(define (scale-to-max-fileglob
file-pattern
out-dir
newmax
)
(let* ((filelist (cadr (file-glob file-pattern 1))))
(while (not (null? filelist))
(let* ((in-file (car filelist))
(image (car (gimp-file-load RUN-NONINTERACTIVE in-file in-file)))
(drawable (car (gimp-image-get-active-drawable image)))
(old-width (car (gimp-image-width image)))
(old-height (car (gimp-image-height image)))
(old-max (max old-width old-height))
(new-width (round (/ (* old-width newmax) old-max)))
(new-height (round (/ (* old-height newmax) old-max))))
;; http://tinyurl.com/7bvura2 states "... because saving undo
;; steps can be time and memory intensive" and so we don't
;; care about undo operations for batch runs:
(gimp-image-undo-disable image)
(gimp-image-scale image new-width new-height)
(let ((out-file
(string-append out-dir
;; Insert a slash character if
;; not already at the tail-end
;; of out-dir:
(if (char=? #\/ (car (last (string->list out-dir))))
""
"/")
;; Take the basename of in-file which may be a fully-qualified path:
(car (last (strbreakup in-file "/"))))))
;; The print function does not show output on standard
;; output, so use gimp-message instead:
(gimp-message (string-append " scale-to-max-fileglob: scaling "
in-file " into " out-file
" with these dimensions: "
(number->string new-width) "x" (number->string new-height)))
(gimp-file-save RUN-NONINTERACTIVE image drawable out-file out-file))
(gimp-image-delete image))
(set! filelist (cdr filelist)))))
file-pattern
out-dir
newmax
)
(let* ((filelist (cadr (file-glob file-pattern 1))))
(while (not (null? filelist))
(let* ((in-file (car filelist))
(image (car (gimp-file-load RUN-NONINTERACTIVE in-file in-file)))
(drawable (car (gimp-image-get-active-drawable image)))
(old-width (car (gimp-image-width image)))
(old-height (car (gimp-image-height image)))
(old-max (max old-width old-height))
(new-width (round (/ (* old-width newmax) old-max)))
(new-height (round (/ (* old-height newmax) old-max))))
;; http://tinyurl.com/7bvura2 states "... because saving undo
;; steps can be time and memory intensive" and so we don't
;; care about undo operations for batch runs:
(gimp-image-undo-disable image)
(gimp-image-scale image new-width new-height)
(let ((out-file
(string-append out-dir
;; Insert a slash character if
;; not already at the tail-end
;; of out-dir:
(if (char=? #\/ (car (last (string->list out-dir))))
""
"/")
;; Take the basename of in-file which may be a fully-qualified path:
(car (last (strbreakup in-file "/"))))))
;; The print function does not show output on standard
;; output, so use gimp-message instead:
(gimp-message (string-append " scale-to-max-fileglob: scaling "
in-file " into " out-file
" with these dimensions: "
(number->string new-width) "x" (number->string new-height)))
(gimp-file-save RUN-NONINTERACTIVE image drawable out-file out-file))
(gimp-image-delete image))
(set! filelist (cdr filelist)))))
Store this into ~/.gimp-2.6/scripts/batch-resize.scm and the definition of scale-to-max-fileglob will load into all future gimp sessions.
Example run: This was executed using GIMP 2.6 on a 64-bit Debian Linux machine. The "script-fu-Warning" is coming from the gimp-message function:
user@somehost:/tmp/images_dir$ time gimp -i -b '(begin (scale-to-max-fileglob "*.jpg" "outdir" 1000) (gimp-quit 0))'
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-43-42_676.jpg into outdir/2012-05-19_16-43-42_676.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-44-35_210.jpg into outdir/2012-05-19_16-44-35_210.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-41-21_785.jpg into outdir/2012-05-19_16-41-21_785.jpg with these dimensions: 1000x562
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-44-02_760.jpg into outdir/2012-05-19_16-44-02_760.jpg with these dimensions: 1000x562
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-45-34_771.jpg into outdir/2012-05-19_16-45-34_771.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-43-15_141.jpg into outdir/2012-05-19_16-43-15_141.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-42-39_886.jpg into outdir/2012-05-19_16-42-39_886.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-45-13_128.jpg into outdir/2012-05-19_16-45-13_128.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-42-52_376.jpg into outdir/2012-05-19_16-42-52_376.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-41-49_429.jpg into outdir/2012-05-19_16-41-49_429.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-42-08_196.jpg into outdir/2012-05-19_16-42-08_196.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-41-54_552.jpg into outdir/2012-05-19_16-41-54_552.jpg with these dimensions: 562x1000
script-fu-Warning: scale-to-max-fileglob: scaling 2012-05-19_16-42-34_497.jpg into outdir/2012-05-19_16-42-34_497.jpg with these dimensions: 562x1000
real 0m16.179s
user 0m13.229s
sys 0m2.236s
The above code was cobbled together from these sources:
- Christopher Campbell's blog: Batch image scaling with Gimp
- TinySCHEME Version 1.40 Manual is rather skimpy so you may desire to refer to The Racket Reference instead.
- Gimp Batch Mode Introduction
