147 lines
4.4 KiB
PHP
147 lines
4.4 KiB
PHP
<?php
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/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
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/**
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* Image_Graph - PEAR PHP OO Graph Rendering Utility.
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*
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* PHP versions 4 and 5
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*
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* LICENSE: This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at your
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* option) any later version. This library is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
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* General Public License for more details. You should have received a copy of
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* the GNU Lesser General Public License along with this library; if not, write
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* to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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* 02111-1307 USA
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*
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* @category Images
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* @package Image_Graph
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* @subpackage Dataset
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* @author Jesper Veggerby <pear.nosey@veggerby.dk>
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* @copyright Copyright (C) 2003, 2004 Jesper Veggerby Hansen
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* @license http://www.gnu.org/copyleft/lesser.html LGPL License 2.1
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* @version CVS: $Id: Function.php,v 1.7 2005/08/24 20:35:57 nosey Exp $
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* @link http://pear.php.net/package/Image_Graph
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*/
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/**
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* Include file Image/Graph/Dataset.php
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*/
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require_once 'Image/Graph/Dataset.php';
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/**
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* Function data set, points are generated by calling an external function.
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*
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* The function must be a single variable function and return a the result,
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* builtin functions that are fx sin() or cos(). User defined function can be
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* used if they are such, i.e: function myFunction($variable)
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*
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* @category Images
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* @package Image_Graph
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* @subpackage Dataset
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* @author Jesper Veggerby <pear.nosey@veggerby.dk>
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* @copyright Copyright (C) 2003, 2004 Jesper Veggerby Hansen
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* @license http://www.gnu.org/copyleft/lesser.html LGPL License 2.1
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* @version Release: 0.7.2
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* @link http://pear.php.net/package/Image_Graph
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*/
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class Image_Graph_Dataset_Function extends Image_Graph_Dataset
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{
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/**
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* The name of the function
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* @var string
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* @access private
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*/
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var $_dataFunction;
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/**
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* Image_Graph_FunctionDataset [Constructor]
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*
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* @param double $minimumX The minimum X value
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* @param double $maximumX The maximum X value
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* @param string $function The name of the function, if must be a single
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* parameter function like fx sin(x) or cos(x)
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* @param int $points The number of points to create
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*/
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function Image_Graph_Dataset_Function($minimumX, $maximumX, $function, $points)
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{
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parent::Image_Graph_Dataset();
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$this->_minimumX = $minimumX;
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$this->_maximumX = $maximumX;
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$this->_dataFunction = $function;
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$this->_count = $points;
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$this->_calculateMaxima();
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}
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/**
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* Add a point to the dataset.
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*
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* You can't add points to a function dataset
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*
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* @param int $x The X value to add
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* @param int $y The Y value to add, can be omited
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* @param var $ID The ID of the point
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*/
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function addPoint($x, $y = false, $ID = false)
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{
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}
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/**
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* Gets a Y point from the dataset
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*
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* @param var $x The variable to apply the function to
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* @return var The function applied to the X value
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* @access private
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*/
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function _getPointY($x)
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{
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$function = $this->_dataFunction;
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return $function ($x);
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}
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/**
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* The number of values in the dataset
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*
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* @return int The number of values in the dataset
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* @access private
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*/
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function _count()
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{
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return $this->_count;
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}
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/**
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* The interval between 2 adjacent Y values
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*
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* @return var The interval
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* @access private
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*/
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function _stepX()
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{
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return ($this->_maximumX - $this->_minimumX) / $this->_count();
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}
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/**
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* Calculates the Y extrema of the function
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*
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* @access private
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*/
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function _calculateMaxima()
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{
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$x = $this->_minimumX;
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while ($x <= $this->_maximumX) {
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$y = $this->_getPointY($x);
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$this->_minimumY = min($y, $this->_minimumY);
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$this->_maximumY = max($y, $this->_maximumY);
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$x += $this->_stepX();
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}
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}
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}
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?>
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