/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2014, 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 *
 * ----------------
 * BarRenderer.java
 * ----------------
 * (C) Copyright 2002-2014, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Christian W. Zuckschwerdt;
 *                   Peter Kolb (patches 2497611, 2791407);
 *
 * Changes
 * -------
 * 14-Mar-2002 : Version 1 (DG);
 * 23-May-2002 : Added tooltip generator to renderer (DG);
 * 29-May-2002 : Moved tooltip generator to abstract super-class (DG);
 * 25-Jun-2002 : Changed constructor to protected and removed redundant
 *               code (DG);
 * 26-Jun-2002 : Added axis to initialise method, and record upper and lower
 *               clip values (DG);
 * 24-Sep-2002 : Added getLegendItem() method (DG);
 * 09-Oct-2002 : Modified constructor to include URL generator (DG);
 * 05-Nov-2002 : Base dataset is now TableDataset not CategoryDataset (DG);
 * 10-Jan-2003 : Moved get/setItemMargin() method up from subclasses (DG);
 * 17-Jan-2003 : Moved plot classes into a separate package (DG);
 * 25-Mar-2003 : Implemented Serializable (DG);
 * 01-May-2003 : Modified clipping to allow for dual axes and datasets (DG);
 * 12-May-2003 : Merged horizontal and vertical bar renderers (DG);
 * 12-Jun-2003 : Updates for item labels (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 02-Sep-2003 : Changed initialise method to fix bug 790407 (DG);
 * 16-Sep-2003 : Changed ChartRenderingInfo --> PlotRenderingInfo (DG);
 * 07-Oct-2003 : Added renderer state (DG);
 * 27-Oct-2003 : Merged drawHorizontalItem() and drawVerticalItem()
 *               methods (DG);
 * 28-Oct-2003 : Added support for gradient paint on bars (DG);
 * 14-Nov-2003 : Added 'maxBarWidth' attribute (DG);
 * 10-Feb-2004 : Small changes inside drawItem() method to ease cut-and-paste
 *               overriding (DG);
 * 19-Mar-2004 : Fixed bug introduced with separation of tool tip and item
 *               label generators.  Fixed equals() method (DG);
 * 11-May-2004 : Fix for null pointer exception (bug id 951127) (DG);
 * 05-Nov-2004 : Modified drawItem() signature (DG);
 * 26-Jan-2005 : Provided override for getLegendItem() method (DG);
 * 20-Apr-2005 : Generate legend labels, tooltips and URLs (DG);
 * 18-May-2005 : Added configurable base value (DG);
 * 09-Jun-2005 : Use addItemEntity() method from superclass (DG);
 * 01-Dec-2005 : Update legend item to use/not use outline (DG);
 * ------------: JFreeChart 1.0.x ---------------------------------------------
 * 06-Dec-2005 : Fixed bug 1374222 (JDK 1.4 specific code) (DG);
 * 11-Jan-2006 : Fixed bug 1401856 (bad rendering for non-zero base) (DG);
 * 04-Aug-2006 : Fixed bug 1467706 (missing item labels for zero value
 *               bars) (DG);
 * 04-Dec-2006 : Fixed bug in rendering to non-primary axis (DG);
 * 13-Dec-2006 : Add support for GradientPaint display in legend items (DG);
 * 20-Apr-2007 : Updated getLegendItem() for renderer change (DG);
 * 11-May-2007 : Check for visibility in getLegendItem() (DG);
 * 17-May-2007 : Set datasetIndex and seriesIndex in getLegendItem() (DG);
 * 18-May-2007 : Set dataset and seriesKey for LegendItem (DG);
 * 07-May-2008 : If minimumBarLength is > 0.0, extend the non-base end of the
 *               bar (DG);
 * 17-Jun-2008 : Apply legend shape, font and paint attributes (DG);
 * 24-Jun-2008 : Added barPainter mechanism (DG);
 * 26-Jun-2008 : Added crosshair support (DG);
 * 13-Aug-2008 : Added shadowPaint attribute (DG);
 * 14-Jan-2009 : Added support for seriesVisible flags (PK);
 * 03-Feb-2009 : Added defaultShadowsVisible flag - see patch 2511330 (PK);
 * 03-Jul-2013 : Use ParamChecks (DG);
 *
 */

package org.jfree.chart.renderer.category;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import org.jfree.chart.LegendItem;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.event.RendererChangeEvent;
import org.jfree.chart.labels.CategoryItemLabelGenerator;
import org.jfree.chart.labels.ItemLabelAnchor;
import org.jfree.chart.labels.ItemLabelPosition;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.util.ParamChecks;
import org.jfree.data.Range;
import org.jfree.data.category.CategoryDataset;
import org.jfree.io.SerialUtilities;
import org.jfree.text.TextUtilities;
import org.jfree.ui.GradientPaintTransformer;
import org.jfree.ui.RectangleEdge;
import org.jfree.ui.StandardGradientPaintTransformer;
import org.jfree.util.ObjectUtilities;
import org.jfree.util.PaintUtilities;
import org.jfree.util.PublicCloneable;

