w5_4.2_ascii_art.ml

type image = int -> int -> bool;;

let all_white = fun x y -> false;;

let all_black = fun x y -> true;;

let checkers = fun x y -> y/2 mod 2 = x/2 mod 2;;

let square cx cy s = fun x y ->
  let minx = cx - s / 2 in
  let maxx = cx + s / 2 in
  let miny = cy - s / 2 in
  let maxy = cy + s / 2 in
  x >= minx && x <= maxx && y >= miny && y <= maxy
;;

let disk cx cy r = fun x y ->
  let x' = x - cx in
  let y' = y - cy in
  (x' * x' + y' * y') <= r * r
;;

type blend =
  | Image of image
  | And of blend * blend
  | Or of blend * blend
  | Rem of blend * blend
;;

let display_image width height f_image =
  for row = 0 to height do
    for col = 0 to width do
      match f_image col row with
      | false -> print_char ' '
      | true -> print_char '#'
    done;
    print_newline ()
  done
;;

let rec render blend x y =
  match blend with
  | Image b -> b x y
  | And (b1, b2) -> ((render b1) x y) && ((render b2) x y)
  | Or (b1, b2) -> ((render b1) x y) || ((render b2) x y)
  | Rem (b1, b2) -> ((render b1) x y) && not ((render b2) x y)
;;

let display_blend width height blend =
  display_image width height (render blend)
;;