Add `image-format` prefix to library name

1 files changed, 123 insertions, 0 deletions

diff --git a/image-format/pnm/write.scm b/image-format/pnm/write.scm
new file mode 100644
index 0000000..b2f807c
--- /dev/null
+++ b/image-format/pnm/write.scm
@@ -0,0 +1,123 @@
+;;; 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 (image-format pnm write)
+  (export pnm-image-write)
+  (import (scheme base)
+          (scheme case-lambda)
+          (image-format pnm image))
+  (begin
+    (define pnm-image-write
+      (case-lambda
+        ((pnm-image out)
+         (case (pnm-image-type pnm-image)
+           ((ppm)
+            (write-string-u8 "P6\n" out))
+           ((pgm)
+            (write-string-u8 "P5\n" out))
+           ((pbm)
+            (write-string-u8 "P4\n" out))
+           (else
+            (error "(image-format pnm write) pnm-image-write: Not supported type" (pnm-image-type pnm-image))))
+         (write-string-u8 (number->string (pnm-image-width pnm-image)) out)
+         (write-string-u8 " " out)
+         (write-string-u8 (number->string (pnm-image-height pnm-image)) out)
+         (write-string-u8 "\n" out)
+         (case (pnm-image-type pnm-image)
+           ((pgm ppm)
+            (write-string-u8 (number->string (pnm-image-maxval pnm-image)) out)
+            (write-string-u8 "\n" out)))
+         (write-bytevector (pnm-image-data pnm-image) out))
+        ((pnm-image out plain?)
+         (if plain?
+             (pnm-image-write/plan pnm-image out)
+             (pnm-image-write pnm-image out)))))
+
+    (define (pnm-image-write/plan pnm-image out)
+      (case (pnm-image-type pnm-image)
+        ((ppm)
+         (write-string-u8 "P3\n" out))
+        ((pgm)
+         (write-string-u8 "P2\n" out))
+        ((pbm)
+         (write-string-u8 "P1\n" out))
+        (else
+         (error "(image-format pnm write) image-write: Not supported type" (pnm-image-type pnm-image))))
+      (write-string-u8 (number->string (pnm-image-width pnm-image)) out)
+      (write-string-u8 " " out)
+      (write-string-u8 (number->string (pnm-image-height pnm-image)) out)
+      (write-string-u8 "\n" out)
+      (case (pnm-image-type pnm-image)
+        ((pgm ppm)
+         (write-string-u8 (number->string (pnm-image-maxval pnm-image)) out)
+         (write-string-u8 "\n" out)))
+      (let-values (((write-token write-newline)
+                    (limit-line-length-writer 70 out)))
+        (let ((width (pnm-image-width pnm-image))
+              (height (pnm-image-height pnm-image)))
+          (define (write-raster write-pixel)
+            (do ((y 0 (+ y 1)))
+                ((= y height))
+              (write-pixel 0 y)
+              (do ((x 1 (+ x 1)))
+                  ((= x width))
+                (write-pixel x y))
+              (write-newline)))
+          (case (pnm-image-type pnm-image)
+            ((ppm)
+             (write-raster
+              (lambda (x y)
+                (let-values (((r g b) (pnm-image-ref pnm-image x y)))
+                  (write-token (number->string r))
+                  (write-token (number->string g))
+                  (write-token (number->string b))))))
+            ((pgm)
+             (write-raster
+              (lambda (x y)
+                (let ((v (pnm-image-ref pnm-image x y)))
+                  (write-token (number->string v))))))
+            ((pbm)
+             (write-raster
+              (lambda (x y)
+                (let ((b (pnm-image-ref pnm-image x y)))
+                  (write-token (if b "1" "0"))))))))))
+
+    (define (write-string-u8 str out)
+      (string-for-each (lambda (c) (write-u8 (char->integer c) out))
+                       str))
+
+    (define (limit-line-length-writer limit out)
+      (let ((current-length 0))
+        (define (write-token str)
+          (let ((str-len (string-length str)))
+            (cond ((zero? current-length)
+                   (write-string-u8 str out)
+                   (set! current-length str-len))
+                  ((<= (+ current-length str-len 1) limit)
+                   (write-string-u8 " " out)
+                   (write-string-u8 str out)
+                   (set! current-length (+ current-length 1 str-len)))
+                  (else
+                   (write-string-u8 "\n" out)
+                   (write-string-u8 str out)
+                   (set! current-length str-len)))))
+        (define (write-newline)
+          (write-string-u8 "\n" out)
+          (set! current-length 0))
+        (values write-token
+                write-newline)))))