gimp/plug-ins/script-fu/scripts/drop-shadow.scm

; The GIMP -- an image manipulation program
; Copyright (C) 1995 Spencer Kimball and Peter Mattis
; 
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.  
; 
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
; 
; You should have received a copy of the GNU General Public License
; along with this program; if not, write to the Free Software
; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
;
;
; drop-shadow.scm   version 1.04   1999/12/21 
;
; CHANGE-LOG:
; 1.00 - initial release
; 1.01 - fixed the problem with a remaining copy of the selection
; 1.02 - some code cleanup, no real changes
; 1.03 - can't call gimp-edit-fill until layer is added to image!
;
;
; Copyright (C) 1997-1999 Sven Neumann <sven@gimp.org>
; 
;  
; Adds a drop-shadow of the current selection or alpha-channel. 
;
; This script is derived from my script add-shadow, which has become 
; obsolete now. Thanks to Andrew Donkin (ard@cs.waikato.ac.nz) for his 
; idea to add alpha-support to add-shadow.

  
(define (script-fu-drop-shadow image
			       drawable
			       shadow-transl-x
			       shadow-transl-y
			       shadow-blur
			       shadow-color
			       shadow-opacity
			       allow-resize)
  (let* ((shadow-blur (max shadow-blur 0))
	 (shadow-opacity (min shadow-opacity 100))
	 (shadow-opacity (max shadow-opacity 0))
	 (type (car (gimp-drawable-type-with-alpha drawable)))
	 (image-width (car (gimp-image-width image)))
	 (image-height (car (gimp-image-height image)))
	 (from-selection 0)
	 (active-selection 0)
	 (shadow-layer 0))

    (gimp-context-push)

    (gimp-image-set-active-layer image drawable)

    (gimp-image-undo-group-start image)
  
    (gimp-layer-add-alpha drawable)
    (if (= (car (gimp-selection-is-empty image)) TRUE)
	(begin
	  (gimp-selection-layer-alpha drawable)
	  (set! from-selection FALSE))
	(begin
	  (set! from-selection TRUE)
	  (set! active-selection (car (gimp-selection-save image)))))

    (let* ((selection-bounds (gimp-selection-bounds image))
	   (select-offset-x (cadr selection-bounds))
	   (select-offset-y (caddr selection-bounds))
	   (select-width (- (cadr (cddr selection-bounds)) select-offset-x))
	   (select-height (- (caddr (cddr selection-bounds)) select-offset-y))
  
	   (shadow-width (+ select-width (* 2 shadow-blur)))
	   (shadow-height (+ select-height (* 2 shadow-blur)))
	   
	   (shadow-offset-x (- select-offset-x shadow-blur))
	   (shadow-offset-y (- select-offset-y shadow-blur)))

      (if (= allow-resize TRUE)
	  (let* ((new-image-width image-width)
		 (new-image-height image-height)
		 (image-offset-x 0)
		 (image-offset-y 0))

	    (if (< (+ shadow-offset-x shadow-transl-x) 0)
		(begin
		  (set! image-offset-x (- 0 (+ shadow-offset-x
					       shadow-transl-x)))
		  (set! shadow-offset-x (- 0 shadow-transl-x))
		  (set! new-image-width (- new-image-width image-offset-x))))

	    (if (< (+ shadow-offset-y shadow-transl-y) 0)
		(begin
		  (set! image-offset-y (- 0 (+ shadow-offset-y
					       shadow-transl-y)))
		  (set! shadow-offset-y (- 0 shadow-transl-y))
		  (set! new-image-height (- new-image-height image-offset-y))))

	    (if (> (+ (+ shadow-width shadow-offset-x) shadow-transl-x)
		   new-image-width)
		(set! new-image-width
		      (+ (+ shadow-width shadow-offset-x) shadow-transl-x)))

	    (if (> (+ (+ shadow-height shadow-offset-y) shadow-transl-y)
		   new-image-height)
		(set! new-image-height
		      (+ (+ shadow-height shadow-offset-y) shadow-transl-y)))

	    (gimp-image-resize image
			       new-image-width
			       new-image-height
			       image-offset-x
			       image-offset-y)))

      (set! shadow-layer (car (gimp-layer-new image
					      shadow-width
					      shadow-height
					      type
					      "Drop-Shadow"
					      shadow-opacity
					      NORMAL-MODE)))
      (gimp-image-add-layer image shadow-layer -1)
      (gimp-layer-set-offsets shadow-layer
			      shadow-offset-x
			      shadow-offset-y))

    (gimp-drawable-fill shadow-layer TRANSPARENT-FILL)
    (gimp-context-set-background shadow-color)
    (gimp-edit-fill shadow-layer BACKGROUND-FILL)
    (gimp-selection-none image)
    (gimp-layer-set-lock-alpha shadow-layer FALSE)
    (if (>= shadow-blur 1.0) (plug-in-gauss-rle 1
						image
						shadow-layer
						shadow-blur
						TRUE
						TRUE))
    (gimp-layer-translate shadow-layer shadow-transl-x shadow-transl-y)

    (if (= from-selection TRUE)
	(begin
	  (gimp-selection-load active-selection)
	  (gimp-edit-clear shadow-layer)
	  (gimp-image-remove-channel image active-selection)))

    (if (and
	 (= (car (gimp-layer-is-floating-sel drawable)) 0)
	 (= from-selection FALSE))
	(gimp-image-raise-layer image drawable))

    (gimp-image-set-active-layer image drawable)
    (gimp-image-undo-group-end image)
    (gimp-displays-flush)

    (gimp-context-pop)))

(script-fu-register "script-fu-drop-shadow"
		    _"_Drop-Shadow..."
		    "Add a drop-shadow of the current selection or alpha-channel"
		    "Sven Neumann <sven@gimp.org>"
		    "Sven Neumann"
		    "1999/12/21"
		    "RGB* GRAY*"
		    SF-IMAGE       "Image"          0
		    SF-DRAWABLE    "Drawable"       0
		    SF-ADJUSTMENT _"Offset X"       '(8 -4096 4096 1 10 0 1)
		    SF-ADJUSTMENT _"Offset Y"       '(8 -4096 4096 1 10 0 1)
		    SF-ADJUSTMENT _"Blur radius"    '(15 0 1024 1 10 0 1)
		    SF-COLOR      _"Color"          '(0 0 0)
		    SF-ADJUSTMENT _"Opacity"        '(80 0 100 1 10 0 0)
		    SF-TOGGLE     _"Allow resizing" TRUE)

(script-fu-menu-register "script-fu-drop-shadow"
			 "<Image>/Filters/Light and Shadow/Shadow")