;; layer-align.scm -*-scheme-*-
;; adapted from 
;; file-place.scm -*-scheme-*-
;; see file-place for more info

;; when I'm done I'll put this in the Public Domain
;; until then this is Copyright Alan Horkan
;; you may not modify or distribute it, for personal use only.  
;; feel free to remind me.  

;; TODO NEEDS more testing and a lot of cleanup but it works

(define (script-fu-layer-align image drawable horizontal x-offset vertical y-offset)  
  (let* (
;;    (image2 (car (gimp-file-load 1 file2 file2)))

    (height2 (car (gimp-drawable-height drawable)))
    (width2 (car (gimp-drawable-width drawable)))

    (height (car (gimp-image-height image)))
    (width (car (gimp-image-width image)))

    ;; layer type is based on the current image, not the layer being placed
    (layer-type (car (gimp-drawable-type-with-alpha drawable)))
   
    ;; lazy fix(es) for gimp 2, makes keeping back compatibility easier 
    (RGBA_IMAGE RGBA-IMAGE) ; no longer needed
    )

    (gimp-image-undo-group-start image) ;; make undoable

    ;; flatten the image in case it has more than one layer
;;    (gimp-image-flatten image2)
    ;; now get the drawable
;;    (set! drawable2 (car (gimp-image-get-active-drawable image2)))

    ;; create a new layer, set the file name as the layer name  
;;    (set! layer-one (car (gimp-layer-new image width2 height2 layer-type layer-name 100 NORMAL)))

;; really should check if it is a layer first
(set! layer-one drawable)


    ;; offsets for the layer
    (set! x-offset x-offset)
    (set! y-offset y-offset)

;; TODO rewrite to use cond instead of if statement
    ;; Horizontal
    ;; current position + x-offset (same as top edge + x-offset) 
    (if (= 0 horizontal) (set! x-offset (+ x-offset)))
    ;; left edge + x-offset (same as current position + x-offset) 
    (if (= 1 horizontal) (set! x-offset (+ x-offset)))
    ;; centre, the usual defualt.  same as cut & paste or drag & drop layer
    (if (= 2 horizontal) (set! x-offset (+ x-offset (/ (- width width2) 2))))
    ;; right edge
    (if (= 3 horizontal) (set! x-offset (+ x-offset (- width width2))))     

    ;; Vertical 
    ;; current position + x-offset (same as top edge + y-offset) 
    (if (= 0 vertical) (set! y-offset (+ y-offset)))
    ;; top edge + y-offset (same as current position + y-offset) 
    (if (= 1 vertical) (set! y-offset (+ y-offset)))
    ;; centre, the usual defualt.  same as cut & paste or drag & drop layer
    (if (= 2 vertical) (set! y-offset (+ y-offset (/ (- height height2) 2))))
    ;; bottom edge
    (if (= 3 vertical) (set! y-offset (+ y-offset (- height height2))))     

    ;; offset the layer, finally
    (gimp-layer-set-offsets layer-one x-offset y-offset)

    (gimp-image-undo-group-end image)
    (gimp-displays-flush) 
    ) ; close the let statement
)



(set! menu-item _"<Image>/Layer/Align Layer...") ; old name

(script-fu-register "script-fu-layer-align"
    menu-item
;; Help Description
"Takes the current layer and re aligns it.  
Alignment is based on the image size.  " 

    "Alan Horkan.  " ; author(s)
;; when finished will be Public Domain.  not yet
    "Alan Horkan, 2004.  Copyright " ; rights  
    "2004 08 12 UTC" ; date
    "" ; supports all image types  
    SF-IMAGE "Image" 0
    SF-DRAWABLE "Drawable" 0 ; is this even necessary? 

    ;; Offsets.  
    ;; Horizontal:  [ Current Position     ] [ 0   ] pixels
    ;;   Vertical:  [ Current Position     ] [ 0   ] pixels
    SF-OPTION _"Horizontal"  '(
        ;_"None                                              "  ; 0
        _"Current Position                                  "  ; 0
        _"Left Edge                                         "  ; 1
        _"Centre                                            "  ; 2
        _"Right Edge                                        "  ; 3
    )
    SF-ADJUSTMENT _"pixels" '(0 -1000 1000 1 10 0 1) ; no slider 
    SF-OPTION _"Vertical"  '(
        ;_"None                                              "  ; 0
        _"Current Position                                  "  ; 0
        _"Top Edge                                          "  ; 1
        _"Centre                                            "  ; 2
        _"Bottom Edge                                       "  ; 3
    )     
    SF-ADJUSTMENT _"pixels" '(0 -1000 1000 1 10 0 1) ; no slider
)

;; TODO I have no idea if Current Position is any different from Left/Top Edge
;; Need to find out, documentation was too vague and cannot tell from testing