(************************************************************
   prototype.ml		Created      : Thu Jun 20 00:58:19 2002
  			Last modified: Fri Jun 21 11:45:39 2002
  Compile: ocamlopt graphics.cmxa prototype.ml -o prototype #
  (*	$Id: prototype.ml,v 1.2 2002/06/21 02:33:47 tak Exp tak $	*)
************************************************************)
(* リンクによるグラフ表現
 * v1.1 とりあえず簡単な描画
 *
 *
 *
 *
 *
 *)

type point2d = Point2D of int * int
type node = Node of point2d * string * (node list)

let radius = 20
let threshold_of_square_distance = 
  let tmp = 2*20+10 in tmp * tmp

let background_color = Graphics.white
let node_color = Graphics.magenta
let label_color = Graphics.green
let edge_color = Graphics.red

let label_size = 20
let open_option = " 200x200+0-0"

open Graphics
let draw_node (Node((Point2D(x,y)),label,_)) = 
  begin
    set_color node_color;
    fill_circle x y radius;
    moveto (x-5) (y-5);
    set_color label_color;
    draw_string label;
  end

(* draw_edge from to *)
let draw_edge_sub (Point2D(x1,y1)) (Node((Point2D(x2,y2)),_,_)) =
  let diff_x = x2-x1 and
      diff_y = y2-y1 in
  let c = (float_of_int diff_y)/.(float_of_int diff_x) and
      r2 = float_of_int (radius * radius) in
  let c2 = c *. c in
  let delta_x = sqrt (r2 /. (1.0 +. c2)) in (* |△x| *)
  let dy = int_of_float (c *. delta_x) in
  let dx = int_of_float delta_x in
  let sign_x = (if diff_x < 0 then -1 else 1) and
      sign_y = (if diff_y < 0 then -1 else 1) in
  let nx1 = x1 + sign_x * dx and
      ny1 = y1 + sign_y * dy and
      nx2 = x2 - sign_x * dx and
      ny2 = y2 - sign_y * dy in
  begin
    Graphics.set_color edge_color;
    Graphics.moveto nx1 ny1;
    Graphics.lineto nx2 ny2;
  end

let draw_edges (Node(p,_,lst)) =
  List.iter (draw_edge_sub p) lst

(************************************************************
 * 描画エンジン
 * 
 *)

let square_distance_of_edge (Node((Point2D(x1,y1)),_,_))
    (Node((Point2D(x2,y2)),_,_)) =
  let diff_x = x1-x2 and
      diff_y = y1-y2 in
  diff_x*diff_x + diff_y*diff_y

let erase_node (Node((Point2D(x,y)),_,_)) =
  begin 
    Graphics.set_color background_color;
    fill_circle x y radius;
  end

(*let correct_node ((Node((Point2D(x,y)),_)) as node) =*)
(*  (* judge *)*)
(*  let threshold_of_square_distance*)
(*  erase_node node;*)

(************************************************************
 * テキスト表現からデータへ
 * a: b c d   (b->a, c->a, d->a)
 *)


let init () =
  begin
    open_graph open_option;
    set_text_size label_size;
  end

let _ =
  begin
    init ();
    let	n2 = Node((Point2D(100,70)),"mamewo",[]) and
	n3 = Node((Point2D(50,120)),"au",[]) in
    let n1 = Node((Point2D(20,30)),"tak",[n2;n3]) in
    List.iter draw_node [n1; n2; n3];
    draw_edges n1;
    while true do () done
  end