; Original version : Elias <elias@users.sf.net>
;
; 0.1a Raymond Ostertag 2004/10
;  - changed menu entry

; vim: expandtab : tabstop=3 : shiftwidth=3 : smarttab

; plot a pixel with color (r, g, b) at position (x, y) to drawable (draw)
(define (plot draw x y r g b)
   (set! pixel (cons-array 3 'byte))
   (aset pixel 0 r)
   (aset pixel 1 g)
   (aset pixel 2 b)
   (gimp-drawable-set-pixel draw x y 3 pixel)
   (gimp-drawable-update draw x y 1 1)
)

(define (layers-to-grid orig-image orig-draw width height x-gap y-gap max-line)
   
   (set! n (car (gimp-image-get-layers orig-image)))
   (set! grid-width (if (< n max-line) n max-line))
   (set! grid-height (trunc (/ (- (+ n grid-width) 1) grid-width)))
   (set! new-width (- (* grid-width (+ width x-gap)) x-gap))
   (set! new-height (- (* grid-height (+ height y-gap)) y-gap))

   ; create new image, with layer and drawable
   (set! image (car (gimp-image-new new-width new-height RGB)))
   (set! layer (car (gimp-layer-new image new-width new-height RGBA-IMAGE "Layer" 100 NORMAL-MODE)))
   (gimp-image-add-layer image layer -1)
   (set! draw (car (gimp-image-get-active-drawable image)))

   (gimp-edit-clear draw)

   (set! layers (cadr (gimp-image-get-layers orig-image)))
   (set! i n)

   (set! y 0)
   (while (and (< y new-height) (> i 0))
      (set! x 0)
      (while (and (< x new-width) (> i 0))
         (set! i (+ -1 i))
         (gimp-image-set-active-layer orig-image (aref layers i))
         (set! orig-draw (car (gimp-image-get-active-drawable orig-image)))

         ; copy rect out of orig
	      (gimp-rect-select orig-image 0 0 width height REPLACE 0 0)
	      (gimp-edit-copy orig-draw)
	      (gimp-selection-none orig-image)

         ; paste into current layer
	      (set! sel (car (gimp-edit-paste draw 1)))
	      (gimp-layer-set-offsets sel x y)
	      (gimp-floating-sel-anchor sel)

         (set! x (+ x (+ width x-gap)))
	   )
	   (set! y (+ y (+ height y-gap)))
   )
  
   (gimp-display-new image)
)

(define (grid-to-layers orig-image orig-draw width height x-gap y-gap max-line)
   ; create new image
   (set! image (car (gimp-image-new width height RGB)))
   (set! orig-width (car (gimp-image-width orig-image)))
   (set! orig-height (car (gimp-image-height orig-image)))

   (gimp-image-undo-group-start orig-image)

   (set! y 0)
   (while (< y orig-height)
      (set! x 0)
      (while (< x orig-width)

         ; create, add and activate layer
         (set! layer (car (gimp-layer-new image width height RGBA-IMAGE "Layer" 100 NORMAL-MODE)))
         (gimp-image-add-layer image layer -1)
         (gimp-image-set-active-layer image layer)
         (set! draw (car (gimp-image-get-active-drawable image)))

         (gimp-edit-clear draw)

         ; copy rect out of orig
	      (gimp-rect-select orig-image x y width height REPLACE 0 0)
	      (gimp-edit-copy orig-draw)
	      (gimp-selection-none orig-image)

         ; paste into current layer
	      (set! sel (car (gimp-edit-paste draw 1)))
	      (gimp-layer-set-offsets sel 0 0)
	      (gimp-floating-sel-anchor sel)

         (set! x (+ (+ x width) x-gap))
	   )
	   (set! y (+ (+ y height) y-gap))
   )

   (gimp-image-undo-group-end orig-image)
   (gimp-display-new image)
)

(define (script-fu-layergrid orig-image orig-draw width height x-gap y-gap max-line direction)
   (if (= direction 0)
      (layers-to-grid orig-image orig-draw width height x-gap y-gap max-line)
      (grid-to-layers orig-image orig-draw width height x-gap y-gap max-line)
   )
)

(script-fu-register "script-fu-layergrid"
   _"<Image>/Script-Fu/Utils/LayerGrid..."
	"Transforms layers into a grid, or a grid into layers."
	"Elias <elias@users.sf.net>"
	""
	"2003-11-13"
	"*"
	SF-IMAGE "Input Image" 0
	SF-DRAWABLE "Input Drawable" 0
	SF-ADJUSTMENT "Picture Width" '(32 1 1000 1 10 0 1)
	SF-ADJUSTMENT "Picture Height" '(32 1 1000 1 10 0 1)
	SF-ADJUSTMENT "Gap Width" '(0 0 1000 1 10 0 1)
	SF-ADJUSTMENT "Gap Height" '(0 0 1000 1 10 0 1)
	SF-ADJUSTMENT "Max pictures in row " '(8 1 1000 1 10 0 1)
   SF-OPTION     "Direction" '("Layers->Grid" "Grid->Layers")
)