/**
 * A {@link CategoryItemRenderer} that draws individual data items as bars.
 * The example shown here is generated by the <code>BarChartDemo1.java</code>
 * program included in the JFreeChart Demo Collection:
 * <br><br>
 * <img src="../../../../../images/BarRendererSample.png"
 * alt="BarRendererSample.png">
 */
public class BarRenderer extends AbstractCategoryItemRenderer
        implements Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 6000649414965887481L;

    /** The default item margin percentage. */
    public static final double DEFAULT_ITEM_MARGIN = 0.20;

    /**
     * Constant that controls the minimum width before a bar has an outline
     * drawn.
     */
    public static final double BAR_OUTLINE_WIDTH_THRESHOLD = 3.0;

    /**
     * The default bar painter assigned to each new instance of this renderer.
     *
     * @since 1.0.11
     */
    private static BarPainter defaultBarPainter = new GradientBarPainter();

    /**
     * Returns the default bar painter.
     *
     * @return The default bar painter.
     *
     * @since 1.0.11
     */
    public static BarPainter getDefaultBarPainter() {
        return BarRenderer.defaultBarPainter;
    }

    /**
     * Sets the default bar painter.
     *
     * @param painter  the painter (<code>null</code> not permitted).
     *
     * @since 1.0.11
     */
    public static void setDefaultBarPainter(BarPainter painter) {
        ParamChecks.nullNotPermitted(painter, "painter");
        BarRenderer.defaultBarPainter = painter;
    }

    /**
     * The default value for the initialisation of the shadowsVisible flag.
     */
    private static boolean defaultShadowsVisible = true;

    /**
     * Returns the default value for the <code>shadowsVisible</code> flag.
     *
     * @return A boolean.
     *
     * @see #setDefaultShadowsVisible(boolean)
     *
     * @since 1.0.13
     */
    public static boolean getDefaultShadowsVisible() {
        return BarRenderer.defaultShadowsVisible;
    }

    /**
     * Sets the default value for the shadows visible flag.
     *
     * @param visible  the new value for the default.
     *
     * @see #getDefaultShadowsVisible()
     *
     * @since 1.0.13
     */
    public static void setDefaultShadowsVisible(boolean visible) {
        BarRenderer.defaultShadowsVisible = visible;
    }

    /** The margin between items (bars) within a category. */
    private double itemMargin;

    /** A flag that controls whether or not bar outlines are drawn. */
    private boolean drawBarOutline;

    /** The maximum bar width as a percentage of the available space. */
    private double maximumBarWidth;

    /** The minimum bar length (in Java2D units). */
    private double minimumBarLength;

    /**
     * An optional class used to transform gradient paint objects to fit each
     * bar.
     */
    private GradientPaintTransformer gradientPaintTransformer;

    /**
     * The fallback position if a positive item label doesn't fit inside the
     * bar.
     */
    private ItemLabelPosition positiveItemLabelPositionFallback;

    /**
     * The fallback position if a negative item label doesn't fit inside the
     * bar.
     */
    private ItemLabelPosition negativeItemLabelPositionFallback;

    /** The upper clip (axis) value for the axis. */
    private double upperClip;
    // TODO:  this needs to move into the renderer state

    /** The lower clip (axis) value for the axis. */
    private double lowerClip;
    // TODO:  this needs to move into the renderer state

    /** The base value for the bars (defaults to 0.0). */
    private double base;

    /**
     * A flag that controls whether the base value is included in the range
     * returned by the findRangeBounds() method.
     */
    private boolean includeBaseInRange;

    /**
     * The bar painter (never <code>null</code>).
     *
     * @since 1.0.11
     */
    private BarPainter barPainter;

    /**
     * The flag that controls whether or not shadows are drawn for the bars.
     *
     * @since 1.0.11
     */
    private boolean shadowsVisible;

    /**
     * The shadow paint.
     *
     * @since 1.0.11
     */
    private transient Paint shadowPaint;

    /**
     * The x-offset for the shadow effect.
     *
     * @since 1.0.11
     */
    private double shadowXOffset;

    /**
     * The y-offset for the shadow effect.
     *
     * @since 1.0.11
     */
    private double shadowYOffset;

    /**
     * Creates a new bar renderer with default settings.
     */
    public BarRenderer() {
        super();
        this.base = 0.0;
        this.includeBaseInRange = true;
        this.itemMargin = DEFAULT_ITEM_MARGIN;
        this.drawBarOutline = false;
        this.maximumBarWidth = 1.0;
            // 100 percent, so it will not apply unless changed
        this.positiveItemLabelPositionFallback = null;
        this.negativeItemLabelPositionFallback = null;
        this.gradientPaintTransformer = new StandardGradientPaintTransformer();
        this.minimumBarLength = 0.0;
        setBaseLegendShape(new Rectangle2D.Double(-4.0, -4.0, 8.0, 8.0));
        this.barPainter = getDefaultBarPainter();
        this.shadowsVisible = getDefaultShadowsVisible();
        this.shadowPaint = Color.gray;
        this.shadowXOffset = 4.0;
        this.shadowYOffset = 4.0;
    }

    /**
     * Returns the base value for the bars.  The default value is
     * <code>0.0</code>.
     *
     * @return The base value for the bars.
     *
     * @see #setBase(double)
     */
    public double getBase() {
        return this.base;
    }

