;*******************************************************************************
;* Copyright (c) 2005 IBM Corporation and others.
;* All rights reserved. This program and the accompanying materials 
;* are made available under the terms of the Common Public License v1.0
;* which accompanies this distribution, and is available at
;* http://www.eclipse.org/legal/cpl-v10.html
;* 
;* Contributors:
;*     IBM Corporation - initial API and implementation
;*******************************************************************************/

; Scale all images matching a given pattern by the provided scaling factor.  An html 
; file containing links to the original as well as image tags will be created.
(define (batch-scale pattern factor htmlfile)
  (set! output (fopen htmlfile "w"))
  (let* ((filelist (cadr (file-glob pattern 1))))
    (while filelist
           (let* ((filename (car filelist))
                  (image (car (gimp-file-load RUN-NONINTERACTIVE filename filename)))
                  (newfilename (string-append "T_" filename))
                  )
             (pre-process image)
             (set! dimensions (scale-by-factor image factor))
             (post-process image)
             (make-html output filename newfilename dimensions)
             
             (set! drawable (car (gimp-image-get-active-drawable image)))
             (gimp-file-save RUN-NONINTERACTIVE image drawable newfilename newfilename)
             (gimp-image-delete image)
             )
           (set! filelist (cdr filelist))
           )
    (fclose output)
    ))

; Perform pre-scaling processing to the image.  Currently a no-op.
(define (pre-process image) 
  )
  
; Perform post-scaling processing to the image.  Currently applies an unsharpen mask to 
; the image.
(define (post-process image) 
  (gimp-image-undo-group-start image)
  (set! drawable (car (gimp-image-get-active-drawable image)))
  (plug-in-unsharp-mask 1 image drawable 1.0 0.3 0)
  (gimp-image-undo-group-end image)
  (gimp-displays-flush)
  )

; Write an href/image pair to the html file.
(define (make-html output link thumbnail dimensions)
  (fwrite "<a href=\"" output)
  (fwrite link output)
  (fwrite "\">" output)
  (fwrite "<img src=\"" output)
  (fwrite thumbnail output)
  (fwrite "\" width=\"" output)
  (fwrite (number->string (car dimensions) 10) output)
  (fwrite "\" height=\"" output)
  (fwrite (number->string (cadr dimensions) 10) output)
  (fwrite "\"></a>" output)
  )

; Scale the image by the given factor.  Returns the new width and height.
(define (scale-by-factor image factor)
  (gimp-image-undo-group-start image)
  (gimp-image-flatten image)
  (set! width  (* (car (gimp-image-width  image)) factor))
  (set! height (* (car (gimp-image-height image)) factor))
  (gimp-image-scale image width height)
  (gimp-image-undo-group-end image)
  (gimp-displays-flush)
  (list width height)
  )

; Registers the script with The Gimp.
(script-fu-register 
 "batch-scale"
 "<Toolbox>/Xtns/Script-Fu/Scale By Factor"
 "Scale a batch of images by a certain factor and write an html file."
 "Kim Horne <kim@pookzilla.com>"
 "IBM Corporation"
 "12/02/2005"
 ""
 SF-VALUE "File pattern"                 "*.JPG"
 SF-VALUE "Scaling factor (float)"       ".25"
 )