/* ============================================================
    * JRobin : Pure java implementation of RRDTool's functionality
    * ============================================================
    *
    * Project Info:  http://www.jrobin.org
    * Project Lead:  Sasa Markovic (saxon@jrobin.org)
    *
    * Developers:    Sasa Markovic (saxon@jrobin.org)
    *
   *
   * (C) Copyright 2003-2005, by Sasa Markovic.
   *
   * 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., 59 Temple Place, Suite 330,
   * Boston, MA 02111-1307, USA.
   */
  package org.jrobin.graph;
  
  import java.awt.Font;
  import java.awt.Paint;
  import java.io.File;
  import java.io.InputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.jrobin.core.RrdException;
  import org.jrobin.core.Util;
  import org.jrobin.data.Plottable;
  
  /**
   * Class which should be used to define new JRobin graph. Once constructed and populated with data
   * object of this class should be passed to the constructor of the {@link RrdGraph} class which
   * will actually create the graph.
   * <p/>
   * The text printed below the actual graph can be formated by appending
   * special escaped characters at the end of a text. When ever such a
   * character occurs, all pending text is pushed onto the graph according to
   * the character specified.
   * <p/>
   * Valid markers are: \j for justified, \l for left aligned, \r for right
   * aligned and \c for centered.
   * <p/>
   * Normally there are two space characters inserted between every two
   * items printed into the graph. The space following a string can be
   * suppressed by putting a \g at the end of the string. The \g also squashes
   * any space inside the string if it is at the very end of the string.
   * This can be used in connection with %s to suppress empty unit strings.
   * <p/>
   * A special case is COMMENT:\s this inserts some additional vertical
   * space before placing the next row of legends.
   * <p/>
   * When text has to be formated without special instructions from your
   * side, RRDTool will automatically justify the text as soon as one string
   * goes over the right edge. If you want to prevent the justification
   * without forcing a newline, you can use the special tag \J at the end of
   * the string to disable the auto justification.
   */
  public class RrdGraphDef implements RrdGraphConstants {
  	boolean poolUsed = false; // ok
  	boolean antiAliasing = false; // ok
  	String filename = RrdGraphConstants.IN_MEMORY_IMAGE; // ok
  	long startTime, endTime; // ok
  	TimeAxisSetting timeAxisSetting = null; // ok
  	ValueAxisSetting valueAxisSetting = null; // ok
  	boolean altYGrid = false; // ok
  	boolean noMinorGrid = false; // ok
  	boolean altYMrtg = false; // ok
  	boolean altAutoscale = false; // ok
  	boolean altAutoscaleMax = false; // ok
  	int unitsExponent = Integer.MAX_VALUE; // ok
  	int unitsLength = DEFAULT_UNITS_LENGTH; // ok
  	String verticalLabel = null; // ok
  	int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT; // ok
  	boolean interlaced = false; // ok
  	String imageInfo = null; // ok
  	String imageFormat = DEFAULT_IMAGE_FORMAT; // ok
  	float imageQuality = DEFAULT_IMAGE_QUALITY; // ok
  	String backgroundImage = null; // ok
  	String overlayImage = null; // ok
  	String unit = null; // ok
  	String signature = "Created with JRobin"; // ok
  	boolean lazy = false; // ok
  	double minValue = Double.NaN; // ok
  	double maxValue = Double.NaN; // ok
  	boolean rigid = false; // ok
  	double base = DEFAULT_BASE;  // ok
  	boolean logarithmic = false; // ok
  	Paint[] colors = new Paint[] {
  			// ok
 			DEFAULT_CANVAS_COLOR,
 			DEFAULT_BACK_COLOR,
 			DEFAULT_SHADEA_COLOR,
 			DEFAULT_SHADEB_COLOR,
 			DEFAULT_GRID_COLOR,
 			DEFAULT_MGRID_COLOR,
 			DEFAULT_FONT_COLOR,
 			DEFAULT_FRAME_COLOR,
 			DEFAULT_ARROW_COLOR
 	};
 	boolean noLegend = false; // ok
 	boolean onlyGraph = false; // ok
 	boolean forceRulesLegend = false; // ok
 	String title = null; // ok
 	long step = 0; // ok
 	protected Font smallFont;
 	protected Font largeFont;
 	boolean drawXGrid = true; // ok
 	boolean drawYGrid = true; // ok
 	int firstDayOfWeek = FIRST_DAY_OF_WEEK; // ok
 	boolean showSignature = true;
 	File fontDir = null;
 	
 	List<Source> sources = new ArrayList<Source>();
 	List<CommentText> comments = new ArrayList<CommentText>();
 	List<PlotElement> plotElements = new ArrayList<PlotElement>();
 
 	/**
 	 * Creates RrdGraphDef object and sets default time span (default ending time is 'now',
 	 * default starting time is 'end-1day'.
 	 */
 	public RrdGraphDef() {
 		try {
 			setTimeSpan(Util.getTimestamps(DEFAULT_START, DEFAULT_END));
 		} catch (RrdException e) {
 			throw new RuntimeException(e);
 		}
 		
