GIMP Plugin Registry

Hi,

I have tried to add fading and it works on my GIMP 2.6.8 (Windows XP). Here is my proposal:

- to "undo" context changes (e.g. I set a gradient) insert
(gimp-context-push)
below the undo-group-start and
(gimp-context-pop)
above the undo-group-end

- in the let* block add a layer mask and a gradient:
(mask (car (gimp-layer-create-mask layer2 ADD-ALPHA-MASK)))
(gradient (car (gimp-gradient-new "Gray to Black for fade-out")))

- (optional) rename the new layer and move it below orig layer on layer stack (instead of param "1"):
(gimp-image-add-layer img layer2 (+ (car (gimp-image-get-layer-position img layer1)) 1))
(gimp-layer-set-name layer2 (string-append (car (gimp-layer-get-name layer1)) "-Reflection"))

- add a layer mask and initialise the gradient (I deceideed to create an own gradient because (a) linear fading looks not good for me and (b) we can't copy a predefined gradient because they are identified by name which is unfortunately language-dependent):
(gimp-layer-add-mask layer2 mask)
; Initialize the gradient
(gimp-gradient-segment-set-left-color gradient 0 '(160 160 160) 100)
(gimp-gradient-segment-set-right-color gradient 0 '(0 0 0) 100)
; this goes to black very fast...
(gimp-gradient-segment-range-set-blending-function gradient 0 -1 GRADIENT-SEGMENT-SPHERE-INCREASING)
; ...so we could move the middle pos to fade-out not soo fast
; (gimp-gradient-segment-set-middle-pos gradient 0 0.6)
; finally make it active
(gimp-context-set-gradient gradient)
Note: The start color '(160 160 160) could become script parameter to make it selectable by user

- now draw the gradient to the layer mask:
(gimp-layer-set-edit-mask layer2 TRUE)
(gimp-edit-blend mask CUSTOM-MODE NORMAL-MODE GRADIENT-LINEAR 100 0 REPEAT-NONE FALSE FALSE 1 0 FALSE 0 old-height 0 (/ (* old-height 1) 3))
(gimp-layer-set-edit-mask layer2 FALSE)
Note: The layer is not transformed yet so we must fade from bottom to top. The last parameter (old-height/3) could also be made user-selectable.

- now we could apply the mask
(gimp-layer-remove-mask layer2 MASK-APPLY)
or keep it separate

- then original transformation follows and finally we should delete our gradient:
(gimp-gradient-delete gradient)

- optionally you can apply Mr. Gauss to soften the reflection ;)

I hope this is useful and thanks for the possibility to lern a bit scripting GIMP - it was my first try :)
Hoffi