Table of Contents
- Layout Algorithms
- Layout Architecture
- Concepts
- Advanced Layout Features
- Layout Stages
- Class ComponentLayouter
- Class GraphLayoutLineWrapper
- Major Layout Algorithms
- Incremental Layout
- Circular Layout
- Hierarchical Layout
- Hierarchical Layout of Hierarchically Organized Graphs
- Incremental Hierarchical Layout
- Organic Layout
- Smart Organic Layout
- Interactive Organic Layout
- Orthogonal Layout
- Orthogonal Layout of Hierarchically Organized Graphs
- Directed Orthogonal Layout
- Compact Orthogonal Layout
- Tree Layout
- Generic Tree Layout
- Edge Routing Algorithms
- Organic Edge Routing
- Orthogonal Edge Routing
- Channel Edge Routing
- Automatic Label Placement
This chapter discusses the yFiles layout algorithms, and explains their options and customization possibilities. It shows how to create and invoke the algorithms, and how to achieve aesthetic and clear graph layouts. Also, the general layout architecture is introduced, and common concepts for the layout algorithms are described.
The yFiles package
y.layout
together with its sub-packages provides a multitude of different layout
algorithms and styles.
The algorithms divide into three main categories:
- Graph layout algorithms are responsible for assigning coordinates to all graph elements. More precisely, the nodes of a graph are placed according to some optimization criteria, and edge paths are also generated.
- Edge routing algorithms process only edges, i.e., they compute edge paths. The nodes of a graph are left unchanged, neither their position nor their size is altered in any way.
- Label placement algorithms leave both a graph's nodes and its edge paths unaltered, but compute suitable positions for labels. Their criteria for the arrangement are such that the labels do not overlap with each other or any of the graph elements.
Optimization criteria for graph layout algorithms are numerous. They vary from minimizing the length of edge paths to minimizing the number of bends, from placing highly connected components tightly together to placing nodes in a hierarchical top-to-bottom manner. Besides the rather unemotional nature of such optimization, a graph layout algorithm at the same time also aims at making its outcome an aesthetically pleasing experience for a user.
The yFiles graph layout algorithms support a number of sophisticated features when calculating a graph's layout. Most notably, hierarchically organized graphs and arranging their grouped nodes is supported. Bus-like edge paths can be generated for edges connecting to a common node, and both starting point and end point of an edge path can be constrained to a specific side of a node or even explicit coordinates. Additionally, some algorithms provide labeling as an integrated part of layout generation.