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khosb/includes/pear/Image/Graph/Tool.php

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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Image_Graph - Main class for the graph creation.
*
* 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
* @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: Tool.php,v 1.4 2005/09/14 20:27:24 nosey Exp $
* @link http://pear.php.net/package/Image_Graph
*/
/**
* This class contains a set of tool-functions.
*
* These functions are all to be called statically
*
* @category Images
* @package Image_Graph
* @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_Tool
{
/**
* Return the average of 2 points
*
* @param double P1 1st point
* @param double P2 2nd point
* @return double The average of P1 and P2
* @static
*/
function mid($p1, $p2)
{
return ($p1 + $p2) / 2;
}
/**
* Mirrors P1 in P2 by a amount of Factor
*
* @param double $p1 1st point, point to mirror
* @param double $o2 2nd point, mirror point
* @param double $factor Mirror factor, 0 returns $p2, 1 returns a pure
* mirror, ie $p1 on the exact other side of $p2
* @return double $p1 mirrored in $p2 by Factor
* @static
*/
function mirror($p1, $p2, $factor = 1)
{
return $p2 + $factor * ($p2 - $p1);
}
/**
* Calculates a Bezier control point, this function must be called for BOTH
* X and Y coordinates (will it work for 3D coordinates!?)
*
* @param double $p1 1st point
* @param double $p2 Point to
* @param double $factor Mirror factor, 0 returns P2, 1 returns a pure
* mirror, i.e. P1 on the exact other side of P2
* @return double P1 mirrored in P2 by Factor
* @static
*/
function controlPoint($p1, $p2, $factor, $smoothFactor = 0.75)
{
$sa = Image_Graph_Tool::mirror($p1, $p2, $smoothFactor);
$sb = Image_Graph_Tool::mid($p2, $sa);
$m = Image_Graph_Tool::mid($p2, $factor);
$pC = Image_Graph_Tool::mid($sb, $m);
return $pC;
}
/**
* Calculates a Bezier point, this function must be called for BOTH X and Y
* coordinates (will it work for 3D coordinates!?)
*
* @param double $t A position between $p2 and $p3, value between 0 and 1
* @param double $p1 Point to use for calculating control points
* @param double $p2 Point 1 to calculate bezier curve between
* @param double $p3 Point 2 to calculate bezier curve between
* @param double $p4 Point to use for calculating control points
* @return double The bezier value of the point t between $p2 and $p3 using
* $p1 and $p4 to calculate control points
* @static
*/
function bezier($t, $p1, $p2, $p3, $p4)
{
// (1-t)^3*p1 + 3*(1-t)^2*t*p2 + 3*(1-t)*t^2*p3 + t^3*p4
return pow(1 - $t, 3) * $p1 +
3 * pow(1 - $t, 2) * $t * $p2 +
3 * (1 - $t) * pow($t, 2) * $p3 +
pow($t, 3) * $p4;
}
/**
* For a given point (x,y) return a point rotated by a given angle aroung the center (xy,yc)
*
* @param int $x x coordinate of the point to rotate
* @param int $y y coordinate of the point to rotate
* @param int $xc x coordinate of the center of the rotation
* @param int $yc y coordinate of the center of the rotation
* @param int $angle angle of the rotation
* @return array the coordinate of the new point
* @static
*/
function rotate($x, $y, $xc, $yc, $angle)
{
$cos = cos(deg2rad($angle));
$sin = sin(deg2rad($angle));
$xr= $x - $xc;
$yr= $y - $yc;
$x1= $xc + $cos * $xr - $sin * $yr;
$y1= $yc + $sin * $xr + $cos * $yr;
return array((int) $x1,(int) $y1);
}
/**
* If a number is close 0 zero (i.e. 0 within $decimal decimals) it is rounded down to zero
*
* @param double $value The value to round
* @param int $decimal The number of decimals
* @return double The value or zero if "close enough" to zero
* @static
*/
function close2zero($value, $decimal)
{
if (abs($value) < pow(10, -$decimal)) {
return 0;
}
else {
return $value;
}
}
/**
* Calculate the dimensions and center point (of gravity) for an arc
*
* @param int $v1 The angle at which the arc starts
* @param int $v2 The angle at which the arc ends
* @return array An array with the dimensions in a fraction of a circle width radius 1 'rx', 'ry' and the
* center point of gravity ('cx', 'cy')
* @static
*/
function calculateArcDimensionAndCenter($v1, $v2)
{
// $v2 always larger than $v1
$r1x = Image_Graph_Tool::close2zero(cos(deg2rad($v1)), 3);
$r2x = Image_Graph_Tool::close2zero(cos(deg2rad($v2)), 3);
$r1y = Image_Graph_Tool::close2zero(sin(deg2rad($v1)), 3);
$r2y = Image_Graph_Tool::close2zero(sin(deg2rad($v2)), 3);
// $rx = how many percent of the x-diameter of the entire ellipse does the arc x-diameter occupy: 1 entire width, 0 no width
// $cx = at what percentage of the diameter does the center lie
// if the arc passes through 0/360 degrees the "highest" of r1x and r2x is replaced by 1!
