(PHP 5 <= 5.3.0, PECL ming SVN)
SWFText::getWidth — Computes string's width
$string
   )This function is EXPERIMENTAL. The behaviour of this function, its name, and surrounding documentation may change without notice in a future release of PHP. This function should be used at your own risk.
   Returns the rendered width of the string at the
   text object's current font, scale, and spacing settings.