/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, 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.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * -------------------------
 * XYDifferenceRenderer.java
 * -------------------------
 * (C) Copyright 2003-2005, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Christian W. Zuckschwerdt;
 *
 * $Id: XYDifferenceRenderer.java,v 1.12.2.6 2005/12/10 21:51:02 mungady Exp $
 *
 * Changes:
 * --------
 * 30-Apr-2003 : Version 1 (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 20-Aug-2003 : Implemented Cloneable and PublicCloneable (DG);
 * 16-Sep-2003 : Changed ChartRenderingInfo --> PlotRenderingInfo (DG);
 * 09-Feb-2004 : Updated to support horizontal plot orientation (DG);
 * 10-Feb-2004 : Added default constructor, setter methods and updated 
 *               Javadocs (DG);
 * 25-Feb-2004 : Replaced CrosshairInfo with CrosshairState (DG);
 * 30-Mar-2004 : Fixed bug in getNegativePaint() method (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 * 25-Aug-2004 : Fixed a bug preventing the use of crosshairs (DG);
 * 11-Nov-2004 : Now uses ShapeUtilities to translate shapes (DG);
 * 19-Jan-2005 : Now accesses only primitive values from dataset (DG);
 * 22-Feb-2005 : Override getLegendItem(int, int) to return "line" items (DG);
 * 13-Apr-2005 : Fixed shape positioning bug (id = 1182062) (DG);
 * 20-Apr-2005 : Use generators for legend tooltips and URLs (DG);
 * 04-May-2005 : Override equals() method, renamed get/setPlotShapes() -->
 *               get/setShapesVisible (DG);
 * 09-Jun-2005 : Updated equals() to handle GradientPaint (DG);
 * 16-Jun-2005 : Fix bug (1221021) affecting stroke used for each series (DG);
 * 
 */

package org.jfree.chart.renderer.xy;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
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.jfree.chart.LegendItem;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.entity.XYItemEntity;
import org.jfree.chart.event.RendererChangeEvent;
import org.jfree.chart.labels.XYToolTipGenerator;
import org.jfree.chart.plot.CrosshairState;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.xy.XYDataset;
import org.jfree.io.SerialUtilities;
import org.jfree.ui.RectangleEdge;
import org.jfree.util.PaintUtilities;
import org.jfree.util.PublicCloneable;
import org.jfree.util.ShapeUtilities;

/**
 * A renderer for an {@link XYPlot} that highlights the differences between two
 * series.  The renderer expects a dataset that:
 * <ul>
 * <li>has exactly two series;</li>
 * <li>each series has the same x-values;</li>
 * <li>no <code>null</code> values;
 * </ul>
 */
public class XYDifferenceRenderer extends AbstractXYItemRenderer 
                                  implements XYItemRenderer, 
                                             Cloneable,
                                             PublicCloneable,
                                             Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -8447915602375584857L;
    
    /** The paint used to highlight positive differences (y(0) > y(1)). */
    private transient Paint positivePaint;

    /** The paint used to highlight negative differences (y(0) < y(1)). */
    private transient Paint negativePaint;

    /** Display shapes at each point? */
    private boolean shapesVisible;
    
    /** The shape to display in the legend item. */
    private transient Shape legendLine;

    /**
     * Creates a new renderer with default attributes.
     */
    public XYDifferenceRenderer() {
        this(Color.green, Color.red, false);
    }
    
    /**
     * Creates a new renderer.
     *
     * @param positivePaint  the highlight color for positive differences 
     *                       (<code>null</code> not permitted).
     * @param negativePaint  the highlight color for negative differences 
     *                       (<code>null</code> not permitted).
     * @param shapes  draw shapes?
     */
    public XYDifferenceRenderer(Paint positivePaint, Paint negativePaint, 
                                boolean shapes) {
        if (positivePaint == null) {
            throw new IllegalArgumentException(
                    "Null 'positivePaint' argument.");
        }
        if (negativePaint == null) {
            throw new IllegalArgumentException(
                    "Null 'negativePaint' argument.");
        }
        this.positivePaint = positivePaint;
        this.negativePaint = negativePaint;
        this.shapesVisible = shapes;
        this.legendLine = new Line2D.Double(-7.0, 0.0, 7.0, 0.0);
    }

