Tree

Tree layout requires a tree or a collection of trees as its input. A tree is a graph that contains no undirected cyclic edge path.

General Tab

Layout Style

The layout style determines the overall style of the resulting tree layout. The remaining option tabs allow for the configuration of the chosen layout style in more detail.

Directed
The tree will be laid out hierarchically with the root node at the top. This is a good choice for directed trees with a unique root node and a moderate number of nodes on a single hierarchy level. This layout style uses the input graph as a sketch to determine the order of siblings at a common node. This means that the order of x-coordinates of the nodes in the input graph determine the order of siblings in the resulting layout.
Balloon
The tree will be routed in a quasi-radial style which we call balloon style. This is a good choice for undirected trees or dense or huge trees with a high number of nodes on a single hierarchy level.
Horizontal-Vertical
The children of a node will be either arranged on a horizontal or on a vertical line. The edges will be routed orthogonally in a bus-like fashion. This layout can be very compact if the user has chosen the right alignment type for the children of a node. Subgraphs rooted at selected nodes will be laid out vertically. Subgraphs rooted at unselected nodes will be laid out horizontally.
Compact
Generates compact orthogonal tree drawings. As a layout constraint a preferred aspect ratio (relation of width to height) can be given. This is especially useful when the graph should fit perfectly on a page of given size.

Act on Selection Only

Whether or not to act on selected nodes and edges that are connected to selected nodes only.

Directed Tab

These options configure the layout style Directed in more detail.

Minimal Layer Distance

Determines the minimal distance between parent and child nodes.

Minimal Node Distance

Determines the minimal distance between the siblings of a node.

Orientation

Determines the main layout orientation. The layouter tries to arrange nodes in such a way that all edges point in the main layout direction.

Top to Bottom
The main layout orientation will be from top to bottom. Note that the documentation for the other layout options assumes that this default layout orientation is being used.
Bottom to Top
The main layout orientation will be from bottom to top.
Left to Right
The main layout orientation will be from left to right.
Right to Left
The main layout orientation will be from right to left.

Port Style

Determines the port assignment policy to be used.

Node Centered
Ports will be placed in the center of the corresponding nodes.
Border Centered
Ports will be placed in the center of the border of the corresponding nodes.
Border Distributed
Ports will be distributed along the border of the corresponding nodes.

Orthogonal Edge Routing

If set, all edges will be routed orthogonally in a bus-like fashion. If not set, the edges will be routed as straight line segments.

Balloon Tab

These options configure the layout style Balloon in more detail.

Root Node Policy

Determines which node should be used as root of the tree.

Directed Root
Chooses a node with indegree zero if present A good choice for directed rooted trees.
Center Root
Chooses the root such that the depth of the resulting tree gets minimized.
Weighted Center Root
Chooses the root such that highest number of the all pairs paths traverse this node. This seems to be a natural root for undirected trees.

Preferred Child Wedge

This setting determines the angular range of the sector that will be reserved for the children of a node. The possible angluar range lies between 1 and 359. The remaining angular range (360-x) will be automatically used to accommodate the edge that connects to the root node.

The smaller the chosen value, the more one will gain the impression that the nodes drive away from their root nodes and the center of the graph.

Generally speaking, the compactness of the layout will decrease with smaller values. Very small values will lead to layouts that consume a lot of space.

Preferred Root Wedge

This setting determines the angular range of the sector that will be reserved around the root node of the graph to accommodate the attached subtrees.

Minimal Edge Length

Determines the minimal length of an edge.

Compactness Factor

This parameter influences the length of the tree edges as it is computed by the layouter. The smaller the compactness factor, the shorter the tree-edges and the more compact the overall layout. The bigger the compactness factor the more difficult, and hence slower, the layout computation.

Allow Overlaps

If activated this option further increases compactness of the resulting layout but potentially introduces slight node overlaps.

Horizontal-Vertical Tab

These options configure the layout style Horizontal-Vertical in more detail. Subgraphs rooted at selected nodes will be laid out vertically. Subgraphs rooted at unselected nodes will be laid out horizontally.

Horizontal Space

The minimal horizontal distance between adjacent nodes.

Vertical Space

The minimal vertical distance between adjacent nodes.

Compact Tab

These options configure the layout style Compact in more detail. Children rooted at selected nodes will be laid out in vertical columns. Children rooted at unselected nodes will be laid out in horizontal rows.

Horizontal Space

The minimal horizontal distance between adjacent nodes.

Vertical Space

The minimal vertical distance between adjacent nodes.

Bend Distance

Determines the preferred minimal distance between each two bends of an edge and between the first and last edges and the corresponding ports.

Preferred Aspect Ratio

Determines the preferred aspect ratio (width by height) of the resulting layout. This option allows for creating layouts which for example fit perfectly onto the page of a book.

This option will only be respected if the Use Aspect Ratio of View option is disabled.

Use Aspect Ratio of View

The current aspect ratio of the view will be used to determine the preferred aspect ration of the calculated drawing.