<?php

/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**
 * Class for axis handling.
 *
 * PHP versions 4 and 5
 *
 * LICENSE: 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
 *
 * @category   Images
 * @package    Image_Graph
 * @subpackage Axis
 * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
 * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
 * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
 * @version    CVS: $Id$
 * @link       http://pear.php.net/package/Image_Graph
 */
 
/**
 * Include file Image/Graph/Plotarea/Element.php
 */
require_once 'Image/Graph/Plotarea/Element.php';

/**
 * Diplays a normal linear axis (either X- or Y-axis).
 *
 * @category   Images
 * @package    Image_Graph
 * @subpackage Axis
 * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
 * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
 * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
 * @version    Release: @package_version@
 * @link       http://pear.php.net/package/Image_Graph
 */
 class Image_Graph_Axis extends Image_Graph_Plotarea_Element
{
    
    /**
     * The type of the axis, possible values are:
     * <ul>
     * <li>IMAGE_GRAPH_AXIS_X / IMAGE_GRAPH_AXIS_HORIZONTAL
     * <li>IMAGE_GRAPH_AXIS_Y / IMAGE_GRAPH_AXIS_VERTICAL /
     * IMAGE_GRAPH_AXIS_Y_SECONDARY
     * </ul>
     * @var int
     * @access private
     */
    var $_type;

    /**
     * The minimum value the axis displays
     * @var int
     * @access private
     */
    var $_minimum = false;

    /**
     * The minimum value the axis has been explicitly set by the user
     * @var bool
     * @access private
     */
    var $_minimumSet = false;

    /**
     * The maximum value the axis displays
     * @var int
     * @access private
     */
    var $_maximum = false;

    /**
     * The maximum value the axis has been explicitly set by the user
     * @var bool
     * @access private
     */
    var $_maximumSet = false;

    /**
     * The value span of the axis.
     * This is primarily included for performance reasons
     * @var double
     * @access private
     */
    var $_axisSpan = false;

    /**
     * The value span of the axis.
     * This is primarily included for performance reasons
     * @var double
     * @access private
     */
    var $_axisValueSpan = false;
    
    /**
     * The axis padding.
     * The index 'low' specifies the padding for the low axis values (when not
     * inverted), i.e. to the left on an x-axis and on the bottom of an y-axis,
     * vice versa for 'high'.
     * 
     * Axis padding does not make sense on a normal linear y-axis with a 'y-min'
     * of 0 since this corresponds to displaying a small part of the y-axis
     * below 0!
     * 
     * @var array
     * @access private
     */
    var $_axisPadding = array('low' => 0, 'high' => 0);

    /**
     * The number of "pixels" representing 1 unit on the axis
     *
     * This is primarily included for performance reasons
     * @var double
     * @access private
     */
    var $_delta = false;
    
    /**
     * Specify if the axis should label the minimum value
     * @var bool
     * @access private
     */
    var $_showLabelMinimum = true;

    /**
     * Specify if the axis should label 0 (zero)
     * @var bool
     * @access private
     */
    var $_showLabelZero = false;

    /**
     * Specify if the axis should label the maximum value
     * @var bool
     * @access private
     */
    var $_showLabelMaximum = true;

    /**
     * Show arrow heads at the 'end' of the axis, default: false
     * @var bool
     * @access private
     */
    var $_showArrow = false;

    /**
     * Intersection data of axis
     * @var array
     * @access private
     */
    var $_intersect = array('value' => 'default', 'axis' => 'default');

    /**
     * The fixed size of the axis (i.e. width for y-axis, height for x-axis)
     * @var mixed
     * @access private
     */
    var $_fixedSize = false;

    /**
     * The label options
     *
     * Should text be shows, preferences for ticks. The indexes start at level
     * 1, which is chosen for readability
     * @var array
     * @access private
     */
    var $_labelOptions = array(
        1 => array(
            'interval' => 1,
            'type' => 'auto',
            'tick' => array(
                'start' => -2, 
                'end' => 2, 
                'color' => false // default color
            ),
            'showtext' => true,
            'showoffset' => false,
            'font' => array(),
            'offset' => 0,
            'position' => 'outside',            
        )
    );

    /**
     * The labels that are shown.
     *
     * This is used to make values show only once...
     * @access private
     */
    var $_labelText = array();

    /**
     * A data preprocessor for formatting labels, fx showing dates as a standard
     * date instead of Unix time stamp
     * @var Image_Graph_DatePreProcessor
     * @access private
     * @see Image_Graph_DataPreProcessor
     */
    var $_dataPreProcessor = null;

    /**
     * Point marked in the axis
     * @var array
     * @access private
     */
    var $_marks = array();

    /**
     * Specifies whether the values should be 'pushed' by 0.5
     * @var bool
     * @access private
     */
    var $_pushValues = false;

    /**
     * The title of this axis
     * @var string
     * @access private
     */
    var $_title = '';

    /**
     * The font used for the title of this axis
     * @var Image_Graph_Font
     * @access private
     */
    var $_titleFont = false;
    
    /**
     * Invert the axis (i.e. if an y-axis normally displays minimum values at
     * the bottom, they are not displayed at the top
     * @var bool
     * @access private
     * @since 0.3.0dev3
     */
    var $_invert = false;
    
    /**
     * Transpose the axis (i.e. is a normal y-axis transposed, so thats it's not show
     * vertically as normally expected, but instead horizontally)
     * @var bool
     * @access private
     */
    var $_transpose = false;

    /**
     * Image_Graph_Axis [Constructor].
     * Normally a manual creation should not be necessary, axis are created
     * automatically by the {@link Image_Graph_Plotarea} constructor unless
     * explicitly defined otherwise
     *
     * @param int $type The type (direction) of the Axis, use IMAGE_GRAPH_AXIS_X
     * for an X-axis (default, may be omitted) and IMAGE_GRAPH_AXIS_Y for Y-
     * axis)
     */
    function Image_Graph_Axis($type = IMAGE_GRAPH_AXIS_X)
    {
        parent::Image_Graph_Element();
        $this->_type = $type;
        $this->_fillStyle = 'black';
    }

