gridmaker.scm

;; Gimp script-fu plugin
;;
;; Draws a sqaure grid with the specified size into a new layer.
;; The lines of the grid are drawn using the current brush & foreground color.
;;
;; Author: Anthony J. Thibault
;; email: ajt@hyperlogic.org
;;
;; Copyright (c) 2009 Anthony J. Thibault
;;
;; Permission is hereby granted, free of charge, to any person obtaining a copy
;; of this software and associated documentation files (the "Software"), to deal
;; in the Software without restriction, including without limitation the rights
;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;; copies of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:
;;
;; The above copyright notice and this permission notice shall be included in
;; all copies or substantial portions of the Software.
;;
;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
;; THE SOFTWARE.

;; globals
(define (g-image nil))
(define (g-size nil))
(define (g-width nil))
(define (g-height nil))
(define (g-layer nil))

(define (draw-line a b)
  (let ((v (car (gimp-vectors-new g-image "grid"))))
	(gimp-image-add-vectors g-image v -1)
	(let ((stroke-id (car (gimp-vectors-bezier-stroke-new-moveto v (car a) (cdr a)))))
	  (gimp-vectors-bezier-stroke-lineto v stroke-id (car b) (cdr b))
	  (gimp-vectors-stroke-close v stroke-id)
	  (gimp-edit-stroke-vectors g-layer v))))

(define (draw-horiz-lines n)
  (if (> n 0)
	  (let ((y (* n g-size)))
		(draw-line (cons 0 y) (cons g-width y))
		(draw-horiz-lines (- n 1)))
	  #t))

(define (draw-vert-lines n)
  (if (> n 0)
	  (let ((x (* n g-size)))
		(draw-line (cons x 0) (cons x g-height))
		(draw-vert-lines (- n 1)))
	  #t))

(define (script-fu-grid-render image size)

  ;; set globals
  (set! g-image image)
  (set! g-size size)
  (set! g-width (car (gimp-image-width image)))
  (set! g-height (car (gimp-image-height image)))
  (set! g-layer (car (gimp-layer-new image
									 g-width
									 g-height
									 1 ; rbga
									 "grid" ; name
									 100 ; opacity
									 0))) ; combination mode

  (gimp-image-undo-disable image)
  (gimp-image-add-layer image g-layer -1)
  (gimp-drawable-fill g-layer 3) ; transparent fill

  (let ((num-columns (quotient g-width g-size))
		(num-rows (quotient g-height g-size)))
	(draw-horiz-lines num-rows)
 	(draw-vert-lines num-columns))

  (gimp-image-undo-enable image))

;; register
(script-fu-register
 "script-fu-grid-render"                     ;func name
 "GridRender"                                ;menu label
 "Draws a sqaure grid with the specified size into a new layer. The lines of the grid are drawn using the current brush & foreground color."
 "Anthony Thibault"                          ;author
 "Copyright 2009, Anthony Thibault"          ;copyright notice
 "Feb 23, 2009"                              ;date created
 "RGB*"                                      ;image type that the script works on
 SF-IMAGE "Image" 0
 SF-VALUE "Grid Size" "32"                   ;size
 )
(script-fu-menu-register "script-fu-grid-render"  "<Image>/Script-Fu")