Shifts the vertices horizontally ensuring that there is no more
than "distx" units between each column of vertices.
The resulting layout is a denser visual that maintains the existing
structure of the original layout.
For the purposes of this algorithm, vertices with the same value
of the X coordinate are deemed to be in the same "column".
vertices - list of vertices that will be displayed
public edu.uci.ics.jung.graph.Graph<V,E> getGraph()
getGraph in interface edu.uci.ics.jung.algorithms.layout.Layout<V,E>