~ubuntu-branches/ubuntu/maverick/ocamlgraph/maverick

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(*
 * Graph: generic graph library
 * Copyright (C) 2004
 * Sylvain Conchon, Jean-Christophe Filliatre and Julien Signoles
 * 
 * This software is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License version 2, as published by the Free Software Foundation.
 * 
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * See the GNU Library General Public License version 2 for more details
 * (enclosed in the file LGPL).
 *)

(* $Id: delaunay.mli,v 1.8 2004/02/20 14:37:40 signoles Exp $ *)

(** Delaunay triangulation *)

(** Delaunay triangulation is available for any CCC system in the sense
    of Knuth's ``Axioms and Hulls'' *)
module type CCC = sig

  type point

  val ccw : point -> point -> point -> bool
    (** The counterclockwise relation [ccw p q r] states that the 
      circle through points [(p,q,r)] is traversed counterclockwise 
      when we encounter the points in cyclic order [p,q,r,p,...] **)

  val in_circle : point -> point -> point -> point -> bool
    (** The relation [in_circle p q r s] states that [s] lies 
      inside the circle [(p,q,r)] if [ccw p q r] is true, or outside that 
      circle if [ccw p q r] is false. *)

end

(** The result of triangulation is an abstract value of type [triangulation].
  Then one can iterate over all edges of the triangulation. *)
module type Triangulation = sig

  module S : CCC

  type triangulation

  val triangulate : S.point array -> triangulation
    (** [triangulate a] computes the Delaunay triangulation of a set of 
      points, given as an array [a]. If [N] is the number of points
      (that is [Array.length a]), then the running time is $O(N \log N)$
      on the average and $O(N^2)$ on the worst-case. The space used is 
      always $O(N)$. *)

  val iter : (S.point -> S.point -> unit) -> triangulation -> unit
    (** [iter f t] iterates over all edges of the triangulation [t]. 
      [f u v] is called once for each undirected edge [(u,v)]. *)

  val fold : (S.point -> S.point -> 'a -> 'a) -> triangulation -> 'a -> 'a

end

(** Generic Delaunay triangulation *)
module Make(S : CCC) : Triangulation with module S = S

(** Points with integer coordinates *)
module IntPoints : CCC with type point = int * int

(** Delaunay triangulation with integer coordinates *)
module Int : Triangulation with module S = IntPoints

(** Points with floating point coordinates *)
module FloatPoints : CCC with type point = float * float

(** Delaunay triangulation with floating point coordinates *)
module Float : Triangulation with module S = FloatPoints