    /**
     * Push the values by 0.5 (for bar and step chart)
     *
     * @access private
     */
    function _pushValues()
    {
        $this->_pushValues = true;
    }
    
    /**
     * Sets the axis padding for a given position ('low' or 'high')
     * @param string $where The position
     * @param int $value The number of pixels to "pad"
     * @access private
     */
    function _setAxisPadding($where, $value)
    {
        $this->_axisPadding[$where] = $value;
    }     

    /**
     * Gets the font of the title.
     *
     * If not font has been set, the parent font is propagated through it's
     * children.
     *
     * @return array An associated array used for canvas
     * @access private
     */
    function _getTitleFont()
    {
        if ($this->_titleFont === false) {
            if ($this->_defaultFontOptions !== false) {
                return $this->_defaultFontOptions;
            } else {
                return $this->_getFont();
            }
        } else {
            if (is_object($this->_titleFont)) {
                return $this->_titleFont->_getFont();
            } elseif (is_array($this->_titleFont)) {
                return $this->_getFont($this->_titleFont);
            } elseif (is_int($this->_titleFont)) {
                return $this->_getFont(array('size' => $this->_titleFont));
            }
        }
        return array();
    }

    /**
     * Shows a label for the the specified values.
     *
     * Allowed values are  combinations of:
     * <ul>
     * <li>IMAGE_GRAPH_LABEL_MINIMUM
     * <li>IMAGE_GRAPH_LABEL_ZERO
     * <li>IMAGE_GRAPH_LABEL_MAXIMUM
     * </ul>
     * By default none of these are shows on the axis
     *
     * @param int $value The values to show labels for
     */
    function showLabel($value)
    {
        $this->_showLabelMinimum = ($value & IMAGE_GRAPH_LABEL_MINIMUM);
        $this->_showLabelZero = ($value & IMAGE_GRAPH_LABEL_ZERO);
        $this->_showLabelMaximum = ($value & IMAGE_GRAPH_LABEL_MAXIMUM);
    }

    /**
     * Sets a data preprocessor for formatting the axis labels
     *
     * @param Image_Graph_DataPreprocessor $dataPreProcessor The data preprocessor
     * @see Image_Graph_DataPreprocessor
     */
    function setDataPreProcessor(& $dataPreProcessor)
    {
        $this->_dataPreProcessor =& $dataPreProcessor;
    }

    /**
     * Gets the minimum value the axis will show
     *
     * @return double The minumum value
     * @access private
     */
    function _getMinimum()
    {
        return $this->_minimum;
    }

    /**
     * Gets the maximum value the axis will show
     *
     * @return double The maximum value
     * @access private
     */
    function _getMaximum()
    {
        return $this->_maximum;
    }

    /**
     * Sets the minimum value the axis will show
     *
     * @param double $minimum The minumum value to use on the axis
     * @access private
     */
    function _setMinimum($minimum)
    {
        if ($this->_minimum === false) {
            $this->forceMinimum($minimum, false);
        } else {
            $this->forceMinimum(min($this->_minimum, $minimum), false);
        }
    }

    /**
     * Sets the maximum value the axis will show
     *
     * @param double $maximum The maximum value to use on the axis
     * @access private
     */
    function _setMaximum($maximum)
    {
        if ($this->_maximum === false) {
            $this->forceMaximum($maximum, false);
        } else {
            $this->forceMaximum(max($this->_maximum, $maximum), false);
        }
    }

    /**
     * Forces the minimum value of the axis
     *
     * @param double $minimum The minumum value to use on the axis
     * @param bool $userEnforce This value should not be set, used internally
     */
    function forceMinimum($minimum, $userEnforce = true)
    {        
        if (($userEnforce) || (!$this->_minimumSet)) {
            $this->_minimum = $minimum;
            $this->_minimumSet = $userEnforce;
        }
        $this->_calcLabelInterval();
    }

    /**
     * Forces the maximum value of the axis
     *
     * @param double $maximum The maximum value to use on the axis
     * @param bool $userEnforce This value should not be set, used internally
     */
    function forceMaximum($maximum, $userEnforce = true)
    {
        if (($userEnforce) || (!$this->_maximumSet)) {
            $this->_maximum = $maximum;
            $this->_maximumSet = $userEnforce;
        }
        $this->_calcLabelInterval();
    }

    /**
     * Show an arrow head on the 'end' of the axis
     */
    function showArrow()
    {
        $this->_showArrow = true;
    }

    /**
     * Do not show an arrow head on the 'end' of the axis (default)
     */
    function hideArrow()
    {
        $this->_showArrow = false;
    }

    /**
     * Return the label distance.
     *
     * @param int $level The label level to return the distance of
     * @return int The distance between 2 adjacent labels
     * @access private
     */
    function _labelDistance($level = 1)
    {
        $l1 = $this->_getNextLabel(false, $level);
        $l2 = $this->_getNextLabel($l1, $level);;
        return abs($this->_point($l2) - $this->_point($l1));
    }

    /**
     * Sets an interval for when labels are shown on the axis.
     *
     * By default 'auto' is used, forcing the axis to calculate a approximate
     * best label interval to be used. Specify an array to use user-defined
     * values for labels.
     *
     * @param mixed $labelInterval The interval with which labels are shown
     * @param int $level The label level to set the interval on
     */
    function setLabelInterval($labelInterval = 'auto', $level = 1)
    {
        if (!isset($this->_labelOptions[$level])) {
            $this->_labelOptions[$level] = array();
        }

        if ($labelInterval === 'auto') {
            $this->_labelOptions[$level]['type'] = 'auto';
            $this->_calcLabelInterval();
        } else {
            $this->_labelOptions[$level]['type'] = 'manual';
            $this->_labelOptions[$level]['interval'] = $labelInterval;
        }
    }

