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<?php
Session_Start ();
/*
* File:CaptchaSecurityImages.php
* Author:simon Jarvis
* copyright:2006 Simon Jarvis
* date:03/08/06
* updated:07/02/07
* requirements:php 4/5 with GD and FreeType libraries
* link:http://www.white-hat-web-design.co.uk/articles/php-captcha.php
*
* This are 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 2
* of the License, or (at your option) any later version.
*
* This are distributed in the hope that it'll be useful,
* but without any WARRANTY; Without even the implied warranty of
* merchantability or FITNESS for A particular purpose. The
* GNU general public License for more details:
* http://www.gnu.org/licenses/gpl.html
*
*/
Class Captchasecurityimages {
var $font = ' Monofont.ttf ';
function Generatecode ($characters) {
/* List all possible characters, similar looking characters and vowels have been * *
$possible = ' 23456789bcdfghjkmnpqrstvwxyz ';
$code = ';
$i = 0;
while ($i < $characters) {
$code. = substr ($possible, Mt_rand (0, strlen ($possible)-1), 1);
$i + +;
}
return $code;
}
function captchasecurityimages ($width = ' a ', $height = ', ' $characters = ' 6 ') {
$code = $this->generatecode ($characters);
/* Font size would be 75% of the image height * *
$font _size = $height * 0.75;
$image = @imagecreate ($width, $height) or Die (' cannot initialize new GD image stream ');
/* Set the colours * *
$background _color = imagecolorallocate ($image, 255, 255, 255);
$text _color = Imagecolorallocate ($image, 20, 40, 100);
$noise _color = imagecolorallocate ($image, 100, 120, 180);
/* generate random dots in background * *
For ($i =0 $i < ($width * $height)/3; $i + +) {
Imagefilledellipse ($image, Mt_rand (0, $width), Mt_rand (0, $height), 1, 1, $noise _color);
}
/* Generate random lines in background * *
For ($i =0 $i < ($width * $height)/150 $i + +) {
Imageline ($image, Mt_rand (0, $width), Mt_rand (0, $height), Mt_rand (0, $width), Mt_rand (0, $height), $noise _color);
}
/* Create textbox and add text * *
$textbox = Imagettfbbox ($font _size, 0, $this->font, $code) or Die (' Error in Imagettfbbox function ');
$x = ($width-$textbox [4])/2;
$y = ($height-$textbox [5])/2;
Imagettftext ($image, $font _size, 0, $x, $y, $text _color, $this->font, $code) or Die (' Error in Imagettftext function ');
/* Output CAPTCHA image to Browser * *
Header (' Content-type:image/jpeg ');
Imagejpeg ($image);
Imagedestroy ($image);
$_session[' security_code ' = $code;
}
}
$width = Isset ($_get[' width ')? $_get[' width ': ' 120 ';
$height = isset ($_get[' height '])? $_get[' height ']: ' 40 ';
$characters = Isset ($_get[' characters ']) && $_get[' characters '] > 1? $_get[' characters ']: ' 6 ';
$captcha = new Captchasecurityimages ($width, $height, $characters);
?>
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