<?php
# KCAPTCHA PROJECT VERSION 1.2.4
# Automatic test to tell computers and humans apart
# Copyright by Kruglov Sergei, 2006
# 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 building 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 customizing
session_start();
$captcha = new KCAPTCHA();
$_SESSION['captcha'] = $captcha->getKeyString();
class KCAPTCHA {
// generates keystring and image
private $keystring = '';
public function __construct() {
$alphabet = "0123456789abcdefghijklmnopqrstuvwxyz"; # do not change without changing font files!
$allowed_symbols = "23456789abcdeghkmnpqsuvxyz"; #alphabet without similar symbols (o=0, 1=l, i=j, t=f)
$length = 8;
$width = 200;
$height = 54;
$fluctuation_amplitude = 2;
$no_spaces = true;
$show_credits = false; # set to false to remove credits line. Credits adds 12 pixels to image height
$foreground_color = array( mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100) );
$background_color = array( mt_rand(230, 255), mt_rand(230, 255), mt_rand(230, 255) );
$jpeg_quality = 90;
$font_file = "im/images/TimesNewRoman.png";
$alphabet_length = strlen($alphabet);
while (true) {
// 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/', $this->keystring)) {
break;
}
}
$font = imagecreatefrompng($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
$x = 1;
for ($i = 0; $i < $length; $i++) {
$m = $font_metrics[$this->keystring[$i]];
$y = mt_rand(-$fluctuation_amplitude, $fluctuation_amplitude) + ( $height - $fontfile_height ) / 2;
if ($no_spaces) {
$shift = 0;
if ($i > 0) {
$shift = 1000;
for ($sy = 7; $sy < $fontfile_height - 20; $sy += 1) {
for ($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 - 12 && $px >= 0; $px -= 1) {
$px = intval($px);
$py = intval ($py);
$color = imagecolorat($img, $px, $py) & 0xff;
if ($color + $opacity < 190) {
if ($shift > $left - $px) {
$shift = $left - $px;
}
break;
}
}
break;
}
}
}
if ($shift == 1000) {
$shift = mt_rand(4, 6);
}
}
}
else {
$shift = 1;
}
$y = intval ($y);
imagecopy($img, $font, $x - $shift, $y, $m['start'], 1, $m['end'] - $m['start'], $fontfile_height);
//imagecopyresampled($img,$font,$x-$shift,$y,$m['start'],1, ($m['end']-$m['start'])/*1.5*/, $height, $m['end']-$m['start'], $fontfile_height);
$x += mt_rand(0, 15) + ( $m['end'] - $m['start'] - $shift );//*1.2;
}
if ($x < $width - 10) {
break;
} // fit in canvas
}
for ($i = 0; $i <= 3; $i++) {
$yl = mt_rand(15, 45);
imageline($img, 0, $yl, $x - $shift, $yl, imagecolorallocate($img, 0, 0, 0));
}
$center = $x / 2;
// credits. To remove, see configuration file
$img2 = imagecreatetruecolor($width, $height);
// 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, 3141592) / 500000;
$rand6 = mt_rand(0, 3141592) / 500000;
$rand7 = mt_rand(0, 3141592) / 500000;
$rand8 = mt_rand(0, 3141592) / 500000;
// amplitudes
$rand9 = mt_rand(330, 420) / 110;
$rand10 = mt_rand(330, 450) / 110;
//wave distortion
for ($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) {
$color = 255;
$color_x = 255;
$color_y = 255;
$color_xy = 255;
}
else {
$sx = intval($sx);
$sy = intval($sy);
$color = imagecolorat($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 == 0 && $color_x == 0 && $color_y == 0 && $color_xy == 0) {
$newred = $foreground_color[0];
$newgreen = $foreground_color[1];
$newblue = $foreground_color[2];
}
else {
if ($color == 255 && $color_x == 255 && $color_y == 255 && $color_xy == 255) {
$newred = $background_color[0];
$newgreen = $background_color[1];
$newblue = $background_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];
}
}
$x = intval($x);
$y = intval($y);
$newred = intval ($newred);
$newgreen = intval ($newgreen);
$newblue = intval ($newblue);
imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newred, $newgreen, $newblue));
}
}
if (function_exists("imagejpeg")) {
imagejpeg($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;
}
}
?>
