;
;  poster.scm - quick and easy posterization
;
;
;;; --------------------------------------------------------------------
;;; 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.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
;  Helper function to create a new layer
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(define (copylayer layer layername)
  (set! new (car(gimp-layer-copy layer 1))) ; Add an alpha channel
  (gimp-drawable-set-name new layername)
  
  new
  )

;  Now, the real function . . .

(define (script-fu-poster inImage inLayer)
  (let*
      (
       (posterlayer (copylayer inLayer "Poster Layer"))
       )
    
    (gimp-image-undo-group-start inImage)

    (gimp-image-add-layer inImage posterlayer -1)
    (gimp-layer-set-mode posterlayer 14) ; VALUE-MODE
    (gimp-desaturate posterlayer)
    (gimp-posterize posterlayer 4)	; 4 levels (=64 colors)
    )

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





(script-fu-register
 "script-fu-poster"
 _"<Image>/Script-Fu/Alchemy/Poster"
 "Converts an image into a poster by placing a posterized, desaturated copy of the original in value mode over the original image.  This implements a technique posted by Guillermo Romero to the Gimp-user mailing list."
 "Jeff Trefftzs"
 "Copyright 2001, Jeff Trefftzs"
 "March 31, 2001"
 "RGB* GRAY* INDEXED*"
 SF-IMAGE "The Image" 0
 SF-DRAWABLE "The Layer" 0
)