    /**
     * Sets options for the label at a specific level.
     *
     * Possible options are:
     * 
     * 'showtext' true or false whether label text should be shown or not
     * 
     * 'showoffset' should the label be shown at an offset, i.e. should the
     * label be shown at a position so that it does not overlap with prior
     * levels. Only applies to multilevel labels with text
     * 
     * 'font' The font options as an associated array
     * 
     * 'position' The position at which the labels are written ('inside' or
     * 'outside' the axis). NB! This relative position only applies to the
     * default location of the axis, i.e. if an x-axis is inverted then
     * 'outside' still refers to the "left" side of a normal y-axis (since this
     * is normally 'outside') but the actual output will be labels on the
     * "inside"!
     *
     * 'format' To format the label text according to a sprintf statement
     *
     * 'dateformat' To format the label as a date, fx. j. M Y = 29. Jun 2005
     *
     * @param string $option The label option name (see detailed description
     * for possible values)
     * @param mixed $value The value for the option
     * @param int $level The label level to set the interval on
     */
    function setLabelOption($option, $value, $level = 1)
    {
        if (!isset($this->_labelOptions[$level])) {
            $this->_labelOptions[$level] = array('type' => 'auto');
        }

        $this->_labelOptions[$level][$option] = $value;
    }

    /**
     * Sets options for the label at a specific level.
     *
     * The possible options are specified in {@link Image_Graph_Axis::
     * setLabelOption()}.
     *
     * @param array $options An assciated array with label options
     * @param int $level The label level to set the interval on
     */
    function setLabelOptions($options, $level = 1)
    {
        if (is_array($options)) {
            if (isset($this->_labelOptions[$level])) {
                $this->_labelOptions[$level] = array_merge($this->_labelOptions[$level], $options);
            } else {
                $this->_labelOptions[$level] = $options;
            }
                
        }
    }    
    
    /**
     * Sets the title of this axis.
     *
     * This is used as an alternative (maybe better) method, than using layout's
     * for axis-title generation.
     * 
     * To use the current propagated font, but just set it vertically, simply
     * pass 'vertical' as second parameter for vertical alignment down-to-up or
     * 'vertical2' for up-to-down alignment.
     *
     * @param string $title The title of this axis
     * @param Image_Graph_Font $font The font used for the title
     * @since 0.3.0dev2
     */
    function setTitle($title, $font = false)
    {
        $this->_title = $title;
        if ($font === 'vertical') {
            $this->_titleFont = array('vertical' => true, 'angle' => 90);
        } elseif ($font === 'vertical2') {
            $this->_titleFont = array('vertical' => true, 'angle' => 270);
        } else {
            $this->_titleFont =& $font;
        }
    }

    /**
     * Sets a fixed "size" for the axis.
     * 
     * If the axis is any type of y-axis the size relates to the width of the
     * axis, if an x-axis is concerned the size is the height.
     *
     * @param int $size The fixed size of the axis
     * @since 0.3.0dev5
     */
    function setFixedSize($size)
    {
        $this->_fixedSize = $size;
    }

    /**
     * Preprocessor for values, ie for using logarithmic axis
     *
     * @param double $value The value to preprocess
     * @return double The preprocessed value
     * @access private
     */
    function _value($value)
    {
        return $value - $this->_getMinimum() + ($this->_pushValues ? 0.5 : 0);
    }

    /**
     * Apply the dataset to the axis
     *
     * @param Image_Graph_Dataset $dataset The dataset
     * @access private
     */
    function _applyDataset(&$dataset)
    {
        if ($this->_type == IMAGE_GRAPH_AXIS_X) {
            $this->_setMinimum($dataset->minimumX());
            $this->_setMaximum($dataset->maximumX());
        } else {
            $this->_setMinimum($dataset->minimumY());
            $this->_setMaximum($dataset->maximumY());
        }
    }

    /**
     * Get the pixel position represented by a value on the canvas
     *
     * @param double $value the value to get the pixel-point for
     * @return double The pixel position along the axis
     * @access private
     */
    function _point($value)    
    {        
        if ((($this->_type == IMAGE_GRAPH_AXIS_X) && (!$this->_transpose)) ||
           (($this->_type != IMAGE_GRAPH_AXIS_X) && ($this->_transpose))) 
        {
            if ($this->_invert) {                
                return max($this->_left, $this->_right - $this->_axisPadding['high'] - $this->_delta * $this->_value($value));
            } else {
                return min($this->_right, $this->_left + $this->_axisPadding['low'] + $this->_delta * $this->_value($value));
            }                
        } else {
            if ($this->_invert) {                
                return min($this->_bottom, $this->_top + $this->_axisPadding['high'] + $this->_delta * $this->_value($value));
            } else {
                return max($this->_top, $this->_bottom - $this->_axisPadding['low'] - $this->_delta * $this->_value($value));
            }
        }
    }


    /**
     * Get the axis intersection pixel position
     *
     * This is only to be called prior to output! I.e. between the user
     * invokation of Image_Graph::done() and any actual output is performed.
     * This is because it can change the axis range.
     *
     * @param double $value the intersection value to get the pixel-point for
     * @return double The pixel position along the axis
     * @access private
     */
    function _intersectPoint($value)
    {

        if (($value === 'min') || ($value < $this->_getMinimum())) {
            if ($this->_type == IMAGE_GRAPH_AXIS_X) {
                if ($this->_invert) {
                    return ($this->_transpose ? $this->_top : $this->_right);
                } else {
                    return ($this->_transpose ? $this->_bottom : $this->_left);
                }
            } else {
                if ($this->_invert) {
                    return ($this->_transpose ? $this->_right : $this->_top);
                } else {
                    return ($this->_transpose ? $this->_left : $this->_bottom);
                }
            }
        } elseif (($value === 'max') || ($value > $this->_getMaximum())) {
            if ($this->_type == IMAGE_GRAPH_AXIS_X) {
                if ($this->_invert) {
                    return ($this->_transpose ? $this->_bottom : $this->_left);
                } else {
                    return ($this->_transpose ? $this->_top : $this->_right);
                }
            } else {
                if ($this->_invert) {
                    return ($this->_transpose ? $this->_left : $this->_bottom);
                } else {
                    return ($this->_transpose ? $this->_right : $this->_top);
                }
            }
        } 
        
