; setup-brush.scm
; by Rob Antonishen
; http://ffaat.pointclark.net

; Version 1.1 (20080201)

; Description
;
; Script to aid in the creation of animated brushes that rotate as the brush moves.
; Will appear in the Script-fu\Utils Menu
;

; 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 2 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.
;
; The GNU Public License is available at
; http://www.gnu.org/copyleft/gpl.html

(define (script-fu-setup-brush img inLayer inCount inNumber inColour)
  (let* 
    (
      (pi 3.141592654)
	  (img (car (gimp-image-duplicate img)))  ;create a duplicate
	  (width (car (gimp-image-width img)))
	  (height (car (gimp-image-height img)))
	  (side width)
	  (srcLayer 0)
	  (floatSel 0)
	  (counter 1)
	  (counter2 0)
	  (aRad 0)
	)
	
	;check for square source image(s)
	(if (<> (* width (truncate inNumber)) height)
	  (gimp-message "Source image(s) must have an equal width and height")
      ;else
	  (begin 
		; it begins here
		(gimp-image-undo-group-start img)

		;get active layer in new image
		(set! inLayer (aref (cadr (gimp-image-get-layers img)) 0))
		
		; set the colour mode based on the checkbox
		(if (and (= inColour TRUE) (= (car (gimp-drawable-is-gray inLayer)) TRUE))
		  (gimp-image-convert-rgb img) 0
		)
		(if (and (= inColour FALSE) (= (car (gimp-drawable-is-rgb inLayer)) TRUE))
		  (gimp-image-convert-grayscale img) 0
		)
		
		; enlarge to largest side and for ratated shapes
		(gimp-image-resize img (* side (truncate inCount)) height 0 0)
		
		(gimp-layer-resize-to-image-size inLayer)

		(set! srcLayer (car (gimp-image-merge-visible-layers img 1)))
		
		;add alpha if none
		(gimp-layer-add-alpha srcLayer) 
		
		(while (< counter2 (truncate inNumber))
		  (while (< counter (truncate inCount))
			; get circular selection
			(gimp-ellipse-select img 0 (* counter2 side) side side CHANNEL-OP-REPLACE TRUE FALSE 0)
			; copy
			(gimp-edit-copy srcLayer)
			; paste as floating
			(set! floatSel (car (gimp-edit-paste srcLayer FALSE)))

			(set! aRad (* (/ (* pi 2) (truncate inCount)) counter))
			; rotate and move the floating layer
			(gimp-drawable-transform-2d floatSel (/ side 2) (+ (* counter2 side) (/ side 2)) 1 1 aRad 
										(+ (* side counter) (/ side 2)) (+ (* counter2 side) (/ side 2)) 
										TRANSFORM-FORWARD INTERPOLATION-CUBIC TRUE 3 TRANSFORM-RESIZE-ADJUST)
			; anchor down
			(gimp-floating-sel-anchor floatSel)
			(set! counter (+ counter 1))
		  )
		  (set! counter 1)
		  (set! counter2 (+ counter2 1))  
		)
		(gimp-image-undo-group-end img)
		(gimp-display-new img)
	  )
	)
  )
)

(script-fu-register "script-fu-setup-brush"
        		    "<Image>/Script-Fu/Utils/Setup _Rotating Brush..."
                    "Set-up an animated brush that rotates.  Needs to be saved as a .GIH after creating."
                    "Rob Antonishen"
                    "Rob Antonishen"
                    "2004"
                    ""
                    SF-IMAGE      "image"      0
                    SF-DRAWABLE   "drawable"   0
                    SF-ADJUSTMENT "How many images to create?" '(12 2 36 1 2 0 1)
                    SF-ADJUSTMENT "How many source images?" '(1 1 6 1 2 0 1)
				    SF-TOGGLE     "Make it a Colour Brush (needs transparent background)?" FALSE
)