;;;
;;; synthetic-edges.scm
;;;
;;;
;;; --------------------------------------------------------------------
;;; version 0.1  by Jeff Trefftzs <trefftzs@tcsn.net>
;;;     - Initial relase
;;; version 0.2 Raymond Ostertag <r.ostertag@caramail.com>
;;;     - ported to Gimp 2.0, changed menu entry
;;;
;;; --------------------------------------------------------------------
;;;
;;; This program is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 2 of the License, or
;;; (at your option) any later version.
;;; 
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;; 
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software
;;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Changelog:
;;; 020113 - Version 1.0.  Initial Release.

;;; Define the function:

(define (script-fu-synthetic-edges inImage inLayer
				 inWeight inMono)
  (let*
      (
       (EdgeLayer (car (gimp-layer-copy inLayer TRUE)))
       (tmpLayer (car (gimp-layer-copy inLayer TRUE)))
       )
    
    (gimp-image-undo-group-start inImage)

    (gimp-image-add-layer inImage EdgeLayer -1)
  
    (gimp-drawable-set-name EdgeLayer "Synthetic Edges")

    ;; Real work goes in here

    (gimp-image-add-layer inImage tmpLayer -1)
    (gimp-layer-set-mode tmpLayer DIVIDE-MODE)
    (plug-in-gauss-iir TRUE inImage tmpLayer inWeight TRUE TRUE)
    (set! EdgeLayer 
	  (car (gimp-image-merge-down inImage tmpLayer
				      EXPAND-AS-NECESSARY)))
    (gimp-levels EdgeLayer HISTOGRAM-VALUE
		 (- 255 inWeight) ; low input
		 255		; high input
		 1.0		; gamma
		 0 255)		; output 
    
    (gimp-layer-set-mode EdgeLayer NORMAL-MODE) ; 

    (if (= inMono TRUE)
	(gimp-desaturate EdgeLayer)
	)

    (gimp-image-set-active-layer inImage inLayer)
    (gimp-image-undo-group-end inImage)
    (gimp-displays-flush)
    )
  )

(script-fu-register
 "script-fu-synthetic-edges"
 _"<Image>/Script-Fu/Line-Art/Synthetic Edges..."
 "Synthetic edge detection merges a blurred copy in DIVIDE-MODE with a copy of the original image.  The edges are then enhanced with levels (255 - blur radius) becomes the lower limit for input."

 "Jeff Trefftzs"
 "Copyright 2002, Jeff Trefftzs"
 "January 12, 2002"
 "RGB* GRAY*"
 SF-IMAGE "The Image" 0
 SF-DRAWABLE "The Layer" 0
 SF-ADJUSTMENT "Line Weight (Fine) 1 <----> 128 (Thick)" 
 '(3 1 128 1 8 0 1)
 SF-TOGGLE "Monochrome?" FALSE
)