 		String fontdirProperty = System.getProperty("jrobin.fontdir");
 		if (fontdirProperty != null && fontdirProperty.length() != 0) {
 			fontDir = new File(fontdirProperty);
 		}
 		
 		// smallFont = this.getFontFromResourceName(RrdGraphConstants.DEFAULT_MONOSPACE_FONT_FILE).deriveFont(10);
 		// largeFont = this.getFontFromResourceName(RrdGraphConstants.DEFAULT_MONOSPACE_FONT_FILE).deriveFont(12);
 		smallFont = new Font(DEFAULT_FONT_NAME, Font.PLAIN, 10);
 		largeFont = new Font(DEFAULT_FONT_NAME, Font.BOLD, 12);
 	}
 
 	protected Font getFontFromResourceName(String name) {
 		Font font = null;
 		Exception exception = null;
 		URL file = null;
 		
 		if (fontDir != null) {
 			try {
 				file = new URL("file://" + new File(fontDir, name).getAbsolutePath());
 			} catch (MalformedURLException e) {
 				// fall through to the jar
 				exception = e;
 			}
 		}
 		if (file == null) {
 			file = this.getClass().getResource(name);
 		}
 		
 		if (file != null) {
 			// System.err.println("Found a font URL: " + file.toExternalForm());
 			try {
 				InputStream fontStream = file.openStream();
 				font = Font.createFont(Font.TRUETYPE_FONT, fontStream);
 				fontStream.close();
 			} catch (Exception e) {
 				exception = e;
 			}
 		} else {
 			// we can't find our fonts, fall back to the system font
 			System.err.println("An error occurred loading the font '" + name + "'.  Falling back to the default.");
 			if (exception != null) {
 				System.err.println(exception.getLocalizedMessage());
 			}
 			font = new Font(DEFAULT_FONT_NAME, Font.PLAIN, 10);
 		}
 
 		if (font == null) {
 			font = new Font(null, Font.PLAIN, 10);
 		}
 		return font;
 	}
 	
 	/**
 	 * Sets the signature string that runs along the right-side of the graph.
 	 * Defaults to "Created with JRobin".
 	 * 
 	 * @param signature the string to print
 	 */
 	public void setSignature(String signature) {
 		this.signature = signature;
 	}
 
 	/**
 	 * Gets the signature string that runs along the right-side of the graph.
 	 * @return the signature string
 	 */
 	public String getSignature() {
 		return this.signature;
 	}
 
 	/**
 	 * Sets the time when the graph should begin. Time in seconds since epoch
 	 * (1970-01-01) is required. Negative numbers are relative to the current time.
 	 *
 	 * @param time Starting time for the graph in seconds since epoch
 	 */
 	public void setStartTime(long time) {
 		this.startTime = time;
 		if (time <= 0) {
 			this.startTime += Util.getTime();
 		}
 	}
 
 	/**
 	 * Sets the time when the graph should end. Time in seconds since epoch
 	 * (1970-01-01) is required. Negative numbers are relative to the current time.
 	 *
 	 * @param time Ending time for the graph in seconds since epoch
 	 */
 	public void setEndTime(long time) {
 		this.endTime = time;
 		if (time <= 0) {
 			this.endTime += Util.getTime();
 		}
 	}
 
 	/**
 	 * Sets starting and ending time for the for the graph. Timestamps in seconds since epoch are
 	 * required. Negative numbers are relative to the current time.
 	 *
 	 * @param startTime Starting time in seconds since epoch
 	 * @param endTime   Ending time in seconds since epoch
 	 */
 	public void setTimeSpan(long startTime, long endTime) {
 		setStartTime(startTime);
 		setEndTime(endTime);
 	}
 
 	/**
 	 * Sets starting and ending time for the for the graph. Timestamps in seconds since epoch are
 	 * required.
 	 *
 	 * @param timestamps Array of timestamps. The first array item will be chosen for the starting
 	 *                   timestamp. The last array item will be chosen for the ending timestamp.
 	 */
 	public void setTimeSpan(long[] timestamps) {
 		setTimeSpan(timestamps[0], timestamps[timestamps.length - 1]);
 	}
 
 	/**
 	 * Sets RrdDbPool usage policy (defaults to true). If set to true,
 	 * {@link org.jrobin.core.RrdDbPool RrdDbPool} will be used to
 	 * access individual RRD files. If set to false, RRD files will be accessed directly.
 	 *
 	 * @param poolUsed true, if RrdDbPool class should be used. False otherwise.
 	 */
 	public void setPoolUsed(boolean poolUsed) {
 		this.poolUsed = poolUsed;
 	}
 
 	/**
 	 * Sets the name of the graph to generate. Since JRobin outputs GIFs, PNGs,
 	 * and JPEGs it's recommended that the filename end in either .gif,
 	 * .png or .jpg. JRobin does not enforce this, however. If the filename is
 	 * set to '-' the image will be created only in memory (no file will be created).
 	 * PNG and GIF formats are recommended but JPEGs should be avoided.
 	 *
 	 * @param filename Path to the image file
 	 */
 	public void setFilename(String filename) {
 		this.filename = filename;
 	}
 
