Gazelle/sections/captcha/index.php

<?
if (!function_exists('imagettftext')) {
	die('Captcha requires both the GD library and the FreeType library.');
}

function get_font() {
	global $CaptchaFonts;
	return SERVER_ROOT.'/classes/fonts/'.$CaptchaFonts[mt_rand(0,count($CaptchaFonts)-1)];
}

function make_captcha_img() {
	global $CaptchaBGs;

	$Length = 6;
	$ImageHeight = 75;
	$ImageWidth = 300;

	$Chars = 'abcdefghjkmprstuvwxyzABCDEFGHJKLMPQRSTUVWXY23456789';
	$CaptchaString = '';

	for ($i = 0; $i < $Length; $i++) {
		$CaptchaString.=$Chars[mt_rand(0,strlen($Chars) - 1)];
	}

	for ($x = 0; $x < $Length; $x++) {
		$FontDisplay[$x]['size'] = mt_rand(24,32);
		$FontDisplay[$x]['top'] = mt_rand($FontDisplay[$x]['size'] + 5,$ImageHeight - ($FontDisplay[$x]['size'] / 2));
		$FontDisplay[$x]['angle'] = mt_rand(-30,30);
		$FontDisplay[$x]['font'] = get_font();
	}

	$Img = imagecreatetruecolor($ImageWidth,$ImageHeight);
	$BGImg = imagecreatefrompng(SERVER_ROOT.'/captcha/'.$CaptchaBGs[mt_rand(0,count($CaptchaBGs) - 1)]);
	imagecopymerge($Img,$BGImg,0,0,0,0,300,75,50);

	$ForeColor = imagecolorallocatealpha($Img,255,255,255,65);

	for ($i = 0; $i < strlen($CaptchaString); $i++) {
		$CharX = (($ImageWidth / $Length) * ($i + 1)) - (($ImageWidth / $Length) * 0.75);
		imagettftext($Img,$FontDisplay[$i]['size'],$FontDisplay[$i]['angle'],$CharX,
						$FontDisplay[$i]['top'],$ForeColor,
						$FontDisplay[$i]['font'],$CaptchaString[$i]
					);
	}

	header('Content-type: image/png');
	imagepng($Img);
	imagedestroy($Img);

	return $CaptchaString;
}

$_SESSION['captcha'] = make_captcha_img();
?>