(define (script-fu-decompose-indexed image layer numcolors posterize keeplayer workcopy RGBmode)
(let* (
(work-image 0)
(new-layer 0)
(index 0)
(map 0)
(red 0)
(green 0)
(blue 0)
)
(if (= workcopy TRUE)
(begin
(set! work-image (car (gimp-image-duplicate image)))
(gimp-display-new work-image)
)
(begin
(set! work-image image)
(gimp-image-undo-group-start image)
)
)
(set! layer (car (gimp-image-get-active-layer work-image)))
(if (> (car (gimp-image-get-layers work-image)) 1)
(set! layer (car (gimp-image-merge-visible-layers work-image EXPAND-AS-NECESSARY)))
)
(set! layer (car (gimp-image-get-active-layer work-image)))
(gimp-selection-all work-image)
(if (= (car (gimp-drawable-is-rgb layer)) 0)
(gimp-image-convert-rgb work-image)
)
(if (= posterize TRUE)
(gimp-posterize layer numcolors)
)
(gimp-image-convert-indexed work-image NO-DITHER MAKE-PALETTE numcolors 0 TRUE "")
(set! map (gimp-image-get-colormap work-image))
(set! index 0)
(set! numcolors (/ (car map) 3))
(set! map (cadr map))
(if (> numcolors 0) ;; 0 means not indexed
(begin
(while (> numcolors 0)
(set! red (fmod (aref map index) 256))
(set! green (fmod (aref map (+ 1 index)) 256))
(set! blue (fmod (aref map (+ 2 index)) 256))
(gimp-by-color-select layer
(list red green blue) ;; color
0 CHANNEL-OP-REPLACE FALSE 0 0 0 ;; Threshold=0, NO Feather, Layer Only
)
(set! new-layer (car (gimp-layer-copy layer TRUE)))
(gimp-drawable-set-name new-layer
(string-append "RGB=[" (number->string red) ", " (number->string green) ", " (number->string blue) "]")
)
(gimp-image-add-layer work-image new-layer -1)
(gimp-selection-invert work-image)
(gimp-edit-clear new-layer)
(set! numcolors (- numcolors 1))
(set! index (+ index 3))
)
)
)
(if (= RGBmode TRUE)
(gimp-image-convert-rgb work-image)
)
(if (= keeplayer FALSE)
(gimp-image-remove-layer work-image layer)
)
(gimp-selection-none work-image)
(gimp-displays-flush)
)
(if (= workcopy FALSE)
(gimp-image-undo-group-end image)
)
)
(script-fu-register "script-fu-decompose-indexed"
"<Image>/Filters/Colors/_Indexed Decompose" ;; I prefer it appear in the Filters menu but others
; "<Image>/Script-Fu/Colors/_Indexed Decompose" ;; might like to keep it separate from the standard plugins
"Separates image into separate layers based on color"
"Saul Goode"
"Saul Goode"
"3/11/2006"
""
SF-IMAGE "Image" 0
SF-DRAWABLE "Drawable" 0
SF-ADJUSTMENT "Number of colors (2-255)" '( 8 2 255 1 5 0 0 )
SF-TOGGLE "Posterize first (slightly different shading)" TRUE
SF-TOGGLE "Keep original layer" FALSE
SF-TOGGLE "Work on copy" TRUE
SF-TOGGLE "Convert result to RGB" FALSE
)