; The GIMP -- an image manipulation program
; Copyright (C) 1995 Spencer Kimball and Peter Mattis
; 
; Check Tile --- create a check tile pattern image
; Copyright (C) 2001 Iccii <iccii@hotmail.com>
; 
; --------------------------------------------------------------------
; version 0.1  2001/12/08 Iccii <iccii@hotmail.com>
;     - Initial relase
; version 0.2 2004/09 Raymond Ostertag
;     - Ported to Gimp2
; --------------------------------------------------------------------
;     Reference Web site
; http://www.sx.sakura.ne.jp/~koki/ex-21-30/example25.html
; --------------------------------------------------------------------
; 
; 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 (script-fu-checktile
		tile-size	; Size of one tile
		ntiles		; Number of tiles (if ntiles is n, create nxn pattern)
		band-width	; Colored band width in pixel
		layer-mode	; Layer mode for each layers
		color-balance	; Balance for coloring
		rand-seed	; Random seed (if rand-seed isn't -1, it's user specific)
		mirror?		; Create symmenterical pattern?
		same-width?	; Fix band width or add width +-50% ?
	)

  (define (modulo n m)
    (fmod n m))

  (define (get-layer-mode mode)
    (cond                                     ; bg-color: 0 = white, 1 = Black
      ((= mode 0) (list MULTIPLY-MODE     0)) ; 0
      ((= mode 1) (list SCREEN-MODE       1)) ; 1
      ((= mode 2) (list DIFFERENCE-MODE   1)) ; 1 (or 0)
      ((= mode 3) (list ADDITION-MODE     1)) ; 1
      ((= mode 4) (list DARKEN-ONLY-MODE  0)) ; 0
      ((= mode 5) (list LIGHTEN-ONLY-MODE 1)) ; 1
      ('else      (list NORAML-MODE       0)) ))

  (let* (
         (seed (if (= rand-seed -1) (modulo (realtime) 32768) rand-seed))
         (old-fg (car (gimp-palette-get-foreground)))
         (old-bg (car (gimp-palette-get-background)))
         (width (max tile-size band-width))
         (height (max tile-size band-width))
         (img (car (gimp-image-new width height RGB)))
         (layer (car (gimp-layer-new img width height RGB-IMAGE
                                     (string-append "Check Pattern #" (number->string seed))
                                     100 NORMAL-MODE)))
         (tile-length-limit (if (equal? mirror? TRUE) (/ tile-size 2) tile-size))
         (count 0)
        ) ; end variable definition

    (srand seed)
    (gimp-image-undo-disable img)
    (gimp-palette-set-background '(0 0 0))
    (gimp-image-add-layer img layer -1)
    (gimp-drawable-fill layer WHITE-FILL)

    (while (< count tile-length-limit)
      (let* ((band-step (if (equal? same-width? TRUE)
                            band-width
                            (+ band-width (* (- (rand band-width) (/ band-width 2))
                                             0.5)))))	;; band-width+-50%
        (gimp-rect-select img 0 count width (+ count band-step)
                          CHANNEL-OP-REPLACE FALSE 0)
        (gimp-palette-set-foreground (list (rand 256) (rand 256) (rand 256)))
        (gimp-edit-fill layer (if (< (rand 100) (- 100 color-balance))		; 0-100%
                                  (if (= (cadr (get-layer-mode layer-mode)) 0)
                                      WHITE-FILL
                                      BACKGROUND-FILL)
                                  FOREGROUND-FILL))
        (gimp-selection-none img)
        (set! count (+ count band-step))))

    (if (equal? mirror? TRUE)
        (begin
          (gimp-rect-select img 0 0 width (/ height 2) CHANNEL-OP-REPLACE FALSE 0)
          (gimp-edit-copy layer)
          (gimp-rect-select img 0 (/ height 2) width height CHANNEL-OP-REPLACE FALSE 0)
          (gimp-floating-sel-anchor (car (gimp-edit-paste layer 0)))
          (gimp-rect-select img 0 (/ height 2) width height CHANNEL-OP-REPLACE FALSE 0)
          (gimp-flip layer ORIENTATION-VERTICAL)
          (gimp-floating-sel-anchor (car (gimp-image-get-floating-sel img)))
          (gimp-selection-none img)))

    (set! layer-copy (car (gimp-layer-copy layer TRUE)))
    (gimp-image-add-layer img layer-copy -1)
    (gimp-layer-set-mode layer-copy (car (get-layer-mode layer-mode)))
    (plug-in-rotate 1 img layer-copy 1 FALSE)
    (set! result-layer (car (gimp-image-merge-down img layer-copy EXPAND-AS-NECESSARY)))
    (plug-in-tile 1 img result-layer (* width ntiles) (* height ntiles) FALSE)

    (gimp-palette-set-foreground old-fg)
    (gimp-palette-set-background old-bg)
    (gimp-image-undo-enable img)
    (gimp-display-new img)
))

(script-fu-register
  "script-fu-checktile"
  "<Toolbox>/Xtns/Script-Fu/Patterns/Check Tile..."
  "Create an check tile pattern image"
  "Iccii <iccii@hotmail.com>"
  "Iccii"
  "Dec, 2001"
  ""
  SF-ADJUSTMENT "Tile Size"         '(100 2 1000 1 1 0 1)
  SF-ADJUSTMENT "Number of Tiles"   '(3 1 100 1 1 0 1)
  SF-ADJUSTMENT "Width of Bands"    '(2 1 100 1 1 0 1)
  SF-OPTION     "Layer Mode"        '("Multiply" "Screen" "Difference"
                                      "Addition" "Darken Only" "Lighten Only")
  SF-ADJUSTMENT "Color Balance (%)" '(60 0 100 1 1 0 0)
  SF-ADJUSTMENT "Random Seed"       '(-1 -1 32767 1 1 0 1)
  SF-TOGGLE     "Mirror"            TRUE
  SF-TOGGLE     "Same Band Width"   FALSE
)