 	/**
 	 * Configures x-axis grid and labels. The x-axis label is quite complex to configure.
 	 * So if you don't have very special needs, you can rely on the autoconfiguration to
 	 * get this right.
 	 * <p/>
 	 * Otherwise, you have to configure three elements making up the x-axis labels
 	 * and grid. The base grid, the major grid and the labels.
 	 * The configuration is based on the idea that you first specify a well
 	 * known amount of time and then say how many times
 	 * it has to pass between each minor/major grid line or label. For the label
 	 * you have to define two additional items: The precision of the label
 	 * in seconds and the format used to generate the text
 	 * of the label.
 	 * <p/>
 	 * For example, if you wanted a graph with a base grid every 10 minutes and a major
 	 * one every hour, with labels every hour you would use the following
 	 * x-axis definition.
 	 * <p/>
 	 * <pre>
 	 * setTimeAxis(RrdGraphConstants.MINUTE, 10,
 	 *             RrdGraphConstants.HOUR, 1,
 	 *             RrdGraphConstants.HOUR, 1,
 	 *             0, "%H:%M")
 	 * </pre>
 	 * <p/>
 	 * The precision in this example is 0 because the %X format is exact.
 	 * If the label was the name of the day, we would have had a precision
 	 * of 24 hours, because when you say something like 'Monday' you mean
 	 * the whole day and not Monday morning 00:00. Thus the label should
 	 * be positioned at noon. By defining a precision of 24 hours or
 	 * rather 86400 seconds, you make sure that this happens.
 	 *
 	 * @param minorUnit		Minor grid unit. Minor grid, major grid and label units
 	 *                         can be one of the following constants defined in
 	 *                         {@link RrdGraphConstants}: {@link RrdGraphConstants#SECOND SECOND},
 	 *                         {@link RrdGraphConstants#MINUTE MINUTE}, {@link RrdGraphConstants#HOUR HOUR},
 	 *                         {@link RrdGraphConstants#DAY DAY}, {@link RrdGraphConstants#WEEK WEEK},
 	 *                         {@link RrdGraphConstants#MONTH MONTH}, {@link RrdGraphConstants#YEAR YEAR}.
 	 * @param minorUnitCount   Number of minor grid units between minor grid lines.
 	 * @param majorUnit		Major grid unit.
 	 * @param majorUnitCount   Number of major grid units between major grid lines.
 	 * @param labelUnit		Label unit.
 	 * @param labelUnitCount   Number of label units between labels.
 	 * @param labelSpan		Label precision
 	 * @param simpleDateFormat Date format (SimpleDateFormat pattern of strftime-like pattern)
 	 */
 	public void setTimeAxis(int minorUnit, int minorUnitCount, int majorUnit, int majorUnitCount,
 							int labelUnit, int labelUnitCount, int labelSpan, String simpleDateFormat) {
 		timeAxisSetting = new TimeAxisSetting(minorUnit, minorUnitCount, majorUnit, majorUnitCount,
 				labelUnit, labelUnitCount, labelSpan, simpleDateFormat);
 	}
 
 	/**
 	 * Sets vertical axis grid and labels. Makes vertical grid lines appear
 	 * at gridStep interval. Every labelFactor*gridStep, a major grid line is printed,
 	 * along with label showing the value of the grid line.
 	 *
 	 * @param gridStep	Minor grid step
 	 * @param labelFactor Specifies how many minor minor grid steps will appear between labels
 	 *                    (major grid lines)
 	 */
 	public void setValueAxis(double gridStep, int labelFactor) {
 		valueAxisSetting = new ValueAxisSetting(gridStep, labelFactor);
 	}
 
 	/**
 	 * Places Y grid dynamically based on graph Y range. Algorithm ensures
 	 * that you always have grid, that there are enough but not too many
 	 * grid lines and the grid is metric. That is grid lines are placed
 	 * every 1, 2, 5 or 10 units.
 	 *
 	 * @param altYGrid true, if Y grid should be calculated dynamically (defaults to false)
 	 */
 	public void setAltYGrid(boolean altYGrid) {
 		this.altYGrid = altYGrid;
 	}
 
 	/**
 	 * Use this method to turn off minor grid lines (printed by default)
 	 *
 	 * @param noMinorGrid true, to turn off, false to turn on (default)
 	 */
 	public void setNoMinorGrid(boolean noMinorGrid) {
 		this.noMinorGrid = noMinorGrid;
 	}
 
 	/**
 	 * Use this method to request MRTG-like graph (false by default)
 	 *
 	 * @param altYMrtg true, to create MRTG-like graph, false otherwise (default)
 	 */
 	public void setAltYMrtg(boolean altYMrtg) {
 		this.altYMrtg = altYMrtg;
 	}
 
