I am automating a "LAB Enhancement" process. It is found here: http://www.dslreports.com/forum/remark,15173919
In short, you decompose to LAB. You monkey with the A and B channels, then use curves on L. Finally, you recompose. One issue is that you have to copy the resulting A1 and B1 channels, and then anchor them back into the original A and B channels so that you can recompose. Merging down into A or B apparently creates new layers and you lose the ability to recompose. The attached script for version 2.6.2 gets to the last step that I am going to (I'm stopping before applying curves to the L channel because I'll do that manually depending on the image). I create the altered A1 and B1 channels. I paste B1 and anchor it into B. However, when I paste A1, it is anchoring into B, instead of A. A is the top layer, but I can't get the script to anchor into it. When I anchor manually, it also anchors into B. I'm frustrated and mystified in equal measure. Another side effect is that running this script wipes out the filters, and I have to refresh them. :-( Can any Script-fu wizards out there tell me what I am doing wrong? Dave ---- script follows and is attached ---- ; LAB Enhance ; David Hathaway <dave77...@gmail.com> ; ; Based on: ; ; http://www.dslreports.com/forum/remark,15173919 ; ; v 0.5 - 21 OCT 2009 (first working version) (define (LAB-Enhance img drawable) (gimp-image-undo-group-start img) ; set some system variables (let* ( (width (car (gimp-image-width img))) (height (car (gimp-image-height img))) (blend-layer) (b-copy1-layer) (b-copy2-layer) (a-copy1-layer) (a-copy2-layer) (layers (gimp-image-get-layers img)) (B1) (B2) (B3) (editcopy) (A1) (A2) (A3) ) ; copy A channel and add as second layer (set! A1 (car (gimp-layer-new-from-drawable ( aref (cadr layers) 1) img))) (gimp-drawable-set-name A1 "A 1") (gimp-image-add-layer img A1 1) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; copy B channel and set as 4th layer (set! B1 (car (gimp-layer-new-from-drawable ( aref (cadr layers) 2) img))) (gimp-drawable-set-name B1 "B 1") (gimp-image-add-layer img B1 3) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; copy the B channel copy and make overlay, inserting as 4th layer (set! B2 (car (gimp-layer-new-from-drawable ( aref (cadr layers) 2) img))) (gimp-drawable-set-name B2 "B 2") (gimp-layer-set-mode B2 OVERLAY-MODE) (gimp-image-add-layer img B2 3) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; merge new B channels (set! B3 (gimp-image-merge-down img B2 EXPAND-AS-NECESSARY)) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; copy the A channel copy and make overlay, inserting as 2nd layer (set! A2 (car (gimp-layer-new-from-drawable ( aref (cadr layers) 1) img))) (gimp-drawable-set-name A2 "A 2") (gimp-layer-set-mode A2 OVERLAY-MODE) (gimp-image-add-layer img A2 1) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; merge new B channels (set! A3 (gimp-image-merge-down img A2 EXPAND-AS-NECESSARY)) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; move B to top (gimp-image-raise-layer-to-top img (aref (cadr layers) 2)) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; cut B1, paste into layer, and anchor (gimp-image-set-active-layer img (aref (cadr (gimp-image-get-layers img)) 4)) (gimp-selection-all img) (gimp-edit-cut (aref (cadr (gimp-image-get-layers img)) 4)) (gimp-image-set-active-layer img (aref (cadr (gimp-image-get-layers img)) 0)) (gimp-floating-sel-anchor (car (gimp-edit-paste drawable TRUE))) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; move A to top (gimp-image-raise-layer-to-top img (aref (cadr layers) 1)) (gimp-image-set-active-layer img (aref (cadr layers) 1)) (gimp-image-undo-group-end img) (gimp-image-undo-group-start img) ; cut A1, paste into layer, and anchor (gimp-image-set-active-layer img (aref (cadr (gimp-image-get-layers img)) 3)) (gimp-selection-all img) (gimp-edit-cut (aref (cadr (gimp-image-get-layers img)) 3)) (gimp-image-set-active-layer img (aref (cadr (gimp-image-get-layers img)) 0)) (gimp-edit-paste drawable TRUE) ; (gimp-floating-sel-anchor (car (gimp-edit-paste drawable TRUE))) ; move L back to top ; (gimp-image-raise-layer-to-top img (aref (cadr layers) 0)) ; (gimp-image-set-active-layer img (aref (cadr (gimp-image-get-layers img)) 0)) ) ; let* ; Flush the display (gimp-image-undo-group-end img) (gimp-displays-flush) ) (script-fu-register "LAB-Enhance" "LAB-Enhance" "Perform LAB Enhancement" "David Hathaway <dave77...@gmail.com>" "(c) David Hathaway" "2009 10 21" "GRAYSCALE*" SF-IMAGE "Image" 0 SF-DRAWABLE "Layer to start on (unused)" 0) (script-fu-menu-register "LAB-Enhance" "<Image>/Filters/Dave77459")
LAB-Enhance.scm
Description: Binary data
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