File Source for AntiSpam.class.php

<?php
/*
* This work is hereby released into the Public Domain.
* To view a copy of the public domain dedication,
* visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
* Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
*
*/
require_once dirname(__FILE__)."/Image.class.php";
/**
* AntiSpam
* String printed on the images are case insensitive.
*
* @package linea21.externals
* @subpackage artichow
*/
class awAntiSpam extends awImage {
/**
* Anti-spam string
*
* @var string
*/
protected $string;
/**
* Noise intensity
*
* @var int
*/
protected $noise = 0;
/**
* Construct a new awAntiSpam image
*
* @param string $string A string to display
*/
public function __construct($string = '') {
parent::__construct();
$this->string = (string)$string;
}
/**
* Create a random string
*
* @param int $length String length
* @return string String created
*/
public function setRand($length) {
$length = (int)$length;
$this->string = '';
$letters = 'aAbBCDeEFgGhHJKLmMnNpPqQRsStTuVwWXYZz2345679';
$number = strlen($letters);
for($i = 0; $i < $length; $i++) {
$this->string .= $letters{mt_rand(0, $number - 1)};
}
return $this->string;
}
/**
* Set noise on image
*
* @param int $nois Noise intensity (from 0 to 10)
*/
public function setNoise($noise) {
if($noise < 0) {
$noise = 0;
}
if($noise > 10) {
$noise = 10;
}
$this->noise = (int)$noise;
}
/**
* Save string value in session
* You can use check() to verify the value later
*
* @param string $qName A name that identify the anti-spam image
*/
public function save($qName) {
$this->session();
$session = 'artichow_'.(string)$qName;
$_SESSION[$session] = $this->string;
}
/**
* Verify user entry
*
* @param string $qName A name that identify the anti-spam image
* @param string $value User-defined value
* @param bool $case TRUE for case insensitive check, FALSE for case sensitive check ? (default to TRUE)
* @return bool TRUE if the value is correct, FALSE otherwise
*/
public function check($qName, $value, $case = TRUE) {
$this->session();
$session = 'artichow_'.(string)$qName;
return (
array_key_exists($session, $_SESSION) === TRUE and
$case ?
(strtolower($_SESSION[$session]) === strtolower((string)$value)) :
($_SESSION[$session] === (string)$value)
);
}
/**
* Draw image
*/
public function draw() {
$fonts = array(
'Tuffy',
'TuffyBold',
'TuffyItalic',
'TuffyBoldItalic'
);
$sizes = array(12, 12.5, 13, 13.5, 14, 15, 16, 17, 18, 19);
$widths = array();
$heights = array();
$texts = array();
// Set up a temporary driver to allow font size calculations...
$this->setSize(10, 10);
$driver = $this->getDriver();
for($i = 0; $i < strlen($this->string); $i++) {
$fontKey = array_rand($fonts);
$sizeKey = array_rand($sizes);
$font = new awTTFFont(
$fonts[$fontKey], $sizes[$sizeKey]
);
$text = new awText(
$this->string{$i},
$font,
NULL,
mt_rand(-15, 15)
);
$widths[] = $driver->getTextWidth($text);
$heights[] = $driver->getTextHeight($text);
$texts[] = $text;
}
// ... and get rid of it.
$this->driver = NULL;
$width = array_sum($widths);
$height = array_max($heights);
$totalWidth = $width + 10 + count($texts) * 10;
$totalHeight = $height + 20;
$this->setSize($totalWidth, $totalHeight);
$this->create();
for($i = 0; $i < strlen($this->string); $i++) {
$this->driver->string(
$texts[$i],
new awPoint(
5 + array_sum(array_slice($widths, 0, $i)) + $widths[$i] / 2 + $i * 10,
10 + ($height - $heights[$i]) / 2
)
);
}
$this->drawNoise($totalWidth, $totalHeight);
$this->send();
}
protected function drawNoise($width, $height) {
$points = $this->noise * 30;
$color = new awColor(0, 0, 0);
for($i = 0; $i < $points; $i++) {
$this->driver->point(
$color,
new awPoint(
mt_rand(0, $width),
mt_rand(0, $height)
)
);
}
}
protected function session() {
// Start session if needed
if(!session_id()) {
session_start();
}
}
}
registerClass('AntiSpam');
?>

Source for file AntiSpam.class.php