        return $this->_point($value);
    }
    
    /**
     * Calculate the delta value (the number of pixels representing one unit
     * on the axis)
     *
     * @return double The label interval
     * @access private
     */
    function _calcDelta()
    {
        if ($this->_axisValueSpan == 0) {
            $this->_delta = false;
        } elseif ($this->_type == IMAGE_GRAPH_AXIS_X) {
            $this->_delta = (($this->_transpose ? $this->height() : $this->width()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / ($this->_axisValueSpan + ($this->_pushValues ? 1 : 0));
        } else {
            $this->_delta = (($this->_transpose ? $this->width() : $this->height()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / ($this->_axisValueSpan + ($this->_pushValues ? 1 : 0));
        }
    }        
    
    /**
     * Calculate the label interval
     *
     * If explicitly defined this will be calucated to an approximate best.
     *
     * @return double The label interval
     * @access private
     */
    function _calcLabelInterval()
    {
        $min = $this->_getMinimum();
        $max = $this->_getMaximum();
        
        $this->_axisValueSpan = $this->_axisSpan = abs($max - $min);
        
        if ((!empty($min)) && (!empty($max)) && ($min > $max)) {
            $this->_labelOptions[1]['interval'] = 1;
            return true;
        }

        $span = 0;
        foreach($this->_labelOptions as $level => $labelOptions) {
            if ((!isset($labelOptions['type'])) || ($labelOptions['type'] !== 'auto')) {
                $span = false;
            } elseif ($level == 1) {
                $span = $this->_axisValueSpan;
            } else {
                $l1 = $this->_getNextLabel(false, $level - 1);
                $l2 = $this->_getNextLabel($l1, $level - 1);
                if ((!is_numeric($l1)) || (!is_numeric($l2))) {
                    $span == false;
                } else {
                    $span = $l2 - $l1;
                }
            }

            if ($span !== false) {
                $interval = pow(10, floor(log10($span)));

                if ($interval == 0) {
                    $interval = 1;
                }

                if ((($span) / $interval) < 3) {
                    $interval = $interval / 4;
                } elseif ((($span) / $interval) < 5) {
                    $interval = $interval / 2;
                } elseif ((($span) / $interval) > 10) {
                    $interval = $interval * 2;
                }

                if (($interval -floor($interval) == 0.5) && ($interval != 0.5)) {
                    $interval = floor($interval);
                }

                // just to be 100% sure that an interval of 0 is not returned some
                // additional checks are performed
                if ($interval == 0) {
                    $interval = ($span) / 5;
                }

                if ($interval == 0) {
                    $interval = 1;
                }

                $this->_labelOptions[$level]['interval'] = $interval;
            }
        }
    }

    /**
     * Get next label point
     *
     * @param doubt $currentLabel The current label, if omitted or false, the
     *   first is returned
     * @param int $level The label level to get the next label from
     * @return double The next label point
     * @access private
     */
    function _getNextLabel($currentLabel = false, $level = 1)
    {
        if (!isset($this->_labelOptions[$level])) {
            return false;
        }

        if (is_array($this->_labelOptions[$level]['interval'])) {
            if ($currentLabel === false) {
                reset($this->_labelOptions[$level]['interval']);
            }

            if (list(, $label) = each($this->_labelOptions[$level]['interval'])) {
                return $label;
            } else {
                return false;
            }
        } else {
            $li = $this->_labelInterval($level);
            if (($this->_axisSpan == 0) || ($this->_axisValueSpan == 0) ||
                ($li == 0)
            ) {
                return false;
            }

            $labelInterval = $this->_axisSpan / ($this->_axisValueSpan / $li);

            if ($labelInterval == 0) {
                return false;
            }

            if ($currentLabel === false) {
                $label = ((int) ($this->_getMinimum() / $labelInterval)) *
                    $labelInterval - $labelInterval;
                while ($label < $this->_getMinimum()) {
                    $label += $labelInterval;
                }
                return $label;
            } else {
                if ($currentLabel + $labelInterval > $this->_getMaximum()) {
                    return false;
                } else {
                    return $currentLabel + $labelInterval;
                }
            }
        }
    }

    /**
     * Get the interval with which labels are shown on the axis.
     *
     * If explicitly defined this will be calucated to an approximate best.
     *
     * @param int $level The label level to get the label interval for
     * @return double The label interval
     * @access private
     */
    function _labelInterval($level = 1)
    {
        if ((!isset($this->_labelOptions[$level])) ||
            (!isset($this->_labelOptions[$level]['interval']))
        ) {
            return 1;
        }

        return (is_array($this->_labelOptions[$level]['interval'])
            ? 1
            : $this->_labelOptions[$level]['interval']
        );
    }

    /**
     * Get the size in pixels of the axis.
     *
     * For an x-axis this is the width of the axis including labels, and for an
     * y-axis it is the corrresponding height
     *
     * @return int The size of the axis
     * @access private
     */
    function _size()
    {
        if (!$this->_visible) {
            return 0;
        }
        
        if ($this->_fixedSize !== false) {
            return $this->_fixedSize;
        }
         
        krsort($this->_labelOptions);