 	/**
 	 * Computes Y range based on function absolute minimum and maximum
 	 * values. Default algorithm uses predefined set of ranges.  This is
 	 * good in many cases but it fails miserably when you need to graph
 	 * something like 260 + 0.001 * sin(x). Default algorithm will use Y
 	 * range from 250 to 300 and on the graph you will see almost straight
 	 * line. With --alt-autoscale Y range will be from slightly less the
 	 * 260 - 0.001 to slightly more then 260 + 0.001 and periodic behavior
 	 * will be seen.
 	 *
 	 * @param altAutoscale true to request alternative autoscaling, false otherwise
 	 *                     (default).
 	 */
 	public void setAltAutoscale(boolean altAutoscale) {
 		this.altAutoscale = altAutoscale;
 	}
 
 	/**
 	 * Computes Y range based on function absolute minimum and maximum
 	 * values. Where setAltAutoscale(true) will modify both the absolute maximum AND
 	 * minimum values, this option will only affect the maximum value. The
 	 * minimum value, if not defined elsewhere, will be 0. This
 	 * option can be useful when graphing router traffic when the WAN line
 	 * uses compression, and thus the throughput may be higher than the
 	 * WAN line speed.
 	 *
 	 * @param altAutoscaleMax true to request alternative autoscaling, false
 	 *                        otherwise (default)
 	 */
 	public void setAltAutoscaleMax(boolean altAutoscaleMax) {
 		this.altAutoscaleMax = altAutoscaleMax;
 	}
 
 	/**
 	 * Sets the 10**unitsExponent scaling of the y-axis values. Normally
 	 * values will be scaled to the appropriate units (k, M, etc.). However
 	 * you may wish to display units always in k (Kilo, 10e3) even if
 	 * the data is in the M (Mega, 10e6) range for instance.  Value should
 	 * be an integer which is a multiple of 3 between -18 and 18, inclu-
 	 * sive. It is the exponent on the units you which to use.  For example,
 	 * use 3 to display the y-axis values in k (Kilo, 10e3, thou-
 	 * sands), use -6 to display the y-axis values in u (Micro, 10e-6,
 	 * millionths). Use a value of 0 to prevent any scaling of the y-axis
 	 * values.
 	 *
 	 * @param unitsExponent
 	 */
 	public void setUnitsExponent(int unitsExponent) {
 		this.unitsExponent = unitsExponent;
 	}
 
 	/**
 	 * Sets the character width on the left side of the graph for
 	 * y-axis values.
 	 *
 	 * @param unitsLength Number of characters on the left side of the graphs
 	 *                    reserved for vertical axis labels.
 	 */
 	public void setUnitsLength(int unitsLength) {
 		this.unitsLength = unitsLength;
 	}
 
 	/**
 	 * Sets vertical label on the left side of the graph. This is normally used
 	 * to specify the units used.
 	 *
 	 * @param verticalLabel Vertical axis label
 	 */
 	public void setVerticalLabel(String verticalLabel) {
 		this.verticalLabel = verticalLabel;
 	}
 
 	/**
 	 * Sets width of the drawing area within the graph. This affects the total
 	 * size of the image.
 	 *
 	 * @param width Width of the drawing area.
 	 */
 	public void setWidth(int width) {
 		this.width = width;
 	}
 
 	/**
 	 * Sets height of the drawing area within the graph. This affects the total
 	 * size of the image.
 	 *
 	 * @param height Height of the drawing area.
 	 */
 	public void setHeight(int height) {
 		this.height = height;
 	}
 
 	/**
 	 * Creates interlaced GIF image (currently not supported,
 	 * method is present only for RRDTool comaptibility).
 	 *
 	 * @param interlaced true, if GIF image should be interlaced.
 	 */
 	public void setInterlaced(boolean interlaced) {
 		this.interlaced = interlaced;
 	}
 
 	/**
 	 * Creates additional image information.
 	 * After the image has been created, the graph function uses imageInfo
 	 * format string (printf-like) to create output similar to
 	 * the {@link #print(String, String, String)} function.
 	 * The format string is supplied with the following parameters:
 	 * filename, xsize and ysize (in that particular order).
 	 * <p/>
 	 * For example, in order to generate an IMG tag
 	 * suitable for including the graph into a web page, the command
 	 * would look like this:
 	 * <pre>
 	 * setImageInfo(&quot;&lt;IMG SRC='/img/%s' WIDTH='%d' HEIGHT='%d' ALT='Demo'&gt;&quot;);
 	 * </pre>
 	 *
 	 * @param imageInfo Image info format. Use %s placeholder for filename, %d placeholder for
 	 *                  image width and height.
 	 */
 	public void setImageInfo(String imageInfo) {
 		this.imageInfo = imageInfo;
 	}
 
 	/**
 	 * Sets image format.
 	 *
 	 * @param imageFormat "PNG", "GIF" or "JPG".
 	 */
 	public void setImageFormat(String imageFormat) {
 		this.imageFormat = imageFormat;
 	}
 
 	/**
 	 * Sets background image - currently, only PNG images can be used as background.
 	 *
 	 * @param backgroundImage Path to background image
 	 */
 	public void setBackgroundImage(String backgroundImage) {
 		this.backgroundImage = backgroundImage;
 	}
 
