;; pattern-swirly.scm -*-scheme-*-

;; Inspired by Swirly-Pattern by Federico Mena Quintero (Quartic) 
;; but has been completely rewritten (more than once) by Alan Horkan.  

;; compare and contrast different types of 'invert'/flip/rotate 
(define (script-fu-transform image drawable)
    (gimp-flip drawable 0) ; fast and effecient
    ;; original, invert colour, suitable only for black and white.  
    ;(gimp-invert drawable))  
    ;; invert by flipping, works because of the specific pattern  
    ;(gimp-flip drawable 0))  
    ;(gimp-flip drawable 1)) ;; not invert, but interesting
    ;; swap position of the two colours by rotating 270 degrees instead of inverting
    ;; gimp-rotate, built-in, gauranteed to be there, probably not optimal for *90 rotations
    ;(gimp-rotate drawable FALSE (* (/ 3 2) *pi*)) )
    ;; plug-in-rotate, probably a matrix transformation optimized for *90 degree rotations 
    ;(plug-in-rotate 1 image drawable 3 FALSE)) 
)

;; must whirl at least once
(define (script-fu-whirl-pinch-repeat image drawable angle times)
    (plug-in-whirl-pinch 1 image drawable angle 0.0 1.0)
    (if (> times 0) (script-fu-whirl-pinch-repeat image drawable angle (- times 1)))
)

;; input image and drawable are ignored, not the most elegant code but it'll do
(define (script-fu-pattern-swirly image drawable block-size angle times)
    (let* (
            (height (car (gimp-drawable-height drawable)))
            (width (car (gimp-drawable-width drawable)))

            (temp-size (* 2 block-size))
            (temp-image (car (gimp-image-new temp-size temp-size RGB)))
            (temp-drawable (car (gimp-layer-new temp-image temp-size temp-size RGB "Swirly Pattern" 100 NORMAL)))
        )
        ;; disable undo, dont need it here
        (gimp-image-undo-disable temp-image)  
        (gimp-image-add-layer temp-image temp-drawable 0)
        (gimp-layer-add-alpha temp-drawable)
      
        ;; Render checkerboard, current foreground and background colours used
        (plug-in-checkerboard 1 temp-image temp-drawable 0 block-size)
        ;; do the whirl
        (script-fu-whirl-pinch-repeat temp-image temp-drawable angle times)
       
        (set! tile-size (* 2 temp-size))
        (gimp-image-resize temp-image tile-size tile-size 0 0)

        (define (copy-add-offset image drawable x y) 
            (set! new-layer (car (gimp-layer-copy drawable TRUE)))
            (gimp-image-add-layer image new-layer -1)
            (gimp-layer-set-offsets new-layer x y)
        )

        ;; lower right quadrant (same as top left)
        (copy-add-offset temp-image temp-drawable temp-size temp-size)

        ;; create a second drawable
        (set! temp-drawable2 (car (gimp-layer-copy temp-drawable TRUE)))   

        ;; upper right quadrant        
        (copy-add-offset temp-image temp-drawable2 temp-size 0)

        (set! active-drawable (car (gimp-image-get-active-drawable temp-image)))
        ;; version 2.x is stricter, must add drawable to an image before flip
        ;(gimp-flip temp-drawable2 0)
        (script-fu-transform temp-image active-drawable)

        ;; lower left quadrant (same as upper right)
        (copy-add-offset temp-image active-drawable 0 temp-size )

        (set! temp-drawable (car (gimp-image-flatten temp-image)))        

        (gimp-image-undo-enable temp-image)  
        ;; do not remove, useful for testing
        ;(gimp-display-new temp-image)  
        ;(gimp-displays-flush)

        ;; make undoable in one step.  
        (gimp-image-undo-group-start image)  
        
        (gimp-edit-copy temp-drawable)
        (set! pattern (car (gimp-edit-paste drawable FALSE)))
        (gimp-layer-set-offsets pattern 0 0)
        (gimp-floating-sel-to-layer pattern)       
        (plug-in-tile 1 image pattern width height FALSE)
        (gimp-drawable-set-name pattern "Swirly Pattern")

        (gimp-image-undo-group-end image)  
        (gimp-displays-flush)
    )    
)

(script-fu-register "script-fu-pattern-swirly"
    _"<Image>/Filters/Render/Pattern/Swirly..."
    "Creates a pattern made from four Swirls.  
Uses the current Foreground and Background colours.    
For best results use strongly contrasting colours.  
For example Black & White, Red & Cyan, Green & Magenta, Blue & Yellow.  

Block Size is 1/8 of size of the generated pattern.  

Requires plug-in-whirl-pinch and plug-in-tile.  "
    "Alan Horkan.  
Federico Mena Quintero (Quartic).  " ; author(s)
    "Alan Horkan.  Public Domain.  " ; rights
    "2004 08 12 UTC" ; date
    "" ; supports all types 

    SF-IMAGE "Image" 0
    SF-DRAWABLE "Drawable" 0
    ; bugfix, minimum must be at least 1 pixel or script fails
    SF-ADJUSTMENT _"Block Size" '(20 1 2048 1 10 0 1) 
    SF-ADJUSTMENT _"Whirl Angle" '(90 0 360 1 10 0 0)
    SF-ADJUSTMENT _"Whirl Times" '(4 1 128 1 10 0 1) 
)

(script-fu-register "script-fu-whirl-pinch-repeat"
    _"<Image>/Filters/Distorts/Whirl Repeat..."
    "Whirl repeatedly.  
Script to compensate for Whirl-Pinch plugin not supporting Rotations greater than 360 degrees.  
Part of the Swirly Pattern script.  

If you don't like this please fix Whirl-Pinch so this can be removed.  
Doesn't work perfectly, cannot inlcude a (gimp-displays-flush) without breaking other script.  "
    "" "" "" ""  
    SF-IMAGE "Image" 0
    SF-DRAWABLE "Drawable" 0
    SF-ADJUSTMENT _"Whirl Angle" '(90 -360 360 1 10 0 0)
    SF-ADJUSTMENT _"Whirl Times" '(4 1 128 1 10 0 1) 
)

;; DONE script uses the current background and foreground colours, 
;; instead of just hardcoded black and white.  
;; DONE colours swap positions (rotate 270) instead of invert
;; DONE abstracted the invert/transform, changed it to flip horizontal instead
;; DONE gimp-flip fix.  version 2.x is stricter, drawable must be added to image 
;; before it could be flipped.  

;; Whirling is time consuming, particularly when repeated multiple times.  
;; Copy+Transform is more efficient than whirling from scratch.  
;; Rewrote script to make it ~3-4 orders of magnitude more effecient
;; This also means less annoying progress bars.  

;; TODO use just the selection not the whole drawable