Split pnm/pgm.scm and pnm/ppm.scm to organize interfaces

1 files changed, 25 insertions, 0 deletions

diff --git a/pnm/write.scm b/pnm/write.scm
new file mode 100644
index 0000000..038bf82
--- /dev/null
+++ b/pnm/write.scm
@@ -0,0 +1,25 @@
+(define-library (pnm write)
+  (export image-write)
+  (import (scheme base)
+          (pnm image))
+  (begin
+    (define (image-write image out)
+      (define (write-string-u8 str)
+        (string-for-each (lambda (c) (write-u8 (char->integer c) out))
+                         str))
+      (case (image-type image)
+        ((ppm)
+         (write-string-u8 "P6\n"))
+        ((pgm)
+         (write-string-u8 "P5\n"))
+        (else
+         (error "(pnm write) pnm-write: Not supported type" (image-type image))))
+      (write-string-u8 (number->string (image-width image)))
+      (write-string-u8 "\n")
+      (write-string-u8 (number->string (image-height image)))
+      (write-string-u8 "\n")
+      (case (image-type image)
+        ((pgm ppm)
+         (write-string-u8 (number->string (image-maxval image)))
+         (write-string-u8 "\n")))
+      (write-bytevector (image-data image) out))))