 	/**
 	 * Sets overlay image - currently, only PNG images can be used as overlay. Overlay image is
 	 * printed on the top of the image, once it is completely created.
 	 *
 	 * @param overlayImage Path to overlay image
 	 */
 	public void setOverlayImage(String overlayImage) {
 		this.overlayImage = overlayImage;
 	}
 
 	/**
 	 * Sets unit to be displayed on y axis. It is wise to use only short units on graph, however.
 	 *
 	 * @param unit Unit description
 	 */
 	public void setUnit(String unit) {
 		this.unit = unit;
 	}
 
 	/**
 	 * Creates graph only if the current graph is out of date or not existent.
 	 *
 	 * @param lazy true, if graph should be 'lazy', false otherwise (defualt)
 	 */
 	public void setLazy(boolean lazy) {
 		this.lazy = lazy;
 	}
 
 	/**
 	 * Sets the lower limit of a graph. But rather, this is the
 	 * maximum lower bound of a graph. For example, the value -100 will
 	 * result in a graph that has a lower limit of -100 or less.  Use this
 	 * method to expand graphs down.
 	 *
 	 * @param minValue Minimal value displayed on the graph
 	 */
 	public void setMinValue(double minValue) {
 		this.minValue = minValue;
 	}
 
 	/**
 	 * Defines the value normally located at the upper border of the
 	 * graph. If the graph contains higher values, the upper border will
 	 * move upwards to accommodate these values as well.
 	 * <p/>
 	 * If you want to define an upper-limit which will not move in any
 	 * event you have to use {@link #setRigid(boolean)} method as well.
 	 *
 	 * @param maxValue Maximal value displayed on the graph.
 	 */
 	public void setMaxValue(double maxValue) {
 		this.maxValue = maxValue;
 	}
 
 	/**
 	 * Sets rigid boundaries mode. Normally JRObin will automatically expand
 	 * the lower and upper limit if the graph contains a value outside the
 	 * valid range. With the <code>true</code> argument you can disable this behavior.
 	 *
 	 * @param rigid true if uper and lower limits should not be expanded to accomodate
 	 *              values outside of the specified range. False otherwise (default).
 	 */
 	public void setRigid(boolean rigid) {
 		this.rigid = rigid;
 	}
 
 	/**
 	 * Sets default base for magnitude scaling. If you are graphing memory
 	 * (and NOT network traffic) this switch should be set to 1024 so that 1Kb is 1024 byte.
 	 * For traffic measurement, 1 kb/s is 1000 b/s.
 	 *
 	 * @param base Base value (defaults to 1000.0)
 	 */
 	public void setBase(double base) {
 		this.base = base;
 	}
 
 	/**
 	 * Sets logarithmic y-axis scaling.
 	 *
 	 * @param logarithmic true, for logarithmic scaling, false otherwise (default).
 	 */
 	public void setLogarithmic(boolean logarithmic) {
 		this.logarithmic = logarithmic;
 	}
 
 	/**
      * Overrides the colors for the standard elements of the graph. The colorTag
      * must be one of the following constants defined in the
      * {@link RrdGraphConstants}:
      * {@link RrdGraphConstants#COLOR_BACK COLOR_BACK} background,
      * {@link RrdGraphConstants#COLOR_CANVAS COLOR_CANVAS} canvas,
      * {@link RrdGraphConstants#COLOR_SHADEA COLOR_SHADEA} left/top border,
      * {@link RrdGraphConstants#COLOR_SHADEB COLOR_SHADEB} right/bottom border,
      * {@link RrdGraphConstants#COLOR_GRID COLOR_GRID} major grid,
      * {@link RrdGraphConstants#COLOR_MGRID COLOR_MGRID} minor grid,
      * {@link RrdGraphConstants#COLOR_FONT COLOR_FONT} font,
      * {@link RrdGraphConstants#COLOR_FRAME COLOR_FRAME} axis of the graph,
      * {@link RrdGraphConstants#COLOR_ARROW COLOR_ARROW} arrow. This method can
      * be called multiple times to set several colors.
      * 
      * @param colorTag
      *            Color tag, as explained above.
      * @param color
      *            Any color (paint) you like
      * @throws RrdException
      *             Thrown if invalid colorTag is supplied.
      */
     public void setColor(int colorTag, Paint color) throws RrdException {
         if (colorTag >= 0 && colorTag < colors.length) {
             colors[colorTag] = color;
         } else {
             throw new RrdException("Invalid color index specified: " + colorTag);
         }
     }
 
 	/**
 	 * Overrides the colors for the standard elements of the graph by element name.
 	 * See {@link #setColor(int, java.awt.Paint)} for full explanation.
 	 *
 	 * @param colorName One of the following strings: "BACK", "CANVAS", "SHADEA", "SHADEB",
 	 *                  "GRID", "MGRID", "FONT", "FRAME", "ARROW"
 	 * @param color	 Any color (paint) you like
 	 * @throws RrdException Thrown if invalid element name is supplied.
 	 */
 	public void setColor(String colorName, Paint color) throws RrdException {
 		setColor(getColorTagByName(colorName), color);
 	}
 
 	private static int getColorTagByName(String colorName) throws RrdException {
 		for (int i = 0; i < COLOR_NAMES.length; i++) {
 			if (COLOR_NAMES[i].equalsIgnoreCase(colorName)) {
 				return i;
 			}
 		}
 		throw new RrdException("Unknown color name specified: " + colorName);
 	}
 
