[Le coin des Questions.]

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;
; SCRIPT-FU-FLUTTERING-FLAG animates a flat image of a flag by blowing wind on it
; Copyright (c) 2006-2008  Tharsice Demand <www.td-e.com>
; version 1.00  2006.08.17  french
; version 1.10  2007.09.16  replaced set! with define for future compatibility,
;                          mast now optional, mast thickness can be adjusted,
;                          smoothing the hitch of the repetition of the images
; version 1.20  2007.10.25, migration to Gimp 2.4
; version 1.21  2008.04.05  indexed pictures without grey in their palette did not produce correct results, bug corrected
; version 1.22  2008.11.29  improvement of the flag edges when the bg is transparent, thx Peter PKHG from NL
;
;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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
;
;Copy of the license at http://td-e.com/site/gpl.php

(define (addReplaceToName image)
  (let* (
    (layerNr 0)
    (tmp 0)
    (teller 0)
    (layerName "vlagPKHG ")
    (flagLayersVec (cadr (gimp-image-get-layers image)))
    (nrOfLayers (vector-length flagLayersVec))
    )   
    (while (< teller nrOfLayers)
      (set! layerNr (vector-ref flagLayersVec teller))
      (set! tmp (string-append "vlagNEU" (number->string teller) "(replace)"))
      (gimp-drawable-set-name layerNr tmp)
     
      (set! teller  (+ teller 1))
      )   
    )
  )


(define (script-fu-fluttering-flag image flatflag layertotal ripple windstrength formf mthickness hitch skycolor mastcolorl mastcolorr formrand skytrans irregular)
  (let*
    (
      (old-fg (car (gimp-context-get-foreground)))
      (old-bg (car (gimp-context-get-background)))
      (owidth (car (gimp-image-width image)))
      (oheight (car (gimp-image-height image)))
      (borderx (/ owidth 10))
      (bordery borderx)
      (mastlef (* borderx (- 0.80 (/ (* 0.60 mthickness) 100))))
      (mastrig (* borderx (+ 0.80 (/ (* 0.60 mthickness) 100))))
      (width (+ owidth (* 2 borderx)))
      (height (+ oheight (* 2 bordery)))
      (snx (/ ripple 10)) ;5..150 default to 25 -> 0.5..15 defaults to 2.5
      (sny 0.1) ;~ 0.1
      (flutterx (/ owidth (- layertotal 1))) ;dependent on num of layers
      (fluttery (/ oheight (- layertotal 1)))
      (layerindex 0)
      (formseed (if (= formrand TRUE) (rand 4294967295) (* formf 10000000))) ;(2^32-1 = 4 294 967 295)
      (fgcolormax hitch)
      (fgcolormin 0)
      (fgcolorval 0)
      (fgcolorvalar '(0 0 0))
      (attenmax (+ 0.40 (/ (* hitch 0.59) 255)))
      (attenmin 0.40)
      (attenval 0.40)
      ;---factors for smoothing the repetition---
      ; y = ax^2 + bx + c
      ; a = 4 (max - min) / layerindex^2  ; b= 4 (min -max) / layerindex  ; c= max
      ;
      ; attenuation
      ; max = 0.95  ; min = 0.40  ; a = 2.20 / layertotal^2 ;  b = - 2.20 / layertotal ;  c = 0.95
      ;
      ; foreground color
      ; max = 160  ; min = 0  ; a = 640 / layertotal^2 ;  b = - 640 / layertotal ;  c = 160
      ;
      (attena (/ (* 4 (- attenmax attenmin)) (* layertotal layertotal)))
      (attenb (/ (* 4 (- attenmin attenmax)) layertotal))
      (attenc attenmax)
      (fgcolora (/ (* 4 (- fgcolormax fgcolormin)) (* layertotal layertotal)))
      (fgcolorb (/ (* 4 (- fgcolormin fgcolormax)) layertotal))
      (fgcolorc fgcolormax)
    )
    (srand (realtime))
    (gimp-image-undo-group-start image)

    (gimp-context-set-background '(255 255 255))
    (define flatflagf (car (gimp-image-flatten image)))

    ;---if not an RGB, make one---
    (if (= (car (gimp-drawable-is-rgb flatflagf)) 0) (gimp-image-convert-rgb image))