    /**
     * Sets the base value for the bars and sends a {@link RendererChangeEvent}
     * to all registered listeners.
     *
     * @param base  the new base value.
     *
     * @see #getBase()
     */
    public void setBase(double base) {
        this.base = base;
        fireChangeEvent();
    }

    /**
     * Returns the item margin as a percentage of the available space for all
     * bars.
     *
     * @return The margin percentage (where 0.10 is ten percent).
     *
     * @see #setItemMargin(double)
     */
    public double getItemMargin() {
        return this.itemMargin;
    }

    /**
     * Sets the item margin and sends a {@link RendererChangeEvent} to all
     * registered listeners.  The value is expressed as a percentage of the
     * available width for plotting all the bars, with the resulting amount to
     * be distributed between all the bars evenly.
     *
     * @param percent  the margin (where 0.10 is ten percent).
     *
     * @see #getItemMargin()
     */
    public void setItemMargin(double percent) {
        this.itemMargin = percent;
        fireChangeEvent();
    }

    /**
     * Returns a flag that controls whether or not bar outlines are drawn.
     *
     * @return A boolean.
     *
     * @see #setDrawBarOutline(boolean)
     */
    public boolean isDrawBarOutline() {
        return this.drawBarOutline;
    }

    /**
     * Sets the flag that controls whether or not bar outlines are drawn and
     * sends a {@link RendererChangeEvent} to all registered listeners.
     *
     * @param draw  the flag.
     *
     * @see #isDrawBarOutline()
     */
    public void setDrawBarOutline(boolean draw) {
        this.drawBarOutline = draw;
        fireChangeEvent();
    }

    /**
     * Returns the maximum bar width, as a percentage of the available drawing
     * space.
     *
     * @return The maximum bar width.
     *
     * @see #setMaximumBarWidth(double)
     */
    public double getMaximumBarWidth() {
        return this.maximumBarWidth;
    }

    /**
     * Sets the maximum bar width, which is specified as a percentage of the
     * available space for all bars, and sends a {@link RendererChangeEvent} to
     * all registered listeners.
     *
     * @param percent  the percent (where 0.05 is five percent).
     *
     * @see #getMaximumBarWidth()
     */
    public void setMaximumBarWidth(double percent) {
        this.maximumBarWidth = percent;
        fireChangeEvent();
    }

    /**
     * Returns the minimum bar length (in Java2D units).  The default value is
     * 0.0.
     *
     * @return The minimum bar length.
     *
     * @see #setMinimumBarLength(double)
     */
    public double getMinimumBarLength() {
        return this.minimumBarLength;
    }

    /**
     * Sets the minimum bar length and sends a {@link RendererChangeEvent} to
     * all registered listeners.  The minimum bar length is specified in Java2D
     * units, and can be used to prevent bars that represent very small data
     * values from disappearing when drawn on the screen.  Typically you would
     * set this to (say) 0.5 or 1.0 Java 2D units.  Use this attribute with
     * caution, however, because setting it to a non-zero value will
     * artificially increase the length of bars representing small values,
     * which may misrepresent your data.
     *
     * @param min  the minimum bar length (in Java2D units, must be &gt;= 0.0).
     *
     * @see #getMinimumBarLength()
     */
    public void setMinimumBarLength(double min) {
        if (min < 0.0) {
            throw new IllegalArgumentException("Requires 'min' >= 0.0");
        }
        this.minimumBarLength = min;
        fireChangeEvent();
    }

    /**
     * Returns the gradient paint transformer (an object used to transform
     * gradient paint objects to fit each bar).
     *
     * @return A transformer (<code>null</code> possible).
     *
     * @see #setGradientPaintTransformer(GradientPaintTransformer)
     */
    public GradientPaintTransformer getGradientPaintTransformer() {
        return this.gradientPaintTransformer;
    }

    /**
     * Sets the gradient paint transformer and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param transformer  the transformer (<code>null</code> permitted).
     *
     * @see #getGradientPaintTransformer()
     */
    public void setGradientPaintTransformer(
            GradientPaintTransformer transformer) {
        this.gradientPaintTransformer = transformer;
        fireChangeEvent();
    }

    /**
     * Returns the fallback position for positive item labels that don't fit
     * within a bar.
     *
     * @return The fallback position (<code>null</code> possible).
     *
     * @see #setPositiveItemLabelPositionFallback(ItemLabelPosition)
     */
    public ItemLabelPosition getPositiveItemLabelPositionFallback() {
        return this.positiveItemLabelPositionFallback;
    }

    /**
     * Sets the fallback position for positive item labels that don't fit
     * within a bar, and sends a {@link RendererChangeEvent} to all registered
     * listeners.
     *
     * @param position  the position (<code>null</code> permitted).
     *
     * @see #getPositiveItemLabelPositionFallback()
     */
    public void setPositiveItemLabelPositionFallback(
            ItemLabelPosition position) {
        this.positiveItemLabelPositionFallback = position;
        fireChangeEvent();
    }

    /**
     * Returns the fallback position for negative item labels that don't fit
     * within a bar.
     *
     * @return The fallback position (<code>null</code> possible).
     *
     * @see #setPositiveItemLabelPositionFallback(ItemLabelPosition)
     */
    public ItemLabelPosition getNegativeItemLabelPositionFallback() {
        return this.negativeItemLabelPositionFallback;
    }

