Activity diagrams experience an increasing importance in the design
and description of software systems. Unfortunately, previous
approaches for automatic layout support fail or are just
insufficient to capture the complexity of the related requirements.
We propose a new approach tailored to the needs of activity diagrams
which combines the advantages of two fundamental layout concepts called
"Sugiyama's approach" and "topology-shape-metrics approach", originally
developed for layered layouts of directed graphs and for orthogonal layout of
undirected graphs respectively
