CompactOrthogonalLayout

Layout Style

This layout algorithm is a variant of OrthogonalLayout that tries to arrange nodes in a more compact way. It allows to specify a desired aspect ratio for the bounds of the calculated layout. Nodes of a given graph are arranged such that each edge is drawn as an alternating sequence of horizontal and vertical segments.

CompactOrthogonalLayout is well suited for small and medium-sized sparse graphs and produces compact drawings with no overlapping nodes, few crossings and few bends. It is also especially suitable for printing the diagram on a paper of predefined size. As a disadvantage, this algorithm will usually produce less elegant edge routes than the ones of OrthogonalLayout.

Application domains of orthogonal drawings are software engineering, project management, function call graphs and object-oriented class diagrams.

Sample output of the layout algorithm with aspect ratio 1.0

Concept

This algorithm is implemented as a PartitionLayout and applies the following steps:

• Divides the graph into smaller partitions using the partition finder instance created by createEdgeBetweennessPartitionFinder.
• Arranges the nodes of each graph partition using OrthogonalLayout.
• Arranges the partitions themselves in a compact manner using the partition placer instance created by createComponentPartitionPlacer.
• Routes the edges between partitions (inter-edges) using the router instance created by createChannelInterEdgeRouter.

Each of these steps can be individually configured and/or replaced. To do so, use methods partitionFinder, coreLayout, partitionPlacer and interEdgeRouter, respectively.

Features

The aspect ratio of the resulting layout bounds, i.e., the ratio of width/height of the layout, can be configured using aspectRatio. CompactOrthogonalLayout tries to reach this preferred value. However, depending on the actual graph structure, this may not always be possible.

Octilinear routing of edges can be supported by appending PolylineLayoutStage.