Color correction for GIMP Script-Fu

gimp_color_correction.scm

(define (string-replace strIn strReplace strReplaceWith)
	(let* (
			(curIndex 0)
			(replaceLen (string-length strReplace))
			(replaceWithLen (string-length strReplaceWith))
			(inLen (string-length strIn))
			(result strIn)
		)
		;loop through the main string searching for the substring
		(while (<= (+ curIndex replaceLen) inLen)
			;check to see if the substring is a match
			(if (substring-equal? strReplace result curIndex (+ curIndex replaceLen))
				(begin
					;create the result string
					(set! result (string-append (substring result 0 curIndex) strReplaceWith (substring result (+ curIndex replaceLen) inLen)))
					;now set the current index to the end of the replacement. it will get incremented below so take 1 away so we don't miss anything
					(set! curIndex (-(+ curIndex replaceWithLen) 1))
					;set new length for inLen so we can accurately grab what we need
					(set! inLen (string-length result))
				)
			)
			(set! curIndex (+ curIndex 1))
		)
	   (string-append result "")
	)
)

(define (correct-color input)
	(let* (
			(img (car (gimp-file-load 1 input input)))
			(layer (car (gimp-image-get-active-layer img)))
			(output (string-replace input ".png" ".jpg"))
		)
		(gimp-drawable-hue-saturation layer HUE-RANGE-ALL 0 0 100 0)
		(gimp-drawable-hue-saturation layer HUE-RANGE-RED 0 0 -5 0)
		;; (gimp-drawable-hue-saturation layer HUE-RANGE-BLUE 0 0 -50 0)
		;; (gimp-drawable-hue-saturation layer HUE-RANGE-YELLOW 0 0 -50 0)
		(gimp-drawable-hue-saturation layer HUE-RANGE-MAGENTA 0 0 -10 0)
		(gimp-curves-spline layer HISTOGRAM-VALUE 10 #(32 0 80 80 160 180 240 250 255 255))
		;; (gimp-display-new img)
		(file-jpeg-save RUN-NONINTERACTIVE img layer output output 0.99 0.01 1 0 "" 0 1 0 0)
		(gimp-image-delete img)
	)
)

(for-each correct-color
	(map 
		(lambda (x) (string-append "/path/to/" x))
		'(
			"test.png"
		)
	)
)