generateCode($characters); /* font size will 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['height'] < 600 ? $_GET['width'] : '120'; $height = isset($_GET['height']) && $_GET['height'] < 200 ? $_GET['height'] : '40'; $characters = isset($_GET['characters']) && $_GET['characters'] > 2 ? $_GET['characters'] : '6'; $captcha = new CaptchaSecurityImages($width, $height, $characters);