gt:             rectY = rectY - rectHeight / 2.0;
context: /* ===========================================================
   * 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.]
   *
   * -------------------------
   * WaterfallBarRenderer.java
   * -------------------------
   * (C) Copyright 2003-2014, by Object Refinery Limited and Contributors.
   *
   * Original Author:  Darshan Shah;
   * Contributor(s):   David Gilbert (for Object Refinery Limited);
   *
   * Changes
   * -------
   * 20-Oct-2003 : Version 1, contributed by Darshan Shah (DG);
   * 06-Nov-2003 : Changed order of parameters in constructor, and added support
   *               for GradientPaint (DG);
   * 10-Feb-2004 : Updated drawItem() method to make cut-and-paste overriding
   *               easier.  Also fixed a bug that meant the minimum bar length
   *               was being ignored (DG);
   * 04-Oct-2004 : Reworked equals() method and renamed PaintUtils
   *               --> PaintUtilities (DG);
   * 05-Nov-2004 : Modified drawItem() signature (DG);
   * 07-Jan-2005 : Renamed getRangeExtent() --> findRangeBounds (DG);
   * 23-Feb-2005 : Added argument checking (DG);
   * 20-Apr-2005 : Renamed CategoryLabelGenerator
   *               --> CategoryItemLabelGenerator (DG);
   * 09-Jun-2005 : Use addItemEntity() from superclass (DG);
   * 27-Mar-2008 : Fixed error in findRangeBounds() method (DG);
   * 26-Sep-2008 : Fixed bug with bar alignment when maximumBarWidth is
   *               applied (DG);
   * 04-Feb-2009 : Updated findRangeBounds to handle null dataset consistently
   *               with other renderers (DG);
   * 19-May-2009 : Fixed FindBugs warnings, patch by Michal Wozniak (DG);
   * 03-Jul-2013 : Use ParamChecks (DG);
   *
   */
  
  package org.jfree.chart.renderer.category;
  
  import java.awt.Color;
  import java.awt.GradientPaint;
  import java.awt.Graphics2D;
  import java.awt.Paint;
  import java.awt.Stroke;
  import java.awt.geom.Rectangle2D;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  
  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.plot.CategoryPlot;
  import org.jfree.chart.plot.PlotOrientation;
  import org.jfree.chart.renderer.AbstractRenderer;
  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.ui.GradientPaintTransformType;
  import org.jfree.ui.RectangleEdge;
  import org.jfree.ui.StandardGradientPaintTransformer;
  import org.jfree.util.PaintUtilities;
  
  /**
   * A renderer that handles the drawing of waterfall bar charts, for use with
   * the {@link CategoryPlot} class.  Some quirks to note:
   * <ul>
   * <li>the value in the last category of the dataset should be (redundantly)
   *   specified as the sum of the items in the preceding categories - otherwise
   *   the final bar in the plot will be incorrectly plotted;</li>
   * <li>the bar colors are defined using special methods in this class - the
   *   inherited methods (for example,
   *   {@link AbstractRenderer#setSeriesPaint(int, Paint)}) are ignored;</li>
   * </ul>
   * The example shown here is generated by the
   * <code>WaterfallChartDemo1.java</code> program included in the JFreeChart
   * Demo Collection:
   * <br><br>
   * <img src="../../../../../images/WaterfallBarRendererSample.png"
   * alt="WaterfallBarRendererSample.png">
   */
  public class WaterfallBarRenderer extends BarRenderer {
  
      /** For serialization. */
      private static final long serialVersionUID = -2482910643727230911L;
  
      /** The paint used to draw the first bar. */
      private transient Paint firstBarPaint;
  
      /** The paint used to draw the last bar. */
      private transient Paint lastBarPaint;
  
      /** The paint used to draw bars having positive values. */
      private transient Paint positiveBarPaint;
  
      /** The paint used to draw bars having negative values. */
      private transient Paint negativeBarPaint;
  
