org.jfree.chart.renderer.BarRenderer3D.java Source code

Java tutorial

Introduction

Here is the source code for org.jfree.chart.renderer.BarRenderer3D.java

Source

/*
 * ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.
 * Project Info: http://www.jfree.org/jfreechart/index.html
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 * ------------------
 * BarRenderer3D.java
 * ------------------
 * (C) Copyright 2001-2004, by Serge V. Grachov and Contributors.
 * Original Author: Serge V. Grachov;
 * Contributor(s): David Gilbert (for Object Refinery Limited);
 * Tin Luu;
 * Milo Simpson;
 * Richard Atkinson;
 * Rich Unger;
 * Christian W. Zuckschwerdt;
 * $Id: BarRenderer3D.java,v 1.1 2011-01-31 09:02:47 klukas Exp $
 * Changes
 * -------
 * 31-Oct-2001 : First version, contributed by Serge V. Grachov (DG);
 * 15-Nov-2001 : Modified to allow for null data values (DG);
 * 13-Dec-2001 : Added tooltips (DG);
 * 16-Jan-2002 : Added fix for single category or single series datasets, pointed out by
 * Taoufik Romdhane (DG);
 * 24-May-2002 : Incorporated tooltips into chart entities (DG);
 * 11-Jun-2002 : Added check for (permitted) null info object, bug and fix reported by David
 * Basten. Also updated Javadocs. (DG);
 * 19-Jun-2002 : Added code to draw labels on bars (TL);
 * 26-Jun-2002 : Added bar clipping to avoid PRExceptions (DG);
 * 05-Aug-2002 : Small modification to drawCategoryItem method to support URLs for HTML image
 * maps (RA);
 * 06-Aug-2002 : Value labels now use number formatter, thanks to Milo Simpson (DG);
 * 08-Aug-2002 : Applied fixed in bug id 592218 (DG);
 * 20-Sep-2002 : Added fix for categoryPaint by Rich Unger, and fixed errors reported by
 * Checkstyle (DG);
 * 24-Oct-2002 : Amendments for changes in CategoryDataset interface and CategoryToolTipGenerator
 * interface (DG);
 * 05-Nov-2002 : Replaced references to CategoryDataset with TableDataset (DG);
 * 06-Nov-2002 : Moved to the com.jrefinery.chart.renderer package (DG);
 * 28-Jan-2003 : Added an attribute to control the shading of the left and bottom walls in the
 * plot background (DG);
 * 25-Mar-2003 : Implemented Serializable (DG);
 * 10-Apr-2003 : Removed category paint usage (DG);
 * 13-May-2003 : Renamed VerticalBarRenderer3D --> BarRenderer3D and merged with
 * HorizontalBarRenderer3D (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 19-Aug-2003 : Implemented Cloneable and PublicCloneable (DG);
 * 07-Oct-2003 : Added renderer state (DG);
 * 08-Oct-2003 : Removed clipping (replaced with flag in CategoryPlot to control order in which
 * the data items are processed) (DG);
 * 20-Oct-2003 : Fixed bug (outline stroke not being used for bar outlines) (DG);
 * 21-Oct-2003 : Bar width moved into CategoryItemRendererState (DG);
 * 24-Nov-2003 : Fixed bug 846324 (item labels not showing) (DG);
 * 27-Nov-2003 : Added code to respect maxBarWidth setting (DG);
 * 02-Feb-2004 : Fixed bug where 'drawBarOutline' flag is not respected (DG);
 * 10-Feb-2004 : Small change to drawItem() method to make cut-and-paste overriding easier (DG);
 */

package org.jfree.chart.renderer;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Paint;
import java.awt.Stroke;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import org.BioStatisticalCategoryDataset;
import org.jfree.chart.Effect3D;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.CategoryItemEntity;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.labels.CategoryLabelGenerator;
import org.jfree.chart.labels.CategoryToolTipGenerator;
import org.jfree.chart.labels.ItemLabelAnchor;
import org.jfree.chart.labels.ItemLabelPosition;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.Marker;
import org.jfree.chart.plot.Plot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.ValueMarker;
import org.jfree.data.CategoryDataset;
import org.jfree.data.Range;
import org.jfree.io.SerialUtilities;
import org.jfree.ui.RectangleEdge;
import org.jfree.ui.TextAnchor;
import org.jfree.util.PublicCloneable;