    /**
     * Sets the fallback position for negative item labels that don't fit
     * within a bar, and sends a {@link RendererChangeEvent} to all registered
     * listeners.
     *
     * @param position  the position (<code>null</code> permitted).
     *
     * @see #getNegativeItemLabelPositionFallback()
     */
    public void setNegativeItemLabelPositionFallback(
            ItemLabelPosition position) {
        this.negativeItemLabelPositionFallback = position;
        fireChangeEvent();
    }

    /**
     * Returns the flag that controls whether or not the base value for the
     * bars is included in the range calculated by
     * {@link #findRangeBounds(CategoryDataset)}.
     *
     * @return <code>true</code> if the base is included in the range, and
     *         <code>false</code> otherwise.
     *
     * @since 1.0.1
     *
     * @see #setIncludeBaseInRange(boolean)
     */
    public boolean getIncludeBaseInRange() {
        return this.includeBaseInRange;
    }

    /**
     * Sets the flag that controls whether or not the base value for the bars
     * is included in the range calculated by
     * {@link #findRangeBounds(CategoryDataset)}.  If the flag is changed,
     * a {@link RendererChangeEvent} is sent to all registered listeners.
     *
     * @param include  the new value for the flag.
     *
     * @since 1.0.1
     *
     * @see #getIncludeBaseInRange()
     */
    public void setIncludeBaseInRange(boolean include) {
        if (this.includeBaseInRange != include) {
            this.includeBaseInRange = include;
            fireChangeEvent();
        }
    }

    /**
     * Returns the bar painter.
     *
     * @return The bar painter (never <code>null</code>).
     *
     * @see #setBarPainter(BarPainter)
     *
     * @since 1.0.11
     */
    public BarPainter getBarPainter() {
        return this.barPainter;
    }

    /**
     * Sets the bar painter for this renderer and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param painter  the painter (<code>null</code> not permitted).
     *
     * @see #getBarPainter()
     *
     * @since 1.0.11
     */
    public void setBarPainter(BarPainter painter) {
        ParamChecks.nullNotPermitted(painter, "painter");
        this.barPainter = painter;
        fireChangeEvent();
    }

    /**
     * Returns the flag that controls whether or not shadows are drawn for
     * the bars.
     *
     * @return A boolean.
     *
     * @since 1.0.11
     */
    public boolean getShadowsVisible() {
        return this.shadowsVisible;
    }

    /**
     * Sets the flag that controls whether or not shadows are
     * drawn by the renderer.
     *
     * @param visible  the new flag value.
     *
     * @since 1.0.11
     */
    public void setShadowVisible(boolean visible) {
        this.shadowsVisible = visible;
        fireChangeEvent();
    }

    /**
     * Returns the shadow paint.
     *
     * @return The shadow paint.
     *
     * @see #setShadowPaint(Paint)
     *
     * @since 1.0.11
     */
    public Paint getShadowPaint() {
        return this.shadowPaint;
    }

    /**
     * Sets the shadow paint and sends a {@link RendererChangeEvent} to all
     * registered listeners.
     *
     * @param paint  the paint (<code>null</code> not permitted).
     *
     * @see #getShadowPaint()
     *
     * @since 1.0.11
     */
    public void setShadowPaint(Paint paint) {
        ParamChecks.nullNotPermitted(paint, "paint");
        this.shadowPaint = paint;
        fireChangeEvent();
    }

    /**
     * Returns the shadow x-offset.
     *
     * @return The shadow x-offset.
     *
     * @since 1.0.11
     */
    public double getShadowXOffset() {
        return this.shadowXOffset;
    }

    /**
     * Sets the x-offset for the bar shadow and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param offset  the offset.
     *
     * @since 1.0.11
     */
    public void setShadowXOffset(double offset) {
        this.shadowXOffset = offset;
        fireChangeEvent();
    }

    /**
     * Returns the shadow y-offset.
     *
     * @return The shadow y-offset.
     *
     * @since 1.0.11
     */
    public double getShadowYOffset() {
        return this.shadowYOffset;
    }

    /**
     * Sets the y-offset for the bar shadow and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param offset  the offset.
     *
     * @since 1.0.11
     */
    public void setShadowYOffset(double offset) {
        this.shadowYOffset = offset;
        fireChangeEvent();
    }

    /**
     * Returns the lower clip value.  This value is recalculated in the
     * initialise() method.
     *
     * @return The value.
     */
    public double getLowerClip() {
        // TODO:  this attribute should be transferred to the renderer state.
        return this.lowerClip;
    }

    /**
     * Returns the upper clip value.  This value is recalculated in the
     * initialise() method.
     *
     * @return The value.
     */
    public double getUpperClip() {
        // TODO:  this attribute should be transferred to the renderer state.
        return this.upperClip;
    }

    /**
     * Initialises the renderer and returns a state object that will be passed
     * to subsequent calls to the drawItem method.  This method gets called
     * once at the start of the process of drawing a chart.
     *
     * @param g2  the graphics device.
     * @param dataArea  the area in which the data is to be plotted.
     * @param plot  the plot.
     * @param rendererIndex  the renderer index.
     * @param info  collects chart rendering information for return to caller.
     *
     * @return The renderer state.
     */
    @Override
    public CategoryItemRendererState initialise(Graphics2D g2, 
            Rectangle2D dataArea, CategoryPlot plot, int rendererIndex,
            PlotRenderingInfo info) {