        $totalMaxSize = 0;

        foreach ($this->_labelOptions as $level => $labelOptions) {
            if ((isset($labelOptions['showoffset'])) && ($labelOptions['showoffset'] === true)) {
                $this->_labelOptions[$level]['offset'] += $totalMaxSize;
            } elseif (!isset($this->_labelOptions[$level]['offset'])) {
                $this->_labelOptions[$level]['offset'] = 0;
            }
            if (
                (isset($labelOptions['showtext'])) &&                
                ($labelOptions['showtext'] === true) &&
                (
                    (!isset($labelOptions['position'])) ||
                    ($labelOptions['position'] == 'outside')
                )               
            ) {
                if (isset($labelOptions['font'])) {
                    $font = $this->_getFont($labelOptions['font']);
                } else {
                    if ($this->_defaultFontOptions !== false) {
                        $font = $this->_defaultFontOptions;
                    } else {
                        $font = $this->_getFont();
                    }
                }
                $this->_canvas->setFont($font);

                $value = false;
                $maxSize = 0;
                while (($value = $this->_getNextLabel($value, $level)) !== false) {
                    if ((abs($value) > 0.0001) && ($value > $this->_getMinimum()) &&
                        ($value < $this->_getMaximum()))
                    {
                        if (is_object($this->_dataPreProcessor)) {
                            $labelText = $this->_dataPreProcessor->_process($value);
                        } elseif (isset($labelOptions['format'])) {
                            $labelText = sprintf($labelOptions['format'], $value);
                        } elseif (isset($labelOptions['dateformat'])) {
                            $labelText = date($labelOptions['dateformat'], $value);
                        } else {
                            $labelText = $value;
                        }

                        if ((($this->_type == IMAGE_GRAPH_AXIS_X) && (!$this->_transpose)) ||
                           (($this->_type != IMAGE_GRAPH_AXIS_X) && ($this->_transpose)))
                        {
                            $maxSize = max($maxSize, $this->_canvas->textHeight($labelText));
                        } else {
                            $maxSize = max($maxSize, $this->_canvas->textWidth($labelText));
                        }
                    }
                }
                if ((isset($labelOptions['showoffset'])) && ($labelOptions['showoffset'] === true)) {
                    $totalMaxSize += $maxSize;
                } else {
                    $totalMaxSize = max($totalMaxSize, $maxSize);
                }
            }
        }

        if ($this->_title) {
            $this->_canvas->setFont($this->_getTitleFont());

            if ((($this->_type == IMAGE_GRAPH_AXIS_X) && (!$this->_transpose)) ||
               (($this->_type != IMAGE_GRAPH_AXIS_X) && ($this->_transpose)))
            {
                $totalMaxSize += $this->_canvas->textHeight($this->_title);
            } else {
                $totalMaxSize += $this->_canvas->textWidth($this->_title);
            }
            $totalMaxSize += 10;
        }

        return $totalMaxSize + 3;
    }

    /**
     * Adds a mark to the axis at the specified value
     *
     * @param double $value The value
     * @param double $value2 The second value (for a ranged mark)
     */
    function addMark($value, $value2 = false, $text = false)
    {
        if ($value2 === false) {
            $this->_marks[] = $value;
        } else {
            $this->_marks[] = array($value, $value2);
        }
    }

    /**
     * Is the axis numeric or not?
     *
     * @return bool True if numeric, false if not
     * @access private
     */
    function _isNumeric()
    {
        return true;
    }

    /**
     * Set the major tick appearance.
     *
     * The positions are specified in pixels relative to the axis, meaning that
     * a value of -1 for start will draw the major tick 'line' starting at 1
     * pixel outside (negative) value the axis (i.e. below an x-axis and to the
     * left of a normal y-axis).
     *
     * @param int $start The start position relative to the axis
     * @param int $end The end position relative to the axis
     * @param int $level The label level to set the tick options for
     * @since 0.3.0dev2
     */
    function setTickOptions($start, $end, $level = 1)
    {
        if (!isset($this->_labelOptions[$level])) {
            $this->_labelOptions[$level] = array();
        }

        $this->_labelOptions[$level]['tick'] = array(
            'start' => $start,
            'end' => $end
        );
    }
    
    /**
     * Invert the axis direction
     * 
     * If the minimum values are normally displayed fx. at the bottom setting
     * axis inversion to true, will cause the minimum values to be displayed at
     * the top and maximum at the bottom.
     *
     * @param bool $invert True if the axis is to be inverted, false if not
     * @since 0.3.0dev3
     */
    function setInverted($invert)
    {
        $this->_invert = $invert;
    }

    /**
     * Set axis intersection.
     *
     * Sets the value at which the axis intersects other axis, fx. at which Y-
     * value the x-axis intersects the y-axis (normally at 0).
     * 
     * Possible values are 'default', 'min', 'max' or a number between axis min
     * and max (the value will automatically be limited to this range).
     * 
     * For a coordinate system with 2 y-axis, the x-axis can either intersect
     * the primary or the secondary y-axis. To make the x-axis intersect the
     * secondary y-axis at a given value pass IMAGE_GRAPH_AXIS_Y_SECONDARY as
     * second parameter.
     *
     * @param mixed $intersection The value at which the axis intersect the
     * 'other' axis
     * @param mixed $axis The axis to intersect. Only applies to x-axis with
     * both a primary and secondary y-axis available.
     * @since 0.3.0dev2
     */
    function setAxisIntersection($intersection, $axis = 'default')
    {
        if ($axis == 'x') {
            $axis = IMAGE_GRAPH_AXIS_X;
        } elseif ($axis == 'y') {
            $axis = IMAGE_GRAPH_AXIS_Y;
        } elseif ($axis == 'ysec') {
            $axis = IMAGE_GRAPH_AXIS_Y_SECONDARY;
        }
        $this->_intersect = array(
            'value' => $intersection,
            'axis' => $axis
        );
    }