/**
 * A renderer for bars with a 3D effect, for use with the {@link org.jfree.chart.plot.CategoryPlot} class.
 * 
 * @author Serge V. Grachov
 */
public class BarRenderer3D extends BarRenderer implements Effect3D, Cloneable, PublicCloneable, Serializable {

    /** The default x-offset for the 3D effect. */
    public static final double DEFAULT_X_OFFSET = 12.0;

    /** The default y-offset for the 3D effect. */
    public static final double DEFAULT_Y_OFFSET = 8.0;

    /** The default wall paint. */
    public static final Paint DEFAULT_WALL_PAINT = new Color(0xDD, 0xDD, 0xDD);

    /** The size of x-offset for the 3D effect. */
    private double xOffset;

    /** The size of y-offset for the 3D effect. */
    private double yOffset;

    /** The paint used to shade the left and lower 3D wall. */
    private transient Paint wallPaint;

    /**
     * Default constructor, creates a renderer with a ten pixel '3D effect'.
     */
    public BarRenderer3D() {
        this(DEFAULT_X_OFFSET, DEFAULT_Y_OFFSET);
    }

    /**
     * Constructs a new renderer with the specified '3D effect'.
     * 
     * @param xOffset
     *           the x-offset for the 3D effect.
     * @param yOffset
     *           the y-offset for the 3D effect.
     */
    public BarRenderer3D(double xOffset, double yOffset) {

        super();
        this.xOffset = xOffset;
        this.yOffset = yOffset;
        this.wallPaint = DEFAULT_WALL_PAINT;
        // set the default item label positions
        ItemLabelPosition p1 = new ItemLabelPosition(ItemLabelAnchor.INSIDE12, TextAnchor.TOP_CENTER);
        setPositiveItemLabelPosition(p1);
        ItemLabelPosition p2 = new ItemLabelPosition(ItemLabelAnchor.INSIDE12, TextAnchor.TOP_CENTER);
        setNegativeItemLabelPosition(p2);

    }

    /**
     * Returns the x-offset for the 3D effect.
     * 
     * @return the 3D effect.
     */
    public double getXOffset() {
        return this.xOffset;
    }

    /**
     * Returns the y-offset for the 3D effect.
     * 
     * @return the 3D effect.
     */
    public double getYOffset() {
        return this.yOffset;
    }

    /**
     * Returns the paint used to highlight the left and bottom wall in the plot background.
     * 
     * @return The paint.
     */
    public Paint getWallPaint() {
        return this.wallPaint;
    }

    /**
     * Sets the paint used to hightlight the left and bottom walls in the plot background.
     * 
     * @param paint
     *           the paint.
     */
    public void setWallPaint(Paint paint) {
        this.wallPaint = paint;
    }

    /**
     * Draws the background for the plot.
     * 
     * @param g2
     *           the graphics device.
     * @param plot
     *           the plot.
     * @param dataArea
     *           the area inside the axes.
     */
    public void drawBackground(Graphics2D g2, CategoryPlot plot, Rectangle2D dataArea) {

        float x0 = (float) dataArea.getX();
        float x1 = x0 + (float) Math.abs(this.xOffset);
        float x3 = (float) dataArea.getMaxX();
        float x2 = x3 - (float) Math.abs(this.xOffset);

        float y0 = (float) dataArea.getMaxY();
        float y1 = y0 - (float) Math.abs(this.yOffset);
        float y3 = (float) dataArea.getMinY();
        float y2 = y3 + (float) Math.abs(this.yOffset);

        GeneralPath clip = new GeneralPath();
        clip.moveTo(x0, y0);
        clip.lineTo(x0, y2);
        clip.lineTo(x1, y3);
        clip.lineTo(x3, y3);
        clip.lineTo(x3, y1);
        clip.lineTo(x2, y0);
        clip.closePath();

        // fill background...
        Paint backgroundPaint = plot.getBackgroundPaint();
        if (backgroundPaint != null) {
            g2.setPaint(backgroundPaint);
            g2.fill(clip);
        }

