;+
; NAME        : EIT_SUB_UTIL_NUB
;
; PURPOSE     :
;
; CATEGORY    :
;
; EXPLANATION : 
;
; SYNTAX      : 
;
; EXAMPLES    : none
;
; CALLED BY   :
;
; CALLS TO    : none
;
; ARGURMENTS  :	none
;
; KEYWORDS    : none
;
; OUTPUTS     : none
;
; COMMON      : none
;
; RESTRICTIONS: none
;
; SIDE EFFECTS: none
;
; PROJECT     : SOHO - EIT
;
; HISTORY     : V1,  Elaine Einfalt (HSTX)
;
; CONTACT     : eit@xanado.nascom.nasa.gov
;-

pro EIT_SUB_UTIL_NUB, x0, y0, color, top=top, bottom=bottom, left=left, $
			right=right, pix_per=pix_per

common highlight_box, $
		last_resize,    $	; window size last time through here.
					;
		h_line,		$	; dotted horz. long grid
		solid_h_line,	$	; solid horz. line for side
		solid_v_line, 	$	; solid vert. line for top/bottom side
		h_nub, 		$	; solid "nubby" for mid-point sides
		v_line,		$	; dotted vert. long grid
		v_nub, 		$	; solid "nubby" for mid-point sides
		dot_h_line,	$	; dotted horz line for unhighlighting
		dot_v_line		; dotted vert line for unhighlighting

 ; Draw 2 horizontal and 2 vertical "nubbies" at the midpoint of each
      ; side of the square, pointing to the middle of the square.
      ; Color = 0 means erase, Color = 1 means draw
   
 ; 2 is length of nubby line
 ; 29 is size of block
 ; 14.5 is half a block
 ; don't let nubbies touch the box or erasures will leave gaps

 half_block = pix_per / 2
 nublen = pix_per * .069


 if keyword_set(top)    then $ 
    tv, v_nub*color, x0+half_block, y0+pix_per-2 	; top nub
 if keyword_set(bottom) then $ 
    tv, v_nub*color, x0+half_block, y0+1		; bottom 
 if keyword_set(left)   then $ 
    tv, h_nub*color, x0+1, y0+half_block     		; left nub
 if keyword_set(right)  then $ 
    tv, h_nub*color, x0+pix_per-2, y0+half_block  	; right 

return
end