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   1  <?php
   2  
   3  /* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
   4  
   5  /**
   6   * Class for axis handling.
   7   *
   8   * PHP versions 4 and 5
   9   *
  10   * LICENSE: This library is free software; you can redistribute it and/or modify
  11   * it under the terms of the GNU Lesser General Public License as published by
  12   * the Free Software Foundation; either version 2.1 of the License, or (at your
  13   * option) any later version. This library is distributed in the hope that it
  14   * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  15   * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
  16   * General Public License for more details. You should have received a copy of
  17   * the GNU Lesser General Public License along with this library; if not, write
  18   * to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19   * 02111-1307 USA
  20   *
  21   * @category   Images
  22   * @package    Image_Graph
  23   * @subpackage Axis
  24   * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
  25   * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
  26   * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
  27   * @version    CVS: $Id: Logarithmic.php,v 1.15 2006/03/02 12:35:57 nosey Exp $
  28   * @link       http://pear.php.net/package/Image_Graph
  29   */
  30   
  31  /**
  32   * Include file Image/Graph/Axis.php
  33   */
  34  require_once  'Image/Graph/Axis.php';
  35  
  36  /**
  37   * Diplays a logarithmic axis (either X- or Y-axis).
  38   *
  39   * @category   Images
  40   * @package    Image_Graph
  41   * @subpackage Axis
  42   * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
  43   * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
  44   * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
  45   * @version    Release: 0.7.2
  46   * @link       http://pear.php.net/package/Image_Graph
  47   */
  48  class Image_Graph_Axis_Logarithmic extends Image_Graph_Axis
  49  {
  50  
  51      /**
  52       * Image_Graph_AxisLogarithmic [Constructor].
  53       *
  54       * Normally a manual creation should not be necessary, axis are
  55       * created automatically by the {@link Image_Graph_Plotarea} constructor
  56       * unless explicitly defined otherwise
  57       *
  58       * @param int $type The type (direction) of the Axis, use IMAGE_GRAPH_AXIS_X
  59       *   for an X-axis (default, may be omitted) and IMAGE_GRAPH_AXIS_Y for Y-
  60       *   axis)
  61       */
  62      function Image_Graph_Axis_Logarithmic($type = IMAGE_GRAPH_AXIS_X)
  63      {
  64          parent::Image_Graph_Axis($type);
  65          $this->showLabel(IMAGE_GRAPH_LABEL_MINIMUM + IMAGE_GRAPH_LABEL_MAXIMUM);
  66          $this->_minimum = 1;
  67          $this->_minimumSet = true;
  68      }
  69  
  70      /**
  71       * Calculate the label interval
  72       *
  73       * If explicitly defined this will be calucated to an approximate best.
  74       *
  75       * @return double The label interval
  76       * @access private
  77       */
  78      function _calcLabelInterval()
  79      {
  80          $result = parent::_calcLabelInterval();
  81          $this->_axisValueSpan = $this->_value($this->_axisSpan);                
  82          return $result;
  83      }
  84  
  85      /**
  86       * Preprocessor for values, ie for using logarithmic axis
  87       *
  88       * @param double $value The value to preprocess
  89       * @return double The preprocessed value
  90       * @access private
  91       */
  92      function _value($value)
  93      {
  94          return log10($value) - log10($this->_minimum);
  95      }
  96  
  97      /**
  98       * Get next label point
  99       *
 100       * @param doubt $point The current point, if omitted or false, the first is
 101       *   returned
 102       * @return double The next label point
 103       * @access private
 104       */
 105      function _getNextLabel($currentLabel = false, $level = 1)
 106      {
 107          if (is_array($this->_labelOptions[$level]['interval'])) {
 108              return parent::_getNextLabel($currentLabel, $level);
 109          }
 110  
 111          if ($currentLabel !== false) {
 112              $value = log10($currentLabel);
 113              $base = floor($value);
 114              $frac = $value - $base;
 115              for ($i = 2; $i < 10; $i++) {
 116                  if ($frac <= (log10($i)-0.01)) {                    
 117                      $label = pow(10, $base)*$i;
 118                      if ($label > $this->_getMaximum()) {
 119                          return false;
 120                      } else {
 121                          return $label;
 122                      }
 123                  }
 124              }
 125              return pow(10, $base+1);
 126          }
 127  
 128          return max(1, $this->_minimum);
 129      }
 130  
 131      /**
 132       * Get the axis intersection pixel position
 133       *
 134       * This is only to be called prior to output! I.e. between the user
 135       * invokation of Image_Graph::done() and any actual output is performed.
 136       * This is because it can change the axis range.
 137       *
 138       * @param double $value the intersection value to get the pixel-point for
 139       * @return double The pixel position along the axis
 140       * @access private
 141       */
 142      function _intersectPoint($value)
 143      {        
 144          if (($value <= 0) && ($value !== 'max') && ($value !== 'min')) {
 145              $value = 1;
 146          }
 147          return parent::_intersectPoint($value);
 148      }
 149      
 150  }
 151  
 152  ?>