/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2007, 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.]
 *
 * ---------------------------
 * StandardXYItemRenderer.java
 * ---------------------------
 * (C) Copyright 2001-2007, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Mark Watson (www.markwatson.com);
 *                   Jonathan Nash;
 *                   Andreas Schneider;
 *                   Norbert Kiesel (for TBD Networks);
 *                   Christian W. Zuckschwerdt;
 *                   Bill Kelemen;
 *                   Nicolas Brodu (for Astrium and EADS Corporate Research 
 *                   Center);
 *
 * $Id: StandardXYItemRenderer.java,v 1.18.2.10 2007/03/23 13:43:46 mungady Exp $
 *
 * Changes:
 * --------
 * 19-Oct-2001 : Version 1, based on code by Mark Watson (DG);
 * 22-Oct-2001 : Renamed DataSource.java --> Dataset.java etc. (DG);
 * 21-Dec-2001 : Added working line instance to improve performance (DG);
 * 22-Jan-2002 : Added code to lock crosshairs to data points.  Based on code 
 *               by Jonathan Nash (DG);
 * 23-Jan-2002 : Added DrawInfo parameter to drawItem() method (DG);
 * 28-Mar-2002 : Added a property change listener mechanism so that the 
 *               renderer no longer needs to be immutable (DG);
 * 02-Apr-2002 : Modified to handle null values (DG);
 * 09-Apr-2002 : Modified draw method to return void.  Removed the translated 
 *               zero from the drawItem method.  Override the initialise() 
 *               method to calculate it (DG);
 * 13-May-2002 : Added code from Andreas Schneider to allow changing 
 *               shapes/colors per item (DG);
 * 24-May-2002 : Incorporated tooltips into chart entities (DG);
 * 25-Jun-2002 : Removed redundant code (DG);
 * 05-Aug-2002 : Incorporated URLs for HTML image maps into chart entities (RA);
 * 08-Aug-2002 : Added discontinuous lines option contributed by 
 *               Norbert Kiesel (DG);
 * 20-Aug-2002 : Added user definable default values to be returned by 
 *               protected methods unless overridden by a subclass (DG);
 * 23-Sep-2002 : Updated for changes in the XYItemRenderer interface (DG);
 * 02-Oct-2002 : Fixed errors reported by Checkstyle (DG);
 * 25-Mar-2003 : Implemented Serializable (DG);
 * 01-May-2003 : Modified drawItem() method signature (DG);
 * 15-May-2003 : Modified to take into account the plot orientation (DG);
 * 29-Jul-2003 : Amended code that doesn't compile with JDK 1.2.2 (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 20-Aug-2003 : Implemented Cloneable and PublicCloneable (DG);
 * 24-Aug-2003 : Added null/NaN checks in drawItem (BK);
 * 08-Sep-2003 : Fixed serialization (NB);
 * 16-Sep-2003 : Changed ChartRenderingInfo --> PlotRenderingInfo (DG);
 * 21-Jan-2004 : Override for getLegendItem() method (DG);
 * 27-Jan-2004 : Moved working line into state object (DG);
 * 10-Feb-2004 : Changed drawItem() method to make cut-and-paste overriding 
 *               easier (DG);
 * 25-Feb-2004 : Replaced CrosshairInfo with CrosshairState.  Renamed 
 *               XYToolTipGenerator --> XYItemLabelGenerator (DG);
 * 08-Jun-2004 : Modified to use getX() and getY() methods (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 * 25-Aug-2004 : Created addEntity() method in superclass (DG);
 * 08-Oct-2004 : Added 'gapThresholdType' as suggested by Mike Watts (DG);
 * 11-Nov-2004 : Now uses ShapeUtilities to translate shapes (DG);
 * 23-Feb-2005 : Fixed getLegendItem() method to show lines.  Fixed bug
 *               1077108 (shape not visible for first item in series) (DG);
 * 10-Apr-2005 : Fixed item label positioning with horizontal orientation (DG);
 * 20-Apr-2005 : Use generators for legend tooltips and URLs (DG);
 * 27-Apr-2005 : Use generator for series label in legend (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 15-Jun-2006 : Fixed bug (1380480) for rendering series as path (DG); 
 * 06-Feb-2007 : Fixed bug 1086307, crosshairs with multiple axes (DG);
 * 14-Mar-2007 : Fixed problems with the equals() and clone() methods (DG);
 * 23-Mar-2007 : Clean-up of shapesFilled attributes (DG);
 *
 */

package org.jfree.chart.renderer.xy;