    /**
     * Returns the paint used to highlight positive differences.
     *
     * @return The paint (never <code>null</code>).
     */
    public Paint getPositivePaint() {
        return this.positivePaint;
    }

    /**
     * Sets the paint used to highlight positive differences.
     * 
     * @param paint  the paint (<code>null</code> not permitted).
     */
    public void setPositivePaint(Paint paint) {
        if (paint == null) {
            throw new IllegalArgumentException("Null 'paint' argument.");
        }
        this.positivePaint = paint;
        notifyListeners(new RendererChangeEvent(this));
    }

    /**
     * Returns the paint used to highlight negative differences.
     *
     * @return The paint (never <code>null</code>).
     */
    public Paint getNegativePaint() {
        return this.negativePaint;
    }
    
    /**
     * Sets the paint used to highlight negative differences.
     * 
     * @param paint  the paint (<code>null</code> not permitted).
     */
    public void setNegativePaint(Paint paint) {
        if (paint == null) {
            throw new IllegalArgumentException("Null 'paint' argument.");
        }
        this.negativePaint = paint;
        notifyListeners(new RendererChangeEvent(this));
    }

    /**
     * Returns a flag that controls whether or not shapes are drawn for each 
     * data value.
     * 
     * @return A boolean.
     */
    public boolean getShapesVisible() {
        return this.shapesVisible;
    }

    /**
     * Sets a flag that controls whether or not shapes are drawn for each 
     * data value.
     * 
     * @param flag  the flag.
     */
    public void setShapesVisible(boolean flag) {
        this.shapesVisible = flag;
        notifyListeners(new RendererChangeEvent(this));
    }
    
    /**
     * Returns the shape used to represent a line in the legend.
     * 
     * @return The legend line (never <code>null</code>).
     */
    public Shape getLegendLine() {
        return this.legendLine;   
    }
    
    /**
     * Sets the shape used as a line in each legend item and sends a 
     * {@link RendererChangeEvent} to all registered listeners.
     * 
     * @param line  the line (<code>null</code> not permitted).
     */
    public void setLegendLine(Shape line) {
        if (line == null) {
            throw new IllegalArgumentException("Null 'line' argument.");   
        }
        this.legendLine = line;
        notifyListeners(new RendererChangeEvent(this));
    }

    /**
     * Initialises the renderer and returns a state object that should be 
     * passed to subsequent calls to the drawItem() method.  This method will 
     * be called before the first item is rendered, giving the renderer an 
     * opportunity to initialise any state information it wants to maintain.  
     * The renderer can do nothing if it chooses.
     *
     * @param g2  the graphics device.
     * @param dataArea  the area inside the axes.
     * @param plot  the plot.
     * @param data  the data.
     * @param info  an optional info collection object to return data back to 
     *              the caller.
     *
     * @return A state object.
     */
    public XYItemRendererState initialise(Graphics2D g2,
                                          Rectangle2D dataArea,
                                          XYPlot plot,
                                          XYDataset data,
                                          PlotRenderingInfo info) {

        return super.initialise(g2, dataArea, plot, data, info);

    }

    /**
     * Returns <code>2</code>, the number of passes required by the renderer.  
     * The {@link XYPlot} will run through the dataset this number of times.
     * 
     * @return The number of passes required by the renderer.
     */
    public int getPassCount() {
        return 2;
    }
    
    /**
     * Draws the visual representation of a single data item.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the area within which the data is being drawn.
     * @param info  collects information about the drawing.
     * @param plot  the plot (can be used to obtain standard color 
     *              information etc).
     * @param domainAxis  the domain (horizontal) axis.
     * @param rangeAxis  the range (vertical) axis.
     * @param dataset  the dataset.
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * @param crosshairState  crosshair information for the plot 
     *                        (<code>null</code> permitted).
     * @param pass  the pass index.
     */
    public void drawItem(Graphics2D g2,
                         XYItemRendererState state,
                         Rectangle2D dataArea,
                         PlotRenderingInfo info,
                         XYPlot plot,
                         ValueAxis domainAxis,
                         ValueAxis rangeAxis,
                         XYDataset dataset,
                         int series,