pro findmax,image,xpos,ypos,maximum,ap = ap,nodisp = nodisp

if n_params() lt 1 then	 begin
   print,'Usage: pro findmax,imgs,[/ap],[nodisp]'
   return
end

; find the peak pixel within some radius of the location
; defined by the cursor


if keyword_set(ap) eq 0 then ap = 6

print
print,'    left or middle button to center apertures'
print,'    right button to finish'
print
 
sz = size(image)


;print,format='(a4," ",a4)','xpeak ',' ypeak  '

repeat begin
   cursor,x,y,/device,/wait
   if (!err eq 1) or (!err eq 2) then begin


      x0 = floor(x-ap)
      x1 = ceil(x+ap)
      y0 = floor(y-ap)
      y1 = ceil(y+ap)
      if (x0 lt 0.0) or (x1 gt (sz(1)-1)) $ 
         or (y0 lt 0.0) or (y0 gt (sz(2)-1)) then begin
             print,'** WARNING: aperture is off the image! **'
      endif

      x0 = x0 > 0.0
      x1 = x1 < (sz(1)-1)
      y0 = y0 > 0.0
      y1 = y1 < (sz(2)-1)

      img = image(x0:x1,y0:y1)

      maximum = max(img)
      w = where( image eq maximum)

      ; Find the corresponding x & y

      whereis,image,w,xpos,ypos


      print,format='(i5,i5,g9.3)', xpos,ypos,maximum


      if keyword_set(nodisp) eq 0 then tvh,image,/silent

      tvcircle,ap,xpos,ypos

      wait,0.2
   endif
endrep until (!err eq 4)


end