/* ===========================================================
 * 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.]
 *
 * ---------
 * Axis.java
 * ---------
 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Bill Kelemen; Nicolas Brodu
 *
 * $Id: Axis.java,v 1.11.2.2 2005/10/25 20:37:34 mungady Exp $
 *
 * Changes (from 21-Aug-2001)
 * --------------------------
 * 21-Aug-2001 : Added standard header, fixed DOS encoding problem (DG);
 * 18-Sep-2001 : Updated header (DG);
 * 07-Nov-2001 : Allow null axis labels (DG);
 *             : Added default font values (DG);
 * 13-Nov-2001 : Modified the setPlot() method to check compatibility between 
 *               the axis and the plot (DG);
 * 30-Nov-2001 : Changed default font from "Arial" --> "SansSerif" (DG);
 * 06-Dec-2001 : Allow null in setPlot() method (BK);
 * 06-Mar-2002 : Added AxisConstants interface (DG);
 * 23-Apr-2002 : Added a visible property.  Moved drawVerticalString to 
 *               RefineryUtilities.  Added fixedDimension property for use in 
 *               combined plots (DG);
 * 25-Jun-2002 : Removed unnecessary imports (DG);
 * 05-Sep-2002 : Added attribute for tick mark paint (DG);
 * 18-Sep-2002 : Fixed errors reported by Checkstyle (DG);
 * 07-Nov-2002 : Added attributes to control the inside and outside length of 
 *               the tick marks (DG);
 * 08-Nov-2002 : Moved to new package com.jrefinery.chart.axis (DG);
 * 18-Nov-2002 : Added axis location to refreshTicks() parameters (DG);
 * 15-Jan-2003 : Removed monolithic constructor (DG);
 * 17-Jan-2003 : Moved plot classes to separate package (DG);
 * 26-Mar-2003 : Implemented Serializable (DG);
 * 03-Jul-2003 : Modified reserveSpace method (DG);
 * 13-Aug-2003 : Implemented Cloneable (DG);
 * 11-Sep-2003 : Took care of listeners while cloning (NB);
 * 29-Oct-2003 : Added workaround for font alignment in PDF output (DG);
 * 06-Nov-2003 : Modified refreshTicks() signature (DG);
 * 06-Jan-2004 : Added axis line attributes (DG);
 * 16-Mar-2004 : Added plot state to draw() method (DG);
 * 07-Apr-2004 : Modified text bounds calculation (DG);
 * 18-May-2004 : Eliminated AxisConstants.java (DG);
 * 30-Sep-2004 : Moved drawRotatedString() from RefineryUtilities --> 
 *               TextUtilities (DG);
 * 04-Oct-2004 : Modified getLabelEnclosure() method to treat an empty String 
 *               the same way as a null string - see bug 1026521 (DG);
 * 21-Apr-2005 : Replaced Insets with RectangleInsets (DG);
 * 26-Apr-2005 : Removed LOGGER (DG);
 * 01-Jun-2005 : Added hasListener() method for unit testing (DG);
 * 08-Jun-2005 : Fixed equals() method to handle GradientPaint (DG);
 */

package org.jfree.chart.axis;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.AffineTransform;
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 java.util.Arrays;
import java.util.EventListener;
import java.util.List;

import javax.swing.event.EventListenerList;

import org.jfree.chart.event.AxisChangeEvent;
import org.jfree.chart.event.AxisChangeListener;
import org.jfree.chart.plot.Plot;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.io.SerialUtilities;
import org.jfree.text.TextUtilities;
import org.jfree.ui.RectangleEdge;
import org.jfree.ui.RectangleInsets;
import org.jfree.ui.TextAnchor;
import org.jfree.util.ObjectUtilities;
import org.jfree.util.PaintUtilities;

/**
 * The base class for all axes in JFreeChart.  Subclasses are divided into 
 * those that display values ({@link ValueAxis}) and those that display 
 * categories ({@link CategoryAxis}).
 */
public abstract class Axis implements Cloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 7719289504573298271L;
    
    /** The default axis visibility. */
    public static final boolean DEFAULT_AXIS_VISIBLE = true;