        CategoryItemRendererState state = super.initialise(g2, dataArea, plot,
                rendererIndex, info);

        // get the clipping values...
        ValueAxis rangeAxis = plot.getRangeAxisForDataset(rendererIndex);
        this.lowerClip = rangeAxis.getRange().getLowerBound();
        this.upperClip = rangeAxis.getRange().getUpperBound();

        // calculate the bar width
        calculateBarWidth(plot, dataArea, rendererIndex, state);

        return state;

    }

    /**
     * Calculates the bar width and stores it in the renderer state.
     *
     * @param plot  the plot.
     * @param dataArea  the data area.
     * @param rendererIndex  the renderer index.
     * @param state  the renderer state.
     */
    protected void calculateBarWidth(CategoryPlot plot,
                                     Rectangle2D dataArea,
                                     int rendererIndex,
                                     CategoryItemRendererState state) {

        CategoryAxis domainAxis = getDomainAxis(plot, rendererIndex);
        CategoryDataset dataset = plot.getDataset(rendererIndex);
        if (dataset != null) {
            int columns = dataset.getColumnCount();
            int rows = state.getVisibleSeriesCount() >= 0
                    ? state.getVisibleSeriesCount() : dataset.getRowCount();
            double space = 0.0;
            PlotOrientation orientation = plot.getOrientation();
            if (orientation == PlotOrientation.HORIZONTAL) {
                space = dataArea.getHeight();
            }
            else if (orientation == PlotOrientation.VERTICAL) {
                space = dataArea.getWidth();
            }
            double maxWidth = space * getMaximumBarWidth();
            double categoryMargin = 0.0;
            double currentItemMargin = 0.0;
            if (columns > 1) {
                categoryMargin = domainAxis.getCategoryMargin();
            }
            if (rows > 1) {
                currentItemMargin = getItemMargin();
            }
            double used = space * (1 - domainAxis.getLowerMargin()
                                     - domainAxis.getUpperMargin()
                                     - categoryMargin - currentItemMargin);
            if ((rows * columns) > 0) {
                state.setBarWidth(Math.min(used / (rows * columns), maxWidth));
            }
            else {
                state.setBarWidth(Math.min(used, maxWidth));
            }
        }
    }

    /**
     * Calculates the coordinate of the first "side" of a bar.  This will be
     * the minimum x-coordinate for a vertical bar, and the minimum
     * y-coordinate for a horizontal bar.
     *
     * @param plot  the plot.
     * @param orientation  the plot orientation.
     * @param dataArea  the data area.
     * @param domainAxis  the domain axis.
     * @param state  the renderer state (has the bar width precalculated).
     * @param row  the row index.
     * @param column  the column index.
     *
     * @return The coordinate.
     */
    protected double calculateBarW0(CategoryPlot plot, 
            PlotOrientation orientation, Rectangle2D dataArea, 
            CategoryAxis domainAxis, CategoryItemRendererState state,
            int row, int column) {
        // calculate bar width...
        double space;
        if (orientation == PlotOrientation.HORIZONTAL) {
            space = dataArea.getHeight();
        }
        else {
            space = dataArea.getWidth();
        }
        double barW0 = domainAxis.getCategoryStart(column, getColumnCount(),
                dataArea, plot.getDomainAxisEdge());
        int seriesCount = state.getVisibleSeriesCount() >= 0
                ? state.getVisibleSeriesCount() : getRowCount();
        int categoryCount = getColumnCount();
        if (seriesCount > 1) {
            double seriesGap = space * getItemMargin()
                               / (categoryCount * (seriesCount - 1));
            double seriesW = calculateSeriesWidth(space, domainAxis,
                    categoryCount, seriesCount);
            barW0 = barW0 + row * (seriesW + seriesGap)
                          + (seriesW / 2.0) - (state.getBarWidth() / 2.0);
        }
        else {
            barW0 = domainAxis.getCategoryMiddle(column, getColumnCount(),
                    dataArea, plot.getDomainAxisEdge()) - state.getBarWidth()
                    / 2.0;
        }
        return barW0;
    }

    /**
     * Calculates the coordinates for the length of a single bar.
     *
     * @param value  the value represented by the bar.
     *
     * @return The coordinates for each end of the bar (or <code>null</code> if
     *         the bar is not visible for the current axis range).
     */
    protected double[] calculateBarL0L1(double value) {
        double lclip = getLowerClip();
        double uclip = getUpperClip();
        double barLow = Math.min(this.base, value);
        double barHigh = Math.max(this.base, value);
        if (barHigh < lclip) {  // bar is not visible
            return null;
        }
        if (barLow > uclip) {   // bar is not visible
            return null;
        }
        barLow = Math.max(barLow, lclip);
        barHigh = Math.min(barHigh, uclip);
        return new double[] {barLow, barHigh};
    }

