session_start(); 
//-------------------- 
// CAPTCHA Function 
//-------------------- 
function captcha($length = 6) { 
    $length = isset($_GET['chars']) ? $_GET['chars'] : 6; 
     
    // Let's generate a totally random string using md5 
    $hash = md5(rand(0, 999));  
    // We don't need a 32 character long string so we trim it down to 5  
    $code = substr($hash, 15, $length);  

    // Set the session to store the security code 
    $_SESSION["captcha"] = $code; 

    // Set the image width and height 
    $width = 200; 
    $height = 50; 

    // Create the image resource  
    $image = imagecreate($width, $height); 
    // Random RGB colours 
    $rgb1 = rand(0, 255); 
    $rgb2 = rand(0, 255); 
    $rgb3 = rand(0, 255); 
     
    $background = imagecolorallocate($image, $rgb1, $rgb2, $rgb3); 
    $text = imagecolorallocate($image, ($rgb1 - 50), ($rgb2 - 50), ($rgb3 - 50)); 

    // Make the background colour 
    imagefill($image, 0, 0, $background);  

    // Add randomly generated string in the image 
    for($i = 1; $i <= $length; $i++) { 
        $counter = rand(1, 2); 
         
        if ($counter == 1) { 
            $angle = rand(0, 45); 
        } 
        if ($counter == 2) { 
            $angle = rand(315, 360); 
        } 
         
       /*problem*/ imagettftext($image, rand(14, 20), $angle, ($i * 25), 30, $text, "templates/ChalkboardBold.ttf", substr($code, ($i - 1), 1)); 
    } 

    // Add a border 
    imagerectangle($image, 0, 0, $width - 1, $height - 1, $text);  
  
    // Tell the browser what kind of file is come in  
    header("Content-Type: image/png");  

    // Output the newly created image in jpeg format  
    imagepng($image); 
    
    // Free up resources 
    imagedestroy($image);  
} 
!isset($_GET['chars']) ? captcha() : captcha($_GET['chars']);