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/*******************************************************************************
 * Copyright (c) 2003, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.draw2d.graph;

/**
 * Performs a graph layout on a CompoundDirectedGraph. The input
 * format is the same as for {@link DirectedGraphLayout}. All nodes, including
 * subgraphs and their children, should be added to the
 * {@link DirectedGraph#nodes} field.
 * 
 * The requirements for this algorithm are the same as those of
 * DirectedGraphLayout, with the following exceptions:
 * 

 * There is an implied edge between a subgraph and each of its member nodes.
 * These edges form the containment graph T. Thus, the compound
 * directed graph CG is said to be connected iff Union(G,
 * T) is connected, where G represents the given nodes (including
 * subgraphs) and edges.
 * 
 * 
This algorithm will remove any compound cycles found in the input graph
 * G by inverting edges according to a heuristic until no more cycles
 * are found. A compound cycle is defined as: a cycle comprised of edges from
 * G, T, and T^-1, in the form
 * (c^*e⁺p^*e⁺)*, where
 * T^-1 is the backwards graph of T, c element of T,
 * e element of G, and p element of T^-1.
 * 
 * 
 * @author Randy Hudson
 * @since 2.1.2
 */
public final class CompoundDirectedGraphLayout extends DirectedGraphLayout {

	void init() {
		steps.add(new CompoundTransposeMetrics());
		steps.add(new CompoundBreakCycles());
		steps.add(new RouteEdges());
		steps.add(new ConvertCompoundGraph());
		steps.add(new InitialRankSolver());
		steps.add(new TightSpanningTreeSolver());
		steps.add(new RankAssignmentSolver());
		steps.add(new CompoundPopulateRanks());
		steps.add(new CompoundVerticalPlacement());
		steps.add(new MinCross(new CompoundRankSorter()));
		steps.add(new SortSubgraphs());
		steps.add(new CompoundHorizontalPlacement());
	}

}