    /**
     * Returns the range of values the renderer requires to display all the
     * items from the specified dataset.  This takes into account the range
     * of values in the dataset, plus the flag that determines whether or not
     * the base value for the bars should be included in the range.
     *
     * @param dataset  the dataset (<code>null</code> permitted).
     * @param includeInterval  include the interval if the dataset has one?
     *
     * @return The range (or <code>null</code> if the dataset is
     *         <code>null</code> or empty).
     */
    @Override
    public Range findRangeBounds(CategoryDataset dataset,
            boolean includeInterval) {
        if (dataset == null) {
            return null;
        }
        Range result = super.findRangeBounds(dataset, includeInterval);
        if (result != null) {
            if (this.includeBaseInRange) {
                result = Range.expandToInclude(result, this.base);
            }
        }
        return result;
    }

    /**
     * Returns a legend item for a series.
     *
     * @param datasetIndex  the dataset index (zero-based).
     * @param series  the series index (zero-based).
     *
     * @return The legend item (possibly <code>null</code>).
     */
    @Override
    public LegendItem getLegendItem(int datasetIndex, int series) {

        CategoryPlot cp = getPlot();
        if (cp == null) {
            return null;
        }

        // check that a legend item needs to be displayed...
        if (!isSeriesVisible(series) || !isSeriesVisibleInLegend(series)) {
            return null;
        }

        CategoryDataset dataset = cp.getDataset(datasetIndex);
        String label = getLegendItemLabelGenerator().generateLabel(dataset,
                series);
        String description = label;
        String toolTipText = null;
        if (getLegendItemToolTipGenerator() != null) {
            toolTipText = getLegendItemToolTipGenerator().generateLabel(
                    dataset, series);
        }
        String urlText = null;
        if (getLegendItemURLGenerator() != null) {
            urlText = getLegendItemURLGenerator().generateLabel(dataset,
                    series);
        }
        Shape shape = lookupLegendShape(series);
        Paint paint = lookupSeriesPaint(series);
        Paint outlinePaint = lookupSeriesOutlinePaint(series);
        Stroke outlineStroke = lookupSeriesOutlineStroke(series);

        LegendItem result = new LegendItem(label, description, toolTipText,
                urlText, true, shape, true, paint, isDrawBarOutline(),
                outlinePaint, outlineStroke, false, new Line2D.Float(),
                new BasicStroke(1.0f), Color.black);
        result.setLabelFont(lookupLegendTextFont(series));
        Paint labelPaint = lookupLegendTextPaint(series);
        if (labelPaint != null) {
            result.setLabelPaint(labelPaint);
        }
        result.setDataset(dataset);
        result.setDatasetIndex(datasetIndex);
        result.setSeriesKey(dataset.getRowKey(series));
        result.setSeriesIndex(series);
        if (this.gradientPaintTransformer != null) {
            result.setFillPaintTransformer(this.gradientPaintTransformer);
        }
        return result;
    }

    /**
     * Draws the bar for a single (series, category) data item.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the data area.
     * @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).
     * @param pass  the pass index.
     */
    @Override
    public void drawItem(Graphics2D g2, CategoryItemRendererState state,
            Rectangle2D dataArea, CategoryPlot plot, CategoryAxis domainAxis,
            ValueAxis rangeAxis, CategoryDataset dataset, int row,
            int column, int pass) {

        // nothing is drawn if the row index is not included in the list with
        // the indices of the visible rows...
        int visibleRow = state.getVisibleSeriesIndex(row);
        if (visibleRow < 0) {
            return;
        }
        // nothing is drawn for null values...
        Number dataValue = dataset.getValue(row, column);
        if (dataValue == null) {
            return;
        }

        final double value = dataValue.doubleValue();
        PlotOrientation orientation = plot.getOrientation();
        double barW0 = calculateBarW0(plot, orientation, dataArea, domainAxis,
                state, visibleRow, column);
        double[] barL0L1 = calculateBarL0L1(value);
        if (barL0L1 == null) {
            return;  // the bar is not visible
        }

        RectangleEdge edge = plot.getRangeAxisEdge();
        double transL0 = rangeAxis.valueToJava2D(barL0L1[0], dataArea, edge);
        double transL1 = rangeAxis.valueToJava2D(barL0L1[1], dataArea, edge);

        // in the following code, barL0 is (in Java2D coordinates) the LEFT
        // end of the bar for a horizontal bar chart, and the TOP end of the
        // bar for a vertical bar chart.  Whether this is the BASE of the bar
        // or not depends also on (a) whether the data value is 'negative'
        // relative to the base value and (b) whether or not the range axis is
        // inverted.  This only matters if/when we apply the minimumBarLength
        // attribute, because we should extend the non-base end of the bar
        boolean positive = (value >= this.base);
        boolean inverted = rangeAxis.isInverted();
        double barL0 = Math.min(transL0, transL1);
        double barLength = Math.abs(transL1 - transL0);
        double barLengthAdj = 0.0;
        if (barLength > 0.0 && barLength < getMinimumBarLength()) {
            barLengthAdj = getMinimumBarLength() - barLength;
        }
        double barL0Adj = 0.0;
        RectangleEdge barBase;
        if (orientation == PlotOrientation.HORIZONTAL) {
            if (positive && inverted || !positive && !inverted) {
                barL0Adj = barLengthAdj;
                barBase = RectangleEdge.RIGHT;
            }
            else {
                barBase = RectangleEdge.LEFT;
            }
        }
        else {
            if (positive && !inverted || !positive && inverted) {
                barL0Adj = barLengthAdj;
                barBase = RectangleEdge.BOTTOM;
            }
            else {
                barBase = RectangleEdge.TOP;
            }
        }

