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khosb/includes/pear/Image/Graph/Axis/Logarithmic.php

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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Class for axis handling.
*
* 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 Axis
* @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: Logarithmic.php,v 1.15 2006/03/02 12:35:57 nosey Exp $
* @link http://pear.php.net/package/Image_Graph
*/
/**
* Include file Image/Graph/Axis.php
*/
require_once 'Image/Graph/Axis.php';
/**
* Diplays a logarithmic axis (either X- or Y-axis).
*
* @category Images
* @package Image_Graph
* @subpackage Axis
* @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_Axis_Logarithmic extends Image_Graph_Axis
{
/**
* Image_Graph_AxisLogarithmic [Constructor].
*
* Normally a manual creation should not be necessary, axis are
* created automatically by the {@link Image_Graph_Plotarea} constructor
* unless explicitly defined otherwise
*
* @param int $type The type (direction) of the Axis, use IMAGE_GRAPH_AXIS_X
* for an X-axis (default, may be omitted) and IMAGE_GRAPH_AXIS_Y for Y-
* axis)
*/
function Image_Graph_Axis_Logarithmic($type = IMAGE_GRAPH_AXIS_X)
{
parent::Image_Graph_Axis($type);
$this->showLabel(IMAGE_GRAPH_LABEL_MINIMUM + IMAGE_GRAPH_LABEL_MAXIMUM);
$this->_minimum = 1;
$this->_minimumSet = true;
}
/**
* Calculate the label interval
*
* If explicitly defined this will be calucated to an approximate best.
*
* @return double The label interval
* @access private
*/
function _calcLabelInterval()
{
$result = parent::_calcLabelInterval();
$this->_axisValueSpan = $this->_value($this->_axisSpan);
return $result;
}
/**
* Preprocessor for values, ie for using logarithmic axis
*
* @param double $value The value to preprocess
* @return double The preprocessed value
* @access private
*/
function _value($value)
{
return log10($value) - log10($this->_minimum);
}
/**
* Get next label point
*
* @param doubt $point The current point, if omitted or false, the first is
* returned
* @return double The next label point
* @access private
*/
function _getNextLabel($currentLabel = false, $level = 1)
{
if (is_array($this->_labelOptions[$level]['interval'])) {
return parent::_getNextLabel($currentLabel, $level);
}
if ($currentLabel !== false) {
$value = log10($currentLabel);
$base = floor($value);
$frac = $value - $base;
for ($i = 2; $i < 10; $i++) {
if ($frac <= (log10($i)-0.01)) {
$label = pow(10, $base)*$i;
if ($label > $this->_getMaximum()) {
return false;
} else {
return $label;
}
}
}
return pow(10, $base+1);
}
return max(1, $this->_minimum);
}
/**
* Get the axis intersection pixel position
*
* This is only to be called prior to output! I.e. between the user
* invokation of Image_Graph::done() and any actual output is performed.
* This is because it can change the axis range.
*
* @param double $value the intersection value to get the pixel-point for
* @return double The pixel position along the axis
* @access private
*/
function _intersectPoint($value)
{
if (($value <= 0) && ($value !== 'max') && ($value !== 'min')) {
$value = 1;
}
return parent::_intersectPoint($value);
}
}
?>