<?php
# KCAPTCHA PROJECT VERSION 2.0
# Automatic test to tell computers and humans apart
# Copyright by Kruglov Sergei, 2006, 2007, 2008, 2011
# www.captcha.ru, www.kruglov.ru
# System requirements: PHP 4.0.6+ w/ GD
# KCAPTCHA is a free software. You can freely use it for developing own site or software.
# If you use this software as a part of own sofware, you must leave copyright notices intact or add KCAPTCHA copyright notices to own.
# As a default configuration, KCAPTCHA has a small credits text at bottom of CAPTCHA image.
# You can remove it, but I would be pleased if you left it. ;)
# See kcaptcha_config.php for customization
class KCAPTCHA{
// generates keystring and image
function KCAPTCHA(){
global $config;
$alphabet = "0123456789abcdefghijklmnopqrstuvwxyz"; # do not change without changing font files!
# CAPTCHA image size (you do not need to change it, this parameters is optimal)
$width = 100;
$height = 50;
# symbols used to draw CAPTCHA
//$allowed_symbols = "0123456789"; #digits
//$allowed_symbols = "23456789abcdegkmnpqsuvxyz"; #alphabet without similar symbols (o=0, 1=l, i=j, t=f)
$allowed_symbols = $config['captcha_symbols']; #alphabet without similar symbols (o=0, 1=l, i=j, t=f)
# folder with fonts
$fontsdir = '../assets/captcha';
# CAPTCHA string length
$length = mt_rand(4, $config['captcha_maxlength']); # random 4 or 6
# symbol's vertical fluctuation amplitude
$fluctuation_amplitude = $config['captcha_amplitude'];
#noise
//$white_noise_density=0; // no white noise
$white_noise_density = ($config['captcha_noise']) ? 1/10 : 0;
//$black_noise_density=0; // no black noise
$black_noise_density = ($config['captcha_noise']) ? 1/30 : 0;
# increase safety by prevention of spaces between symbols
$spaces = $config['captcha_spaces'];
# show credits
$show_credits = $config['captcha_credits']; # set to false to remove credits line. Credits adds 12 pixels to image height
$credits = ''; # if empty, HTTP_HOST will be shown
# CAPTCHA image colors (RGB, 0-255)
//$foreground_color = array(0, 0, 0);
//$background_color = array(220, 230, 255);
$foreground_color = array(mt_rand(0,80), mt_rand(0,80), mt_rand(0,80));
$background_color = array(mt_rand(220,255), mt_rand(220,255), mt_rand(220,255));
$ellipse_color = array(mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));
# JPEG quality of CAPTCHA image (bigger is better quality, but larger file size)
$jpeg_quality = 90;
$fonts=array();
$fontsdir_absolute=dirname(__FILE__).'/'.$fontsdir;
if ($handle = opendir($fontsdir_absolute)) {
while (false !== ($file = readdir($handle))) {
if (preg_match('/\.png$/i', $file)) {
$fonts[]=$fontsdir_absolute.'/'.$file;
}
}
closedir($handle);
}
$alphabet_length=strlen($alphabet);
do{
// generating random keystring
while(true){
$this->keystring='';
for($i=0;$i<$length;$i++){
$this->keystring.=$allowed_symbols{mt_rand(0,strlen($allowed_symbols)-1)};
}
if(!preg_match('/cp|cb|ck|c6|c9|rn|rm|mm|co|do|cl|db|qp|qb|dp|ww/', $this->keystring)) break;
}
$font_file=$fonts[mt_rand(0, count($fonts)-1)];
$font=imagecreatefrompng($font_file);
imagealphablending($font, true);
$fontfile_width=imagesx($font);
$fontfile_height=imagesy($font)-1;
$font_metrics=array();
$symbol=0;
$reading_symbol=false;
// loading font
for($i=0;$i<$fontfile_width && $symbol<$alphabet_length;$i++){
$transparent = (imagecolorat($font, $i, 0) >> 24) == 127;
if(!$reading_symbol && !$transparent){
$font_metrics[$alphabet{$symbol}]=array('start'=>$i);
$reading_symbol=true;
continue;
}
if($reading_symbol && $transparent){
$font_metrics[$alphabet{$symbol}]['end']=$i;
$reading_symbol=false;
$symbol++;
continue;
}
}
$img=imagecreatetruecolor($width, $height);
imagealphablending($img, true);
$white=imagecolorallocate($img, 255, 255, 255);
$black=imagecolorallocate($img, 0, 0, 0);
imagefilledrectangle($img, 0, 0, $width-1, $height-1, $white);
// draw text
$x=1;
$odd=mt_rand(0,1);
if($odd==0) $odd=-1;
for($i=0;$i<$length;$i++){
$m=$font_metrics[$this->keystring{$i}];
$y=(($i%2)*$fluctuation_amplitude - $fluctuation_amplitude/2)*$odd
+ mt_rand(-round($fluctuation_amplitude/3), round($fluctuation_amplitude/3))
+ ($height-$fontfile_height)/2
+ 5;
if(!$spaces){
$shift=0;
if($i>0){
$shift=10000;
for($sy=3;$sy<$fontfile_height-10;$sy+=1){
for($sx=$m['start']-1;$sx<$m['end'];$sx+=1){
$rgb=imagecolorat($font, $sx, $sy);
$opacity=$rgb>>24;
