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
$x = 1;
for ($i = 0; $i < $length; $i++) {
$m = $font_metrics[$this->keystring{$i}];
$y = mt_rand(-$fluctuation_amplitude, $fluctuation_amplitude) + ($height - $fontfile_height) / 2 + 2;
if ($no_spaces) {
$shift = 0;
if ($i > 0) {
$shift = 10000;
for ($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) {
$color = imagecolorat($img, $px, $py) & 0xff;
if ($color + $opacity < 190) {
if ($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
$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, $background);
imagefilledrectangle($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;
$rand10 = mt_rand(330, 450) / 110;
//wave distortion
for ($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) {
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, $newblue));
}
}
ob_start();
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', FALSE);
header('Pragma: no-cache');
if (function_exists("imagejpeg")) {
header("Content-Type: image/jpeg");
imagejpeg($img2, null, $jpeg_quality);
$ext = 'jpg';
} else if (function_exists("imagegif")) {
header("Content-Type: image/gif");
imagegif($img2);
$ext = 'gif';
} else if (function_exists("imagepng")) {
header("Content-Type: image/x-png");
imagepng($img2);
$ext = 'png';
}
header('Content-Disposition: inline; filename=' . ((rand(10, 9999))) . '.' . $ext);
header('Content-Length: ' . ob_get_length());
ob_end_flush();
}
// returns keystring
function getKeyString() { return $this->keystring; }
}
// Обрабатываем запрос на картинку CAPTCHA
session_name('SESID');
session_start();
$captcha = new KCAPTCHA();
$_SESSION['code'] = $captcha->getKeyString();
?> 
