EvoLens: lens-view visualizations of evolution data

Visualizing software evolution is essential for identifying design erosion that has occurred over the past releases. Making evolutionary aspects explicit via visual representations can help the engineer to focus on particular software parts to identify such hot-spots. Although many tools exist that provide zooming-in and -out within the hierarchical decomposition of a software system, only very few allow an engineer to view a system through a kind of lens view. Our approach called EvoLens is a visualization approach for explorations of evolution data across multiple dimensions. EvoLens is based on temporal lens views. But the graphical representation of this visualization integrates enhanced zooming by navigating through software hierarchies with arbitrary selectable groups of software parts across module or package boundaries. EvoLens allows an engineer to define a focal point for the lens view and navigate along the time dimension by user-defined sliding time windows. The comprehension is supported by using color for metrics of classes. The EvoLens prototype tool has been developed and tested on basis of a large Java application consisting of 580000 LOC that was studied over 18 months of its evolution lifetime.