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   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: VectorFunction.php,v 1.6 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   * Vector Function data set.
  38   *
  39   * Points are generated by calling 2 external functions, fx. x = sin(t) and y =
  40   * cos(t)
  41   *
  42   * @category   Images
  43   * @package    Image_Graph
  44   * @subpackage Dataset
  45   * @author     Jesper Veggerby <pear.nosey@veggerby.dk>
  46   * @copyright  Copyright (C) 2003, 2004 Jesper Veggerby Hansen
  47   * @license    http://www.gnu.org/copyleft/lesser.html  LGPL License 2.1
  48   * @version    Release: 0.7.2
  49   * @link       http://pear.php.net/package/Image_Graph
  50   */
  51  class Image_Graph_Dataset_VectorFunction extends Image_Graph_Dataset
  52  {
  53  
  54      /**
  55       * The name of the X function
  56       * @var string
  57       * @access private
  58       */
  59      var $_functionX;
  60  
  61      /**
  62       * The name of the Y function
  63       * @var string
  64       * @access private
  65       */
  66      var $_functionY;
  67  
  68      /**
  69       * The minimum of the vector function variable
  70       * @var double
  71       * @access private
  72       */
  73      var $_minimumT;
  74  
  75      /**
  76       * The maximum of the vector function variable
  77       * @var double
  78       * @access private
  79       */
  80      var $_maximumT;
  81  
  82      /**
  83       * Image_Graph_VectorFunctionDataset [Constructor]
  84       *
  85       * @param double $minimumT The minimum value of the vector function variable
  86       * @param double $maximumT The maximum value of the vector function variable
  87       * @param string $functionX The name of the X function, if must be a single
  88       *   parameter function like fx sin(x) or cos(x)
  89       * @param string $functionY The name of the Y function, if must be a single
  90       *   parameter function like fx sin(x) or cos(x)
  91       * @param int $points The number of points to create
  92       */
  93      function Image_Graph_Dataset_VectorFunction($minimumT, $maximumT, $functionX, $functionY, $points)
  94      {
  95          parent::Image_Graph_Dataset();
  96          $this->_minimumT = $minimumT;
  97          $this->_maximumT = $maximumT;
  98          $this->_functionX = $functionX;
  99          $this->_functionY = $functionY;
 100          $this->_count = $points;
 101          $this->_calculateMaxima();
 102      }
 103  
 104      /**
 105       * Add a point to the dataset
 106       *
 107       * @param int $x The X value to add
 108       * @param int $y The Y value to add, can be omited
 109       * @param var $ID The ID of the point
 110       */
 111      function addPoint($x, $y = false, $ID = false)
 112      {
 113      }
 114  
 115      /**
 116       * Gets a X point from the dataset
 117       *
 118       * @param var $x The variable to apply the X function to
 119       * @return var The X function applied to the X value
 120       * @access private
 121       */
 122      function _getPointX($x)
 123      {
 124          $functionX = $this->_functionX;
 125          return $functionX ($x);
 126      }
 127  
 128      /**
 129       * Gets a Y point from the dataset
 130       *
 131       * @param var $x The variable to apply the Y function to
 132       * @return var The Y function applied to the X value
 133       * @access private
 134       */
 135      function _getPointY($x)
 136      {
 137          $functionY = $this->_functionY;
 138          return $functionY ($x);
 139      }
 140  
 141      /**
 142       * Reset the intertal dataset pointer
 143       *
 144       * @return var The first T value
 145       * @access private
 146       */
 147      function _reset()
 148      {
 149          $this->_posX = $this->_minimumT;
 150          return $this->_posX;
 151      }
 152  
 153      /**
 154       * The interval between 2 adjacent T values
 155       *
 156       * @return var The interval
 157       * @access private
 158       */
 159      function _stepX()
 160      {
 161          return ($this->_maximumT - $this->_minimumT) / $this->count();
 162      }
 163  
 164      /**
 165       * Calculates the X and Y extrema of the functions
 166       *
 167       * @access private
 168       */
 169      function _calculateMaxima()
 170      {
 171          $t = $this->_minimumT;
 172          while ($t <= $this->_maximumT) {
 173              $x = $this->_getPointX($t);
 174              $y = $this->_getPointY($t);
 175              $this->_minimumX = min($x, $this->_minimumX);
 176              $this->_maximumX = max($x, $this->_maximumX);
 177              $this->_minimumY = min($y, $this->_minimumY);
 178              $this->_maximumY = max($y, $this->_maximumY);
 179              $t += $this->_stepX();
 180          }
 181      }
 182  
 183  }
 184  
 185  ?>