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khosb/includes/pear/Image/Graph/Plot/Fit/Line.php

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<?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 Plot
* @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: Line.php,v 1.2 2005/11/27 22:21:18 nosey Exp $
* @link http://pear.php.net/package/Image_Graph
*/
/**
* Include file Image/Graph/Plot.php
*/
require_once 'Image/Graph/Plot.php';
/**
* Include file Image/Graph/Tool.php
*/
require_once 'Image/Graph/Tool.php';
/**
* Fit the graph (to a line using linear regression).
*
* @category Images
* @package Image_Graph
* @subpackage Plot
* @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_Plot_Fit_Line extends Image_Graph_Plot
{
/**
* Perform the actual drawing on the legend.
*
* @param int $x0 The top-left x-coordinate
* @param int $y0 The top-left y-coordinate
* @param int $x1 The bottom-right x-coordinate
* @param int $y1 The bottom-right y-coordinate
* @access private
*/
function _drawLegendSample($x0, $y0, $x1, $y1)
{
$y = ($y0 + $y1) / 2;
$dy = abs($y1 - $y0) / 6;
$this->_canvas->addVertex(array('x' => $x0, 'y' => $y + $dy));
$this->_canvas->addVertex(array('x' => $x1, 'y' => $y - $dy));
$this->_canvas->polygon(array('connect' => false));
}
/**
* Output the plot
*
* @return bool Was the output 'good' (true) or 'bad' (false).
* @access private
*/
function _done()
{
if (Image_Graph_Plot::_done() === false) {
return false;
}
$this->_canvas->startGroup(get_class($this) . '_' . $this->_title);
$this->_clip(true);
$keys = array_keys($this->_dataset);
foreach ($keys as $key) {
$dataset =& $this->_dataset[$key];
$dataset->_reset();
$data = array();
while ($point = $dataset->_next()) {
$data[] = array(
'X' => $this->_pointX($point),
'Y' => $this->_pointY($point)
);
}
$regression = Image_Graph_Tool::calculateLinearRegression($data);
$this->_getLineStyle($key);
$this->_canvas->line(
array(
'x0' => $this->_left,
'y0' => $this->_left * $regression['slope'] + $regression['intersection'],
'x1' => $this->_right,
'y1' => $this->_right * $regression['slope'] + $regression['intersection']
)
);
}
$this->_clip(false);
$this->_canvas->endGroup();
return true;
}
}
?>