    /**
     * Get axis intersection data.
     * 
     * @return array An array with the axis intersection data.
     * @since 0.3.0dev2
     * @access private
     */
    function _getAxisIntersection()
    {
        $value = $this->_intersect['value'];
        $axis = $this->_intersect['axis'];
        if (($this->_type == IMAGE_GRAPH_AXIS_Y) 
            || ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY)
        ) {
            $axis = IMAGE_GRAPH_AXIS_X;
        } elseif ($axis == 'default') {
            $axis = IMAGE_GRAPH_AXIS_Y;
        }
        
        if ($value === 'default') {
            switch ($this->_type) {
            case IMAGE_GRAPH_AXIS_Y:
                $value = 'min';
                break;
            case IMAGE_GRAPH_AXIS_Y_SECONDARY:
                $value = 'max';
                break;
            case IMAGE_GRAPH_AXIS_X:
                $value = 0;
                break;
            }
        }
        
        return array('value' => $value, 'axis' => $axis);
    }
    
    /**
     * Resets the elements
     *
     * @access private
     */
    function _reset()
    {
        parent::_reset();
        $this->_labelText = array();
    }
    
    /**
     * Output an axis tick mark.
     *
     * @param int $value The value to output
     * @param int $level The label level to draw the tick for
     * @access private
     */
    function _drawTick($value, $level = 1)
    {
        if (isset($this->_labelOptions[$level])) {
            $labelOptions = $this->_labelOptions[$level];
            $labelPosition = $this->_point($value);

            if (isset($labelOptions['offset'])) {
                $offset = $labelOptions['offset'];
            } else {
                $offset = 0;
            }

            if ((isset($labelOptions['showtext'])) && ($labelOptions['showtext'] === true)) {
                if (is_object($this->_dataPreProcessor)) {
                    $labelText = $this->_dataPreProcessor->_process($value);
                } elseif (isset($labelOptions['format'])) {
                    $labelText = sprintf($labelOptions['format'], $value);
                } elseif (isset($labelOptions['dateformat'])) {
                    $labelText = date($labelOptions['dateformat'], $value);
                } else {
                    $labelText = $value;
                }

                if (!in_array($labelText, $this->_labelText)) {
                    $this->_labelText[] = $labelText;

                    if (isset($labelOptions['font'])) {
                        $font = $this->_getFont($labelOptions['font']);
                    } else {
                        if ($this->_defaultFontOptions !== false) {
                            $font = $this->_defaultFontOptions;
                        } else {
                            $font = $this->_getFont();
                        }
                    }
                    $this->_canvas->setFont($font);
                    
                    if (
                        (isset($labelOptions['position'])) && 
                        ($labelOptions['position'] == 'inside')
                    ) {
                        $labelInside = true;
                    } else {
                        $labelInside = false;
                    }
                                        
                    if ($this->_type == IMAGE_GRAPH_AXIS_Y) {
                        if ($this->_transpose) {
                            if ($labelInside) {
                                $this->write(
                                    $labelPosition,
                                    $this->_top - 3 - $offset,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_BOTTOM | IMAGE_GRAPH_ALIGN_CENTER_X,
                                    $font
                                );
                            } else {
                                $this->write(
                                    $labelPosition,
                                    $this->_top + 6 + $offset + $font['size'] * (substr_count($labelText, "\n") + 1),                                                                   
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_BOTTOM | IMAGE_GRAPH_ALIGN_CENTER_X,
                                    $font
                                );
                            }
                        }
                        else {                        
                            if ($labelInside) {
                                $this->write(
                                    $this->_right + 3 + $offset,
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_LEFT,
                                    $font
                                );
                            } else {
                                $this->write(
                                    $this->_right - 3 - $offset,
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_RIGHT,
                                    $font
                                );
                            }
                        }
                    } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY) {
                        if ($this->_transpose) {
                            if ($labelInside) {
                                $this->write(
                                    $labelPosition,
                                    $this->_bottom + 6 + $offset + $font['size'] * (substr_count($labelText, "\n") + 1),
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_BOTTOM | IMAGE_GRAPH_ALIGN_CENTER_X,
                                    $font
                                );
                            } else {
                                $this->write(
                                    $labelPosition,
                                    $this->_bottom - 3 - $offset,                                                                   
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_BOTTOM | IMAGE_GRAPH_ALIGN_CENTER_X,
                                    $font
                                );
                            }
                        }
                        else {
                            if ($labelInside) {
                                $this->write(
                                    $this->_left - 3 - $offset,
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_RIGHT,
                                    $font
                                );
                            } else {
                                $this->write(
                                    $this->_left + 3 + $offset,
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_LEFT,
                                    $font
                                );
                            }
                        }
                    } else {
                        if ($this->_transpose) {
                            if ($labelInside) {
                                $this->write(
                                    $this->_right + 3 + $offset,
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_LEFT,
                                    $font
                                );
                            } else {
                                $this->write(
                                    $this->_right - 3 - $offset,                                                                   
                                    $labelPosition,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_Y | IMAGE_GRAPH_ALIGN_RIGHT,
                                    $font
                                );
                            }
                        }
                        else {
                            if ($labelInside === true) {
                                $this->write(
                                    $labelPosition,
                                    $this->_top - 3 - $offset,
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_X | IMAGE_GRAPH_ALIGN_BOTTOM,
                                    $font
                                );
                            } else {                                
                                $this->write(
                                    $labelPosition,
                                    $this->_top + 6 + $offset + $font['size'] * (substr_count($labelText, "\n") + 1),
                                    $labelText,
                                    IMAGE_GRAPH_ALIGN_CENTER_X | IMAGE_GRAPH_ALIGN_BOTTOM,
                                    $font
                                );
                            }
                        }
                    }
                }
            }