        GeneralPath leftWall = new GeneralPath();
        leftWall.moveTo(x0, y0);
        leftWall.lineTo(x0, y2);
        leftWall.lineTo(x1, y3);
        leftWall.lineTo(x1, y1);
        leftWall.closePath();
        g2.setPaint(getWallPaint());
        g2.fill(leftWall);

        GeneralPath bottomWall = new GeneralPath();
        bottomWall.moveTo(x0, y0);
        bottomWall.lineTo(x1, y1);
        bottomWall.lineTo(x3, y1);
        bottomWall.lineTo(x2, y0);
        bottomWall.closePath();
        g2.setPaint(getWallPaint());
        g2.fill(bottomWall);

        // higlight the background corners...
        g2.setPaint(Color.lightGray);
        Line2D corner = new Line2D.Double(x0, y0, x1, y1);
        g2.draw(corner);
        corner.setLine(x1, y1, x1, y3);
        g2.draw(corner);
        corner.setLine(x1, y1, x3, y1);
        g2.draw(corner);

        // draw background image, if there is one...
        Image backgroundImage = plot.getBackgroundImage();
        if (backgroundImage != null) {
            Composite originalComposite = g2.getComposite();
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC, plot.getBackgroundAlpha()));
            g2.drawImage(backgroundImage, (int) x1, (int) y3, (int) (x3 - x1 + 1), (int) (y1 - y3 + 1), null);
            g2.setComposite(originalComposite);
        }

    }

    /**
     * Draws the outline for the plot.
     * 
     * @param g2
     *           the graphics device.
     * @param plot
     *           the plot.
     * @param dataArea
     *           the area inside the axes.
     */
    public void drawOutline(Graphics2D g2, CategoryPlot plot, Rectangle2D dataArea) {

        float x0 = (float) dataArea.getX();
        float x1 = x0 + (float) Math.abs(this.xOffset);
        float x3 = (float) dataArea.getMaxX();
        float x2 = x3 - (float) Math.abs(this.xOffset);

        float y0 = (float) dataArea.getMaxY();
        float y1 = y0 - (float) Math.abs(this.yOffset);
        float y3 = (float) dataArea.getMinY();
        float y2 = y3 + (float) Math.abs(this.yOffset);

        GeneralPath clip = new GeneralPath();
        clip.moveTo(x0, y0);
        clip.lineTo(x0, y2);
        clip.lineTo(x1, y3);
        clip.lineTo(x3, y3);
        clip.lineTo(x3, y1);
        clip.lineTo(x2, y0);
        clip.closePath();

        // put an outline around the data area...
        Stroke outlineStroke = plot.getOutlineStroke();
        Paint outlinePaint = plot.getOutlinePaint();
        if ((outlineStroke != null) && (outlinePaint != null)) {
            g2.setStroke(outlineStroke);
            g2.setPaint(outlinePaint);
            g2.draw(clip);
        }

    }

    /**
     * Draws a grid line against the domain axis.
     * 
     * @param g2
     *           the graphics device.
     * @param plot
     *           the plot.
     * @param dataArea
     *           the area for plotting data (not yet adjusted for any 3D effect).
     * @param value
     *           the Java2D value at which the grid line should be drawn.
     */
    public void drawDomainGridline(Graphics2D g2, CategoryPlot plot, Rectangle2D dataArea, double value) {

        Line2D line1 = null;
        Line2D line2 = null;
        PlotOrientation orientation = plot.getOrientation();
        if (orientation == PlotOrientation.HORIZONTAL) {
            double y0 = value;
            double y1 = value - getYOffset();
            double x0 = dataArea.getMinX();
            double x1 = x0 + getXOffset();
            double x2 = dataArea.getMaxY();
            line1 = new Line2D.Double(x0, y0, x1, y1);
            line2 = new Line2D.Double(x1, y1, x2, y1);
        } else if (orientation == PlotOrientation.VERTICAL) {
            double x0 = value;
            double x1 = value + getXOffset();
            double y0 = dataArea.getMaxY();
            double y1 = y0 - getYOffset();
            double y2 = dataArea.getMinY();
            line1 = new Line2D.Double(x0, y0, x1, y1);
            line2 = new Line2D.Double(x1, y1, x1, y2);
        }
        Paint paint = plot.getDomainGridlinePaint();
        Stroke stroke = plot.getDomainGridlineStroke();
        g2.setPaint(paint != null ? paint : Plot.DEFAULT_OUTLINE_PAINT);
        g2.setStroke(stroke != null ? stroke : Plot.DEFAULT_OUTLINE_STROKE);
        g2.draw(line1);
        g2.draw(line2);

