;; GIMP "save area" function, (c) Silas S. Brown 2005, 2007.  Version 1.1
;; License: GPL

;; INSTALLATION INSTRUCTIONS
;; -------------------------

;; 1.  If you haven't already run the Gimp, run it.

;; 2.  Find your .gimp directory.  On Unix this will be in
;; your home directory, called .gimp or .gimp-1.2 or
;; similar (if there's more than one then pick the one that
;; corresponds to the version of The GIMP that you're
;; using).  On Windows it'll probably be in
;; C:\Documents and Settings\your user ID\.gimp-2.2 or
;; similar (in other words it will be in the CygWin home
;; directory) or you can find it by searching all files and
;; folders for .gimp.

;; 3.  Save this file (savearea.scm) into the "scripts"
;; subdirectory of the .gimp directory.

;; 4.  Open a new image, right-click on it, go to "File",
;; and there should be an option called "Save area".  It's
;; a good idea to assign a shortcut key to it (personally I
;; use the slash key, /).  In some versions of The GIMP,
;; all you have to do is point at this option and then
;; press the shortcut key that you want to assign to it
;; (and it will then appear next to the menu item).  In
;; other versions of The GIMP, you will have to go to the
;; main window (not the image window) and navigate through
;; File / Preferences / Interface / Configure keyboard
;; shortcuts / Plug-ins, find "Save area" somewhere in the
;; long list that appears, and then type the shortcut key.

;; 5. While configuring The GIMP, I also recommend choosing
;; the Selection tool (the box) if it's not already chosen,
;; and going to File/Preferences/Input Devices and press
;; "Save Input Device Settings Now".  This will cause The
;; GIMP to load with the selection tool by default, which is
;; useful if you do more work with selections than with
;; actual drawing.  (Older versions of The GIMP had the
;; selection tool as the default anyway.)

;; 6.  You should now be able to make a selection and then
;; use that shortcut key to save it quickly, then make
;; another selection and so on.  If this doesn't work in
;; your version of The GIMP then try converting the input
;; images into a different format first (you can use netpbm
;; or imagemagick to batch-convert if necessary).

;; END OF INSTALLATION INSTRUCTIONS

;; ------------------------------------------------------


(define (saveArea img layer)
  (let* ((selection (gimp-selection-bounds img))
    (x1 (cadr selection))
    (y1 (caddr selection))
    (x2 (car (cdr (cdr (cdr selection)))))
    (y2 (car (cdr (cdr (cdr (cdr selection))))))
    (width (- x2 x1))
    (height (- y2 y1))
    (newType (car (gimp-image-base-type img)))
    (myNewType (if (equal? newType 1) 1 0))  ;; "indexed" type (2) is awkward so convert it to RGB (0).  May get a completely-black area anyway, but at least will be able to save as PNG to get the dimensions for derotate.sh.  For other uses I suggest batch-converting first as mentioned in instructions above.
    (newImg (car (gimp-image-new width height myNewType)))
    (newLayer (car (gimp-layer-new newImg width height (* myNewType 2) "layer 1" 100 NORMAL)))
    (_ (gimp-image-add-layer newImg newLayer 0))
    (disp (car (gimp-display-new newImg))) ;; MUST do this otherwise gimp may corrupt when save
    (_ (gimp-edit-copy layer))
    (floatingLayer (car (gimp-edit-paste newLayer 0)))
    (_ (gimp-floating-sel-anchor floatingLayer))
    (_ (plug-in-autocrop 1 newImg newLayer))
    (file (car (gimp-temp-name "-area.png")))
    (_ (file-png-save 1 newImg newLayer file file 0 9 0 0 0 0 0))
    (_ (gimp-display-delete disp))
    ) ()))

   (script-fu-register "saveArea"
      "<Image>/File/Save area"
      "Saves the selected area to a PNG file"
      "Silas S. Brown"
      "Silas S. Brown"
      "2005"
      "" ; any image type
      SF-IMAGE "Image" 0
      SF-DRAWABLE "Layer" 0
      )