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Paint;
import java.awt.Point;
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.event.RendererChangeEvent;
import org.jfree.chart.labels.XYToolTipGenerator;
import org.jfree.chart.plot.CrosshairState;
import org.jfree.chart.plot.Plot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.urls.XYURLGenerator;
import org.jfree.data.xy.XYDataset;
import org.jfree.io.SerialUtilities;
import org.jfree.ui.RectangleEdge;
import org.jfree.util.BooleanList;
import org.jfree.util.BooleanUtilities;
import org.jfree.util.ObjectUtilities;
import org.jfree.util.PublicCloneable;
import org.jfree.util.ShapeUtilities;
import org.jfree.util.UnitType;

/**
 * Standard item renderer for an {@link XYPlot}.  This class can draw (a) 
 * shapes at each point, or (b) lines between points, or (c) both shapes and 
 * lines.
 * <P>
 * This renderer has been retained for historical reasons and, in general, you
 * should use the {@link XYLineAndShapeRenderer} class instead.
 */
public class StandardXYItemRenderer extends AbstractXYItemRenderer 
        implements XYItemRenderer, Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -3271351259436865995L;
    
    /** Constant for the type of rendering (shapes only). */
    public static final int SHAPES = 1;

    /** Constant for the type of rendering (lines only). */
    public static final int LINES = 2;

    /** Constant for the type of rendering (shapes and lines). */
    public static final int SHAPES_AND_LINES = SHAPES | LINES;

    /** Constant for the type of rendering (images only). */
    public static final int IMAGES = 4;

    /** Constant for the type of rendering (discontinuous lines). */
    public static final int DISCONTINUOUS = 8;

    /** Constant for the type of rendering (discontinuous lines). */
    public static final int DISCONTINUOUS_LINES = LINES | DISCONTINUOUS;

    /** A flag indicating whether or not shapes are drawn at each XY point. */
    private boolean baseShapesVisible;

    /** A flag indicating whether or not lines are drawn between XY points. */
    private boolean plotLines;

    /** A flag indicating whether or not images are drawn between XY points. */
    private boolean plotImages;

    /** A flag controlling whether or not discontinuous lines are used. */
    private boolean plotDiscontinuous;

    /** Specifies how the gap threshold value is interpreted. */
    private UnitType gapThresholdType = UnitType.RELATIVE;
    
    /** Threshold for deciding when to discontinue a line. */
    private double gapThreshold = 1.0;

    /** A flag that controls whether or not shapes are filled for ALL series. */
    private Boolean shapesFilled;

    /** 
     * A table of flags that control (per series) whether or not shapes are 
     * filled. 
     */
    private BooleanList seriesShapesFilled;

    /** The default value returned by the getShapeFilled() method. */
    private boolean baseShapesFilled;

    /** 
     * A flag that controls whether or not each series is drawn as a single 
     * path. 
     */
    private boolean drawSeriesLineAsPath;

    /** 
     * The shape that is used to represent a line in the legend. 
     * This should never be set to <code>null</code>. 
     */
    private transient Shape legendLine;
    
    /**
     * Constructs a new renderer.
     */
    public StandardXYItemRenderer() {
        this(LINES, null);
    }

    /**
     * Constructs a new renderer.  To specify the type of renderer, use one of 
     * the constants: {@link #SHAPES}, {@link #LINES} or 
     * {@link #SHAPES_AND_LINES}.
     *
     * @param type  the type.
     */
    public StandardXYItemRenderer(int type) {
        this(type, null);
    }

    /**
     * Constructs a new renderer.  To specify the type of renderer, use one of 
     * the constants: {@link #SHAPES}, {@link #LINES} or 
     * {@link #SHAPES_AND_LINES}.
     *
     * @param type  the type of renderer.
     * @param toolTipGenerator  the item label generator (<code>null</code> 
     *                          permitted).
     */
    public StandardXYItemRenderer(int type, 
                                  XYToolTipGenerator toolTipGenerator) {
        this(type, toolTipGenerator, null);
    }

