[Sommaire] [Imprimer]

   1  <?php
   2  
   3  /* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
   4  
   5  /**
   6   * Image_Graph - PEAR PHP OO Graph Rendering Utility.
   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 Dataset
  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: Function.php,v 1.7 2005/08/24 20:35:57 nosey Exp $
  28   * @link       http://pear.php.net/package/Image_Graph
  29   */
  30  
  31  /**
  32   * Include file Image/Graph/Dataset.php
  33   */
  34  require_once  'Image/Graph/Dataset.php';
  35  
  36  /**
  37   * Function data set, points are generated by calling an external function.
  38   *
  39   * The function must be a single variable function and return a the result,
  40   * builtin  functions that are fx sin() or cos(). User defined function can be
  41   * used if they are such, i.e: function myFunction($variable)
  42   *
  43   * @category   Images
  44   * @package    Image_Graph
  45   * @subpackage Dataset
  46   * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
  47   * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
  48   * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
  49   * @version    Release: 0.7.2
  50   * @link       http://pear.php.net/package/Image_Graph
  51   */
  52  class Image_Graph_Dataset_Function extends Image_Graph_Dataset
  53  {
  54  
  55      /**
  56       * The name of the function
  57       * @var string
  58       * @access private
  59       */
  60      var $_dataFunction;
  61  
  62      /**
  63       * Image_Graph_FunctionDataset [Constructor]
  64       *
  65       * @param double $minimumX The minimum X value
  66       * @param double $maximumX The maximum X value
  67       * @param string $function The name of the function, if must be a single
  68       * parameter function like fx sin(x) or cos(x)
  69       * @param int $points The number of points to create
  70       */
  71      function Image_Graph_Dataset_Function($minimumX, $maximumX, $function, $points)
  72      {
  73          parent::Image_Graph_Dataset();
  74          $this->_minimumX = $minimumX;
  75          $this->_maximumX = $maximumX;
  76          $this->_dataFunction = $function;
  77          $this->_count = $points;
  78          $this->_calculateMaxima();
  79      }
  80  
  81      /**
  82       * Add a point to the dataset.
  83       *
  84       * You can't add points to a function dataset
  85       *
  86       * @param int $x The X value to add
  87       * @param int $y The Y value to add, can be omited
  88       * @param var $ID The ID of the point
  89       */
  90      function addPoint($x, $y = false, $ID = false)
  91      {
  92      }
  93  
  94      /**
  95       * Gets a Y point from the dataset
  96       *
  97       * @param var $x The variable to apply the function to
  98       * @return var The function applied to the X value
  99       * @access private
 100       */
 101      function _getPointY($x)
 102      {
 103          $function = $this->_dataFunction;
 104          return $function ($x);
 105      }
 106  
 107      /**
 108       * The number of values in the dataset
 109       *
 110       * @return int The number of values in the dataset
 111       * @access private
 112       */
 113      function _count()
 114      {
 115          return $this->_count;
 116      }
 117  
 118      /**
 119       * The interval between 2 adjacent Y values
 120       *
 121       * @return var The interval
 122       * @access private
 123       */
 124      function _stepX()
 125      {
 126          return ($this->_maximumX - $this->_minimumX) / $this->_count();
 127      }
 128  
 129      /**
 130       * Calculates the Y extrema of the function
 131       *
 132       * @access private
 133       */
 134      function _calculateMaxima()
 135      {
 136          $x = $this->_minimumX;
 137          while ($x <= $this->_maximumX) {
 138              $y = $this->_getPointY($x);
 139              $this->_minimumY = min($y, $this->_minimumY);
 140              $this->_maximumY = max($y, $this->_maximumY);
 141              $x += $this->_stepX();
 142          }
 143      }
 144  
 145  }
 146  
 147  ?>