    }

    /**
     * Draws a grid line against the range axis.
     * 
     * @param g2
     *           the graphics device.
     * @param plot
     *           the plot.
     * @param axis
     *           the value axis.
     * @param dataArea
     *           the area for plotting data (not yet adjusted for any 3D effect).
     * @param value
     *           the value at which the grid line should be drawn.
     */
    public void drawRangeGridline(Graphics2D g2, CategoryPlot plot, ValueAxis axis, Rectangle2D dataArea,
            double value) {

        Range range = axis.getRange();

        if (!range.contains(value)) {
            return;
        }

        Rectangle2D adjusted = new Rectangle2D.Double(dataArea.getX(), dataArea.getY() + getYOffset(),
                dataArea.getWidth() - getXOffset(), dataArea.getHeight() - getYOffset());

        Line2D line1 = null;
        Line2D line2 = null;
        PlotOrientation orientation = plot.getOrientation();
        if (orientation == PlotOrientation.HORIZONTAL) {
            double x0 = axis.valueToJava2D(value, adjusted, plot.getRangeAxisEdge());
            double x1 = x0 + getXOffset();
            double y0 = dataArea.getMaxY();
            double y1 = y0 - getYOffset();
            double y2 = dataArea.getMinY();
            line1 = new Line2D.Double(x0, y0, x1, y1);
            line2 = new Line2D.Double(x1, y1, x1, y2);
        } else if (orientation == PlotOrientation.VERTICAL) {
            double y0 = axis.valueToJava2D(value, adjusted, plot.getRangeAxisEdge());
            double y1 = y0 - getYOffset();
            double x0 = dataArea.getMinX();
            double x1 = x0 + getXOffset();
            double x2 = dataArea.getMaxX();
            line1 = new Line2D.Double(x0, y0, x1, y1);
            line2 = new Line2D.Double(x1, y1, x2, y1);
        }
        Paint paint = plot.getRangeGridlinePaint();
        Stroke stroke = plot.getRangeGridlineStroke();
        g2.setPaint(paint != null ? paint : Plot.DEFAULT_OUTLINE_PAINT);
        g2.setStroke(stroke != null ? stroke : Plot.DEFAULT_OUTLINE_STROKE);
        g2.draw(line1);
        g2.draw(line2);

    }

    /**
     * Draws a range marker.
     * 
     * @param g2
     *           the graphics device.
     * @param plot
     *           the plot.
     * @param axis
     *           the value axis.
     * @param marker
     *           the marker.
     * @param dataArea
     *           the area for plotting data (not including 3D effect).
     */
    public void drawRangeMarker(Graphics2D g2, CategoryPlot plot, ValueAxis axis, Marker marker,
            Rectangle2D dataArea) {

        if (marker instanceof ValueMarker) {
            ValueMarker vm = (ValueMarker) marker;
            double value = vm.getValue();
            Range range = axis.getRange();
            if (!range.contains(value)) {
                return;
            }

            Rectangle2D adjusted = new Rectangle2D.Double(dataArea.getX(), dataArea.getY() + getYOffset(),
                    dataArea.getWidth() - getXOffset(), dataArea.getHeight() - getYOffset());