            $tickColor = false;
            if (isset($this->_labelOptions[$level]['tick'])) {
                if (isset($this->_labelOptions[$level]['tick']['start'])) {                
                    $tickStart = $this->_labelOptions[$level]['tick']['start'];
                } else {
                    $tickStart = false;
                }

                if (isset($this->_labelOptions[$level]['tick']['end'])) {                
                    $tickEnd = $this->_labelOptions[$level]['tick']['end'];
                } else {
                    $tickEnd = false;
                }
                                    
                if ((isset($this->_labelOptions[$level]['tick']['color'])) && ($this->_labelOptions[$level]['tick']['color'] !== false)) {
                    $tickColor = $this->_labelOptions[$level]['tick']['color'];
                }
            }
            
            if ($tickStart === false) {
                $tickStart = -2;
            }
            
            if ($tickEnd === false) {
                $tickEnd = 2;
            }

            if ($tickColor !== false) {
                $this->_canvas->setLineColor($tickColor);
            }
            else {
                $this->_getLineStyle();
            }
            
            if ($this->_type == IMAGE_GRAPH_AXIS_Y) {
                if ($tickStart === 'auto') {
                    $tickStart = -$offset;
                }
                if ($this->_transpose) {
                    $this->_canvas->line(
                        array(
                            'x0' => $labelPosition,
                            'y0' => $this->_top + $tickStart,
                            'x1' => $labelPosition,
                            'y1' => $this->_top + $tickEnd
                        )
                    );
                }
                else {
                    $this->_canvas->line(
                    	array(
                        	'x0' => $this->_right + $tickStart,
                        	'y0' => $labelPosition,
                        	'x1' => $this->_right + $tickEnd,
                        	'y1' => $labelPosition
                        )
                    );
                }
            } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY) {
                if ($tickStart === 'auto') {
                    $tickStart = $offset;
                }
                if ($this->_transpose) {
                    $this->_canvas->line(
                        array(
                            'x0' => $labelPosition,
                            'y0' => $this->_bottom - $tickStart,
                            'x1' => $labelPosition,
                            'y1' => $this->_bottom - $tickEnd
                        )
                    );
                }
                else {
                    $this->_canvas->line(
                    	array(
                        	'x0' => $this->_left - $tickStart,
                        	'y0' => $labelPosition,
                        	'x1' => $this->_left - $tickEnd,
                        	'y1' => $labelPosition
                        )
                    );
                }
            } else {
                if ($tickStart === 'auto') {
                    $tickStart = $offset;
                }
                if ($this->_transpose) {
                    $this->_canvas->line(
                        array(
                            'x0' => $this->_right + $tickStart,
                            'y0' => $labelPosition,
                            'x1' => $this->_right + $tickEnd,
                            'y1' => $labelPosition
                        )
                    );
                }
                else {
                    $this->_canvas->line(
                    	array(
                        	'x0' => $labelPosition,
                        	'y0' => $this->_top - $tickStart,
                        	'x1' => $labelPosition,
                        	'y1' => $this->_top - $tickEnd
                        )
                    );
                }
            }
        }
    }

    /**
     * Draws axis lines.
     *
     * @access private
     */
    function _drawAxisLines()
    {
        if ($this->_type == IMAGE_GRAPH_AXIS_X) {
            $this->_getLineStyle(); 
            $this->_getFillStyle(); 
            
            if ($this->_transpose) {
                $data = array(
                        'x0' => $this->_right,
                        'y0' => $this->_top,
                        'x1' => $this->_right,
                        'y1' => $this->_bottom
                    );
            } else {
                $data = array(
                        'x0' => $this->_left,
                        'y0' => $this->_top,
                        'x1' => $this->_right,
                        'y1' => $this->_top
                    );
            }
                
            if ($this->_showArrow) {
                if ($this->_getMaximum() <= 0) {
                    $data['end0'] = 'arrow2';
                    $data['size0'] = 7;
                }
                else {
                    $data['end1'] = 'arrow2';
                    $data['size1'] = 7;
                }
            } 
            
            $this->_canvas->line($data);

            if ($this->_title) {
                if (!$this->_transpose) {
                    $y = $this->_bottom;
                    $x = $this->_left + $this->width() / 2;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_CENTER_X + IMAGE_GRAPH_ALIGN_BOTTOM, $this->_getTitleFont());
                }
                else {
                    $y = $this->_top + $this->height() / 2;
                    $x = $this->_left;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_LEFT + IMAGE_GRAPH_ALIGN_CENTER_Y, $this->_getTitleFont());
                }
            }
        } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY) {
            $this->_getLineStyle();
            $this->_getFillStyle(); 
            
            if ($this->_transpose) {
                $data = array(
                        'x0' => $this->_left,
                        'y0' => $this->_bottom,
                        'x1' => $this->_right,
                        'y1' => $this->_bottom
                    );
            } else {
                $data = array(
                        'x0' => $this->_left,
                        'y0' => $this->_bottom,
                        'x1' => $this->_left,
                        'y1' => $this->_top
                    );
            }
            if ($this->_showArrow) {
                if ($this->_getMaximum() <= 0) {
                    $data['end0'] = 'arrow2';
                    $data['size0'] = 7;
                }
                else {
                    $data['end1'] = 'arrow2';
                    $data['size1'] = 7;
                }
            } 
            $this->_canvas->line($data);

            if ($this->_title) {
                if ($this->_transpose) {
                    $y = $this->_top;
                    $x = $this->_left + $this->width() / 2;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_CENTER_X + IMAGE_GRAPH_ALIGN_TOP, $this->_getTitleFont());
                }
                else {
                    $y = $this->_top + $this->height() / 2;
                    $x = $this->_right;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_RIGHT + IMAGE_GRAPH_ALIGN_CENTER_Y, $this->_getTitleFont());
                }
            }
        } else {
            $this->_getLineStyle();
            $this->_getFillStyle(); 
                        
            if ($this->_transpose) {
                $data = array(
                        'x0' => $this->_left,
                        'y0' => $this->_top,
                        'x1' => $this->_right,
                        'y1' => $this->_top
                    );
            } else {
                $data = array(
                        'x0' => $this->_right,
                        'y0' => $this->_bottom,
                        'x1' => $this->_right,
                        'y1' => $this->_top
                    );
            }
            if ($this->_showArrow) {
                if ($this->_getMaximum() <= 0) {
                    $data['end0'] = 'arrow2';
                    $data['size0'] = 7;
                }
                else {
                    $data['end1'] = 'arrow2';
                    $data['size1'] = 7;
                }
            } 
            $this->_canvas->line($data);            

