; 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.

(define (set-pt arr i x y) 
(aset arr (* i 2) x)
(aset arr (+ (* i 2) 1) y)
)
(define (spline-sketch)
  (let*
	((a (cons-array 18 'byte)))
	(set-pt a 0 0 0)
	(set-pt a 1 190 0)
	(set-pt a 2 191 1)
	(set-pt a 3 210 210)
	(set-pt a 4 220 220)
	(set-pt a 5 230 230)
	(set-pt a 6 240 240)
	(set-pt a 7 250 250)
	(set-pt a 8 255 255)
	
a))

(define (sketch inimage indraw bg-colour)
(let*(

(theImage inimage)
(theDraw indraw)
(a)
)
(gimp-image-undo-group-start theImage)
(let*(

(height (car (gimp-drawable-height theDraw)))
(width (car (gimp-drawable-width theDraw)))
)
(plug-in-edge 1 theImage theDraw 2 1 0)
(gimp-equalize theDraw 0)
(gimp-desaturate theDraw)
(let*(
(highpass (car (gimp-layer-copy theDraw 1)))
)
(gimp-image-add-layer theImage highpass 1)
(gimp-curves-spline highpass 0 18 (spline-sketch))
(gimp-invert theDraw)
(gimp-layer-add-alpha theDraw)
(let*(
(imagemask (car (gimp-layer-create-mask theDraw 0)))
)
(gimp-layer-add-mask theDraw imagemask)
(gimp-edit-copy highpass)
(let*(
(copy-paste (car (gimp-edit-paste imagemask 0)))
)
(gimp-floating-sel-anchor copy-paste)
(gimp-context-set-background bg-colour)
(let*(
(background (car (gimp-layer-new theImage width height 1 "background" 100 0)))
)
(gimp-drawable-fill background 1)
(gimp-image-add-layer theImage background 0)
(gimp-image-remove-layer theImage highpass)
(gimp-image-lower-layer theImage background)

(gimp-image-undo-group-end theImage)
(gimp-displays-flush)
)))))))
(script-fu-register 	"sketch"
			"<Image>/Script-Fu/Gimp-talk.com/sketch..."
			"Turns a image into a sketch if the image is a alpha layer it must be flatterned first"
			"Karl Ward"
			"Karl Ward"
			"Feb 2006"
			"RGB"
			SF-IMAGE      	"SF-IMAGE" 0
			SF-DRAWABLE   	"SF-DRAWABLE" 0
			SF-COLOR	"Background Colour" '(255 255 255)
			
)