computer science

Prefuse

Prefuse is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Prefuse rather than just read about it. In short: Prefuse is a Java-based toolkit for building interactive information visualization applications. It supports a rich set of features for data modeling, visualization and interaction.

Key takeaways

Prefuse belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Prefuse to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Prefuse from memory before moving on to harder problems.

Reference excerpt

Prefuse is a Java-based toolkit for building interactive information visualization applications. It supports a rich set of features for data modeling, visualization and interaction. It provides optimized data structures for tables, graphs, and trees, a host of layout and visual encoding techniques, and support for animation, dynamic queries, integrated search, and database connectivity. Prefuse uses the Java 2D graphics library, and is easily integrated into Swing applications or Java applets. Prefuse is licensed under the terms of a BSD license, and can be used freely for commercial and non-commercial purposes.

Overview

Prefuse is a Java-based extensible software framework for creating interactive information visualization applications. It can be used to build standalone applications, visual components and Java applets. Prefuse intends to simplify the processes of visualizing, handling and mapping of data, as well as user interaction. Some of Prefuse's features include:

Table, graph, and tree data structures supporting arbitrary data attributes, data indexing, and selection queries, all with an efficient memory footprint. Components for layout, color, size, and shape encodings, distortion techniques and more. A library of controls for common interactive, direct-manipulation operations. Animation support through a general activity scheduling mechanism. View transformations supporting panning and zooming, including both geometric and semantic zooming. Dynamic queries for interactive filtering of data. Integrated text search using a number of available search engines. A physical force simulation engine for dynamic layout and animation (s.a. Force-directed graph drawing) Flexibility for multiple views, including "overview+detail" and "small multiples" displays. A built in, SQL-like expression language for writing queries to prefuse data structures and creating derived data fields. Support for issuing queries to SQL databases and mapping query results into prefuse data structures. (and perhaps most importantly)

Simple, developer-friendly application programming interfaces (APIs) for creating custom processing, interaction, and rendering components. Prefuse has been used in school course projects, academic and industrial research, and commercial software development.

Architecture The design of the prefuse toolkit is based upon the information visualization reference model, a software architecture pattern that breaks up the visualization process into a series of discrete steps. "Prefuse: a toolkit for interactive information visualization" provides more details on implementation and evaluation. The information visualization reference model was developed in the Ph.D. thesis work of Ed Chi, under the name of the data state model. Chi showed that the framework successfully modeled a wide array of visualization applications. Later, Chi's work showed that the model was functionally equivalent to the data flow model used in existing graphics toolkits such as VTK. In their work, "Readings in Information Visualization: Using Vision to Think", Stuart K. Card, Jock D. Mackinlay, and Ben Shneiderman present their own interpretation of this pattern, dubbing it the "information visualization reference model".

Illustrations

Worked examples

Example 1 — a first encounter with Prefuse

Start with the simplest possible case. Write down what Prefuse claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Prefuse before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Prefuse ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Prefuse

In research: Prefuse appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Prefuse in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Prefuse is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computational science, Free data and information visualization software, Free software programmed in Java, so understanding it makes those chapters shorter.
In everyday life: Look for Prefuse outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Prefuse in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Prefuse means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Prefuse out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Prefuse in simple terms?

Prefuse is a Java-based toolkit for building interactive information visualization applications. It supports a rich set of features for data modeling, visualization and interaction.

Why does Prefuse matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Prefuse?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Prefuse.