xcf-thumbnailer.scm

;xcf-thumbnailer.scm
;==============================================================================
;
;
;Copyright (C) 2020 Melon (https://github.com/Mhlov)
;
; 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 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/>.
;
;==============================================================================
;Tested on GIMP 2.10.8


(define (mhl-save-thumbnail infile outfile size)
  (define image	   (car (gimp-xcf-load 1 infile infile)))

  (define w (car (gimp-image-width  image)))
  (define h (car (gimp-image-height image)))
  (define new_w size)
  (define new_h size)

  (if (and (<= w size) (<= h size))
	(begin
	 (set! new_w w)
	 (set! new_h h))
	; else
	(if (> w h)
	  (set! new_h (round (/ size
							(/ w h))))
	  ; else
	  (set! new_w (round (/ size
							(/ h w))))
	)
  )

  (define drawable (car (gimp-image-merge-visible-layers image 1)))
  ;(define drawable (car (gimp-image-get-active-drawable image)))

  (gimp-layer-scale drawable
					new_w
					new_h
					TRUE)

  (file-png-save-defaults 1
						  image
						  drawable
						  outfile
						  outfile)
)

(script-fu-register "mhl-save-thumbnail"
					"MHL-Save-Thumbnail"
                    "Save Thumbnail"
                    "MHL <mhl@localhost>"
                    "MHL"
                    "2020"
                    "*"
					SF-FILENAME "Infile"  ""
					SF-FILENAME "Outfile" ""
					SF-VALUE    "Thumbnail size" "0"
)