;;; R7RS-PNM --- Library for reading and writing PNM (Portable Any Map) files for R7RS
;;; Copyright © 2024 Masaya Tojo <masaya@tojo.tokyo>
;;;
;;; This file is part of R7RS-PNM.
;;;
;;; R7RS-PNM is free software: you can redistribute it and/or modify it
;;; under the terms of the GNU Lesser General Public License as published
;;; by the Free Software Foundation, either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; R7RS-PNM 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 Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public License
;;; along with R7RS-PNM. If not, see <https://www.gnu.org/licenses/>.

(define-library (pnm image)
  (export make-image
          image?
          image-type
          image-width
          image-height
          image-maxval
          image-data
          image-pixel-getter
          image-pixel-setter
          image-pixel-ref
          image-pixel-set!)
  (import (scheme base)
          (scheme case-lambda))
  (begin
    (define-record-type <image>
      (make-image type width height maxval data pixel-getter pixel-setter)
      image?
      (type image-type)
      (width image-width)
      (height image-height)
      (maxval image-maxval)
      (data image-data)
      (pixel-getter image-pixel-getter)
      (pixel-setter image-pixel-setter))

    (define (image-pixel-ref image x y)
      ((image-pixel-getter image) x y))

    (define image-pixel-set!
      (case-lambda
        ((image x y v)
         ((image-pixel-setter image) x y v))
        ((image x y r g b)
         ((image-pixel-setter image) x y r g b))))))