    /** The default axis label font. */
    public static final Font DEFAULT_AXIS_LABEL_FONT 
        = new Font("SansSerif", Font.PLAIN, 12);

    /** The default axis label paint. */
    public static final Paint DEFAULT_AXIS_LABEL_PAINT = Color.black;

    /** The default axis label insets. */
    public static final RectangleInsets DEFAULT_AXIS_LABEL_INSETS 
        = new RectangleInsets(3.0, 3.0, 3.0, 3.0);

    /** The default axis line paint. */
    public static final Paint DEFAULT_AXIS_LINE_PAINT = Color.gray;
    
    /** The default axis line stroke. */
    public static final Stroke DEFAULT_AXIS_LINE_STROKE = new BasicStroke(1.0f);

    /** The default tick labels visibility. */
    public static final boolean DEFAULT_TICK_LABELS_VISIBLE = true;

    /** The default tick label font. */
    public static final Font DEFAULT_TICK_LABEL_FONT 
        = new Font("SansSerif", Font.PLAIN, 10);

    /** The default tick label paint. */
    public static final Paint DEFAULT_TICK_LABEL_PAINT = Color.black;

    /** The default tick label insets. */
    public static final RectangleInsets DEFAULT_TICK_LABEL_INSETS 
        = new RectangleInsets(2.0, 4.0, 2.0, 4.0);

    /** The default tick marks visible. */
    public static final boolean DEFAULT_TICK_MARKS_VISIBLE = true;

    /** The default tick stroke. */
    public static final Stroke DEFAULT_TICK_MARK_STROKE = new BasicStroke(1);

    /** The default tick paint. */
    public static final Paint DEFAULT_TICK_MARK_PAINT = Color.gray;

    /** The default tick mark inside length. */
    public static final float DEFAULT_TICK_MARK_INSIDE_LENGTH = 0.0f;

    /** The default tick mark outside length. */
    public static final float DEFAULT_TICK_MARK_OUTSIDE_LENGTH = 2.0f;

    /** A flag indicating whether or not the axis is visible. */
    private boolean visible;

    /** The label for the axis. */
    private String label;

    /** The font for displaying the axis label. */
    private Font labelFont;

    /** The paint for drawing the axis label. */
    private transient Paint labelPaint;

    /** The insets for the axis label. */
    private RectangleInsets labelInsets;

    /** The label angle. */
    private double labelAngle;

    /** A flag that controls whether or not the axis line is visible. */
    private boolean axisLineVisible;

    /** The stroke used for the axis line. */
    private transient Stroke axisLineStroke;
    
    /** The paint used for the axis line. */
    private transient Paint axisLinePaint;
    
    /** 
     * A flag that indicates whether or not tick labels are visible for the 
     * axis. 
     */
    private boolean tickLabelsVisible;

    /** The font used to display the tick labels. */
    private Font tickLabelFont;

    /** The color used to display the tick labels. */
    private transient Paint tickLabelPaint;

    /** The blank space around each tick label. */
    private RectangleInsets tickLabelInsets;

    /** 
     * A flag that indicates whether or not tick marks are visible for the 
     * axis. 
     */
    private boolean tickMarksVisible;

    /** The length of the tick mark inside the data area (zero permitted). */
    private float tickMarkInsideLength;

    /** The length of the tick mark outside the data area (zero permitted). */
    private float tickMarkOutsideLength;

    /** The stroke used to draw tick marks. */
    private transient Stroke tickMarkStroke;

    /** The paint used to draw tick marks. */
    private transient Paint tickMarkPaint;

    /** The fixed (horizontal or vertical) dimension for the axis. */
    private double fixedDimension;

    /** 
     * A reference back to the plot that the axis is assigned to (can be 
     * <code>null</code>). 
     */
    private transient Plot plot;

    /** Storage for registered listeners. */
    private transient EventListenerList listenerList;