        // draw the bar...
        Rectangle2D bar;
        if (orientation == PlotOrientation.HORIZONTAL) {
            bar = new Rectangle2D.Double(barL0 - barL0Adj, barW0,
                    barLength + barLengthAdj, state.getBarWidth());
        }
        else {
            bar = new Rectangle2D.Double(barW0, barL0 - barL0Adj,
                    state.getBarWidth(), barLength + barLengthAdj);
        }
        if (getShadowsVisible()) {
            this.barPainter.paintBarShadow(g2, this, row, column, bar, barBase,
                true);
        }
        this.barPainter.paintBar(g2, this, row, column, bar, barBase);

        CategoryItemLabelGenerator generator = getItemLabelGenerator(row,
                column);
        if (generator != null && isItemLabelVisible(row, column)) {
            drawItemLabel(g2, dataset, row, column, plot, generator, bar,
                    (value < 0.0));
        }

        // submit the current data point as a crosshair candidate
        int datasetIndex = plot.indexOf(dataset);
        updateCrosshairValues(state.getCrosshairState(),
                dataset.getRowKey(row), dataset.getColumnKey(column), value,
                datasetIndex, barW0, barL0, orientation);

        // add an item entity, if this information is being collected
        EntityCollection entities = state.getEntityCollection();
        if (entities != null) {
            addItemEntity(entities, dataset, row, column, bar);
        }

    }

    /**
     * Calculates the available space for each series.
     *
     * @param space  the space along the entire axis (in Java2D units).
     * @param axis  the category axis.
     * @param categories  the number of categories.
     * @param series  the number of series.
     *
     * @return The width of one series.
     */
    protected double calculateSeriesWidth(double space, CategoryAxis axis,
                                          int categories, int series) {
        double factor = 1.0 - getItemMargin() - axis.getLowerMargin()
                            - axis.getUpperMargin();
        if (categories > 1) {
            factor = factor - axis.getCategoryMargin();
        }
        return (space * factor) / (categories * series);
    }

    /**
     * Draws an item label.  This method is overridden so that the bar can be
     * used to calculate the label anchor point.
     *
     * @param g2  the graphics device.
     * @param data  the dataset.
     * @param row  the row.
     * @param column  the column.
     * @param plot  the plot.
     * @param generator  the label generator.
     * @param bar  the bar.
     * @param negative  a flag indicating a negative value.
     */
    protected void drawItemLabel(Graphics2D g2,
                                 CategoryDataset data,
                                 int row,
                                 int column,
                                 CategoryPlot plot,
                                 CategoryItemLabelGenerator generator,
                                 Rectangle2D bar,
                                 boolean negative) {

        String label = generator.generateLabel(data, row, column);
        if (label == null) {
            return;  // nothing to do
        }

        Font labelFont = getItemLabelFont(row, column);
        g2.setFont(labelFont);
        Paint paint = getItemLabelPaint(row, column);
        g2.setPaint(paint);

        // find out where to place the label...
        ItemLabelPosition position;
        if (!negative) {
            position = getPositiveItemLabelPosition(row, column);
        }
        else {
            position = getNegativeItemLabelPosition(row, column);
        }

        // work out the label anchor point...
        Point2D anchorPoint = calculateLabelAnchorPoint(
                position.getItemLabelAnchor(), bar, plot.getOrientation());

        if (isInternalAnchor(position.getItemLabelAnchor())) {
            Shape bounds = TextUtilities.calculateRotatedStringBounds(label,
                    g2, (float) anchorPoint.getX(), (float) anchorPoint.getY(),
                    position.getTextAnchor(), position.getAngle(),
                    position.getRotationAnchor());

            if (bounds != null) {
                if (!bar.contains(bounds.getBounds2D())) {
                    if (!negative) {
                        position = getPositiveItemLabelPositionFallback();
                    }
                    else {
                        position = getNegativeItemLabelPositionFallback();
                    }
                    if (position != null) {
                        anchorPoint = calculateLabelAnchorPoint(
                                position.getItemLabelAnchor(), bar,
                                plot.getOrientation());
                    }
                }
            }

        }

        if (position != null) {
            TextUtilities.drawRotatedString(label, g2,
                    (float) anchorPoint.getX(), (float) anchorPoint.getY(),
                    position.getTextAnchor(), position.getAngle(),
                    position.getRotationAnchor());
        }
    }

    /**
     * Calculates the item label anchor point.
     *
     * @param anchor  the anchor.
     * @param bar  the bar.
     * @param orientation  the plot orientation.
     *
     * @return The anchor point.
     */
    private Point2D calculateLabelAnchorPoint(ItemLabelAnchor anchor,
                                              Rectangle2D bar,
                                              PlotOrientation orientation) {

