;;; grid-system.scm -*-scheme-*-
;;; Time-stamp: <1998/01/20 23:22:02 narazaki@InetQ.or.jp>
;;; This file is a part of:
;;;   The GIMP (Copyright (C) 1995-1997 Spencer Kimball and Peter Mattis)
;;; Author: Shuji Narazaki (narazaki@InetQ.or.jp)
;;; Version 0.6

;;; Code:
(if (not (symbol-bound? 'script-fu-grid-system-x-divides (the-environment)))
    (define script-fu-grid-system-x-divides "'(1 g 1)"))
(if (not (symbol-bound? 'script-fu-grid-system-y-divides (the-environment)))
    (define script-fu-grid-system-y-divides "'(1 g 1)"))

(define (script-fu-grid-system img drw x-divides-orig y-divides-orig)
  (define (update-segment! s x0 y0 x1 y1)
    (aset s 0 x0)
    (aset s 1 y0)
    (aset s 2 x1)
    (aset s 3 y1))
  (define (convert-g l)
    (cond ((null? l) '())
	  ((eq? (car l) 'g) (cons 1.618 (convert-g (cdr l))))
	  ((eq? (car l) '1/g) (cons 0.618 (convert-g (cdr l))))
	  ('else (cons (car l) (convert-g (cdr l))))))
  (define (wrap-list l)
    (define (wrap-object obj)
      (cond ((number? obj) (string-append (number->string obj) " "))
	    ((eq? obj 'g) "g ")
	    (eq? ojb '1/g) "1/g "))
    (string-append "'("
		   (apply string-append (map wrap-object l))
		   ")"))
  (let* ((drw-width (car (gimp-drawable-width drw)))
	 (drw-height (car (gimp-drawable-height drw)))
	 (drw-offset-x (nth 0 (gimp-drawable-offsets drw)))
	 (drw-offset-y (nth 1 (gimp-drawable-offsets drw)))
	 (grid-layer #f)
	 (segment (cons-array 4 'double))
	 (stepped-x 0)
	 (stepped-y 0)
	 (temp 0)
	 (total-step-x 0)
	 (total-step-y 0))
    (set! x-divides (convert-g x-divides-orig))
    (set! y-divides (convert-g y-divides-orig))
    (set! total-step-x (apply + x-divides))
    (set! total-step-y (apply + y-divides))
    ;(gimp-undo-push-group-start img)
    (set! grid-layer (car (gimp-layer-copy drw TRUE)))
    (gimp-edit-clear grid-layer)
    (gimp-layer-set-name grid-layer "grid layer")
    (while (not (null? (cdr x-divides)))
      (set! stepped-x (+ stepped-x (car x-divides)))
      (set! temp (* drw-width (/ stepped-x total-step-x)))
      (set! x-divides (cdr x-divides))
      (update-segment! segment
		       (+ drw-offset-x temp) drw-offset-y
		       (+ drw-offset-x temp) (+ drw-offset-y drw-height))
      (gimp-pencil grid-layer 4 segment))
    (while (not (null? (cdr y-divides)))
      (set! stepped-y (+ stepped-y (car y-divides)))
      (set! temp (* drw-height (/ stepped-y total-step-y)))
      (set! y-divides (cdr y-divides))
      (update-segment! segment
		       drw-offset-x (+ drw-offset-y temp)
		       (+ drw-offset-x drw-width) (+ drw-offset-y temp))
      (gimp-pencil grid-layer 4 segment))
    (gimp-image-add-layer img grid-layer 0)
    ;(gimp-undo-push-group-end img)
    (set! script-fu-grid-system-x-divides (wrap-list x-divides-orig))
    (set! script-fu-grid-system-y-divides (wrap-list y-divides-orig))
    (gimp-displays-flush)))

(script-fu-register "script-fu-grid-system"
		    "<Image>/Script-Fu/Render/Make Grid System"
		    "Draw grid as specified by X-DIVIDES (list of propotions relative to the drawable) and Y-DIVIDES. The color and width of grid is detemined by the current settings of brush."
		    "Shuji Narazaki <narazaki@InetQ.or.jp>"
		    "Shuji Narazaki"
		    "1997"
		    "RGB*, INDEXED*, GRAY*"
		    SF-IMAGE "Image to use" 0
		    SF-DRAWABLE "Drawable to draw grid" 0
		    SF-VALUE "Grids: X" script-fu-grid-system-x-divides
		    SF-VALUE "Grids: Y" script-fu-grid-system-y-divides
)
  
;;; grid-system.scm ends here