      /**
       * Constructs a new renderer with default values for the bar colors.
       */
      public WaterfallBarRenderer() {
          this(new GradientPaint(0.0f, 0.0f, new Color(0x22, 0x22, 0xFF),
                  0.0f, 0.0f, new Color(0x66, 0x66, 0xFF)),
                  new GradientPaint(0.0f, 0.0f, new Color(0x22, 0xFF, 0x22),
                  0.0f, 0.0f, new Color(0x66, 0xFF, 0x66)),
                  new GradientPaint(0.0f, 0.0f, new Color(0xFF, 0x22, 0x22),
                  0.0f, 0.0f, new Color(0xFF, 0x66, 0x66)),
                  new GradientPaint(0.0f, 0.0f, new Color(0xFF, 0xFF, 0x22),
                  0.0f, 0.0f, new Color(0xFF, 0xFF, 0x66)));
      }
  
      /**
       * Constructs a new waterfall renderer.
       *
       * @param firstBarPaint  the color of the first bar (<code>null</code> not
       *                       permitted).
       * @param positiveBarPaint  the color for bars with positive values
       *                          (<code>null</code> not permitted).
       * @param negativeBarPaint  the color for bars with negative values
       *                          (<code>null</code> not permitted).
       * @param lastBarPaint  the color of the last bar (<code>null</code> not
       *                      permitted).
       */
      public WaterfallBarRenderer(Paint firstBarPaint, Paint positiveBarPaint,
              Paint negativeBarPaint, Paint lastBarPaint) {
          super();
          ParamChecks.nullNotPermitted(firstBarPaint, "firstBarPaint");
          ParamChecks.nullNotPermitted(positiveBarPaint, "positiveBarPaint");
          ParamChecks.nullNotPermitted(negativeBarPaint, "negativeBarPaint");
          ParamChecks.nullNotPermitted(lastBarPaint, "lastBarPaint");
          this.firstBarPaint = firstBarPaint;
          this.lastBarPaint = lastBarPaint;
          this.positiveBarPaint = positiveBarPaint;
          this.negativeBarPaint = negativeBarPaint;
          setGradientPaintTransformer(new StandardGradientPaintTransformer(
                  GradientPaintTransformType.CENTER_VERTICAL));
          setMinimumBarLength(1.0);
      }
  
      /**
       * Returns the paint used to draw the first bar.
       *
       * @return The paint (never <code>null</code>).
       */
      public Paint getFirstBarPaint() {
          return this.firstBarPaint;
      }
  
      /**
       * Sets the paint that will be used to draw the first bar and sends a
       * {@link RendererChangeEvent} to all registered listeners.
       *
       * @param paint  the paint (<code>null</code> not permitted).
       */
      public void setFirstBarPaint(Paint paint) {
          ParamChecks.nullNotPermitted(paint, "paint");
          this.firstBarPaint = paint;
          fireChangeEvent();
      }
  
      /**
       * Returns the paint used to draw the last bar.
       *
       * @return The paint (never <code>null</code>).
       */
      public Paint getLastBarPaint() {
          return this.lastBarPaint;
      }
  
      /**
       * Sets the paint that will be used to draw the last bar and sends a
       * {@link RendererChangeEvent} to all registered listeners.
       *
       * @param paint  the paint (<code>null</code> not permitted).
       */
      public void setLastBarPaint(Paint paint) {
          ParamChecks.nullNotPermitted(paint, "paint");
          this.lastBarPaint = paint;
          fireChangeEvent();
      }
  
      /**
       * Returns the paint used to draw bars with positive values.
       *
       * @return The paint (never <code>null</code>).
       */
      public Paint getPositiveBarPaint() {
          return this.positiveBarPaint;
      }
  
