GraphRenderer.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program 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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.uqac.lif.synthia.tree;
 
import java.io.PrintStream;
import java.util.ArrayDeque;
import java.util.HashSet;
import java.util.Queue;
import java.util.Set;
 
/**
 * Renders a tree of labeled nodes as a <a href="https://graphviz.org">Graphviz</a>
 * input file.
 * @author Sylvain Hallé
 * @ingroup API
 */
public class GraphRenderer<T> extends GraphCrawler<T>
{
    
    protected boolean m_directed;
    
    protected String m_nodeString;
    
    public GraphRenderer(boolean directed)
    {
        super();
        m_directed = directed;
        m_nodeString = "[style=\"filled\",shape=\"circle\",label=\"\"]";
    }
    
    public GraphRenderer<T> setNodeString(String s)
    {
        m_nodeString = s;
        return this;
    }
    
    public void printToDot(PrintStream ps, Node<T> n)
    {
        if (m_directed)
        {
            ps.println("digraph G {");
        }
        else
        {
            ps.println("graph G {");
        }
        ps.println("node " + m_nodeString + ";");
        Set<Node<T>> visited = new HashSet<Node<T>>();
        Queue<Node<T>> to_visit = new ArrayDeque<Node<T>>();
        to_visit.add(n);
        while (!to_visit.isEmpty())
        {
            Node<T> current = to_visit.remove();
            if (visited.contains(current))
            {
                continue;
            }
            visited.add(current);
            int id = getId(current);
            ps.println(id + " [color=\"" + getColor(current) + "\",label=\"" + getLabel(current) + "\"];");
            for (Node<T> child : current.getChildren())
            {
                int t_id = getId(child);
                if (m_directed)
                {
                    ps.println(id + " -> " + t_id + ";");
                }
                else
                {
                    if (!visited.contains(child))
                    {
                        ps.println(id + " -- " + t_id + ";");   
                    }
                }
                if (!visited.contains(child) && !to_visit.contains(child))
                {
                    to_visit.add(child);
                }
            }
        }
        ps.println("}");
    }
    
    protected String getColor(Node<T> n)
    {
        return "grey";
    }
    
    protected String getLabel(Node<T> n)
    {
        return n.toString();
    }
    
    @SuppressWarnings("unchecked")
    public static void toDot(PrintStream ps, Node<? extends Object> start)
    {
        GraphRenderer<Object> gr = new GraphRenderer<Object>(false);
        gr.printToDot(ps, (Node<Object>) start);
    }
}