 	/**
 	 * Suppress generation of legend, only render the graph.
 	 *
 	 * @param noLegend true if graph legend should be omitted. False otherwise (default).
 	 */
 	public void setNoLegend(boolean noLegend) {
 		this.noLegend = noLegend;
 	}
 
 	/**
 	 * Suppresses anything but the graph, works only for height < 64.
 	 *
 	 * @param onlyGraph true if only graph should be created, false otherwise (default).
 	 */
 	public void setOnlyGraph(boolean onlyGraph) {
 		this.onlyGraph = onlyGraph;
 	}
 
 	/**
 	 * Force the generation of HRULE and VRULE legend even if those HRULE
 	 * or VRULE will not be drawn because out of graph boundaries.
 	 *
 	 * @param forceRulesLegend true if rule legend should be always printed,
 	 *                         false otherwise (default).
 	 */
 	public void setForceRulesLegend(boolean forceRulesLegend) {
 		this.forceRulesLegend = forceRulesLegend;
 	}
 
 	/**
 	 * Defines a title to be written into the graph.
 	 *
 	 * @param title Graph title.
 	 */
 	public void setTitle(String title) {
 		this.title = title;
 	}
 
 	/**
 	 * Suggests which time step should be used by JRobin while processing data from RRD files.
 	 *
 	 * @param step Desired time step (don't use this method if you don't know what you're doing).
 	 */
 	public void setStep(long step) {
 		this.step = step;
 	}
 
 	/**
 	 * Get the default small font for graphing.
 	 * @return the font
 	 */
 	public Font getSmallFont() {
 		return this.smallFont;
 	}
 
 	/**
 	 * Get the default large font for graphing.
 	 * @return the font
 	 */
 	public Font getLargeFont() {
 		return this.largeFont;
 	}
 	
 
 	/**
 	 * Sets default font for graphing. Note that JRobin will behave unpredictably if proportional
 	 * font is selected.
 	 *
 	 * @param smallFont Default font for graphing. Use only monospaced fonts.
 	 */
 	public void setSmallFont(Font smallFont) {
 		this.smallFont = smallFont;
 	}
 
 	/**
 	 * Sets title font.
 	 *
 	 * @param largeFont Font to be used for graph title.
 	 */
 	public void setLargeFont(Font largeFont) {
 		this.largeFont = largeFont;
 	}
 
 	/**
 	 * Defines virtual datasource. This datasource can then be used
 	 * in other methods like {@link #datasource(String, String)} or
 	 * {@link #gprint(String, String, String)}.
 	 *
 	 * @param name	  Source name
 	 * @param rrdPath   Path to RRD file
 	 * @param dsName	Datasource name in the specified RRD file
 	 * @param consolFun Consolidation function (AVERAGE, MIN, MAX, LAST)
 	 */
 	public void datasource(String name, String rrdPath, String dsName, String consolFun) {
 		sources.add(new Def(name, rrdPath, dsName, consolFun));
 	}
 
 	/**
 	 * Defines virtual datasource. This datasource can then be used
 	 * in other methods like {@link #datasource(String, String)} or
 	 * {@link #gprint(String, String, String)}.
 	 *
 	 * @param name	  Source name
 	 * @param rrdPath   Path to RRD file
 	 * @param dsName	Datasource name in the specified RRD file
 	 * @param consolFun Consolidation function (AVERAGE, MIN, MAX, LAST)
 	 * @param backend   Backend to be used while fetching data from a RRD file.
 	 */
 	public void datasource(String name, String rrdPath, String dsName, String consolFun, String backend) {
 		sources.add(new Def(name, rrdPath, dsName, consolFun, backend));
 	}
 
 	/**
 	 * Create a new virtual datasource by evaluating a mathematical
 	 * expression, specified in Reverse Polish Notation (RPN).
 	 *
 	 * @param name		  Source name
 	 * @param rpnExpression RPN expression.
 	 */
 	public void datasource(String name, String rpnExpression) {
 		sources.add(new CDef(name, rpnExpression));
 	}
 
 	/**
 	 * Creates a new (static) virtual datasource. The value of the datasource is constant. This value is
 	 * evaluated by applying the given consolidation function to another virtual datasource.
 	 *
 	 * @param name	  Source name
 	 * @param defName   Other source name
 	 * @param consolFun Consolidation function to be applied to other datasource.
 	 */
 	public void datasource(String name, String defName, String consolFun) {
 		sources.add(new SDef(name, defName, consolFun));
 	}
 
 	/**
 	 * Creates a new (plottable) datasource. Datasource values are obtained from the given plottable
 	 * object.
 	 *
 	 * @param name	  Source name.
 	 * @param plottable Plottable object.
 	 */
 	public void datasource(String name, Plottable plottable) {
 		sources.add(new PDef(name, plottable));
 	}
 