            GeneralPath path = null;
            PlotOrientation orientation = plot.getOrientation();
            if (orientation == PlotOrientation.HORIZONTAL) {
                float x = (float) axis.valueToJava2D(value, adjusted, plot.getRangeAxisEdge());
                float y = (float) adjusted.getMaxY();
                path = new GeneralPath();
                path.moveTo(x, y);
                path.lineTo((float) (x + getXOffset()), y - (float) getYOffset());
                path.lineTo((float) (x + getXOffset()), (float) (adjusted.getMinY() - getYOffset()));
                path.lineTo(x, (float) adjusted.getMinY());
                path.closePath();
            } else if (orientation == PlotOrientation.VERTICAL) {
                float y = (float) axis.valueToJava2D(value, adjusted, plot.getRangeAxisEdge());
                float x = (float) dataArea.getX();
                path = new GeneralPath();
                path.moveTo(x, y);
                path.lineTo(x + (float) this.xOffset, y - (float) this.yOffset);
                path.lineTo((float) (adjusted.getMaxX() + this.xOffset), y - (float) this.yOffset);
                path.lineTo((float) (adjusted.getMaxX()), y);
                path.closePath();
            }
            g2.setPaint(marker.getPaint());
            g2.fill(path);
            g2.setPaint(marker.getOutlinePaint());
            g2.draw(path);
        }
    }

    /**
     * Draws a 3D bar to represent one data item.
     * 
     * @param g2
     *           the graphics device.
     * @param state
     *           the renderer state.
     * @param dataArea
     *           the area for plotting the data.
     * @param plot
     *           the plot.
     * @param domainAxis
     *           the domain axis.
     * @param rangeAxis
     *           the range axis.
     * @param dataset
     *           the dataset.
     * @param row
     *           the row index (zero-based).
     * @param column
     *           the column index (zero-based).
     */
    public void drawItem(Graphics2D g2, CategoryItemRendererState state, Rectangle2D dataArea, CategoryPlot plot,
            CategoryAxis domainAxis, ValueAxis rangeAxis, CategoryDataset dataset, int row, int column) {

        // check the value we are plotting...
        Number dataValue = dataset.getValue(row, column);
        if (dataValue == null) {
            return;
        }

        double value = dataValue.doubleValue();

        Rectangle2D adjusted = new Rectangle2D.Double(dataArea.getX(), dataArea.getY() + getYOffset(),
                dataArea.getWidth() - getXOffset(), dataArea.getHeight() - getYOffset());

        PlotOrientation orientation = plot.getOrientation();

        double barW0 = calculateBarW0(plot, orientation, adjusted, domainAxis, state, row, column);
        double[] barL0L1 = calculateBarL0L1(value);
        if (barL0L1 == null) {
            return; // the bar is not visible
        }

        RectangleEdge edge = plot.getRangeAxisEdge();
        double transL0 = rangeAxis.valueToJava2D(barL0L1[0], adjusted, edge);
        double transL1 = rangeAxis.valueToJava2D(barL0L1[1], adjusted, edge);
        double barL0 = Math.min(transL0, transL1);
        double barLength = Math.abs(transL1 - transL0);

        // draw the bar...
        Rectangle2D bar = null;
        if (orientation == PlotOrientation.HORIZONTAL) {
            bar = new Rectangle2D.Double(barL0, barW0, barLength, state.getBarWidth());
        } else {
            bar = new Rectangle2D.Double(barW0, barL0, state.getBarWidth(), barLength);
        }
        Paint itemPaint = getItemPaint(row, column);
        g2.setPaint(itemPaint);
        g2.fill(bar);

        double x0 = bar.getMinX();
        double x1 = x0 + getXOffset();
        double x2 = bar.getMaxX();
        double x3 = x2 + getXOffset();

        double y0 = bar.getMinY() - getYOffset();
        double y1 = bar.getMinY();
        double y2 = bar.getMaxY() - getYOffset();
        double y3 = bar.getMaxY();

        GeneralPath bar3dRight = null;
        GeneralPath bar3dTop = null;
        if (barLength > 0.0) {
            bar3dRight = new GeneralPath();
            bar3dRight.moveTo((float) x2, (float) y3);
            bar3dRight.lineTo((float) x2, (float) y1);
            bar3dRight.lineTo((float) x3, (float) y0);
            bar3dRight.lineTo((float) x3, (float) y2);
            bar3dRight.closePath();

            if (itemPaint instanceof Color) {
                g2.setPaint(((Color) itemPaint).darker());
            }
            g2.fill(bar3dRight);
        }

        bar3dTop = new GeneralPath();
        bar3dTop.moveTo((float) x0, (float) y1);
        bar3dTop.lineTo((float) x1, (float) y0);
        bar3dTop.lineTo((float) x3, (float) y0);
        bar3dTop.lineTo((float) x2, (float) y1);
        bar3dTop.closePath();

