;
; line-through.scm
;  主線をレイヤ化します
;
;  written by Shinobu Ruho.
;

(define (script-fu-line-through img drawable)

  ; undo グループのはじまり
  (gimp-undo-push-group-start img)

  ; 現在の描画色、背景色保持
  (set! old-fg (car (gimp-palette-get-foreground)))
  (set! old-bg (car (gimp-palette-get-background)))

  ; 元のレイヤをコピーする。
  (set! inv-layer (car (gimp-layer-copy drawable 0)))
  ; コピーしたレイヤを反転
  (gimp-invert img inv-layer)

  ; 主線のレイヤの生成
  (set! width (car (gimp-image-width img)))
  (set! height (car (gimp-image-height img)))
  (set! dtype (car (gimp-drawable-type drawable)))
  (set! line-layer (car (gimp-layer-new img width height dtype "Line-Layer" 100 NORMAL)))

  ; 新たなレイヤを追加する
  (gimp-image-add-layer img inv-layer 0)
  (gimp-image-add-layer img line-layer 0)

  ; 主線のレイヤを塗りつぶす
  (gimp-palette-set-foreground old-bg)
  (gimp-palette-set-background old-fg)
  (gimp-edit-fill img line-layer)

  ; 主線のレイヤにレイヤマスクを追加
  (gimp-layer-add-alpha line-layer)
  (set! layermask (car (gimp-layer-create-mask line-layer 0)))
  (gimp-image-add-layer-mask img line-layer layermask)


  ; 主線内容をコピー
  (gimp-edit-copy img inv-layer)
  ; 主線レイヤのレイヤマスクにペースト
  (set! sel-float (car (gimp-edit-paste img layermask FALSE) ) )
  ; 選択領域の固定
  (gimp-floating-sel-anchor sel-float)

  ; 描画色と背景色を元に戻す
  (gimp-palette-set-foreground old-fg)
  (gimp-palette-set-background old-bg)

  ; アクティブレイヤを主線レイヤに設定
  (gimp-image-set-active-layer img line-layer)
  ; 元のレイヤをコピーしたものを不可視に設定
  (gimp-layer-set-visible inv-layer FALSE)

  ; 本当はこれで色を反転したレイヤを潰しておきたいんだけど、
  ; 入れるとGIMPが落ちる
;  (gimp-layer-delete inv-layer)

  ; undo グループの終わり
  (gimp-undo-push-group-end img)

  ; 出力
  (gimp-displays-flush)
)

(script-fu-register "script-fu-line-through"
        "<Image>/Script-Fu/Original/Line-Through"
        "Line Through a layer"
        "Shinobu Ruho"
        "Shinobu Ruho"
        "2000"
        "RGB*, GRAY*"
        SF-IMAGE "Image" 0
        SF-DRAWABLE "Line to Layer" 0)