      /**
       * Sets the paint that will be used to draw bars having positive values.
       *
       * @param paint  the paint (<code>null</code> not permitted).
       */
      public void setPositiveBarPaint(Paint paint) {
          ParamChecks.nullNotPermitted(paint, "paint");
          this.positiveBarPaint = paint;
          fireChangeEvent();
      }
  
      /**
       * Returns the paint used to draw bars with negative values.
       *
       * @return The paint (never <code>null</code>).
       */
      public Paint getNegativeBarPaint() {
          return this.negativeBarPaint;
      }
  
      /**
       * Sets the paint that will be used to draw bars having negative values,
       * and sends a {@link RendererChangeEvent} to all registered listeners.
       *
       * @param paint  the paint (<code>null</code> not permitted).
       */
      public void setNegativeBarPaint(Paint paint) {
          ParamChecks.nullNotPermitted(paint, "paint");
          this.negativeBarPaint = paint;
          fireChangeEvent();
      }
  
      /**
       * Returns the range of values the renderer requires to display all the
       * items from the specified dataset.
       *
       * @param dataset  the dataset (<code>null</code> not permitted).
       *
       * @return The range (or <code>null</code> if the dataset is empty).
       */
      @Override
      public Range findRangeBounds(CategoryDataset dataset) {
          if (dataset == null) {
              return null;
          }
          boolean allItemsNull = true; // we'll set this to false if there is at
                                       // least one non-null data item...
          double minimum = 0.0;
          double maximum = 0.0;
          int columnCount = dataset.getColumnCount();
          for (int row = 0; row < dataset.getRowCount(); row++) {
              double runningTotal = 0.0;
              for (int column = 0; column <= columnCount - 1; column++) {
                  Number n = dataset.getValue(row, column);
                  if (n != null) {
                      allItemsNull = false;
                      double value = n.doubleValue();
                      if (column == columnCount - 1) {
                          // treat the last column value as an absolute
                          runningTotal = value;
                      }
                      else {
                          runningTotal = runningTotal + value;
                      }
                      minimum = Math.min(minimum, runningTotal);
                      maximum = Math.max(maximum, runningTotal);
                  }
              }
  
          }
          if (!allItemsNull) {
              return new Range(minimum, maximum);
          }
          else {
              return null;
          }
  
      }
  
      /**
       * 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) {
  
          double previous = state.getSeriesRunningTotal();
          if (column == dataset.getColumnCount() - 1) {
              previous = 0.0;
          }
          double current = 0.0;
          Number n = dataset.getValue(row, column);
          if (n != null) {
              current = previous + n.doubleValue();
          }
          state.setSeriesRunningTotal(current);
  
          int categoryCount = getColumnCount();
          PlotOrientation orientation = plot.getOrientation();
  
          double rectX = 0.0;
          double rectY = 0.0;
  
          RectangleEdge rangeAxisLocation = plot.getRangeAxisEdge();
  
          // Y0
          double j2dy0 = rangeAxis.valueToJava2D(previous, dataArea,
                  rangeAxisLocation);
  
          // Y1
          double j2dy1 = rangeAxis.valueToJava2D(current, dataArea,
                  rangeAxisLocation);
  
          double valDiff = current - previous;
          if (j2dy1 < j2dy0) {
              double temp = j2dy1;
              j2dy1 = j2dy0;
              j2dy0 = temp;
          }
  
          // BAR WIDTH
          double rectWidth = state.getBarWidth();
  
          // BAR HEIGHT
          double rectHeight = Math.max(getMinimumBarLength(),
                  Math.abs(j2dy1 - j2dy0));
  
          Comparable seriesKey = dataset.getRowKey(row);
          Comparable categoryKey = dataset.getColumnKey(column);
          if (orientation == PlotOrientation.HORIZONTAL) {
              rectY = domainAxis.getCategorySeriesMiddle(categoryKey, seriesKey,
                      dataset, getItemMargin(), dataArea, RectangleEdge.LEFT);
  
              rectX = j2dy0;
              rectHeight = state.getBarWidth();
  