(PHP 5 <= 5.3.0, PECL ming SVN)
SWFShape::drawCurve — Draws a curve (relative)
$controldx
   , float $controldy
   , float $anchordx
   , float $anchordy
   [, float $targetdx
   ], float $targetdy
   )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.
   swfshape::drawcurve() draws a quadratic curve 
   (using the current line style,set by swfshape::setline()) 
   from the current pen position to the relative position
   (anchorx,anchory) 
   using relative control point 
   (controlx,controly).
   That is, head towards the control point, then smoothly turn to the
   anchor point.
  
   With 6 parameters, it draws a cubic bezier to point
   (x+targetdx, x+targetdy)
   with control points (x+controldx,
   y+controldy) and
   (x+anchordx, y+anchordy).