// Copyright (C) 1996 DIMACS Center, Rutgers, The State University of New Jersey
// Author(s): Sue Mniszewski (Los Alamos Nat. Lab.),Jonathan Berry

// This software is copyrighted by the DIMACS Center at Rutgers, The State
// University of New Jersey.  IT IS PROVIDED AS IS, AND THE AUTHORS, DIMACS, AND
// RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY  DISCLAIM
// ALL LIABILITY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
// DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

// THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
// IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
// NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
// MODIFICATIONS.

// The authors hereby grant permission to use, copy, modify, distribute,
// and license this software and its documentation for any purpose, provided
// that existing copyright notices are retained in all copies and that this
// notice is included verbatim in any distributions. No written agreement,
// license, or royalty fee is required for any of the authorized uses.
// Modifications to this software may be copyrighted by their authors
// and need not follow the licensing terms described here, provided that
// the new terms are clearly indicated on the first page of each file where
// they apply.

// Last File Update: 31-Jul-1996
// 

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <LINK/graph/Graph.h>
#include <LINK/graph/Attribute.h>
#include <LINK/graph/Vertex.h>
#include <LINK/algorithm/Algorithms.h>


//
// layout the vertices of the graph in a circle
//
void 
CircleLayout(Graph* graph)
{
    double xcenter = 0.5, ycenter = 0.5;
    double pi = 3.14159;
    double two_pi = 2*pi;

    int vertex_count = graph->order();

    double radius = 0.4;
    double angle_inc = two_pi/(double)vertex_count;

    Set<Vertex*> ordered_vertices = DepthFirstSearch(graph);
    SortedArray<Vertex*> verts = graph->vertices();

    Iterator<Vertex*> get_vertex(&verts); 
    Vertex* vertex;
    double angle = 0.0;
    double wx, wy;
    while (get_vertex(vertex)) {
	wx = xcenter + (radius*cos(angle));
	wy = ycenter + (radius*sin(angle));
	setAttribute((GraphObject*) vertex, "x", wx);
	setAttribute((GraphObject*) vertex, "y", wy);
	angle += angle_inc;
    }
}