PRO wwassociate,tag,window_id,current=current

;+
; WWASSOCIATE
;
;     Associate a WWPICS file with a window
;
; Calling Sequence
;
;     wwassociate,tag,window
;
; Arguments
;
;     Tag     The tag identifier for a WWPICS archived image.  If set
;             to "ACTIVE" then the current active image is used.
;
;     Window  The number of the window to associate the image with
;
; Keywords
;
;     Current  If set, associate the file with the current window
;-

if keyword_set(current) then window_id=!d.window

; If no windows exist, cut and run

if(!d.window lt 0) then return

; Find out if the requested window is registered in !w.coords, and
; get its index id

used=!w_coords.windex
id=where(used eq window_id)
if (id(0) lt 0) then return
id=id(0)

; See if an image is registered under the requested tag name
; If tag was set to "ACTIVE" this will replace it with the actual
; tag name of the image.

wwpics,'check',tag,stat
if (stat(0) eq 0) then return

; The tag is good and the requested window is registered, so
; associate the two

!w_coords(id).tag=strupcase(tag)

end