    ;---draw 1 pixel border around the flag---
    (if (= irregular FALSE)
      (begin
        (define (gen-contour-array owidth oheight)
          (let*
            ((contourarray (cons-array 10 'double)))
            (aset contourarray 0 0)
            (aset contourarray 1 0)
            (aset contourarray 2 owidth)
            (aset contourarray 3 0)
            (aset contourarray 4 owidth)
            (aset contourarray 5 oheight)
            (aset contourarray 6 0)
            (aset contourarray 7 oheight )
            (aset contourarray 8 0)
            (aset contourarray 9 0)
            contourarray
          )
        )
        (gimp-context-set-foreground '(128 128 128))
        (gimp-context-set-brush "Circle (01)")
        (gimp-paintbrush-default flatflagf 10 (gen-contour-array owidth oheight))
      )
    )
    (gimp-context-set-foreground '(0 0 0))

    ;---add a 10% border---
    (gimp-image-resize image width height borderx bordery)
    (gimp-layer-resize-to-image-size flatflagf)

    (if (= (car (gimp-selection-is-empty image)) 1) (gimp-selection-all image))
    (define flag-select (car (gimp-selection-save image)))
    (gimp-selection-none image)

    ;---make the added border transparent---
    (gimp-fuzzy-select flatflagf 1 1 10 0 FALSE FALSE 0.0 0)
    (gimp-layer-add-alpha flatflagf)
    (gimp-edit-clear flatflagf)
    (gimp-selection-none image)

    ;---draw the mast layer---
    (define mastlayer (car (gimp-layer-new image width height 1 "mast" 100 0)))
    (gimp-layer-add-alpha mastlayer)
    (gimp-drawable-fill mastlayer 3)
    (gimp-image-add-layer image mastlayer 0)

    (gimp-context-set-foreground mastcolorl)
    (gimp-context-set-background mastcolorr)

    (define (gen-mast-array borderx bordery width height mastlef mastrig)
      (let*
        ((mastarray (cons-array 10 'double)))
        (aset mastarray 0 mastlef)
        (aset mastarray 1 (* bordery 0.5))
        (aset mastarray 2 mastrig)
        (aset mastarray 3 (* bordery 0.5))
        (aset mastarray 4 mastrig)
        (aset mastarray 5 height)
        (aset mastarray 6 mastlef)
        (aset mastarray 7 height )
        (aset mastarray 8 mastlef)
        (aset mastarray 9 (* bordery 0.5))
        mastarray
      )
    )

    (define mastsel (gen-mast-array borderx bordery width height mastlef mastrig))
    (gimp-free-select image
                      10
                      mastsel
                      CHANNEL-OP-REPLACE
                      0
                      0
                      0.0)
    (if (>= mthickness 10)
      (gimp-edit-blend
        mastlayer FG-BG-RGB-MODE NORMAL-MODE GRADIENT-LINEAR
        100 0 REPEAT-NONE FALSE FALSE
        0 0 FALSE
        mastlef (/ height 2) mastrig (/ height 2)
      )
    )
    (gimp-selection-none image)

    ;---draw the sky layer---
    (if (= skytrans TRUE)
      (begin
        (define skylayer (car (gimp-layer-new image width height 1 "sky" 0 0)))
        (gimp-layer-add-alpha skylayer)
      )
      (begin
        (define skylayer (car (gimp-layer-new image width height 1 "sky" 100 0)))
        (gimp-layer-add-alpha skylayer)
        (gimp-context-set-foreground skycolor)
        (gimp-drawable-fill skylayer 0)
      )
    )
    (gimp-image-add-layer image skylayer 0)

    ;---draw the flutter layer---
    (define flutterlayer (car (gimp-layer-new image width height 1 "flutter" 100 0)))
    (gimp-drawable-fill flutterlayer 3)
    (gimp-image-add-layer image flutterlayer 0)

    (plug-in-solid-noise 1 image flutterlayer 1 0 formseed 1 snx sny)
    (plug-in-gauss 1 image flutterlayer 5 5 0)
    (plug-in-c-astretch 1 image flutterlayer)
    (gimp-selection-load flag-select)


    (while (< layerindex layertotal)
      ;---stabilize flag at mast---
      (define fluttercopy (car (gimp-layer-copy flutterlayer 1)))
      (gimp-drawable-set-name fluttercopy "fluttercopy")
      (gimp-image-add-layer image fluttercopy -1)

      (define stablemast (car (gimp-layer-new image width height 1 "stablemast" 100 0)))
      (gimp-image-add-layer image stablemast -1)
      (define stablemastmask (car (gimp-layer-create-mask stablemast 0)))
      (gimp-layer-add-mask stablemast stablemastmask)
      (gimp-context-set-foreground '(128 128 128))
      (gimp-drawable-fill stablemast 0)

      ;---smoothing the repetition---
      ; y = ax ^ 2 + bx + c
      (set! attenval  (+ (+ (* attena  (* layerindex layerindex)) (* attenb  layerindex)) attenc))
      (set! fgcolorval (+ (+ (* fgcolora (* layerindex layerindex)) (* fgcolorb layerindex)) fgcolorc))
      (set! fgcolorvalar (list fgcolorval fgcolorval fgcolorval))

