;
; High-pass filter for sharpening script for GIMP 2.4
; Copyright (C) 2008 Aurélien Calonne <aurelcalonne@free.fr>
; --------------------------------------------------------------------
;
; 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 3 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, see <http://www.gnu.org/licenses/>.
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;.


(define (script-fu-high-pass InImage InLayer InBlur InOpacity InFlatten)
  ; Save history
  (gimp-image-undo-group-start InImage)
  ; Create two layer copy
  (let*
      (
       (Copy1Layer (car (gimp-layer-copy InLayer TRUE)))
       (Copy2Layer (car (gimp-layer-copy InLayer TRUE)))
       )
    (gimp-image-add-layer InImage Copy1Layer 0)
    (gimp-image-add-layer InImage Copy2Layer 0)
    ; Apply gaussian blur, invert layer and merge
    (plug-in-gauss 1 InImage Copy2Layer InBlur InBlur 1)
    (gimp-invert Copy2Layer)
    (gimp-layer-set-opacity Copy2Layer 50)
    (let*
	(
	 (merged (car (gimp-image-merge-down InImage Copy2Layer 0)))
	 )      
      ; Set level and layer opacity
      (gimp-levels merged 0 100 155 1.0 0 255)
      (gimp-layer-set-mode merged OVERLAY-MODE)
      (gimp-layer-set-opacity merged InOpacity)
      ; Flatten image if needed
      (cond
       ((= InFlatten TRUE)
	(begin
	  (gimp-image-merge-down InImage merged CLIP-TO-IMAGE)
	  )
	)
       ((= InFlatten FALSE)
	(begin
	  (gimp-drawable-set-name merged "High Pass")
	  )
	)       
       )
      )
    )
  ; Finish
  (gimp-displays-flush)
  (gimp-image-undo-group-end InImage)
  )


(script-fu-register "script-fu-high-pass"
 _"_High Pass Filter"
 _"Apply a high pass filter"
 "Aurélien Calonne"
 "2008, Aurélien Calonne"
 "20th December 2008"
 "RGB* GRAY*"
 SF-IMAGE "Image" 0
 SF-DRAWABLE "Drawable" 0
 SF-ADJUSTMENT "Blur Quantity" '(5 1 30 1 1 0 0)
 SF-ADJUSTMENT "Layer Opacity" '(100 1 100 1 1 0 0)
 SF-TOGGLE _"Flatten Image" FALSE
 )

(script-fu-menu-register "script-fu-high-pass"
                         "<Image>/Script-Fu/Enhance")