 	/**
 	 * Calculates the chosen consolidation function CF over the given datasource
 	 * and creates the result by using the given format string.  In
 	 * the format string there should be a '%[l]f', '%[l]g' or '%[l]e' marker in
 	 * the place where the number should be printed.
 	 * <p/>
 	 * If an additional '%s' is found AFTER the marker, the value will be
 	 * scaled and an appropriate SI magnitude unit will be printed in
 	 * place of the '%s' marker. The scaling will take the '--base' argument
 	 * into consideration!
 	 * <p/>
 	 * If a '%S' is used instead of a '%s', then instead of calculating
 	 * the appropriate SI magnitude unit for this value, the previously
 	 * calculated SI magnitude unit will be used.  This is useful if you
 	 * want all the values in a print statement to have the same SI magnitude
 	 * unit.  If there was no previous SI magnitude calculation made,
 	 * then '%S' behaves like a '%s', unless the value is 0, in which case
 	 * it does not remember a SI magnitude unit and a SI magnitude unit
 	 * will only be calculated when the next '%s' is seen or the next '%S'
 	 * for a non-zero value.
 	 * <p/>
 	 * Print results are collected in the {@link RrdGraphInfo} object which is retrieved
 	 * from the {@link RrdGraph object} once the graph is created.
 	 *
 	 * @param srcName   Virtual source name
 	 * @param consolFun Consolidation function to be applied to the source
 	 * @param format	Format string (like "average = %10.3f %s")
 	 */
 	public void print(String srcName, String consolFun, String format) {
 		comments.add(new PrintText(srcName, consolFun, format, false));
 	}
 
 	/**
 	 * This method does basically the same thing as {@link #print(String, String, String)},
 	 * but the result is printed on the graph itself, below the chart area.
 	 *
 	 * @param srcName   Virtual source name
 	 * @param consolFun Consolidation function to be applied to the source
 	 * @param format	Format string (like "average = %10.3f %s")
 	 */
 	public void gprint(String srcName, String consolFun, String format) {
 		comments.add(new PrintText(srcName, consolFun, format, true));
 	}
 
 	/**
 	 * Comment to be printed on the graph.
 	 *
 	 * @param text Comment text
 	 */
 	public void comment(String text) {
 		comments.add(new CommentText(text));
 	}
 
 	/**
 	 * Draws a horizontal rule into the graph and optionally adds a legend
 	 *
 	 * @param value  Position of the rule
 	 * @param color  Rule color
 	 * @param legend Legend text. If null, legend text will be omitted.
 	 */
 	public void hrule(double value, Paint color, String legend) {
 		hrule(value, color, legend, 1.0F);
 	}
 
 	/**
 	 * Draws a horizontal rule into the graph and optionally adds a legend
 	 *
 	 * @param value  Position of the rule
 	 * @param color  Rule color
 	 * @param legend Legend text. If null, legend text will be omitted.
 	 * @param width  Rule width
 	 */
 	public void hrule(double value, Paint color, String legend, float width) {
 		LegendText legendText = new LegendText(color, legend);
 		comments.add(legendText);
 		plotElements.add(new HRule(value, color, legendText, width));
 	}
 
 	/**
 	 * Draws a vertical rule into the graph and optionally adds a legend
 	 *
 	 * @param timestamp Position of the rule (seconds since epoch)
 	 * @param color	 Rule color
 	 * @param legend	Legend text. Use null to omit the text.
 	 */
 	public void vrule(long timestamp, Paint color, String legend) {
 		vrule(timestamp, color, legend, 1.0F);
 	}
 
 	/**
 	 * Draws a vertical rule into the graph and optionally adds a legend
 	 *
 	 * @param timestamp Position of the rule (seconds since epoch)
 	 * @param color	 Rule color
 	 * @param legend	Legend text. Use null to omit the text.
 	 * @param width	 Rule width
 	 */
 	public void vrule(long timestamp, Paint color, String legend, float width) {
 		LegendText legendText = new LegendText(color, legend);
 		comments.add(legendText);
 		plotElements.add(new VRule(timestamp, color, legendText, width));
 	}
 
 	/**
 	 * Plots requested data as a line, using the color and the line width specified.
 	 *
 	 * @param srcName Virtual source name
 	 * @param color   Line color
 	 * @param legend  Legend text
 	 * @param width   Line width (default: 1.0F)
 	 */
 	public void line(String srcName, Paint color, String legend, float width) {
 		LegendText legendText = new LegendText(color, legend);
 		comments.add(legendText);
 		plotElements.add(new Line(srcName, color, width));
 	}
 
 	/**
 	 * Plots requested data as a line, using the color specified. Line width is assumed to be
 	 * 1.0F.
 	 *
 	 * @param srcName Virtual source name
 	 * @param color   Line color
 	 * @param legend  Legend text
 	 */
 	public void line(String srcName, Paint color, String legend) {
 		line(srcName, color, legend, 1F);
 	}
 
