(* LAYER SPLITTING HEURISTIC *)

PROCEDURE SplitLayers(
    dr: Dwg.T;  
    rnd: Random.T;
    <*UNUSED*> inertia: LONG;
    count: NAT;
    <*UNUSED*> name: TEXT;
  ): Dwg.T =
  (*
    Splits layers of "dr" that are too crowded
    Adds new joint nodes where necessary. *)
    
  VAR changed: BOOL := FALSE;
  BEGIN
    Wr.PutText(stderr, "AdjustYGen...");
    WITH 
      G = dr.G,
      nV = G.nV,
      posOld = SUBARRAY(dr.pos^, 0, nV),
      posNew = NEW(REF Points, G.nV)^
    DO
      posNew := posOld;
      FOR ct := 1 TO count DO
        (* Relax the "y" coordinates: *)
        FOR i := 0 TO nV-1 DO 
          WITH 
            ui = u[i],
            xCur = posNew[ui][0] + 0,
            yCur = posNew[ui][1] + 0,
            yNew = HTools.ChooseLayer(ui, G, posNew, yRef, rnd, method, inertia)
          DO 
            (* Wr.PutText(stderr, "  " & FII(ui,yCur) & "->" FI(yNew) & "\n"); *)
            posNew[ui] := Point{xCur, yNew};
            IF yNew # yCur THEN changed := TRUE END;
          END
        END
      END;
      IF NOT changed THEN RETURN NIL END;
      (* Make a copy of the drawing and move the nodes to the new positions: *)
      WITH dc = dr.copy() DO 
        FOR i := 0 TO nV-1 DO u[i] := i END;
        LDwg.MoveBaseNodes(dc, u, posNew, FreeX, AddPoly);
        Wr.PutText(stderr, "\n");
        RETURN dc
      END
    END;
  END SplitLayers;
(* Last edited on 2000-01-11 11:32:59 by stolfi *)