Software visualization approaches for code reviews are often implemented as standalone applications, which use static code analysis. The goal is to visualize the structural changes introduced by a pull / merge request to facilitate the review process. In this way, for example, structural changes that hinder code evolution can be more easily identified, but understanding the changed program behavior is still mainly done by reading the code. For software visualization to be successful in code review, tools must be provided that go beyond an alternative representation of code changes and integrate well into the developers' daily workflow. In this paper, we report on the novel and in-progress design and implementation of a web-based approach capable of combining static and dynamic analysis data in software city visualizations. Our architectural tool design incorporates modern web technologies such as the integration into common Git hosting services. As a result, code reviewers can explore how the modified software evolves and execute its use cases, which is especially helpful for distributed software systems. In this context, developers can be directly linked from the Git hosting service's issue tracking system to the corresponding software city visualization. This approach eliminates the recurring action of manual data collection and setup. We implement our design by extending the web-based software visualization tool ExplorViz. We invite other researchers to extend our open source software and jointly research this approach. Video URL: https://youtu.be/DYxijdCEdrY

Developers usually use diagrams and source code to jointly discuss and plan software architecture changes. With this poster, we present our on-going work on a novel approach that enables developers to collaboratively use software city visualization to design and plan software architecture changes.

Software visualizations are usually realized as standalone and isolated tools that use embedded code viewers within the visualization. In the context of program comprehension, only few approaches integrate visualizations into code editors, such as integrated development environments. This is surprising since professional developers consider reading source code as one of the most important ways to understand software, therefore spend a lot of time with code editors. In this paper, we introduce the design and proof-of-concept implementation for a software visualization approach that can be embedded into code editors. Our contribution differs from related work in that we use dynamic analysis of a software system's runtime behavior. Additionally, we incorporate distributed tracing. This enables developers to understand how, for example, the currently handled source code behaves as a fully deployed, distributed software system. Our visualization approach enhances common remote pair programming tools and is collaboratively usable by employing shared code cities. As a result, user interactions are synchronized between code editor and visualization, as well as broadcasted to collaborators. To the best of our knowledge, this is the first approach that combines code editors with collaboratively usable code cities. Therefore, we conducted a user study to collect first-time feedback regarding the perceived usefulness and perceived usability of our approach. We additionally collected logging information to provide more data regarding time spent in code cities that are embedded in code editors. Seven teams with two students each participated in that study. The results show that the majority of participants find our approach useful and would employ it for their own use. We provide each participant's video recording, raw results, and all steps to reproduce our experiment as supplementary package. Furthermore, a live demo of our tool is available online.11https.//code.explorviz.dev We invite other researchers to extend our open-source software.22https://github.com/ExplorViz Video URL: https://youtu.be/3qZVSehnEug

Software visualizations are used by software developers, for instance, for program comprehension. In this context, a less researched aspect is the collaborative use of online visual-ization services. This paper presents the conceptual design and a prototype implementation of our approach for a collaborative software visualization service for program comprehension. The central idea is an online available software-as-a-service application that analyzes, persists, and visualizes software applications which users intend to explore and comprehend via software visualization. The resulting implementation is a redevelopment of our live trace visualization tool Explor Viz. In comparison to other approaches, ExplorViz utilizes WebGL and other browser technologies instead of a game engine to render its visualizations. As a result, we achieve a platform-independent interoperability that is crucial for (remote) collaboration. Here, users can explore the same visualization via our collaboratively usable desktop, virtual reality, and also augmented reality modes. Our prototype follows the Twelve-Factor App methodology to build a cloud-native application that comprises multiple scalable microservices. Thanks to horizontal scaling, our implementation is capable to analyze a large amount of visualization data; thus, allowing multiple users to simultaneously use the software visualization service. We conducted a set of preliminary performance exper-iments to benchmark our prototype's scalability. Results show that the evaluated service scales linearly with increasing load.

In the context of program comprehension, learning and working in teams, e.g., via pair programming, shared documentation, and discussions, can facilitate the comprehension tasks. So far, team collaboration is a relatively unexplored aspect in software visualizations, in particular approaches which are designed and explored to enable collaborative program comprehension.In this paper, we introduce our collaboratively usable software visualization environment for program comprehension. Related approaches are often limited to single-user modes, therefore neglect the advantages of multi-user collaboration, or allow only the use of a single type of device. Our approach addresses this topic and allows users to collaboratively explore software visualizations in a device-heterogeneous environment. User events, e.g., sharable pop-up information windows, are synchronized between each session participant, regardless of the employed device.To the best of our knowledge, this is one of the first approaches that combines on-screen, virtual reality, and augmented reality modes in a single web-based SV tool for program comprehension. We conducted a user study to collect initial results regarding the perceived usefulness and enjoyment of co-explored software cities In that study, 20 participants collaboratively solved program comprehension tasks while using each mode consecutively. The results indicate that the majority of participants find our approach useful and enjoyable, with AR being the least favored mode. We provide each participant’s video recording, the study’s raw results, Jupyter Notebooks, and all steps to reproduce our evaluation as supplementary package. Furthermore, a live demo of our tool is available online.1We invite other researchers to extend our open-source software and jointly research this novel approach.Video URL: https://youtu.be/MYAkRMWLVD8

In software visualization research, various approaches strive to create immersive environments by employing extended reality devices. In that context, only few research has been conducted on the effect of collaborative, i.e., multi-user, extended reality environments. We present our journey toward a web-based approach to enable (location-independent) collaborative program comprehension using desktop, virtual reality, and mobile augmented reality devices. We designed and implemented three multi-user modes in our web-based live trace visualization tool ExplorViz. Users can employ desktop, mobile, and virtual reality devices to collaboratively explore software visualizations. We conducted two preliminary user studies in which subjects evaluated our VR and AR modes after solving common program comprehension tasks. The VR and AR environments can be suitable for collaborative work in the context of program comprehension. The analyzed feedback revealed problems regarding the usability, e.g., readability of visualized entities and performance issues. Nonetheless, our approach can be seen as a blueprint for other researchers to replicate or build upon these modes and results. ExplorViz’s multi-user modes are our approach to enable heterogeneous collaborative software visualizations. The preliminary results indicate the need for more research regarding effectiveness, usability, and acceptance. Unlike related work, we approach the latter by introducing a multi-user augmented reality environment for software visualizations based on off-the-shelf mobile devices.