if ((($v1 <= 0) && ($v2 >= 0)) || (($v1 <= 360) && ($v2 >= 360))) {
$r1x = min($r1x, $r2x);
$r2x = 1;
}
// if the arc passes through 180 degrees the "lowest" of r1x and r2x is replaced by -1!
if ((($v1 <= 180) && ($v2 >= 180)) || (($v1 <= 540) && ($v2 >= 540))) {
$r1x = max($r1x, $r2x);
$r2x = -1;
}
if ($r1x >= 0) { // start between [270; 360] or [0; 90]
if ($r2x >= 0) {
$rx = max($r1x, $r2x) / 2;
$cx = 0; // center lies 0 percent along this "vector"
}
else {
$rx = abs($r1x - $r2x) / 2;
$cx = abs($r2x / 2) / $rx;
}
}
else { // start between ]90; 270[
if ($r2x < 0) {
$rx = max(abs($r1x), abs($r2x)) / 2;
$cx = $rx;
}
else {
$rx = abs($r1x - $r2x) / 2;
$cx = abs($r1x / 2) / $rx;
}
}
// $ry = how many percent of the y-diameter of the entire ellipse does the arc y-diameter occupy: 1 entire, 0 none
// $cy = at what percentage of the y-diameter does the center lie
// if the arc passes through 90 degrees the "lowest" of r1x and r2x is replaced by -1!
if ((($v1 <= 90) && ($v2 >= 90)) || (($v1 <= 450) && ($v2 >= 450))) {
$r1y = min($r1y, $r2y);
$r2y = 1;
}
// if the arc passes through 270 degrees the "highest" of r1y and r2y is replaced by -1!
if ((($v1 <= 270) && ($v2 >= 270)) || (($v1 <= 630) && ($v2 >= 630))) {
$r1y = max($r1y, $r2y);
$r2y = -1;
}
if ($r1y >= 0) { // start between [0; 180]
if ($r2y >= 0) {
$ry = max($r1y, $r2y) / 2;
$cy = 0; // center lies 0 percent along this "vector"
}
else {
$ry = abs($r1y - $r2y) / 2;
$cy = abs($r2y / 2) / $ry;
}
}
else { // start between ]180; 360[
if ($r2y < 0) {
$ry = max(abs($r1y), abs($r2y)) / 2;
$cy = $ry;
}
else {
$ry = abs($r1y - $r2y) / 2;
$cy = abs($r1y / 2) / $ry;
}
}
return array(
'rx' => $rx,
'cx' => $cx,
'ry' => $ry,
'cy' => $cy
);
}
/**
* Calculate linear regression on a dataset
* @param array $data The data to calculate regression upon
* @return array The slope and intersection of the "best-fit" line
* @static
*/
function calculateLinearRegression(&$data)
{
$sumX = 0;
$sumY = 0;
foreach ($data as $point) {
$sumX += $point['X'];
$sumY += $point['Y'];
}
$meanX = $sumX / count($data);
$meanY = $sumY / count($data);
$sumXX = 0;
$sumYY = 0;
$sumXY = 0;
foreach ($data as $point) {
$sumXX += ($point['X'] - $meanX) * ($point['X'] - $meanX);
$sumYY += ($point['Y'] - $meanY) * ($point['Y'] - $meanY);
$sumXY += ($point['X'] - $meanX) * ($point['Y'] - $meanY);
}
$result = array();
$result['slope'] = ($sumXY / $sumXX);
$result['intersection'] = $meanY - ($result['slope'] * $meanX);
return $result;
}
}
?>