; The Scheme code in this file provides some compatibility with
; scripts that were originally written for use with older versions of
; PIKA.
;
; It provides PDB procedures that used to be provided by plug-ins that
; were since then removed from the PIKA distribution. You should not
; use these in newly written scripts as the functions defined here may
; be removed at some later date.


(define (plug-in-color-map run-mode img layer
			   src-color-1 src-color-2 dest-color-1 dest-color-2
			   map-mode)
  (pika-levels layer HISTOGRAM-RED
	       (car src-color-1) (car src-color-2) 1.0
	       (- 255 (car dest-color-1)) (- 255 (car dest-color-2)))
  (pika-levels layer  HISTOGRAM-GREEN
	       (cadr 	src-color-1) (cadr src-color-2) 1.0
	       (- 255 (cadr dest-color-1)) (- 255 (cadr dest-color-2)))
  (pika-levels layer HISTOGRAM-BLUE
	       (caddr src-color-1) (caddr src-color-2) 1.0
	       (- 255 (caddr dest-color-1)) (- 255 (caddr dest-color-2)))
  (pika-levels layer HISTOGRAM-VALUE 0 255 1.0 255 0)
)

; since 3.0 a layer selection can be many,
; so PDB methods to get selections return an int and a GObjectArray,
; which in Scheme is a list containing a numeric and a vector.
; and the word "active" changed to "selected".
; Formerly, such PDB methods returned a list of one element, the ID of a layer.

; A compatible replacement for pika-image-get-active-layer.
; This should be used only when you know the image has only one layer.
; In other situations, you may break a contract to process all selected layers.
(define (pika-image-get-active-layer img)
  (list (aref (cadr (pika-image-get-selected-layers img)) 0))
)