; GIMP - The GNU Image Manipulation Program
; Copyright (C) 1995 Spencer Kimball and Peter Mattis
;
; 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/>.
; Allow command line usage of GIMP such as:
;
; gimp -i -b '(with-files "*.png" <body>)'
;
; where <body> is the code that handles whatever processing you want to
; perform on the files. There are three variables that are available within
; the <body>: 'basename', 'image', and 'layer'. The 'basename' is the
; name of the file with its extension removed, while the other two
; variables are self-explanatory. You basically write your code as though
; it were processing a single 'image' and the 'with-files' macro applies
; it to all of the files matching the pattern.
;
; For example, to invert the colors of all of the PNG files in the
; start directory:
;
; gimp -i -b '(with-files "*.png" (gimp-invert layer) \
; (gimp-file-save 1 image layer \
; (string-append basename ".png") \
; (string-append basename ".png") ))'
(define-macro (with-files pattern . body)
(let ((loop (gensym))
(filenames (gensym))
(filename (gensym)))
`(begin
(let ,loop ((,filenames (cadr (file-glob ,pattern 1))))
(unless (null? ,filenames)
(let* ((,filename (car ,filenames))
(image (catch #f (car (gimp-file-load RUN-NONINTERACTIVE
,filename
,filename ))))
(layer (if image (car (gimp-image-get-active-layer image)) #f))
(basename (catch ,filename
(unbreakupstr (butlast (strbreakup ,filename ".")) "."))))
(when image
,@body
(gimp-image-delete image)))
(,loop (cdr ,filenames))))
(gimp-quit 0))))