    /**
     * Constructs a new renderer.  To specify the type of renderer, use one of 
     * the constants: {@link #SHAPES}, {@link #LINES} or 
     * {@link #SHAPES_AND_LINES}.
     *
     * @param type  the type of renderer.
     * @param toolTipGenerator  the item label generator (<code>null</code> 
     *                          permitted).
     * @param urlGenerator  the URL generator.
     */
    public StandardXYItemRenderer(int type,
                                  XYToolTipGenerator toolTipGenerator,
                                  XYURLGenerator urlGenerator) {

        super();
        setToolTipGenerator(toolTipGenerator);
        setURLGenerator(urlGenerator);
        if ((type & SHAPES) != 0) {
            this.baseShapesVisible = true;
        }
        if ((type & LINES) != 0) {
            this.plotLines = true;
        }
        if ((type & IMAGES) != 0) {
            this.plotImages = true;
        }
        if ((type & DISCONTINUOUS) != 0) {
            this.plotDiscontinuous = true;
        }

        this.shapesFilled = null;
        this.seriesShapesFilled = new BooleanList();
        this.baseShapesFilled = true;
        this.legendLine = new Line2D.Double(-7.0, 0.0, 7.0, 0.0);
        this.drawSeriesLineAsPath = false;
    }

    /**
     * Returns true if shapes are being plotted by the renderer.
     *
     * @return <code>true</code> if shapes are being plotted by the renderer.
     * 
     * @see #setBaseShapesVisible
     */
    public boolean getBaseShapesVisible() {
        return this.baseShapesVisible;
    }

    /**
     * Sets the flag that controls whether or not a shape is plotted at each 
     * data point.
     *
     * @param flag  the flag.
     * 
     * @see #getBaseShapesVisible
     */
    public void setBaseShapesVisible(boolean flag) {
        if (this.baseShapesVisible != flag) {
            this.baseShapesVisible = flag;
            notifyListeners(new RendererChangeEvent(this));
        }
    }

    // SHAPES FILLED

    /**
     * Returns the flag used to control whether or not the shape for an item is
     * filled.
     * <p>
     * The default implementation passes control to the 
     * <code>getSeriesShapesFilled</code> method.  You can override this method 
     * if you require different behaviour.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return A boolean.
     * 
     * @see #getSeriesShapesFilled(int)
     */
    public boolean getItemShapeFilled(int series, int item) {
        // return the overall setting, if there is one...
        if (this.shapesFilled != null) {
            return this.shapesFilled.booleanValue();
        }

        // otherwise look up the paint table
        Boolean flag = this.seriesShapesFilled.getBoolean(series);
        if (flag != null) {
            return flag.booleanValue();
        }
        else {
            return this.baseShapesFilled;
        }
    }

    /**
     * Returns the override flag that controls whether or not shapes are filled
     * for ALL series.
     * 
     * @return The flag (possibly <code>null</code>).
     * 
     * @since 1.0.5
     */
    public Boolean getShapesFilled() {
        return this.shapesFilled;
    }
    
    /**
     * Sets the 'shapes filled' for ALL series.
     *
     * @param filled  the flag.
     * 
     * @see #setShapesFilled(Boolean)
     */
    public void setShapesFilled(boolean filled) {
        // here we use BooleanUtilities to remain compatible with JDKs < 1.4 
        setShapesFilled(BooleanUtilities.valueOf(filled));
    }

    /**
     * Sets the override flag that controls whether or not shapes are filled
     * for ALL series and sends a {@link RendererChangeEvent} to all registered
     * listeners. 
     *
     * @param filled  the flag (<code>null</code> permitted).
     * 
     * @see #setShapesFilled(boolean)
     */
    public void setShapesFilled(Boolean filled) {
        this.shapesFilled = filled;
        fireChangeEvent();
    }

    /**
     * Returns the flag used to control whether or not the shapes for a series
     * are filled.
     *
     * @param series  the series index (zero-based).
     *
     * @return A boolean.
     */
    public Boolean getSeriesShapesFilled(int series) {
        return this.seriesShapesFilled.getBoolean(series);
    }

    /**
     * Sets the 'shapes filled' flag for a series.
     *
     * @param series  the series index (zero-based).
     * @param flag  the flag.
     * 
     * @see #getSeriesShapesFilled(int)
     */
    public void setSeriesShapesFilled(int series, Boolean flag) {
        this.seriesShapesFilled.setBoolean(series, flag);
        fireChangeEvent();
    }

    /**
     * Returns the base 'shape filled' attribute.
     *
     * @return The base flag.
     * 
     * @see #setBaseShapesFilled(boolean)
     */
    public boolean getBaseShapesFilled() {
        return this.baseShapesFilled;
    }