        Point2D result = null;
        double offset = getItemLabelAnchorOffset();
        double x0 = bar.getX() - offset;
        double x1 = bar.getX();
        double x2 = bar.getX() + offset;
        double x3 = bar.getCenterX();
        double x4 = bar.getMaxX() - offset;
        double x5 = bar.getMaxX();
        double x6 = bar.getMaxX() + offset;

        double y0 = bar.getMaxY() + offset;
        double y1 = bar.getMaxY();
        double y2 = bar.getMaxY() - offset;
        double y3 = bar.getCenterY();
        double y4 = bar.getMinY() + offset;
        double y5 = bar.getMinY();
        double y6 = bar.getMinY() - offset;

        if (anchor == ItemLabelAnchor.CENTER) {
            result = new Point2D.Double(x3, y3);
        }
        else if (anchor == ItemLabelAnchor.INSIDE1) {
            result = new Point2D.Double(x4, y4);
        }
        else if (anchor == ItemLabelAnchor.INSIDE2) {
            result = new Point2D.Double(x4, y4);
        }
        else if (anchor == ItemLabelAnchor.INSIDE3) {
            result = new Point2D.Double(x4, y3);
        }
        else if (anchor == ItemLabelAnchor.INSIDE4) {
            result = new Point2D.Double(x4, y2);
        }
        else if (anchor == ItemLabelAnchor.INSIDE5) {
            result = new Point2D.Double(x4, y2);
        }
        else if (anchor == ItemLabelAnchor.INSIDE6) {
            result = new Point2D.Double(x3, y2);
        }
        else if (anchor == ItemLabelAnchor.INSIDE7) {
            result = new Point2D.Double(x2, y2);
        }
        else if (anchor == ItemLabelAnchor.INSIDE8) {
            result = new Point2D.Double(x2, y2);
        }
        else if (anchor == ItemLabelAnchor.INSIDE9) {
            result = new Point2D.Double(x2, y3);
        }
        else if (anchor == ItemLabelAnchor.INSIDE10) {
            result = new Point2D.Double(x2, y4);
        }
        else if (anchor == ItemLabelAnchor.INSIDE11) {
            result = new Point2D.Double(x2, y4);
        }
        else if (anchor == ItemLabelAnchor.INSIDE12) {
            result = new Point2D.Double(x3, y4);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE1) {
            result = new Point2D.Double(x5, y6);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE2) {
            result = new Point2D.Double(x6, y5);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE3) {
            result = new Point2D.Double(x6, y3);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE4) {
            result = new Point2D.Double(x6, y1);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE5) {
            result = new Point2D.Double(x5, y0);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE6) {
            result = new Point2D.Double(x3, y0);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE7) {
            result = new Point2D.Double(x1, y0);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE8) {
            result = new Point2D.Double(x0, y1);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE9) {
            result = new Point2D.Double(x0, y3);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE10) {
            result = new Point2D.Double(x0, y5);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE11) {
            result = new Point2D.Double(x1, y6);
        }
        else if (anchor == ItemLabelAnchor.OUTSIDE12) {
            result = new Point2D.Double(x3, y6);
        }

        return result;

    }

    /**
     * Returns <code>true</code> if the specified anchor point is inside a bar.
     *
     * @param anchor  the anchor point.
     *
     * @return A boolean.
     */
    private boolean isInternalAnchor(ItemLabelAnchor anchor) {
        return anchor == ItemLabelAnchor.CENTER
               || anchor == ItemLabelAnchor.INSIDE1
               || anchor == ItemLabelAnchor.INSIDE2
               || anchor == ItemLabelAnchor.INSIDE3
               || anchor == ItemLabelAnchor.INSIDE4
               || anchor == ItemLabelAnchor.INSIDE5
               || anchor == ItemLabelAnchor.INSIDE6
               || anchor == ItemLabelAnchor.INSIDE7
               || anchor == ItemLabelAnchor.INSIDE8
               || anchor == ItemLabelAnchor.INSIDE9
               || anchor == ItemLabelAnchor.INSIDE10
               || anchor == ItemLabelAnchor.INSIDE11
               || anchor == ItemLabelAnchor.INSIDE12;
    }

    /**
     * Tests this instance for equality with an arbitrary object.
     *
     * @param obj  the object (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof BarRenderer)) {
            return false;
        }
        BarRenderer that = (BarRenderer) obj;
        if (this.base != that.base) {
            return false;
        }
        if (this.itemMargin != that.itemMargin) {
            return false;
        }
        if (this.drawBarOutline != that.drawBarOutline) {
            return false;
        }
        if (this.maximumBarWidth != that.maximumBarWidth) {
            return false;
        }
        if (this.minimumBarLength != that.minimumBarLength) {
            return false;
        }
        if (!ObjectUtilities.equal(this.gradientPaintTransformer,
                that.gradientPaintTransformer)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.positiveItemLabelPositionFallback,
            that.positiveItemLabelPositionFallback)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.negativeItemLabelPositionFallback,
            that.negativeItemLabelPositionFallback)) {
            return false;
        }
        if (!this.barPainter.equals(that.barPainter)) {
            return false;
        }
        if (this.shadowsVisible != that.shadowsVisible) {
            return false;
        }
        if (!PaintUtilities.equal(this.shadowPaint, that.shadowPaint)) {
            return false;
        }
        if (this.shadowXOffset != that.shadowXOffset) {
            return false;
        }
        if (this.shadowYOffset != that.shadowYOffset) {
            return false;
        }
        return super.equals(obj);
    }

    /**
     * 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.shadowPaint, 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.shadowPaint = SerialUtilities.readPaint(stream);
    }

}