(define (script-fu-auto-scale image layer 
             left-guide
			 right-guide
			 x-coord
         )
	
		(let* 
			(
		    (layer-width 0)
			(layer-height 0)
			(guide-width 0)
			(width 0)
			(percent 0)
			(new-layer-width 0)
			(new-layer-height 0)
			)
			
			(gimp-image-undo-group-start image)                   ;undo-group in one step
			(gimp-message "start calculation")
			(set! layer-width (car (gimp-drawable-width layer)))
		    (set! layer-height (car (gimp-drawable-height layer)))
			(set! guide-width (- right-guide left-guide))
			(set! width (- x-coord left-guide))
			(set! percent (/(* guide-width 1.0) width))
			(set! new-layer-width (* layer-width percent))
			(set! new-layer-height (* layer-height percent))
			(gimp-message "done calculating")
			(gimp-layer-scale layer new-layer-width new-layer-height TRUE)
			
			(gimp-image-undo-group-end image)                     ;undo group in one step
			(gimp-displays-flush)
	    )
	
	
    
) ;end of define

(script-fu-register
  "script-fu-auto-scale"         ;function name
  "<Image>/Script-Fu/Auto Scale..."    ;menu register
  "Creates multiple layers of hatches automatically."       ;description
  "Tin Tran"                          ;author name
  "copyright info and description"         ;copyright info or description
  "2015"                          ;date
  "RGB*, GRAY*"                        ;mode
  SF-IMAGE      "Image" 0                   
  SF-DRAWABLE   "Layer" 0
  SF-ADJUSTMENT "Left Guide x-coord" '(1000 0 10000 1 10 0 0)
  SF-ADJUSTMENT "Right Guide x-coord" '(1000 0 10000 1 10 0 0)
  SF-ADJUSTMENT "New Right x-coord" '(1000 0 10000 1 10 0 0)
)