;; random_masked.scm -*-scheme-*-
;; Use a brush to paint to paint random pixels a nominated number
;; of times to produce a "random" pattern/.
;; based on:
;; More info at http://members.optusnet.com.au/~charles57/GIMP
;; Version 1.0
;;
;; Copyright (C) 2008 by Charles Cave <charlesweb@optusnet.com.au>
;;
;; 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(define (script-fu-random-masked    img drw
                                    mask
                                    iterations)

  (let* (
        (x1 0)
        (y1 0)
        (ctr 0)
        (x2 (car (gimp-image-width img)))
        (y2 (car (gimp-image-height img)))
        (x 0)
        (y 0)
        (mask-type 0)
        (get-val 0)
        (test 0)
        (thresh 0)
        (*randompoint* (cons-array 2 'double))
        (drw-width 0)
        (drw-height 0)
        )

; define drawable area for the algorithm
  (set! drw-width  (- x2 x1))
  (set! drw-height (- y2 y1))
  ; make sure not indexed
  (set! mask-type (car (gimp-drawable-type mask)))
  (if (or (= mask-type INDEXED-IMAGE) (= mask-type INDEXEDA-IMAGE))
    (gimp-message "Mask can not be indexed")
   (begin
     
     (gimp-context-push)
     (gimp-image-undo-group-start img)

     (gimp-progress-set-text _"Rendering Random Masked Image")
     (while (< ctr iterations)
      (set! x (+ x1 (random drw-width )))
       (set! y (+ y1 (random drw-height)))

       (set! get-val (cadr (gimp-drawable-get-pixel mask x y)))
       (set! thresh (random 255))

       (if (or (= mask-type GRAY-IMAGE) (= mask-type GRAYA-IMAGE))
         (set! test (aref get-val 0))
         (if (or (= mask-type RGB-IMAGE) (= mask-type RGBA-IMAGE))
           (set! test (/ (+ (aref get-val 0) (aref get-val 1) (aref get-val 2)) 3))
         (set! test 255)
         )
       ) 

       (if (< thresh test)
        (begin
          (set! ctr (+ ctr 1))
           (aset *randompoint* 0 x)
           (aset *randompoint* 1 y)
           (gimp-paintbrush-default drw 2 *randompoint*)
         (gimp-progress-update (/ ctr iterations))
         )
       )
     )
     (gimp-image-undo-group-end img)
     (gimp-displays-flush)
     (gimp-progress-end)
     (gimp-context-pop)
    )
  )
  ) 
)

(script-fu-register "script-fu-random-masked"
                    _"Random Masked"
                    _"Draws a specified number of random points using the currently selected brush, with a mask."
                    "Charles Cave <charlesweb@optusnet.com.au>"
                    "Charles Cave"
                    "February 2008"
                    "RGB*, INDEXED*, GRAY*"
                    SF-IMAGE       "Image"         0
                    SF-DRAWABLE    "Drawable"      0
                    SF-DRAWABLE    "Mask"          -1

                    SF-ADJUSTMENT _"Iterations"     '(10 1 10000 10 100 0 0)
                    )

(script-fu-menu-register "script-fu-random-masked"
                         "<Image>/Filters")