Animated Visualization of Software History Using Software Evolution Storyboards
- 1. EPFLEPFL Dirk.Beyer@epfl.chDirk.Beyer@epfl.ch Dirk BeyerDirk Beyer Simon Fraser UniversitySimon Fraser University Dirk.Beyer@sfu.caDirk.Beyer@sfu.ca Animated Visualization of Software History Using Evolution Storyboards Ahmed E. HassanAhmed E. Hassan University Of VictoriaUniversity Of Victoria ahmed@uvic.caahmed@uvic.ca
- 2. Visualizing Software Evolution • Static visualizations of evolution: – fail to capture the dynamics of software evolution • A movie visualization of evolution: – is not easy to control by developers (who want to focus on particular time periods, or parts of a system) • We propose a visualization, evolution storyboards, which strikes a balance between static and movie visualizations
- 3. Storyboard • Produced traditionally beforehand for directors and cinematographers • Used to study movie scenes and to uncover potential problems before they occur
- 5. Evolution Storyboard • An evolution storyboard contains dynamic panels • Each panel depicts consecutively important events and periods in the lifetime of long- lived software systems
- 6. Our Graph Model • Nodes: files/functions/subsystems • Edges: co-change (from CVS) • Layout: energy-based A B C D A B C D C1 C2
- 7. Studied Systems System Years Commits Nodes Edges ArgoUML 8 10,108 20,247 57,036 PostgreSQL 9 7,882 9,086 35,809 Mozilla 6 9,950 11,754 30,938
- 8. Properties of Our Layout Algorithm • Related nodes are placed together, non-related nodes are placed far apart • Strongly connected nodes separate out from the rest of the graph
- 9. Approach Overview • To avoid blur and clutter: – We ignore small movements of a node, • if its degree did not change – We do not highlight a node’s movement, • if it did not move much (e.g. < 1% of panel size) • if its degree is too small – We use a “follow your neighbors” heuristic
- 10. Storyboard Colouring • Authoritative decomposition: – subsystems / directory • Heat Map based on a node’s movement: – Orange (moved in 40% of panels), Yellow (30%), Green (20%), Gray (10%)
- 11. Panels in Evolution Storyboards
- 12. Panels in Evolution Storyboards
- 13. Benefits of Evolution Storyboards • Spot good structure – well separated nodes • Explain decay symptoms: – colouring patterns (separate/mixed colours) • Highlight refactoring candidates: – frequently moving nodes (using heat colouring)
- 15. Mozilla 1st Panel in Storyboard
- 18. Conclusion • Static visualizations of evolution do not capture the dynamics of software evolution • The approach has been applied to several large software systems: Mozilla, ArgoUML, PostgreSQL • Evolution storyboards can help: – Spot good structure – Explain design decay – Highlight refactoring candidates