException {
669 stream.defaultWriteObject();
670 SerialUtilities.writeShape(this.legendArea, stream);
671 }
672 }