Get the appearance of a field (PHP 4 >= 4.3.0, PHP 5)
bool fdf_get_ap ( resource fdf_document, string field, int face, string filename )

The fdf_get_ap() function gets the appearance of a field (i.e. the value of the /AP key) and stores it in a file. The possible values of face are FDFNormalAP, FDFRolloverAP and FDFDownAP. The appearance is stored in filename.