Extending constrained hierarchical layout for drawing UML activity diagrams

While modeling an object-oriented software, a visual language called Unified Modeling Language (UML) may be used. UML is a language and notation for specification, construction, visualization, and documentation of models of software systems. It consists of a variety of diagrams including class diagrams and activity diagrams. Graph layout has become an important area of research in Computer Science for the last couple of decades. There is a wide range of applications for graph layout including data structures, databases, software engineering, VLSI technology, electrical engineering, production planning, chemistry, and biology. Diagrams are more effective means of expressing relational information and automatic graph layout makes them to be more comprehensible. In other words, with graph layout techniques, the readability and the comprehensibility of the graphs increases and the complexity is reduced. UML diagrams are no exception. In this thesis, we present graph layout algorithms for UML activity diagrams based on constrained hierarchical layout. We use an existing implementation of constrained hierarchical layout to draw UML activity diagrams. We analyze and present the results of these new layout algorithms.