;+
;
; @file_comments
;
; @categories
;
; @param BASE {in}{required}
; The id of the widget where apply the drawing.
;
; @param NEWFIELDNAME
;
; @keyword BOXZOOM
; Vector indicating the geographic zone on which we want to cut the map.
; If BOXZOOM has :
;   1 element : The extraction is made on [lon1, lon2, lat1, lat2, 0.,boxzoom[0]]
;   2 elements: The extraction is made on [lon1, lon2, lat1, lat2, boxzoom[0],boxzoom[1]]
;   4 elements: The extraction is made on [Boxzoom, 0, max([gdept, gdepw])]
;   5 elements: The extraction is made on [Boxzoom[0:3], 0, Boxzoom[4]]
;   6 elements: The extraction is made on Boxzoom
; Where lon1, lon2,lat1,lat2 are global variables defined at the last 
; <pro>domdef</pro> !
;
; @returns
;
; @uses
;
; @restrictions
;
; @examples
;
; @history
;
; @version
; $Id$
;
; @todo
; seb
;
;-
PRO changefield, base, newfieldname, BOXZOOM=boxzoom
;
  compile_opt idl2, strictarrsubs
;
  widget_control, base, get_uvalue = top_uvalue
;
; Change exextra :
  exextra = definedefaultextra(newfieldname)
  specifieid = widget_info(base, find_by_uname = 'specifie')
  widget_control, specifieid, set_value = exextra
; Change the variable -> Do we need to change the vertical axis
; according to the type of points (T or W)?
  dthlv1id = widget_info(base, find_by_uname = 'dthlv1')
  widget_control, dthlv1id, get_uvalue = dthlv1_uval
  oldzgridt = dthlv1_uval.grid_t
; get the type of point
  currentfile = extractatt(top_uvalue, 'currentfile')
  listgrid = (*(extractatt(top_uvalue, 'fileparameters'))[currentfile]).listgrid
  listvar = (*(extractatt(top_uvalue, 'fileparameters'))[currentfile]).listvar
;   for i = 0,  n_elements(listvar)-1 do print,  listvar[i], '/', listgrid[i]
  indexvar = where(listvar EQ newfieldname)
  indexvar = 0 > indexvar[0]
  zgridt = strupcase(listgrid[indexvar]) NE 'W'
; if we change the type of point
  if zgridt NE oldzgridt then BEGIN
; update dthlv1_uval.grid_t
    dthlv1_uval.grid_t = zgridt
    widget_control, dthlv1id, set_uvalue = dthlv1_uval
; update cw_domain
    if NOT keyword_set(boxzoom) THEN $
       widget_control, widget_info(base, find_by_uname = 'domain'), get_value = boxzoom
    widget_control, widget_info(base, find_by_uname = 'domain'), set_value = boxzoom
  endif
;
  return
end