extern void compute_form_page(HyperDocPage * page);
extern int window_width(int cols);
#ifdef _FORM_EXT_C
static int window_height(HyperDocPage * page);
static void form_header_extent(HyperDocPage * page);
static void form_footer_extent(HyperDocPage * page);
static void form_scrolling_extent(HyperDocPage * page);
#endif