;;;
;;; draw-spiral.scm
;;;
;;;
;;;  Arch. Giuseppe Conte <http://space.tin.it/edicola/lwcon/>
;;;
;;;  Raymond Ostertag 2004/09 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.

;;; Define the function:

(define (script-fu-draw-spiral inImage inLayer dx dy Spire Passo)

		(set! angolo (/ 360 Passo))
		(set! arco (* angolo (/ 3.14 180)))
		(set! beta 0)
		(set! gamma 0)
		(set! gcount arco)
		(set! npoint 4)
	(let* (	(segment (cons-array 4 'double))   
		(stepx dx)
		(stepy dy)
		(lunghezza (* 2 *pi* Spire))
		
	      )
	       
  
  (while (<= gcount lunghezza) 
		(set! raggio gcount)  	
  		(set! beta (+ beta arco))
  		(set! gamma (- beta arco))
  		(aset segment 0 (+ (* raggio (cos gamma)) stepx))
  		(aset segment 1 (+ (- (* raggio (sin gamma))) stepy))
  		(aset segment 2 (+ (* raggio (cos beta)) stepx))
  		(aset segment 3 (+ (- (* raggio (sin beta))) stepy))
  
		(gimp-pencil inLayer npoint segment )
  
  		(set! gcount (+ gcount arco))
   	  (gimp-displays-flush)
   );end while
   

  ;(gimp-displays-flush)
  
  );;let
) ;;def

(script-fu-register
 "script-fu-draw-spiral"
 _"<Image>/Script-Fu/Geometry/Draw Spiral..."
 "Draw the spiral with the brush and color active."
 "Arch. Giuseppe Conte <http://space.tin.it/edicola/lwcon/>"
 "2002, Giuseppe Conte"
 "08 Maggio 2002 - Florence - Italy"
 "RGB* GRAY* INDEXED*"
 SF-IMAGE "The Image" 0
 SF-DRAWABLE "The Layer" 0
 SF-ADJUSTMENT "X center" '(0 0 9999 1 10 0 1)
 SF-ADJUSTMENT "Y center" '(0 0 9999 1 10 0 1)
 SF-ADJUSTMENT "Number of spire" '(3 0 9999 1 10 0 1)
 SF-ADJUSTMENT "Segments for circle" '(60 0 9999 1 10 0 1)
)