function reset(&$media)
 {
     OutputDriverGeneric::reset($media);
 }
 function update_media($media)
 {
     parent::update_media($media);
     /**
      * Here we use a small hack; media height and width (in millimetres) match
      * the size of screenshot (in pixels), so we take them as-is
      */
     $this->_heightPixels = $media->height();
     $this->_widthPixels = $media->width();
     $this->_image = imagecreatetruecolor($this->_widthPixels, $this->_heightPixels);
     /**
      * Render white background
      */
     $white = imagecolorallocate($this->_image, 255, 255, 255);
     imagefill($this->_image, 0, 0, $white);
     imagecolordeallocate($this->_image, $white);
     $this->_color[0] = array('rgb' => array(0, 0, 0), 'object' => imagecolorallocate($this->_image, 0, 0, 0));
     /**
      * Setup initial clipping region
      */
     $this->_clipping = array();
     $this->_saveClip(new Rectangle(new Point(0, 0), new Point($this->_widthPixels - 1, $this->_heightPixels - 1)));
     $this->_transform = new AffineTransform($this->_heightPixels, $this->_widthPixels / mm2pt($this->media->width()), $this->_heightPixels / mm2pt($this->media->height()));
 }