        // check ttest info
        Paint oldPaint = g2.getPaint();
        if (dataset instanceof BioStatisticalCategoryDataset) {
            BioStatisticalCategoryDataset bds = (BioStatisticalCategoryDataset) dataset;
            boolean isRef = bds.getTTestIsRef(row, column);
            boolean isH1 = bds.getTTestIsH1(row, column);
            if (isRef && isH1) {
                // no t test was done for this data point
            } else {
                GeneralPath ttestMark = new GeneralPath();
                g2.setPaint(getItemOutlinePaint(row, column));

                float x_ = (float) bar.getCenterX();
                float y_ = (float) bar.getCenterY();
                if (isRef) {
                    // don't mark the reference bar
                } else {
                    if (!isH1) {
                    } else {
                        float markSize = bds.getTtestMarkCircleSize();
                        float sxx = markSize;
                        float sxy = markSize;

                        if (orientation == PlotOrientation.HORIZONTAL) {
                            g2.fill(StatisticalBarRenderer.getTTestShape(x_ - sxx, y_ - sxy, sxx * 2, sxy * 2));
                        } else {
                            g2.fill(StatisticalBarRenderer.getTTestShape(x_ - sxx, y_ - sxy, sxx * 2, sxy * 2));
                        }

                        //
                        // ttestMark.moveTo(x_-sxx, y_);
                        // ttestMark.lineTo(x_, y_+sxy);
                        // ttestMark.lineTo(x_+sxx, y_);
                        // ttestMark.lineTo(x_, y_-sxy);
                        // ttestMark.closePath();
                        // g2.fill(ttestMark);
                    }
                }
            }
        }
        g2.setPaint(oldPaint);

        g2.fill(bar3dTop);

        if (isDrawBarOutline() && state.getBarWidth() > BAR_OUTLINE_WIDTH_THRESHOLD) {
            g2.setStroke(getItemOutlineStroke(row, column));
            g2.setPaint(getItemOutlinePaint(row, column));
            g2.draw(bar);

            if (bar3dRight != null) {
                g2.draw(bar3dRight);
            }

            if (bar3dTop != null) {
                g2.draw(bar3dTop);
            }
        }

        CategoryLabelGenerator generator = getLabelGenerator(row, column);
        if (generator != null && isItemLabelVisible(row, column)) {
            drawItemLabel(g2, dataset, row, column, plot, generator, bar, (transL0 < transL1));
        }

        // collect entity and tool tip information...
        if (state.getInfo() != null) {
            EntityCollection entities = state.getInfo().getOwner().getEntityCollection();
            if (entities != null) {
                GeneralPath barOutline = new GeneralPath();
                barOutline.moveTo((float) x0, (float) y3);
                barOutline.lineTo((float) x0, (float) y1);
                barOutline.lineTo((float) x1, (float) y0);
                barOutline.lineTo((float) x3, (float) y0);
                barOutline.lineTo((float) x3, (float) y2);
                barOutline.lineTo((float) x2, (float) y3);
                barOutline.closePath();

                String tip = null;
                CategoryToolTipGenerator tipster = getToolTipGenerator(row, column);
                if (tipster != null) {
                    tip = tipster.generateToolTip(dataset, row, column);
                }
                String url = null;
                if (getItemURLGenerator(row, column) != null) {
                    url = getItemURLGenerator(row, column).generateURL(dataset, row, column);
                }
                CategoryItemEntity entity = new CategoryItemEntity(barOutline, tip, url, dataset, row,
                        dataset.getColumnKey(column), column);
                entities.addEntity(entity);
            }
        }

    }

    /**
     * Provides serialization support.
     * 
     * @param stream
     *           the output stream.
     * @throws IOException
     *            if there is an I/O error.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.defaultWriteObject();
        SerialUtilities.writePaint(this.wallPaint, stream);
    }

    /**
     * Provides serialization support.
     * 
     * @param stream
     *           the input stream.
     * @throws IOException
     *            if there is an I/O error.
     * @throws ClassNotFoundException
     *            if there is a classpath problem.
     */
    private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
        stream.defaultReadObject();
        this.wallPaint = SerialUtilities.readPaint(stream);
    }

}