 	/**
      * Plots requested data in the form of the filled area starting from zero,
      * using the color specified.
      * 
      * @param srcName
      *            Virtual source name.
      * @param color
      *            Color of the filled area.
      * @param legend
      *            Legend text.
      */
     public void area(String srcName, Paint color, String legend) {
         area(srcName, color);
         if (legend.length() > 0) {
             LegendText legendText = new LegendText(color, legend);
             comments.add(legendText);
         }
     }
 
     /**
      * Plots requested data in the form of the filled area starting from zero,
      * using the color specified.
      * 
      * @param srcName
      *            Virtual source name.
      * @param color
      *            Color of the filled area.
      */
     public void area(String srcName, Paint color) {
         plotElements.add(new Area(srcName, color));
     }
 	
 	/**
 	 * Does the same as {@link #line(String, java.awt.Paint, String)},
 	 * but the graph gets stacked on top of the
 	 * previous LINE, AREA or STACK graph. Depending on the type of the
 	 * previous graph, the STACK will be either a LINE or an AREA.  This
 	 * obviously implies that the first STACK must be preceded by an AREA
 	 * or LINE.
 	 * <p/>
 	 * Note, that when you STACK onto *UNKNOWN* data, JRobin will not
 	 * draw any graphics ... *UNKNOWN* is not zero.
 	 *
 	 * @param srcName Virtual source name
 	 * @param color   Stacked graph color
 	 * @param legend  Legend text
 	 * @throws RrdException Thrown if this STACK has no previously defined AREA, STACK or LINE
 	 *                      graph bellow it.
 	 */
 	public void stack(String srcName, Paint color, String legend) throws RrdException {
 		// find parent AREA or LINE
 		SourcedPlotElement parent = null;
 		for (int i = plotElements.size() - 1; i >= 0; i--) {
 			PlotElement plotElement = plotElements.get(i);
 			if (plotElement instanceof SourcedPlotElement) {
 				parent = (SourcedPlotElement) plotElement;
 				break;
 			}
 		}
 		if (parent == null) {
 			throw new RrdException("You have to stack graph onto something (line or area)");
 		}
 		else {
 			LegendText legendText = new LegendText(color, legend);
 			comments.add(legendText);
 			plotElements.add(new Stack(parent, srcName, color));
 		}
 	}
 
 	/**
 	 * Sets visibility of the X-axis grid.
 	 *
 	 * @param drawXGrid True if X-axis grid should be created (default), false otherwise.
 	 */
 	public void setDrawXGrid(boolean drawXGrid) {
 		this.drawXGrid = drawXGrid;
 	}
 
 	/**
 	 * Sets visibility of the Y-axis grid.
 	 *
 	 * @param drawYGrid True if Y-axis grid should be created (default), false otherwise.
 	 */
 	public void setDrawYGrid(boolean drawYGrid) {
 		this.drawYGrid = drawYGrid;
 	}
 
 	/**
 	 * Sets image quality. Relevant only for JPEG images.
 	 *
 	 * @param imageQuality (0F=worst, 1F=best).
 	 */
 	public void setImageQuality(float imageQuality) {
 		this.imageQuality = imageQuality;
 	}
 
 	/**
 	 * Controls if the chart area of the image should be antialiased or not.
 	 *
 	 * @param antiAliasing use true to turn antialiasing on, false to turn it off (default)
 	 */
 	public void setAntiAliasing(boolean antiAliasing) {
 		this.antiAliasing = antiAliasing;
 	}
 
 	/**
 	 * Shows or hides graph signature (gator) in the top right corner of the graph
 	 *
 	 * @param showSignature true, if signature should be seen (default), false otherwise
 	 */
 	public void setShowSignature(boolean showSignature) {
 		this.showSignature = showSignature;
 	}
 
 	/**
 	 * Sets first day of the week.
 	 *
 	 * @param firstDayOfWeek One of the following constants:
 	 *                       {@link RrdGraphConstants#MONDAY MONDAY},
 	 *                       {@link RrdGraphConstants#TUESDAY TUESDAY},
 	 *                       {@link RrdGraphConstants#WEDNESDAY WEDNESDAY},
 	 *                       {@link RrdGraphConstants#THURSDAY THURSDAY},
 	 *                       {@link RrdGraphConstants#FRIDAY FRIDAY},
 	 *                       {@link RrdGraphConstants#SATURDAY SATURDAY},
 	 *                       {@link RrdGraphConstants#SUNDAY SUNDAY}
 	 */
 	public void setFirstDayOfWeek(int firstDayOfWeek) {
 		this.firstDayOfWeek = firstDayOfWeek;
 	}
 
 	// helper methods
 
 	int printStatementCount() {
 		int count = 0;
 		for (CommentText comment : comments) {
 			if (comment instanceof PrintText) {
 				if (comment.isPrint()) {
 					count++;
 				}
 			}
 		}
 		return count;
 	}
 
 	boolean shouldPlot() {
 		if (plotElements.size() > 0) {
 			return true;
 		}
 		for (CommentText comment : comments) {
 			if (comment.isValidGraphElement()) {
 				return true;
 			}
 		}
 		return false;
 	}
 }