            if ($this->_title) {
                if ($this->_transpose) {
                    $y = $this->_bottom;
                    $x = $this->_left + $this->width() / 2;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_CENTER_X + IMAGE_GRAPH_ALIGN_BOTTOM, $this->_getTitleFont());
                }
                else {
                    $y = $this->_top + $this->height() / 2;
                    $x = $this->_left;
                    $this->write($x, $y, $this->_title, IMAGE_GRAPH_ALIGN_LEFT + IMAGE_GRAPH_ALIGN_CENTER_Y, $this->_getTitleFont());
                }
            }
        }
    }

    /**
     * Causes the object to update all sub elements coordinates
     *
     * (Image_Graph_Common, does not itself have coordinates, this is basically
     * an abstract method)
     *
     * @access private
     */
    function _updateCoords()
    {
        parent::_updateCoords();
        $this->_calcDelta();
    }
    
    /**
     * Output the axis
     *
     * @return bool Was the output 'good' (true) or 'bad' (false).
     * @access private
     */
    function _done()
    {
        $this->_canvas->startGroup(get_class($this));        

        if (parent::_done() === false) {
            return false;
        }
        
        $this->_drawAxisLines();

        $this->_canvas->startGroup(get_class($this) . '_ticks');        
        ksort($this->_labelOptions);
        foreach ($this->_labelOptions as $level => $labelOption) {
            $value = false;
            while (($value = $this->_getNextLabel($value, $level)) !== false) {
                if ((((abs($value) > 0.0001) || ($this->_showLabelZero)) &&
                    (($value > $this->_getMinimum()) || ($this->_showLabelMinimum)) &&
                    (($value < $this->_getMaximum()) || ($this->_showLabelMaximum))) &&
                    ($value >= $this->_getMinimum()) && ($value <= $this->_getMaximum())
                ) {
                    $this->_drawTick($value, $level);
                }
            }
        }
        $this->_canvas->endGroup();        

        $tickStart = -3;
        $tickEnd = 2;

        foreach ($this->_marks as $mark) {
            if (is_array($mark)) {
                if ($this->_type == IMAGE_GRAPH_AXIS_X) {
                    if ($this->_transpose) {
                        $x0 = $this->_right + $tickStart;
                        $y0 = $this->_point($mark[1]);
                        $x1 = $this->_right + $tickEnd;
                        $y1 = $this->_point($mark[0]);
                    }
                    else {
                        $x0 = $this->_point($mark[0]);
                        $y0 = $this->_top + $tickStart;
                        $x1 = $this->_point($mark[1]);
                        $y1 = $this->_top + $tickEnd;
                    }
                } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y) {
                    if ($this->_transpose) {
                        $x0 = $this->_point($mark[0]);
                        $y0 = $this->_top + $tickStart;
                        $x1 = $this->_point($mark[1]);
                        $y1 = $this->_top + $tickEnd;
                    }
                    else {
                        $x0 = $this->_right + $tickStart;
                        $y0 = $this->_point($mark[1]);
                        $x1 = $this->_right + $tickEnd;
                        $y1 = $this->_point($mark[0]);
                    }
                } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY) {
                    if ($this->_transpose) {
                        $x0 = $this->_point($mark[0]);
                        $y0 = $this->_bottom + $tickStart;
                        $x1 = $this->_point($mark[1]);
                        $y1 = $this->_bottom + $tickEnd;
                    }
                    else {
                        $x0 = $this->_left + $tickStart;
                        $y0 = $this->_point($mark[1]);
                        $x1 = $this->_left + $tickEnd;
                        $y1 = $this->_point($mark[0]);
                    }                        
                }
                $this->_getFillStyle();
                $this->_getLineStyle();
                $this->_canvas->rectangle(array('x0' => $x0, 'y0' => $y0, 'x1' => $x1, 'y1' => $y1));
            } else {
                if ($this->_type == IMAGE_GRAPH_AXIS_X) {
                    if ($this->_transpose) {
                        $x0 = $this->_right + 5;
                        $y0 = $this->_point($mark);
                        $x1 = $this->_right + 15;
                        $y1 = $y0;
                    }
                    else {
                        $x0 = $this->_point($mark);
                        $y0 = $this->_top - 5;
                        $x1 = $x0;
                        $y1 = $this->_top - 15;
                    }
                } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y) {
                    if ($this->_transpose) {
                        $x0 = $this->_point($mark);
                        $y0 = $this->_top - 5;
                        $x1 = $x0;
                        $y1 = $this->_top - 15;
                    }
                    else {
                        $x0 = $this->_right + 5;
                        $y0 = $this->_point($mark);
                        $x1 = $this->_right + 15;
                        $y1 = $y0;
                    }
                } elseif ($this->_type == IMAGE_GRAPH_AXIS_Y_SECONDARY) {
                    if ($this->_transpose) {
                        $x0 = $this->_point($mark);
                        $y0 = $this->_bottom + 5;
                        $x1 = $x0;
                        $y1 = $this->_bottom + 15;
                    }
                    else {
                        $x0 = $this->_left - 5;
                        $y0 = $this->_point($mark);
                        $x1 = $this->_left - 15;
                        $y1 = $y0;
                    }                        
                }
                $this->_getFillStyle();
                $this->_getLineStyle();
                $this->_canvas->line(
                    array(
                        'x0' => $x0,
                        'y0' => $y0, 
                        'x1' => $x1, 
                        'y1' => $y1, 
                        'end0' => 'arrow2',
                        'size0' => 5                        
                    )
                );
            }
        }
        $this->_canvas->endGroup();        

        return true;
    }

}

?>