(PHP 4, PHP 5, PHP 7)
fdf_set_ap — Set the appearance of a field
$fdf_document
   , string $field_name
   , int $face
   , string $filename
   , int $page_number
   )Sets the appearance of a field (i.e. the value of the /AP key).
fdf_documentThe FDF document handle, returned by fdf_create(), fdf_open() or fdf_open_string().
field_name
face
       The possible values FDFNormalAP,
       FDFRolloverAP and
       FDFDownAP.
      
filename
page_number
   Returns TRUE on success or FALSE on failure.