subr mvfilter_cb
 ;checks if a filter has been specified and sets up flags for mvget_creat_cube
 $mv_filter_flag = 0
 if $radio_state then {		;only if we are turning on
   $mv_filter_flag = 1
   if filter_setup() then return
   s = 'reminder - adjust scaling for the\nfiltered result,\nnot the original!'
   xmmessage,s, '-adobe-helvetica-bold-r-normal--17*', 'gray' ,500,500
 }
 ty,'$mv_filter_flag =', $mv_filter_flag
 endsubr
 ;========================================================