    /**
     * Sets the base 'shapes filled' flag.
     *
     * @param flag  the flag.
     * 
     * @see #getBaseShapesFilled()
     */
    public void setBaseShapesFilled(boolean flag) {
        this.baseShapesFilled = flag;
    }

    /**
     * Returns true if lines are being plotted by the renderer.
     *
     * @return <code>true</code> if lines are being plotted by the renderer.
     * 
     * @see #setPlotLines(boolean)
     */
    public boolean getPlotLines() {
        return this.plotLines;
    }

    /**
     * Sets the flag that controls whether or not a line is plotted between 
     * each data point.
     *
     * @param flag  the flag.
     * 
     * @see #getPlotLines()
     */
    public void setPlotLines(boolean flag) {
        if (this.plotLines != flag) {
            this.plotLines = flag;
            notifyListeners(new RendererChangeEvent(this));
        }
    }

    /**
     * Returns the gap threshold type (relative or absolute).
     * 
     * @return The type.
     * 
     * @see #setGapThresholdType(UnitType)
     */
    public UnitType getGapThresholdType() {
        return this.gapThresholdType;
    }
    
    /**
     * Sets the gap threshold type.
     * 
     * @param thresholdType  the type (<code>null</code> not permitted).
     * 
     * @see #getGapThresholdType()
     */
    public void setGapThresholdType(UnitType thresholdType) {
        if (thresholdType == null) {
            throw new IllegalArgumentException(
                    "Null 'thresholdType' argument.");
        }
        this.gapThresholdType = thresholdType;
        notifyListeners(new RendererChangeEvent(this));
    }
    
    /**
     * Returns the gap threshold for discontinuous lines.
     *
     * @return The gap threshold.
     * 
     * @see #setGapThreshold(double)
     */
    public double getGapThreshold() {
        return this.gapThreshold;
    }

    /**
     * Sets the gap threshold for discontinuous lines.
     *
     * @param t  the threshold.
     * 
     * @see #getGapThreshold()
     */
    public void setGapThreshold(double t) {
        this.gapThreshold = t;
        notifyListeners(new RendererChangeEvent(this));
    }

    /**
     * Returns true if images are being plotted by the renderer.
     *
     * @return <code>true</code> if images are being plotted by the renderer.
     * 
     * @see #setPlotImages(boolean)
     */
    public boolean getPlotImages() {
        return this.plotImages;
    }

    /**
     * Sets the flag that controls whether or not an image is drawn at each 
     * data point.
     *
     * @param flag  the flag.
     * 
     * @see #getPlotImages()
     */
    public void setPlotImages(boolean flag) {
        if (this.plotImages != flag) {
            this.plotImages = flag;
            notifyListeners(new RendererChangeEvent(this));
        }
    }

    /**
     * Returns a flag that controls whether or not the renderer shows
     * discontinuous lines.
     *
     * @return <code>true</code> if lines should be discontinuous.
     */
    public boolean getPlotDiscontinuous() {
        return this.plotDiscontinuous;
    }
    
    /**
     * Sets the flag that controls whether or not the renderer shows
     * discontinuous lines, and sends a {@link RendererChangeEvent} to all
     * registered listeners.
     * 
     * @param flag  the new flag value.
     * 
     * @since 1.0.5
     */
    public void setPlotDiscontinuous(boolean flag) {
        if (this.plotDiscontinuous != flag) {
            this.plotDiscontinuous = flag;
            fireChangeEvent();
        }
    }

    /**
     * Returns a flag that controls whether or not each series is drawn as a 
     * single path.
     * 
     * @return A boolean.
     * 
     * @see #setDrawSeriesLineAsPath(boolean)
     */
    public boolean getDrawSeriesLineAsPath() {
        return this.drawSeriesLineAsPath;
    }
    
    /**
     * Sets the flag that controls whether or not each series is drawn as a 
     * single path.
     * 
     * @param flag  the flag.
     * 
     * @see #getDrawSeriesLineAsPath()
     */
    public void setDrawSeriesLineAsPath(boolean flag) {
        this.drawSeriesLineAsPath = flag;
    }
    
