; scale steps down v0.22 by Con Kolivas <kernel@kolivas.org>
;
; 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.  See COPYING for more details.
(define (script-fu-scale-steps-down image drawable mwidth mheight stepsize flatten interpolation recursion)
	(gimp-image-undo-group-start image)
	
	(if (= flatten TRUE)
		(set! drawable (car(gimp-image-flatten image)))
	)
	
	(let*(
		(sel_width 0)
		(sel_height 0)
		(new_width 0)
		(new_height 0)
		(new_x1 0)
		(new_x2 0)
		(new_y1 0)
		(new_y2 0)
		(orig_height 0)
		(orig_width 0)
		(half_nextstep 0.0)
		(possible_width 0)
		(possible_height 0)
	)
	
	(set! orig_height (car (gimp-drawable-height drawable)))
	(set! orig_width (car (gimp-drawable-width drawable)))
	(set! half_nextstep (* 1.5 stepsize))
	
	(while 
		(and
			(> (car (gimp-drawable-height drawable)) mheight)
			(> (car (gimp-drawable-width drawable)) mwidth)
		)
		(set! sel_width (car (gimp-drawable-width drawable)))
		(set! sel_height (car (gimp-drawable-height drawable)))
		(set! new_width (/ sel_width (/ (+ 100 stepsize) 100)))
		(set! new_height (/ sel_height (/ (+ 100 stepsize) 100)))
		(set! possible_width (/ sel_width (/ (+ 100 half_nextstep) 100)))
		(set! possible_height (/ sel_height (/ (+ 100 half_nextstep) 100)))

		(if (< possible_width mwidth)
			(begin
			  (set! new_width mwidth)
			  (set! new_height (* orig_height (/ mwidth orig_width)))
			)
		)
		(if (< possible_height mheight)
			(begin
			  (set! new_height mheight)
			  (set! new_width (* orig_width (/ mheight orig_height)))
			)
		)
		
		(if (< new_width mwidth)
			(begin
			  (set! new_width mwidth)
			  (set! new_height (* orig_height (/ mwidth orig_width)))
			)
		)
		(if (< new_height mheight)
			(begin
			  (set! new_height mheight)
			  (set! new_width (* orig_width (/ mheight orig_height)))
			)
		)

		(set! new_x1 0)
		(set! new_y1 0)
		(set! new_x2 new_width)
		(set! new_y2 new_height)

        	(gimp-drawable-transform-scale
                                          drawable
					  new_x1
					  new_y1
					  new_x2
					  new_y2
                                          0 interpolation 1 recursion 
                                           TRANSFORM-RESIZE-CROP
;                                           TRANSFORM-RESIZE-CROP-WITH-ASPECT
;                                          TRANSFORM-RESIZE-CLIP
;                                         TRANSFORM-RESIZE-ADJUST
        	)
		(gimp-image-crop image new_width new_height 0 0)
	)
	(if (= flatten TRUE) (gimp-image-flatten image))
	(gimp-image-undo-group-end image)
	(gimp-displays-flush)
)
)

(script-fu-register 
		"script-fu-scale-steps-down"
		"Scale in steps down"
		"Scale in steps until one of width or height is smaller than the supplied values"
		"C.Kolivas"
		"(c) 2010 based on work (c) 2008 K.-M. Hansche"
		"2010-07-15"
		"RGB* GRAY*"
		SF-IMAGE "image" 0
		SF-DRAWABLE "drawable" 0
		SF-ADJUSTMENT "Min Width" '(800 10 99999 1 50 0 1)
		SF-ADJUSTMENT "Min Height" '(1200 10 99999 1 50 0 1)
		SF-ADJUSTMENT "Stepsize in percent" '(10 1 20 1 2 0 1)
		SF-TOGGLE "Flatten Image" TRUE
		SF-ENUM "Interpolation (Scaling)" '("InterpolationType" "lanczos")
		SF-ADJUSTMENT "Recursion level (Scaling)" '(4 1 10 1 1 0 1)
)

(script-fu-menu-register "script-fu-scale-steps-down" "<Image>/Script-Fu")