Data commit

Task/Bitmap-Read-a-PPM-file/OCaml/bitmap-read-a-ppm-file-1.ocaml

@@ -0,0 +1,38 @@
+let read_ppm ~filename =
+  let ic = open_in filename in
+  let line = input_line ic in
+  if line <> "P6" then invalid_arg "not a P6 ppm file";
+  let line = input_line ic in
+  let line =
+    try if line.[0] = '#'  (* skip comments *)
+    then input_line ic
+    else line
+    with _ -> line
+  in
+  let width, height =
+    Scanf.sscanf line "%d %d" (fun w h -> (w, h))
+  in
+  let line = input_line ic in
+  if line <> "255" then invalid_arg "not a 8 bit depth image";
+  let all_channels =
+    let kind = Bigarray.int8_unsigned
+    and layout = Bigarray.c_layout
+    in
+    Bigarray.Array3.create kind layout 3 width height
+  in
+  let r_channel = Bigarray.Array3.slice_left_2 all_channels 0
+  and g_channel = Bigarray.Array3.slice_left_2 all_channels 1
+  and b_channel = Bigarray.Array3.slice_left_2 all_channels 2
+  in
+  for y = 0 to pred height do
+    for x = 0 to pred width do
+      r_channel.{x,y} <- (input_byte ic);
+      g_channel.{x,y} <- (input_byte ic);
+      b_channel.{x,y} <- (input_byte ic);
+    done;
+  done;
+  close_in ic;
+  (all_channels,
+   r_channel,
+   g_channel,
+   b_channel)

Task/Bitmap-Read-a-PPM-file/OCaml/bitmap-read-a-ppm-file-2.ocaml

@@ -0,0 +1,5 @@
+let () =
+  let img = read_ppm ~filename:"logo.ppm" in
+  let img = to_color(to_grayscale ~img) in
+  output_ppm ~oc:stdout ~img;
+;;