The normal layer style, where each node takes up only the depth that it needs.
A layer style where all of the children of a parent node take up the same amount of depth -- this typically causes all cousins to be aligned.
A layer style where all nodes with the same TreeVertex.level throughout the tree take up the same amount of depth -- if the TreeVertex.angle is the same for all nodes, this will result in all nodes in the same layer to be aligned.
This enumeration specifies the manner in which nodes are placed into layers. Used for TreeLayout.layerStyle.
since3.0