    /**
     * Returns the shape used to represent a line in the legend.
     * 
     * @return The legend line (never <code>null</code>).
     * 
     * @see #setLegendLine(Shape)
     */
    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).
     * 
     * @see #getLegendLine()
     */
    public void setLegendLine(Shape line) {
        if (line == null) {
            throw new IllegalArgumentException("Null 'line' argument.");   
        }
        this.legendLine = line;
        notifyListeners(new RendererChangeEvent(this));
    }

    /**
     * Returns a legend item for a series.
     *
     * @param datasetIndex  the dataset index (zero-based).
     * @param series  the series index (zero-based).
     *
     * @return A legend item for the series.
     */
    public LegendItem getLegendItem(int datasetIndex, int series) {
        XYPlot plot = getPlot();
        if (plot == null) {
            return null;
        }
        LegendItem result = null;
        XYDataset dataset = plot.getDataset(datasetIndex);
        if (dataset != null) {
            if (getItemVisible(series, 0)) {
                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 = getSeriesShape(series);
                boolean shapeFilled = getItemShapeFilled(series, 0);
                Paint paint = getSeriesPaint(series);
                Paint linePaint = paint;
                Stroke lineStroke = getSeriesStroke(series);
                result = new LegendItem(label, description, toolTipText, 
                        urlText, this.baseShapesVisible, shape, shapeFilled,
                        paint, !shapeFilled, paint, lineStroke, 
                        this.plotLines, this.legendLine, lineStroke, linePaint);
            }
        }
        return result;
    }

    /**
     * Records the state for the renderer.  This is used to preserve state 
     * information between calls to the drawItem() method for a single chart 
     * drawing.
     */
    public static class State extends XYItemRendererState {
        
        /** The path for the current series. */
        public GeneralPath seriesPath;
        
        /** The series index. */
        private int seriesIndex;
        
        /** 
         * A flag that indicates if the last (x, y) point was 'good' 
         * (non-null). 
         */
        private boolean lastPointGood;
        
        /**
         * Creates a new state instance.
         * 
         * @param info  the plot rendering info.
         */
        public State(PlotRenderingInfo info) {
            super(info);
        }
        
        /**
         * Returns a flag that indicates if the last point drawn (in the 
         * current series) was 'good' (non-null).
         * 
         * @return A boolean.
         */
        public boolean isLastPointGood() {
            return this.lastPointGood;
        }
        
        /**
         * Sets a flag that indicates if the last point drawn (in the current 
         * series) was 'good' (non-null).
         * 
         * @param good  the flag.
         */
        public void setLastPointGood(boolean good) {
            this.lastPointGood = good;
        }
        
        /**
         * Returns the series index for the current path.
         * 
         * @return The series index for the current path.
         */
        public int getSeriesIndex() {
            return this.seriesIndex;
        }
        
        /**
         * Sets the series index for the current path.
         * 
         * @param index  the index.
         */
        public void setSeriesIndex(int index) {
            this.seriesIndex = index;
        }
    }
    
    /**
     * Initialises the renderer.
     * <P>
     * 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 The renderer state.
     */
    public XYItemRendererState initialise(Graphics2D g2,
                                          Rectangle2D dataArea,
                                          XYPlot plot,
                                          XYDataset data,
                                          PlotRenderingInfo info) {

        State state = new State(info);
        state.seriesPath = new GeneralPath();
        state.seriesIndex = -1;
        return state;

    }
    
    /**
     * 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 axis.
     * @param rangeAxis  the range 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, 
                         int item, 
                         CrosshairState crosshairState, 
                         int pass) {

        boolean itemVisible = getItemVisible(series, item);
        
        // setup for collecting optional entity info...
        Shape entityArea = null;
        EntityCollection entities = null;
        if (info != null) {
            entities = info.getOwner().getEntityCollection();
        }

        PlotOrientation orientation = plot.getOrientation();
        Paint paint = getItemPaint(series, item);
        Stroke seriesStroke = getItemStroke(series, item);
        g2.setPaint(paint);
        g2.setStroke(seriesStroke);

        // get the data point...
        double x1 = dataset.getXValue(series, item);
        double y1 = dataset.getYValue(series, item);
        if (Double.isNaN(x1) || Double.isNaN(y1)) {
            itemVisible = false;
        }

