; 210_effects_reflection.scm
; last modified/tested by Paul Sherman [gimphelp.org]
; Thursday, 07/02/2020 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 
; 
; Copyright (C) 2005-2007 Otavio Correa Cordeiro (otavio gmail com)
; Create a reflection effect like Apple iWeb does..
;
; modified by Paul Sherman to work in GIMP 2.4.2 on 11/30/2007
;
; modified by David Cummins and Paul Sherman Dec 2007, tested on GIMP-2.4.3
; * added user settings to control the height of the generated reflection,
;   the gradient mask starting point (presented as Fade Rate %), and options
;   to keep the generated reflection as a separate layer, or on a single layer
;   either transparent or flattened.
; * added code to "play nice" with the current GIMP environment: colors and
;   gradient prior selections are preserved, as well as the original layer
;   name (handled using careful stack order).
;   generated layers are constrained around the original layer.
; * simplified some of the internal logic so repeated calculations are done
;   only once, reformatted, organised the code, added comments, etc.
; * flattened on start (to avoid errors)
; * undo ability functional
;
; Wed Oct  1 22:14:40 EDT 2008
; Modified to remove deprecated procedures as listed:
;     gimp-flip  ==>  gimp-drawable-transform-flip-simple
; added extra parameters
; also flushed before undo-end
;==============================================================
(define (draw-line layer x-from y-from x-to y-to) 
  (let* (
          (points (cons-array 4 'double))
        )
        (aset points 0 x-from)
        (aset points 1 y-from)
        (aset points 2 x-to  )
        (aset points 3 y-to  )
        (gimp-pencil layer 4 points)
  )
)
(define (210-gimp-reflection
         theImage
         theLayer
         userHeight
         userFade
         new_layer
         transparentBG
		 make_line
        )
    (define originalWidth (car (gimp-image-width theImage)))
    (define originalHeight (car (gimp-image-height theImage)))
    (gimp-image-undo-group-start theImage)
	(if (not (= RGB (car (gimp-image-base-type theImage))))
			 (gimp-image-convert-rgb theImage))	
;    (gimp-selection-all theImage)
    (gimp-selection-none theImage)
    (set! theLayer (car(gimp-image-merge-visible-layers theImage 0)))
  (if (= make_line TRUE)
    (begin
		(gimp-context-set-background '(255 255 255))
		(gimp-context-set-foreground '(000 000 000))
		(gimp-context-set-brush "Circle (03)"    )   
		(draw-line theLayer 0 originalHeight originalWidth originalHeight)
    ))
    ;preserve original settings
    (define old-bg   (car (gimp-context-get-background)))
    (define old-fg   (car (gimp-context-get-foreground)))
    (define old-grad (car (gimp-context-get-gradient)))
    ;calculate color for start of gradient fade
    (define fadeStart (* (- 100 userFade) 2.55))
    (define fadeColor (list fadeStart fadeStart fadeStart))
    (define reflectionScale (/ userHeight 100))
    (define stackPos (car(gimp-image-get-item-position theImage theLayer)))
    (define newWidth originalWidth)
    (define newHeight (* originalHeight (+ reflectionScale 1)))
    (define gradX (/ originalWidth 2))
    (define gradY1 (* originalHeight reflectionScale))
    (define gradY2 (* originalHeight reflectionScale -1))
    (gimp-image-resize theImage originalWidth newHeight 0 0)
    (define new-layer (car (gimp-layer-copy theLayer 1)))
    (gimp-image-insert-layer theImage new-layer 0 (+ stackPos 0))
    (gimp-item-set-name new-layer "Reflection")
    (gimp-layer-set-offsets new-layer 0 originalHeight)
    (gimp-item-transform-flip-simple new-layer ORIENTATION-VERTICAL TRUE 0.0)
    (define new-mask (car (gimp-layer-create-mask new-layer 0)))
    (gimp-layer-add-mask new-layer new-mask)
    (gimp-context-set-foreground fadeColor)
    (gimp-edit-blend new-mask FG-TRANSPARENT-MODE LAYER-MODE-NORMAL-LEGACY
		   GRADIENT-LINEAR 100 0 REPEAT-NONE
		   FALSE
		   FALSE 0 0 TRUE
		   gradX gradY1 gradX gradY2)
  (if (= new_layer FALSE)
    (begin
        (if (= transparentBG TRUE)
	      (begin ;# NO separate layer, transparent ##############
	          (gimp-image-merge-visible-layers theImage 1)
	      )
	      (begin ;# NO separate layer, NOT transparent ##########
	          (gimp-image-flatten theImage)
	      )
	    )
        ; final crop not needed for new_layer FALSE
    )
    (begin
        (if (= transparentBG TRUE)
	      (begin ;# separate layer, transparent ###############
	      	  (gimp-image-set-active-layer theImage new-layer)
	      )
	      (begin ;# separate layer, NOT transparent ###########
                (define bg-layer (car(gimp-layer-new theImage originalWidth newHeight 0 "Reflection BG" 100 0)))
                (gimp-image-insert-layer theImage bg-layer 0 (+ stackPos 2))
                (gimp-selection-all theImage)
                (gimp-edit-bucket-fill bg-layer 1 0 100 255 0 1 1)
                (gimp-selection-none theImage)
                (gimp-image-set-active-layer theImage new-layer)
            )
        )
        ; the Reflection layer still overflows the image here
        (gimp-image-crop theImage originalWidth newHeight 0 0)
    )
  )
    ;restore original settings
    (gimp-context-set-foreground old-fg)
    (gimp-context-set-background old-bg)
    (gimp-context-set-gradient old-grad)
    (gimp-displays-flush)
    (gimp-image-undo-group-end theImage)
)
(script-fu-register "210-gimp-reflection"
	"Reflection"
	"Reflection -- extends lower section of an image as a reflection of the original image."
	"Original author Otavio Cordeiro, later edited by David Cummins and Paul Sherman"
	"Paul Sherman <psherman2001@gmail.com>"
	"Last updated 12/19/2007 - tested on GIMP-2.4.3"
	"*"
	SF-IMAGE    	"Image"    								0
	SF-DRAWABLE 	"Drawable" 								0
    SF-ADJUSTMENT 	"Reflection Height (% of original)" 	'( 40 10 99 1 20 0 0)
    SF-ADJUSTMENT 	"Fade Rate (%)" 						'(60 0 100 10 20 0 0)
    SF-TOGGLE 		"Keep Reflection as a separate Layer" 	FALSE
    SF-TOGGLE 		"Transparent Background" 				TRUE
	SF-TOGGLE 		"Include a Separator Line?" 			TRUE
)
(script-fu-menu-register "210-gimp-reflection" "<Image>/Script-Fu/Effects")