piler/webui/system/helper/libchart/classes/view/axis/Axis.php
2012-02-08 23:14:28 +01:00

130 lines
3.2 KiB
PHP

<?php
/* Libchart - PHP chart library
* Copyright (C) 2005-2010 Jean-Marc Trémeaux (jm.tremeaux at gmail.com)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/**
* Automatic axis boundaries and ticks calibration
*
* @author Jean-Marc Trémeaux (jm.tremeaux at gmail.com)
*/
class Axis {
private $min;
private $max;
private $guide;
private $delta;
private $magnitude;
private $displayMin;
private $displayMax;
private $tics;
/**
* Creates a new axis formatter.
*
* @param integer minimum value on the axis
* @param integer maximum value on the axis
*/
public function Axis($min, $max) {
$this->min = $min;
$this->max = $max;
$this->guide = 10;
}
/**
* Computes value between two ticks.
*/
public function quantizeTics() {
// Approximate number of decades, in [1..10[
$norm = $this->delta / $this->magnitude;
// Approximate number of tics per decade
$posns = $this->guide / $norm;
if ($posns > 20) {
$tics = 0.05; // e.g. 0, .05, .10, ...
} else if ($posns > 10) {
$tics = 0.2; // e.g. 0, .1, .2, ...
} else if ($posns > 5) {
$tics = 0.4; // e.g. 0, 0.2, 0.4, ...
} else if ($posns > 3) {
$tics = 0.5; // e.g. 0, 0.5, 1, ...
} else if ($posns > 2) {
$tics = 1; // e.g. 0, 1, 2, ...
} else if ($posns > 0.25) {
$tics = 2; // e.g. 0, 2, 4, 6
} else {
$tics = ceil($norm);
}
$this->tics = $tics * $this->magnitude;
}
/**
* Computes automatic boundaries on the axis
*/
public function computeBoundaries() {
// Range
$this->delta = abs($this->max - $this->min);
// Check for null distribution
if ($this->delta == 0)
$this->delta = 1;
// Order of magnitude of range
$this->magnitude = pow(10, floor(log10($this->delta)));
$this->quantizeTics();
$this->displayMin = floor($this->min / $this->tics) * $this->tics;
$this->displayMax = ceil($this->max / $this->tics) * $this->tics;
$this->displayDelta = $this->displayMax - $this->displayMin;
// Check for null distribution
if ($this->displayDelta == 0) {
$this->displayDelta = 1;
}
}
/**
* Get the lower boundary on the axis3
*
* @return integer lower boundary on the axis
*/
public function getLowerBoundary() {
return $this->displayMin;
}
/**
* Get the upper boundary on the axis3
*
* @return integer upper boundary on the axis
*/
public function getUpperBoundary() {
return $this->displayMax;
}
/**
* Get the value between two ticks3
*
* @return integer value between two ticks
*/
public function getTics() {
return $this->tics;
}
}
?>