        RectangleEdge xAxisLocation = plot.getDomainAxisEdge();
        RectangleEdge yAxisLocation = plot.getRangeAxisEdge();
        double transX1 = domainAxis.valueToJava2D(x1, dataArea, xAxisLocation);
        double transY1 = rangeAxis.valueToJava2D(y1, dataArea, yAxisLocation);

        if (getPlotLines()) {
            if (this.drawSeriesLineAsPath) {
                State s = (State) state;
                if (s.getSeriesIndex() != series) {
                    // we are starting a new series path
                    s.seriesPath.reset();
                    s.lastPointGood = false;
                    s.setSeriesIndex(series);
                }
                
                // update path to reflect latest point
                if (itemVisible && !Double.isNaN(transX1) 
                        && !Double.isNaN(transY1)) {
                    float x = (float) transX1;
                    float y = (float) transY1;
                    if (orientation == PlotOrientation.HORIZONTAL) {
                        x = (float) transY1;
                        y = (float) transX1;
                    }
                    if (s.isLastPointGood()) {
                        // TODO: check threshold
                        s.seriesPath.lineTo(x, y);
                    }
                    else {
                        s.seriesPath.moveTo(x, y);
                    }
                    s.setLastPointGood(true);
                }
                else {
                    s.setLastPointGood(false);
                }
                if (item == dataset.getItemCount(series) - 1) {
                    if (s.seriesIndex == series) {
                        // draw path
                        g2.setStroke(getSeriesStroke(series));
                        g2.setPaint(getSeriesPaint(series));
                        g2.draw(s.seriesPath);
                    }
                }
            }

            else if (item != 0 && itemVisible) {
                // get the previous data point...
                double x0 = dataset.getXValue(series, item - 1);
                double y0 = dataset.getYValue(series, item - 1);
                if (!Double.isNaN(x0) && !Double.isNaN(y0)) {
                    boolean drawLine = true;
                    if (getPlotDiscontinuous()) {
                        // only draw a line if the gap between the current and 
                        // previous data point is within the threshold
                        int numX = dataset.getItemCount(series);
                        double minX = dataset.getXValue(series, 0);
                        double maxX = dataset.getXValue(series, numX - 1);
                        if (this.gapThresholdType == UnitType.ABSOLUTE) {
                            drawLine = Math.abs(x1 - x0) <= this.gapThreshold;
                        }
                        else {
                            drawLine = Math.abs(x1 - x0) <= ((maxX - minX) 
                                / numX * getGapThreshold());
                        }
                    }
                    if (drawLine) {
                        double transX0 = domainAxis.valueToJava2D(x0, dataArea,
                                xAxisLocation);
                        double transY0 = rangeAxis.valueToJava2D(y0, dataArea, 
                                yAxisLocation);

                        // only draw if we have good values
                        if (Double.isNaN(transX0) || Double.isNaN(transY0) 
                            || Double.isNaN(transX1) || Double.isNaN(transY1)) {
                            return;
                        }

                        if (orientation == PlotOrientation.HORIZONTAL) {
                            state.workingLine.setLine(transY0, transX0, 
                                    transY1, transX1);
                        }
                        else if (orientation == PlotOrientation.VERTICAL) {
                            state.workingLine.setLine(transX0, transY0, 
                                    transX1, transY1);
                        }

                        if (state.workingLine.intersects(dataArea)) {
                            g2.draw(state.workingLine);
                        }
                    }
                }
            }
        }
        
        // we needed to get this far even for invisible items, to ensure that
        // seriesPath updates happened, but now there is nothing more we need
        // to do for non-visible items...
        if (!itemVisible) {
            return;
        }

        if (getBaseShapesVisible()) {

            Shape shape = getItemShape(series, item);
            if (orientation == PlotOrientation.HORIZONTAL) {
                shape = ShapeUtilities.createTranslatedShape(shape, transY1, 
                        transX1);
            }
            else if (orientation == PlotOrientation.VERTICAL) {
                shape = ShapeUtilities.createTranslatedShape(shape, transX1, 
                        transY1);
            }
            if (shape.intersects(dataArea)) {
                if (getItemShapeFilled(series, item)) {
                    g2.fill(shape);
                }
                else {
                    g2.draw(shape);
                }
            }
            entityArea = shape;

        }

        if (getPlotImages()) {
            Image image = getImage(plot, series, item, transX1, transY1);
            if (image != null) {
                Point hotspot = getImageHotspot(plot, series, item, transX1, 
                        transY1, image);
                g2.drawImage(image, (int) (transX1 - hotspot.getX()), 
                        (int) (transY1 - hotspot.getY()), null);
                entityArea = new Rectangle2D.Double(transX1 - hotspot.getX(), 
                        transY1 - hotspot.getY(), image.getWidth(null), 
                        image.getHeight(null));
            }

