Set the appearance of a field
(PHP 3>= 3.0.6, PHP 4 )
bool fdf_set_ap ( resourcefdf_document, stringfield_name, intface, stringfilename, intpage_number )
The fdf_set_ap() function sets the
appearance of a field (i.e. the value of the /AP key).
The possible values of face
are FDFNormalAP, FDFRolloverAP
and FDFDownAP.