INTERFACE GDHeurCreator;

(* Creator heuristics for layered drawings *)

IMPORT Random;

IMPORT GDGraph AS Graph;
IMPORT GDLayeredDrawing AS LDwg;
FROM GDGeometry IMPORT LONG, NAT;

(*
  These heuristic procedures ignore the input drawing "dr" and (usually) return
  a new drawing generated from scratch.  Most of them also ignore the
  "inertia" and "count" arguments.
*)

PROCEDURE FastRandom(
    G: Graph.T;
    <*UNUSED*> dr: LDwg.T;
    rnd: Random.T;
    <*UNUSED*> inertia: LONG;
    <*UNUSED*> count: NAT;
    <*UNUSED*> name: TEXT;
  ): LDwg.T;
  (*
    Generates a "random" drawing for teh graph by placing each vertex
    o a separate layer, then adding edges always outside the current 
    edges. *)
  
PROCEDURE NewRandom(
    G: Graph.T;
    <*UNUSED*> dr: LDwg.T;
    rnd: Random.T;
    <*UNUSED*> inertia: LONG;
    <*UNUSED*> count: NAT;
    <*UNUSED*> name: TEXT;
  ): LDwg.T;
  (*
    Creates a new drawing by placing each node on a distinct level,
    then inserting edges through the middle. *)
  
PROCEDURE SmartRandom(
    G: Graph.T;
    <*UNUSED*> dr: LDwg.T;
    rnd: Random.T;
    inertia: LONG;
    count: NAT;
    <*UNUSED*> name: TEXT;
  ): LDwg.T;
  (*
    Composite heuristic: creates a random drawing with "NewRandom",
    them applies a few rounds fo "AdjustY...", then "FixEDirs",
    then "AdjustXDown" and "AdjustXUp". *)

PROCEDURE WiseRandom(
    G: Graph.T;
    <*UNUSED*> dr: LDwg.T;
    rnd: Random.T;
    <*UNUSED*> inertia: LONG;
    <*UNUSED*> count: NAT;
    <*UNUSED*> name: TEXT;
  ): LDwg.T;
  (*
    Uses "HTools.ChooseYCoords" and "HTools.ChooseXCoords" to pick
    the new node coordinates, then "HTools.WiseAddPolyline" 
    to insert the polylines. *)
    
PROCEDURE ReadFile(
    G: Graph.T;
    <*UNUSED*> dr: LDwg.T;
    <*UNUSED*> rnd: Random.T;
    <*UNUSED*> inertia: LONG;
    <*UNUSED*> count: NAT;
    name: TEXT;
  ): LDwg.T;
  (*
    A `cheating' heuristics - reads a new drawing from file "name",
    whose base graph must be isomorphic to "dr.G". *)

END GDHeurCreator.
(* Last edited on 2000-01-12 18:27:35 by stolfi *)