        }

        // draw the item label if there is one...
        if (isItemLabelVisible(series, item)) {
            double xx = transX1;
            double yy = transY1;
            if (orientation == PlotOrientation.HORIZONTAL) {
                xx = transY1;
                yy = transX1;
            }          
            drawItemLabel(g2, orientation, dataset, series, item, xx, yy, 
                    (y1 < 0.0));
        }

        int domainAxisIndex = plot.getDomainAxisIndex(domainAxis);
        int rangeAxisIndex = plot.getRangeAxisIndex(rangeAxis);
        updateCrosshairValues(crosshairState, x1, y1, domainAxisIndex, 
                rangeAxisIndex, transX1, transY1, orientation);

        // add an entity for the item...
        if (entities != null) {
            addEntity(entities, entityArea, dataset, series, item, 
                    transX1, transY1);
        }

    }

    /**
     * Tests this renderer for equality with another object.
     *
     * @param obj  the object (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {

        if (obj == this) {
            return true;
        }
        if (!(obj instanceof StandardXYItemRenderer)) {
            return false;
        }
        StandardXYItemRenderer that = (StandardXYItemRenderer) obj;
        if (this.baseShapesVisible != that.baseShapesVisible) {
            return false;
        }
        if (this.plotLines != that.plotLines) {
            return false;
        }
        if (this.plotImages != that.plotImages) {
            return false;
        }
        if (this.plotDiscontinuous != that.plotDiscontinuous) {
            return false;
        }
        if (this.gapThresholdType != that.gapThresholdType) {
            return false;
        }
        if (this.gapThreshold != that.gapThreshold) {
            return false;
        }
        if (!ObjectUtilities.equal(this.shapesFilled, that.shapesFilled)) {
            return false;
        }
        if (!this.seriesShapesFilled.equals(that.seriesShapesFilled)) {
            return false;
        }
        if (this.baseShapesFilled != that.baseShapesFilled) {
            return false;
        }
        if (this.drawSeriesLineAsPath != that.drawSeriesLineAsPath) {
            return false;
        }
        if (!ShapeUtilities.equal(this.legendLine, that.legendLine)) {
            return false;   
        }
        return super.equals(obj);

    }

    /**
     * Returns a clone of the renderer.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException  if the renderer cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {
        StandardXYItemRenderer clone = (StandardXYItemRenderer) super.clone();
        clone.seriesShapesFilled 
                = (BooleanList) this.seriesShapesFilled.clone();
        clone.legendLine = ShapeUtilities.clone(this.legendLine);
        return clone;
    }

    ////////////////////////////////////////////////////////////////////////////
    // PROTECTED METHODS
    // These provide the opportunity to subclass the standard renderer and 
    // create custom effects.
    ////////////////////////////////////////////////////////////////////////////

    /**
     * Returns the image used to draw a single data item.
     *
     * @param plot  the plot (can be used to obtain standard color information 
     *              etc).
     * @param series  the series index.
     * @param item  the item index.
     * @param x  the x value of the item.
     * @param y  the y value of the item.
     *
     * @return The image.
     * 
     * @see #getPlotImages()
     */
    protected Image getImage(Plot plot, int series, int item, 
                             double x, double y) {
        // this method must be overridden if you want to display images
        return null;
    }

    /**
     * Returns the hotspot of the image used to draw a single data item.
     * The hotspot is the point relative to the top left of the image
     * that should indicate the data item. The default is the center of the
     * image.
     *
     * @param plot  the plot (can be used to obtain standard color information 
     *              etc).
     * @param image  the image (can be used to get size information about the 
     *               image)
     * @param series  the series index
     * @param item  the item index
     * @param x  the x value of the item
     * @param y  the y value of the item
     *
     * @return The hotspot used to draw the data item.
     */
    protected Point getImageHotspot(Plot plot, int series, int item,
                                    double x, double y, Image image) {

        int height = image.getHeight(null);
        int width = image.getWidth(null);
        return new Point(width / 2, height / 2);

    }
    
    /**
     * 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.legendLine = SerialUtilities.readShape(stream);
    }
    
    /**
     * 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.writeShape(this.legendLine, stream);
    }

}