    /**
     * Constructs an axis, using default values where necessary.
     *
     * @param label  the axis label (<code>null</code> permitted).
     */
    protected Axis(String label) {

        this.label = label;
        this.visible = DEFAULT_AXIS_VISIBLE;
        this.labelFont = DEFAULT_AXIS_LABEL_FONT;
        this.labelPaint = DEFAULT_AXIS_LABEL_PAINT;
        this.labelInsets = DEFAULT_AXIS_LABEL_INSETS;
        this.labelAngle = 0.0;
        
        this.axisLineVisible = true;
        this.axisLinePaint = DEFAULT_AXIS_LINE_PAINT;
        this.axisLineStroke = DEFAULT_AXIS_LINE_STROKE;
        
        this.tickLabelsVisible = DEFAULT_TICK_LABELS_VISIBLE;
        this.tickLabelFont = DEFAULT_TICK_LABEL_FONT;
        this.tickLabelPaint = DEFAULT_TICK_LABEL_PAINT;
        this.tickLabelInsets = DEFAULT_TICK_LABEL_INSETS;
        
        this.tickMarksVisible = DEFAULT_TICK_MARKS_VISIBLE;
        this.tickMarkStroke = DEFAULT_TICK_MARK_STROKE;
        this.tickMarkPaint = DEFAULT_TICK_MARK_PAINT;
        this.tickMarkInsideLength = DEFAULT_TICK_MARK_INSIDE_LENGTH;
        this.tickMarkOutsideLength = DEFAULT_TICK_MARK_OUTSIDE_LENGTH;

        this.plot = null;

        this.listenerList = new EventListenerList();

    }

    /**
     * Returns <code>true</code> if the axis is visible, and 
     * <code>false</code> otherwise.
     *
     * @return A boolean.
     */
    public boolean isVisible() {
        return this.visible;
    }

    /**
     * Sets a flag that controls whether or not the axis is visible and sends 
     * an {@link AxisChangeEvent} to all registered listeners.
     *
     * @param flag  the flag.
     */
    public void setVisible(boolean flag) {
        if (flag != this.visible) {
            this.visible = flag;
            notifyListeners(new AxisChangeEvent(this));
        }
    }

    /**
     * Returns the label for the axis.
     *
     * @return The label for the axis (<code>null</code> possible).
     */
    public String getLabel() {
        return this.label;
    }

    /**
     * Sets the label for the axis and sends an {@link AxisChangeEvent} to all 
     * registered listeners.
     *
     * @param label  the new label (<code>null</code> permitted).
     */
    public void setLabel(String label) {
        
        String existing = this.label;
        if (existing != null) {
            if (!existing.equals(label)) {
                this.label = label;
                notifyListeners(new AxisChangeEvent(this));
            }
        }
        else {
            if (label != null) {
                this.label = label;
                notifyListeners(new AxisChangeEvent(this));
            }
        }

    }

    /**
     * Returns the font for the axis label.
     *
     * @return The font (never <code>null</code>).
     */
    public Font getLabelFont() {
        return this.labelFont;
    }

    /**
     * Sets the font for the axis label and sends an {@link AxisChangeEvent} 
     * to all registered listeners.
     *
     * @param font  the font (<code>null</code> not permitted).
     */
    public void setLabelFont(Font font) {
        if (font == null) {
            throw new IllegalArgumentException("Null 'font' argument.");
        }
        if (!this.labelFont.equals(font)) {
            this.labelFont = font;
            notifyListeners(new AxisChangeEvent(this));
        }
    }

    /**
     * Returns the color/shade used to draw the axis label.
     *
     * @return The paint (never <code>null</code>).
     */
    public Paint getLabelPaint() {
        return this.labelPaint;
    }

    /**
     * Sets the paint used to draw the axis label and sends an 
     * {@link AxisChangeEvent} to all registered listeners.
     *
     * @param paint  the paint (<code>null</code> not permitted).
     */
    public void setLabelPaint(Paint paint) {
        if (paint == null) {
            throw new IllegalArgumentException("Null 'paint' argument.");
        }
        this.labelPaint = paint;
        notifyListeners(new AxisChangeEvent(this));
    }

    /**
     * Returns the insets for the label (that is, the amount of blank space
     * that should be left around the label).
     *
     * @return The label insets (never <code>null</code>).
     */
    public RectangleInsets getLabelInsets() {
        return this.labelInsets;
    }

    /**
     * Sets the insets for the axis label, and sends an {@link AxisChangeEvent}
     * to all registered listeners.
     *