if($opacity<127){
$left=$sx-$m['start']+$x;
$py=$sy+$y;
if($py>$height) break;
for($px=min($left,$width-1);$px>$left-200 && $px>=0;$px-=1){
$color=imagecolorat($img, $px, $py) & 0xff;
if($color+$opacity<170){ // 170 - threshold
if($shift>$left-$px){
$shift=$left-$px;
}
break;
}
}
break;
}
}
}
if($shift==10000){
$shift=mt_rand(4,6);
}
}
}else{
$shift=1;
}
imagecopy($img, $font, $x-$shift, $y, $m['start'], 1, $m['end']-$m['start'], $fontfile_height);
$x+=$m['end']-$m['start']-$shift;
}
}while($x>=$width-10); // while not fit in canvas
//noise
$white=imagecolorallocate($font, 255, 255, 255);
$black=imagecolorallocate($font, 0, 0, 0);
for($i=0;$i<(($height-30)*$x)*$white_noise_density;$i++){
imagesetpixel($img, mt_rand(0, $x-1), mt_rand(10, $height-15), $white);
}
for($i=0;$i<(($height-30)*$x)*$black_noise_density;$i++){
imagesetpixel($img, mt_rand(0, $x-1), mt_rand(10, $height-15), $black);
}
$center=$x/2;
// credits. To remove, see configuration file
$img2=imagecreatetruecolor($width, $height+($show_credits?12:0));
$foreground=imagecolorallocate($img2, $foreground_color[0], $foreground_color[1], $foreground_color[2]);
$background=imagecolorallocate($img2, $background_color[0], $background_color[1], $background_color[2]);
imagefilledrectangle($img2, 0, 0, $width-1, $height-1, $background);
/* Moded by Vantuz (http://visavi.net) */
$background2=imagecolorallocate($img2, $ellipse_color[0], $ellipse_color[1], $ellipse_color[2]);
$background3=imagecolorallocate($img2, $ellipse_color[1], $ellipse_color[2], $ellipse_color[0]);
$background4=imagecolorallocate($img2, $ellipse_color[2], $ellipse_color[0], $ellipse_color[1]);
imagefilledellipse($img2, mt_rand(0, $width / 3), mt_rand(0, $height), 60, 60, $background2);
imagefilledellipse($img2, mt_rand($width / 3, $width / (3/2)), mt_rand(0, $height), 60, 60, $background3);
imagefilledellipse($img2, mt_rand($width / (3/2), $width), mt_rand(0, $height), 60, 60, $background4);
imagefilledrectangle($img2, 0, $height, $width-1, $height+12, $foreground);
$credits=empty($credits)?$_SERVER['HTTP_HOST']:$credits;
imagestring($img2, 2, $width/2-imagefontwidth(2)*strlen($credits)/2, $height-2, $credits, $background);
// periods
$rand1=mt_rand(750000,1200000)/10000000;
$rand2=mt_rand(750000,1200000)/10000000;
$rand3=mt_rand(750000,1200000)/10000000;
$rand4=mt_rand(750000,1200000)/10000000;
// phases
$rand5=mt_rand(0,31415926)/10000000;
$rand6=mt_rand(0,31415926)/10000000;
$rand7=mt_rand(0,31415926)/10000000;
$rand8=mt_rand(0,31415926)/10000000;
// amplitudes
$rand9=mt_rand(330,420)/110;
$rand10=mt_rand(330,450)/100;
//wave distortion
for($x=0;$x<$width;$x++){
for($y=0;$y<$height;$y++){
$sx=$x+(sin($x*$rand1+$rand5)+sin($y*$rand3+$rand6))*$rand9-$width/2+$center+1;
$sy=$y+(sin($x*$rand2+$rand7)+sin($y*$rand4+$rand8))*$rand10;
if($sx<0 || $sy<0 || $sx>=$width-1 || $sy>=$height-1){
continue;
}else{
$color=imagecolorat($img, $sx, $sy) & 0xFF;
$color_x=imagecolorat($img, $sx+1, $sy) & 0xFF;
$color_y=imagecolorat($img, $sx, $sy+1) & 0xFF;
$color_xy=imagecolorat($img, $sx+1, $sy+1) & 0xFF;
}
if($color==255 && $color_x==255 && $color_y==255 && $color_xy==255){
continue;
}else if($color==0 && $color_x==0 && $color_y==0 && $color_xy==0){
$newred=$foreground_color[0];
$newgreen=$foreground_color[1];
$newblue=$foreground_color[2];
}else{
$frsx=$sx-floor($sx);
$frsy=$sy-floor($sy);
$frsx1=1-$frsx;
$frsy1=1-$frsy;
$newcolor=(
$color*$frsx1*$frsy1+
$color_x*$frsx*$frsy1+
$color_y*$frsx1*$frsy+
$color_xy*$frsx*$frsy);
if($newcolor>255) $newcolor=255;
$newcolor=$newcolor/255;
$newcolor0=1-$newcolor;
$newred=$newcolor0*$foreground_color[0]+$newcolor*$background_color[0];
$newgreen=$newcolor0*$foreground_color[1]+$newcolor*$background_color[1];
$newblue=$newcolor0*$foreground_color[2]+$newcolor*$background_color[2];
}
imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newred, $newgreen, $newblue));
}
}
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', FALSE);
header('Pragma: no-cache');
if(function_exists("imagejpeg")){
header("Content-Type: image/jpeg");
imagejpeg($img2, null, $jpeg_quality);
}else if(function_exists("imagegif")){
header("Content-Type: image/gif");
imagegif($img2);
}else if(function_exists("imagepng")){
header("Content-Type: image/x-png");
imagepng($img2);
}
}
// returns keystring
function getKeyString(){
return $this->keystring;
}
}
?>