; 210_sharpness-softer_pixel-gradient.scm
; last modified/tested by Paul Sherman [gimphelp.org]
; Wednesday, 07/15/2020 on GIMP 2.10.20
;==================================================
;
; Installation:
; This script should be placed in the user or system-wide script folder.
;
;	Windows 7/10
;	C:\Program Files\GIMP 2\share\gimp\2.0\scripts
;	or
;	C:\Users\YOUR-NAME\AppData\Roaming\GIMP\2.10\scripts
;	
;    
;	Linux
;	/home/yourname/.config/GIMP/2.10/scripts  
;	or
;	Linux system-wide
;	/usr/share/gimp/2.0/scripts
;
;==================================================
;
; 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/>.
;
;==============================================================
; Original information 
; 
; pixel-gradient.scm
; Jeff Trefftzs <trefftzs@tcsn.net>
;==============================================================
(define (210-pixelgradient 
		inImage 
		inLayer 
		minsize 
		maxsize 
		nsteps
	)
	;; If there isn't already a selection, select the whole thing
	(let* (
		(noselection 0)
	   )
	(if (car (gimp-selection-bounds inImage))
	  (begin
		(set! noselection FALSE)
	  )
	  (begin
	   (gimp-selection-all inImage)
	   (set! noselection TRUE)
	  )
	)
    ; start undo group and convert to RGB if image is indexed
	(gimp-image-undo-group-start inImage)
	(define indexed (car (gimp-drawable-is-indexed inLayer)))
	(if (= indexed TRUE)(gimp-image-convert-rgb inImage))
	(let* (
		 (selchannel (car (gimp-selection-save inImage)))
		 (selstuff  (gimp-selection-bounds inImage))
		 (width
		  (cond ((car selstuff)
			 (- (nth 3 selstuff) (nth 1 selstuff)))
			(t (car (gimp-image-width inImage)))))
		 (height
		  (cond ((car selstuff)
			 (- (nth 4 selstuff) (nth 2 selstuff)))
			(t (car (gimp-image-height inImage)))))
		 (x0
		  (cond ((car selstuff)
			 (nth 1 selstuff))
			(t 0)))
		 (y0
		  (cond ((car selstuff)
			 (nth 2 selstuff))
			(t 0)))
		 (x1 width)
		 (y1 height)
		 (stepwidth (/ width nsteps))
		 (pixstep (/ (- maxsize minsize) nsteps))
		 (startx x0)
		 (startsize minsize)
		 )
	  ;; Step across the selection (or image), pixelizing as we go
	  (while (< startx x1)
		 (begin
		   (gimp-image-select-item inImage CHANNEL-OP-REPLACE selchannel)
		   (gimp-image-select-rectangle inImage CHANNEL-OP-INTERSECT startx y0 stepwidth height)
		   (plug-in-pixelize TRUE inImage inLayer startsize)
		   (set! startx (+ startx stepwidth))
		   (set! startsize (+ startsize pixstep))
		  )
		 )
	  (if (equal? TRUE noselection)
		  (gimp-selection-none inImage)
		  (gimp-image-select-item inImage CHANNEL-OP-REPLACE selchannel)
		  )
    )
  (gimp-image-set-active-layer inImage inLayer)
  (gimp-image-undo-group-end inImage)
  (gimp-displays-flush)
  )
)
(script-fu-register "210-pixelgradient"
 	"Pixel Gradient"
	"Pixelizes a selection (or layer) from left to right with increasing pixel sizes."
	"Jeff Trefftzs"
	"Copyright 2003, Jeff Trefftzs"
	"November 17, 2003"
	"*"
	SF-IMAGE "The Image" 0
	SF-DRAWABLE "The Layer" 0
	SF-ADJUSTMENT "Minimum Pixel Size" '(2 1 256 1 5 0 1)
	SF-ADJUSTMENT "Maximum Pixel Size" '(8 1 256 1 5 0 1)
	SF-ADJUSTMENT "Number of Steps"  '(4 1 256 1 5 0 1)
)
(script-fu-menu-register "210-pixelgradient" "<Image>/Script-Fu/Sharpness/Softer")