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
081package org.jfree.chart.renderer.xy;
082
083import java.awt.BasicStroke;
084import java.awt.Graphics2D;
085import java.awt.Paint;
086import java.awt.Polygon;
087import java.awt.Shape;
088import java.awt.Stroke;
089import java.awt.geom.Area;
090import java.awt.geom.GeneralPath;
091import java.awt.geom.Line2D;
092import java.awt.geom.Rectangle2D;
093import java.io.IOException;
094import java.io.ObjectInputStream;
095import java.io.ObjectOutputStream;
096
097import org.jfree.chart.LegendItem;
098import org.jfree.chart.axis.ValueAxis;
099import org.jfree.chart.entity.EntityCollection;
100import org.jfree.chart.event.RendererChangeEvent;
101import org.jfree.chart.labels.XYSeriesLabelGenerator;
102import org.jfree.chart.labels.XYToolTipGenerator;
103import org.jfree.chart.plot.CrosshairState;
104import org.jfree.chart.plot.PlotOrientation;
105import org.jfree.chart.plot.PlotRenderingInfo;
106import org.jfree.chart.plot.XYPlot;
107import org.jfree.chart.urls.XYURLGenerator;
108import org.jfree.data.xy.XYDataset;
109import org.jfree.io.SerialUtilities;
110import org.jfree.util.PublicCloneable;
111import 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 */
123public 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}