;+
; ROUTINE:         lenstr
; USEAGE:          result=lenstr(str)
;
; input:
;  str             a single string or string array.
; 
; output:
;  result          length of the string(s) in normalized units
;                  the number of elements of RESULT matches the number of 
;                  elements of STRING. 
;
; procedure:
;                  This function returns the physical length of the
;                  string on the output device, not the number of
;                  characters.  This is done by first switching to 'X'
;                  and writing the string(s) with XYOUTS in graphics
;                  mode 5, which disables display to the screen but
;                  does not interfere with operation of XYOUTS.  The
;                  WIDTH keyword parameter of XYOUTS is used to
;                  retrieve the physical length of the string(s).
;
;  author:  Paul Ricchiazzi                            7apr93
;           Institute for Computational Earth System Science
;           University of California, Santa Barbara
;
; @todo seb 
;
;-
FUNCTION lenstr, str
;
  compile_opt idl2, strictarrsubs
;
   dsave=!d.name

   thisOS = !VERSION.OS_FAMILY
   thisOS = STRMID(thisOS, 0, 3)
   thisOS = STRUPCASE(thisOS)
   CASE thisOS of
      'MAC': SET_PLOT, thisOS
      'WIN': SET_PLOT, thisOS
      ELSE: SET_PLOT, 'X'
   ENDCASE
   !p.BACKGROUND=(!d.n_colors-1) < 255
   !p.color=0
   if !d.n_colors gt 256 then !p.background='ffffff'x

   device,get_graphics=oldg,set_graphics=5
   if keyword_set(charsize) eq 0 then charsize=1
   nn=n_elements(str)

   case nn of

      0:w=0

      1:xyouts,0,0,/device,str,width=w

      else:begin
         w=fltarr(nn)
         for i=0,nn-1 do begin
            xyouts,0,0,/device,str[i],width=ww
            w[i]=ww
         endfor
      end
   endcase

   fac1=float(!d.x_ch_size)/!d.x_vsize ; ratio of char width to device1 width

   device,set_graphics=oldg
   set_plot,dsave
   IF dsave EQ 'X' OR dsave EQ 'MAC' OR dsave EQ 'WIN' then BEGIN
      !p.BACKGROUND=(!d.n_colors-1) < 255
      !p.color=0
      if !d.n_colors gt 256 then !p.background='ffffff'x
   ENDIF

   fac2=float(!d.x_ch_size)/!d.x_vsize ; ratio of char width to device2 width

   return,w*fac2/fac1           ; string width adjusted for device width
end