Organic Layout with Edge Labeling

This demo shows how to configure the Organic Layout for automatic edge label placement.

Configuring label placement

Label models and their parameters determine the position of a label. For many interactive use cases, it makes sense to choose a model that restricts the available positions in some way. However, for automatic label placement the opposite is true: Models that do not impose restrictions on a label's position work best. For instance, FreeEdgeLabelModel would be a good choice for integrated label placement.

PreferredPlacementDescriptors may be associated with labels to control automatic placement. Such a descriptor determines if the algorithm will place a label close to its owner edge's source or target node, next to or on the edge, or even rotate the label. For better results when using Organic Layout, both the side and angle of the labels has to be specified relative to the edge.

Note that self-loops and parallel edges are handled by SelfLoopRouter and ParallelEdgeRouter respectively. Thus, labels of such edges are not considered by the organic layout algorithm. To place the labels of these edges, a generic labeling algorithm has to be applied as a post-processing step.

Code Snippet

You can copy the code snippet to configure the layout from GitHub.

Demos

See the Edge Label Placement Demo for a more elaborate example regarding automatic edge label placement.

Documentation

The Labeling and Automatic Label Placement sections in the Developer's Guide contain in-depth discussions of the relevant concepts.

See the PreferredPlacementDescriptor API documentation for detailed information on all available placement options.