      (gimp-context-set-foreground fgcolorvalar)
      (gimp-context-set-background '(255 255 255))

      (gimp-edit-blend
          stablemastmask FG-BG-RGB-MODE NORMAL-MODE GRADIENT-LINEAR
          100 0 REPEAT-NONE TRUE FALSE
          0 0 FALSE
          (* borderx 0.80) (/ height 2) (* width attenval) (/ height 2))
      (define fluttermodif (car (gimp-image-merge-down image stablemast 1)))
      (gimp-drawable-set-name fluttermodif "fluttermodif")

      ;---blow onto the flag---
      (define flagcopy (car (gimp-layer-copy flatflagf 1)))
      (gimp-image-add-layer image flagcopy -1)

      (plug-in-bump-map 1 image flagcopy fluttermodif 135 45 10 0 0 0 0 1 0 2)
      (plug-in-displace 1 image flagcopy (/ (* owidth windstrength) 400) (/ (* oheight windstrength) 100) 1 1 fluttermodif fluttermodif 1)
      (gimp-image-remove-layer image fluttermodif)
      (gimp-drawable-offset flutterlayer 1 0 flutterx fluttery)

      ;---add the sky---
      (define skycopy (car (gimp-layer-copy skylayer 1)))
      (gimp-image-add-layer image skycopy -1)
      (gimp-image-lower-layer image skycopy)
      (gimp-image-merge-down image flagcopy 1)

      ;---add the mast---
      (define mastcopy (car (gimp-layer-copy mastlayer 1)))
      (gimp-image-add-layer image mastcopy -1)
      (gimp-image-merge-down image mastcopy 1)

      (set! layerindex (+ layerindex 1))
    )

    (gimp-image-remove-layer image mastlayer)
    (gimp-image-remove-layer image skylayer)
    (gimp-image-remove-layer image flutterlayer)
    (gimp-image-remove-layer image flatflagf)
    (gimp-context-set-foreground old-fg)
    (gimp-context-set-background old-bg)

    (gimp-selection-none image)
    (gimp-image-remove-channel image flag-select)
    (gimp-image-convert-indexed image 0 0 255 0 0 "")
    ;---line below added in case of transparent sky---
    (if (= skytrans TRUE) (addReplaceToName image))
    (gimp-image-undo-group-end image)
    (gimp-displays-flush)
  )
)
(script-fu-register "script-fu-fluttering-flag"
                    "<Image>/Filters/Animation/Drapeau flottant..."
                    "Genere une image animee d'un drapeau flottant au vent
contenant un nombre choisi de calques.
Lors de la sauvegarde en tant que gif, cochez les options suivantes
- Enregistrer en tant qu'animation
- Boucle infinie
- Delai entre les images = 100 ms.
- Disposition des images = Une image par calque
Une ondulation elevee genere un drapeau tres ondule.
Le parametre Vent a une influence sur l'amplitude du mouvement.
Le facteur de forme peut etre un nombre pris au hasard ou un nombre defini.
Des valeurs recommandees sont 5, 14, 134, 199."
                    "Tharsice Demand <td-e.com>"
                    "Tharsice Demand"
                    "2008.11.29"
                    "RGB RGBA GRAY GRAYA INDEXED INDEXEDA"
                    SF-IMAGE      "Image" 0
                    SF-DRAWABLE  "Drawable" 0
                    SF-ADJUSTMENT "Nombre de calques"                  '(8 4 32 1 4 0 1)
                    SF-ADJUSTMENT "Ondulation"                        '(30 5 150 1 5 0 1)
                    SF-ADJUSTMENT "Vent"                              '(5 1 9 1 2 0 1)
                    SF-ADJUSTMENT "Facteur de forme"                  '(5 1 400 1 10 0 1)
                    SF-ADJUSTMENT "Epaisseur du mat"                  '(60 5 100 1 10 0 1)
                    SF-ADJUSTMENT "Reduction des saccades"            '(1 1 255 1 10 0 1)
                    SF-COLOR      "Couleur du ciel"                    '(128 170 255)
                    SF-COLOR      "Couleur gauche du degrade du mat"  '(255 240 176)
                    SF-COLOR      "Couleur droite du degrade du mat"  '(80 48 16)
                    SF-TOGGLE    "Nombre au hasard pour le facteur de forme" FALSE
                    SF-TOGGLE    "Fond transparent au lieu de la couleur du ciel" FALSE
                    SF-TOGGLE    "Drapeau de forme irreguliere non rectangulaire" FALSE
)