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khosb/includes/pear/Image/Graph/Dataset/Function.php
2008-11-26 14:50:40 -08:00

147 lines
4.3 KiB
PHP

<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Image_Graph - PEAR PHP OO Graph Rendering Utility.
*
* 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 Dataset
* @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: Function.php,v 1.7 2005/08/24 20:35:57 nosey Exp $
* @link http://pear.php.net/package/Image_Graph
*/
/**
* Include file Image/Graph/Dataset.php
*/
require_once 'Image/Graph/Dataset.php';
/**
* Function data set, points are generated by calling an external function.
*
* The function must be a single variable function and return a the result,
* builtin functions that are fx sin() or cos(). User defined function can be
* used if they are such, i.e: function myFunction($variable)
*
* @category Images
* @package Image_Graph
* @subpackage Dataset
* @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_Dataset_Function extends Image_Graph_Dataset
{
/**
* The name of the function
* @var string
* @access private
*/
var $_dataFunction;
/**
* Image_Graph_FunctionDataset [Constructor]
*
* @param double $minimumX The minimum X value
* @param double $maximumX The maximum X value
* @param string $function The name of the function, if must be a single
* parameter function like fx sin(x) or cos(x)
* @param int $points The number of points to create
*/
function Image_Graph_Dataset_Function($minimumX, $maximumX, $function, $points)
{
parent::Image_Graph_Dataset();
$this->_minimumX = $minimumX;
$this->_maximumX = $maximumX;
$this->_dataFunction = $function;
$this->_count = $points;
$this->_calculateMaxima();
}
/**
* Add a point to the dataset.
*
* You can't add points to a function dataset
*
* @param int $x The X value to add
* @param int $y The Y value to add, can be omited
* @param var $ID The ID of the point
*/
function addPoint($x, $y = false, $ID = false)
{
}
/**
* Gets a Y point from the dataset
*
* @param var $x The variable to apply the function to
* @return var The function applied to the X value
* @access private
*/
function _getPointY($x)
{
$function = $this->_dataFunction;
return $function ($x);
}
/**
* The number of values in the dataset
*
* @return int The number of values in the dataset
* @access private
*/
function _count()
{
return $this->_count;
}
/**
* The interval between 2 adjacent Y values
*
* @return var The interval
* @access private
*/
function _stepX()
{
return ($this->_maximumX - $this->_minimumX) / $this->_count();
}
/**
* Calculates the Y extrema of the function
*
* @access private
*/
function _calculateMaxima()
{
$x = $this->_minimumX;
while ($x <= $this->_maximumX) {
$y = $this->_getPointY($x);
$this->_minimumY = min($y, $this->_minimumY);
$this->_maximumY = max($y, $this->_maximumY);
$x += $this->_stepX();
}
}
}
?>