; selection_grow_directional.scm
; by Rob Antonishen
; http://ffaat.pointclark.net

; Version 1.1 (20090716)

; Changes:
; 1.1 using new image to avoid the flickering of the layers dialog.
;     made grow code generic to eliminate duplication
;     added new menu registers for 10 pixel grows.

; Description
; Grows the selection orthagonally by one pixel

; License:
;
; 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.
;
; The GNU Public License is available at
; http://www.gnu.org/copyleft/gpl.html

(define (selection-grow-base img direction amt)  ; direction 0 = HORIZONTAL, 1 = VERTICAL, amt can be -ve
  (let* 
    ((active (car (gimp-image-get-active-drawable img)))
     (width (car (gimp-image-width img)))
     (height (car (gimp-image-height img)))
     (buffer (car (gimp-edit-named-copy (car (gimp-image-get-selection img)) "growselbuffer")))
     (imgWork (car (gimp-edit-named-paste-as-new buffer)))
     (layerWork (car (gimp-image-get-active-layer imgWork)))
     (xMove (if (equal? direction HORIZONTAL) (/ amt (abs amt)) 0)) ; -1 or +1
     (yMove (if (equal? direction VERTICAL) (/ amt (abs amt)) 0)) ; -1 or +1    
     (layerDup 0)
     (chanWork 0)
     (count 1))

    (while (<= count (abs amt))
      (set! layerDup (car (gimp-layer-copy layerWork FALSE)))
      (gimp-image-add-layer imgWork layerDup 0)   ;duplicated layer 
      (gimp-layer-translate layerDup (* xMove count) (* yMove count))   ; move
      (gimp-layer-set-mode layerDup LIGHTEN-ONLY-MODE)  ; lighten keeps feathering equal to max of two layers
      (set! count (+ count 1)))

    (gimp-image-merge-visible-layers imgWork CLIP-TO-IMAGE)
    (set! chanWork (car (gimp-channel-new-from-component imgWork GRAY-CHANNEL "temp")))

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

    (gimp-selection-none img) ; must do a clear then add because replace is broken in channel-combine-masks
    (gimp-channel-combine-masks (car (gimp-image-get-selection img)) chanWork CHANNEL-OP-ADD 0 0)

    (gimp-image-undo-group-end img)
    (gimp-displays-flush)

    ;clean up
    (gimp-buffer-delete buffer)
    (gimp-image-delete imgWork)))


(define (selection-grow-right img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img HORIZONTAL 1))))

(script-fu-register "selection-grow-right" "<Image>/Select/Grow Directional/Grow Right"
					          "Grows the current selection 1 px right."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)				

(define (selection-grow-right-10 img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img HORIZONTAL 10))))

(script-fu-register "selection-grow-right-10" "<Image>/Select/Grow Directional/Grow Right 10"
					          "Grows the current selection 10 px right."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)			

(define (selection-grow-left img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img HORIZONTAL -1))))

(script-fu-register "selection-grow-left" "<Image>/Select/Grow Directional/Grow Left"
					          "Grows the current selection 1 px left."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)				

(define (selection-grow-left-10 img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img HORIZONTAL -10))))

(script-fu-register "selection-grow-left-10" "<Image>/Select/Grow Directional/Grow Left 10"
					          "Grows the current selection 10 px left."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)			

(define (selection-grow-down img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img VERTICAL 1))))

(script-fu-register "selection-grow-down" "<Image>/Select/Grow Directional/Grow Down"
					          "Grows the current selection 1 px down."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)				

(define (selection-grow-down-10 img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img VERTICAL 10))))

(script-fu-register "selection-grow-down-10" "<Image>/Select/Grow Directional/Grow Down 10"
					          "Grows the current selection 10 px down."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)			

(define (selection-grow-up img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img VERTICAL -1))))

(script-fu-register "selection-grow-up" "<Image>/Select/Grow Directional/Grow Up"
					          "Grows the current selection 1 px up."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)				

(define (selection-grow-up-10 img inLayer)
  (let* () (if (equal? (car (gimp-selection-is-empty img)) FALSE) (selection-grow-base img VERTICAL -10))))

(script-fu-register "selection-grow-up-10" "<Image>/Select/Grow Directional/Grow Up 10"
					          "Grows the current selection 10 px up."
					          "Rob Antonishen" "Rob Antonishen" "June 2009" "RGB* GRAY*"
					          SF-IMAGE      "image"      0
					          SF-DRAWABLE   "drawable"   0)