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--- magistraleinformaticanetworking:spm:skelfsem [31/03/2011 alle 08:32 (15 anni fa)] – [OCAML functional semantics for the sample skeleton set] Marco Danelutto
+++ magistraleinformaticanetworking:spm:skelfsem [31/03/2011 alle 08:36 (15 anni fa)] (versione attuale) – [Source code] Marco Danelutto
@@ Linea 252: / Linea 252: @@
 end;;
+</code>
+<code ocaml Img.ml>
+(** Sample usage of Skeleton functional semantics
+    We use a dummy Image format (array of array of pixels)
+    and we define some functions over images to be used in
+    pipeline stages.
+    Functions are defined as map s *)
+open Skeleton
+(** the type of black and white pixels: levels of gray *)
+type bw_pixel = BWP of int;;
+(** the type of black and white images: 2 dim array of pixels *)
+type bw_image = BWImage of bw_pixel array array;;
+(** the type of color pixels: RGB *)
+type col_pixel = CP of int * int * int;;
+(** the type of color images: 2 dim array of pixels *)
+type col_image = Image of col_pixel array array;;
+(** sample image definition *)
+let p1 = CP(127,127,127);;
+let p2 = CP(0,0,64);;
+let p3 = CP(0,64,0);;
+let p4 = CP(64,0,0);;
+let a = Image [| [| p1; p1; p1; p2; p2 |] ;
+                 [| p2; p3; p3; p4; p1 |] ;
+	         [| p1; p1; p1; p1; p1 |] ;
+		 [| p1; p2; p2; p2; p1 |] |];;
+(** changes color pixels to black and white *)
+let col_to_bw x  =
+  match x with
+  CP(r,g,b) -> BWP(r+g+b);;
+(** kind of smooth pixel *)
+let average =
+  function
+    CP(x,y,z) ->
+      let n = ((x+y+z)/3) in
+      CP(n,n,n);;
+(** invert colors *)
+let invert = function
+  CP(r,g,b) -> CP(255-r, 255-g, 255-b);;
+(** kind of saturation *)
+let sq = function
+  CP(r,g,b) -> let msq x = ((x*x) mod 256) in
+    CP((msq r), (msq g), (msq b));;
+(** generic stage: takes a pixel processing function (Color to Color) and
+    returns the stage working on the whole array of arrays
+    @param f the function to be applied *)
+let stage f =
+  function
+    Image x -> Image ( (map (map f)) x);;
+(** sample stage definitions *)
+let stage_average = stage average;;
+let stage_sq = stage sq;;
+(** color to black and white stage: this could not be defined through stage function
+    as the type of the output image changes ... *)
+let c_to_bw_stage = function
+  Image x -> BWImage((map (map col_to_bw)) x);;
+(** sample main program *)
+let main =
+  pipe
+    (pipe (stage invert) (stage average))
+    c_to_bw_stage ;;
 </code>