swfdisplayitem->skewyto() sets the y-skew to degrees. For degrees is 1.0, it means a 45-degree forward slant. More is more upward, less is more downward.
The object may be a swfshape(), a swfbutton(), a swftext() or a swfsprite() object. It must have been added using the swfmovie->add().
See also swfdisplayitem->skewy(), swfdisplayitem->skewx() and swfdisplayitem->skewxto().