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

1 files changed, 35 insertions, 0 deletions

diff --git a/pnm/image.scm b/pnm/image.scm
new file mode 100644
index 0000000..449afc6
--- /dev/null
+++ b/pnm/image.scm
@@ -0,0 +1,35 @@
+(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-ref
+          image-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-ref image x y)
+      ((image-pixel-getter image) x y))
+
+    (define image-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))))))