class TasuCaptcha {
  private $bg;
  private $fg;
 
  // picture
  public $width; // width of the picture
  public $height; // height of the picture

  // letters
  public $font; // font for the letters
  public $fontHeight; // height of the letters
  public $maxAngle; // maximum angle for the letters
  public $top; // where the letters should start - y
  public $left; // where the letters should start - x
  public $letterWidth; // approximate width of each letter

  // line
  public $step; // the length of line between turns
  public $stepDiff; // the max height difference for step
  public $lineBorder; // borders for the middle line
  public $thickness; // thickness of the line
  public $antialiased; // if true, makes the line antialiased

  function __construct($text) {
    // picture
    $this->width = 170;
    $this->height = 50;
    $bgColor = ‘113355′;
    $fgColor = ‘CCCCCC’;

    // letters
    $this->text = $text;
    $this->font = ‘./gentium.ttf’;
    $this->fontHeight = 25;
    $this->maxAngle = 15;
    $this->top = 35;
    $this->left = 10;
    $this->letterWidth = 30;

    // center line
    $this->step = 5;
    $this->stepDiff = 5;
    $this->lineBorder = 15;
    $this->thickness = 2;
    $this->antialiased = false;

    $this->setBgColor($bgColor);
    $this->setFgColor($fgColor);
  }

  function setBgColor($color) {
    if (strlen($color) != ‘6′) die(’setBgColor needs 6 letter hex color’);
    $this->bg[‘r’] = hexdec(substr($color, 0, 2));
    $this->bg[‘g’] = hexdec(substr($color, 2, 2));
    $this->bg[‘b’] = hexdec(substr($color, 4, 2));
  }
  function setFgColor($color) {
    if (strlen($color) != ‘6′) die(’setFgColor needs 6 letter hex color’);
    $this->fg[‘r’] = hexdec(substr($color, 0, 2));
    $this->fg[‘g’] = hexdec(substr($color, 2, 2));
    $this->fg[‘b’] = hexdec(substr($color, 4, 2));
  }

  function drawImage() {
    // create image and set colors
    $im = imagecreatetruecolor($this->width, $this->height);
    $background = imagecolorallocate($im,
      $this->bg[‘r’], $this->bg[‘g’], $this->bg[‘b’]);
    imagefill($im, 0, 0, $background);
    $textcolor = imagecolorallocate($im,
      $this->fg[‘r’], $this->fg[‘g’], $this->fg[‘b’]);

    // draw letters
    for ($i = 0; $i < strlen($this->text); $i++) {
      $this->angle = rand(- $this->maxAngle, $this->maxAngle);
      imagettftext($im, $this->fontHeight, $this->angle,
        $this->left + $this->letterWidth * $i, $this->top,
        $textcolor, $this->font, $this->text{$i});
    }

    // draw the line
    $curheight = $this->height / 2;
    for ($i = 0; $i < ($this->width / $this->step); $i++) {
      $lastheight = $curheight;
      $curheight = $curheight + rand(-$this->stepDiff, $this->stepDiff);
      if ($curheight > $this->height - $this->lineBorder)
        $curheight -= $this->stepDiff;
      if ($curheight < $this->lineBorder)
        $curheight += $this->stepDiff;

      // this could be done better…
      for ($j = 0; $j < $this->thickness; $j++) {
        if ($this->antialiased) // draw antialiased line
          drawQSLine($im, $this->step * $i, $lastheight - $j,
            $this->step * $i + $this->step, $curheight - $j,
            $this->fg[‘r’], $this->fg[‘g’], $this->fg[‘b’]);
        else // draw aliased line
          imageline($im, $this->step * $i, $lastheight - $j,
            $this->step * $i + $this->step, $curheight - $j,
            $textcolor);
      }
    }

    // output the image
    header(‘Content-type: image/png’);
    imagepng($im);
    imagedestroy($im);

    // maybe someone could find this useful
    return $this->text;
  }
}

// now we can try to use it:
$captcha = new TasuCaptcha($cnum);
$captcha->antialiased = true;
$captcha->drawImage();

function tasucaptcha($text) {
  // picture
  $width = 170; // width of the picture
  $height = 50; // height of the picture
  $bgcolor = ‘113355′; // please keep this 6 letters long
  $fgcolor = ‘CCCCCC’; // please keep this 6 letters long

  // letters
  $font = ‘./gentium.ttf’; // font for the letters
  $fontHeight = 25; // height of the letters
  $maxAngle = 15; // maximum angle for the letters
  $top = 35; // where the letters should start - y
  $left = 10; // where the letters should start - x
  $letterWidth = 30; // approximate width of each letter

  // center line
  $step = 5; // the length of line between turns
  $stepdiff = 5; // the max height difference for step
  $lineBorder = 15; // borders for the middle line
  $thickness = 2; // thickness of the line
  $antialiased = false; // if true, makes the line antialiased

  // END OF SETTINGS

  // get colors
  $bg[‘r’] = hexdec(substr($bgcolor, 0, 2));
  $bg[‘g’] = hexdec(substr($bgcolor, 2, 2));
  $bg[‘b’] = hexdec(substr($bgcolor, 4, 2));
  $color[‘r’] = hexdec(substr($fgcolor, 0, 2));
  $color[‘g’] = hexdec(substr($fgcolor, 2, 2));
  $color[‘b’] = hexdec(substr($fgcolor, 4, 2));

  // set up the image
  $im = imagecreatetruecolor($width, $height);
  $background = imagecolorallocate($im, $bg[‘r’], $bg[‘g’], $bg[‘b’]);
  imagefill($im, 0, 0, $background);
  $textcolor = imagecolorallocate($im, $color[‘r’], $color[‘g’], $color[‘b’]);

  // draw letters
  for ($i = 0; $i < strlen($text); $i++) {
    $angle = rand(-$maxAngle, $maxAngle);
    imagettftext($im, $fontHeight, $angle, $left + $letterWidth*$i,
      $top, $textcolor, $font, $text{$i});
  }

  // draw the line
  $curheight = $height/2;
  for ($i = 0; $i < ($width / $step); $i++) {
    $lastheight = $curheight;
    $curheight = $curheight + rand(-$stepdiff, $stepdiff);
    if ($curheight > $height - $lineBorder) $curheight -= $stepdiff;
    if ($curheight < $lineBorder) $curheight += $stepdiff;

    //
    for ($j = 0; $j < $thickness; $j++) {
      if ($antialiased) // create antialiased line
        drawQSLine($im, $step * $i, $lastheight - $j, $step * $i + $step,
          $curheight - $j, $color[‘r’], $color[‘g’], $color[‘b’]);
      else // draw aliased line
        imageline($im, $step * $i, $lastheight - $j, $step * $i + $step,
          $curheight - $j, $textcolor);
    }
  }

  // draw the image
  header(‘Content-type: image/png’);
  imagepng($im);
  imagedestroy($im);

  return $text;
}
tasucaptcha($cnum);