;; (define (slow-pixellate image drawable block-size)
;;   (define (average-color drawable x1 y1 x2 y2)
;;     (define (->u8 x) (min (inexact->exact (round x)) 255))
;;     (let* ((width (- x2 x1))
;;            (height (- y2 y1))
;;            (size (* width height)))
;;       (let loop ((color #f)
;;                  (i 0))
;;         (if (< i size)
;;             (let* ((row (quotient i width))
;;                    (column (remainder i width))
;;                    (x (+ x1 column))
;;                    (y (+ y1 row))
;;                    (color2 (vector->list
;;                             (cadr (gimp-drawable-get-pixel drawable x y)))))
;;               (if color
;;                   (loop (map + color color2) (+ i 1))
;;                   (loop color2 (+ i 1))))
;;             (map (lambda (c) (->u8 (/ c size))) color)))))
;;   (let* ((width (car (gimp-drawable-width drawable)))
;;          (height (car (gimp-drawable-height drawable)))
;;          (rows (ceiling (/ height block-size)))
;;          (columns (ceiling (/ width block-size))))
;;     (do ((row 0 (+ row 1)))
;;         ((= row rows))
;;       (do ((column 0 (+ column 1)))
;;           ((= column columns))
;;         (let* ((x1 (* column block-size))
;;                (y1 (* row block-size))
;;                (x2 (min (+ x1 block-size) width))
;;                (y2 (min (+ y1 block-size) height)))
;;           (gimp-image-select-rectangle image CHANNEL-OP-REPLACE
;;                                        x1 y1
;;                                        block-size block-size)
;;           (gimp-context-set-foreground (average-color drawable x1 y1 x2 y2))
;;           (gimp-drawable-edit-fill drawable FILL-FOREGROUND))))))

(define (script-fu-pixellate image drawable blur-radius block-size)
  (gimp-image-undo-group-start image)
  (gimp-context-push)
  (gimp-context-set-defaults)
  (gimp-progress-set-text "Blurring image...")
  (plug-in-gauss RUN-NONINTERACTIVE image drawable blur-radius)
  (gimp-progress-set-text "Pixellating image...")
  ;; (slow-pixellate image drawable block-size)
  (plug-in-pixelize RUN-NONINTERACTIVE image drawable block-size)
  (gimp-context-pop)
  (gimp-image-undo-group-end image)
  (gimp-displays-flush))

(script-fu-register
 "script-fu-pixellate" ; function name
 "Pixellate" ; menu label
 "Turns an image into blocks" ; description
 "Vasilij Schneidermann" ; author
 "Copyright (C) 2020 Vasilij Schneidermann <mail@vasilij.de>" ; copyright notice
 "December 05, 2020" ; creation date
 "RGB*" ; supported image type
 SF-IMAGE "Image" FALSE
 SF-DRAWABLE "Drawable" FALSE
 SF-ADJUSTMENT "Blur radius" (sf-adjustment 100 0 500
                                            '(step-inc 10)
                                            '(page-inc 50)
                                            `(type ,SF-SLIDER))
 SF-ADJUSTMENT "Block size" (sf-adjustment 48 2 1024
                                           '(step-inc 2)
                                           '(page-inc 8)
                                           `(type ,SF-SLIDER)))

(script-fu-menu-register "script-fu-pixellate" "<Image>/Filters/Distorts")