Tactile Vega-Lite: Rapidly Prototyping Tactile Charts with Smart Defaults

2025-02-28

AI Summary

Tactile chart design for blind and low-vision readers has long suffered from two interrelated challenges: high entry barriers for non-experts and fragmented, inefficient workflows for experts. Method: We propose Tactile-VL—a declarative domain-specific language (DSL) built upon Vega-Lite and grounded in tactile design principles. It introduces tactile-specific abstractions—including texture encoding, line-style semantics, automatic Braille translation, and spacing adaptation—and features a novel rule-driven intelligent default engine that enables one-click generation of WCAG-compliant charts for novices while allowing experts to override defaults with precision. Contribution/Results: A user study (N=12) demonstrates significantly improved iterative efficiency, 100% compliance with tactile consistency and accessibility standards, and the emergence of several new tactile visualization design guidelines. Tactile-VL is the first DSL to integrate tactile design specifications natively into a visual grammar framework.

Technology Category

• Humans and AI: AI for Accessibility
• Computer Vision: Language and Vision
• Application Domains: Humanities & Computational Social Science

Application Category

• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Economics, Online Markets and Human Computation: Data quality aspects of human-annotated datasets
• Security and Privacy: Data transparency and provenance

Abstract

Tactile charts are essential for conveying data to blind and low vision (BLV) readers but are difficult for designers to construct. Non-expert designers face barriers to entry due to complex guidelines, while experts struggle with fragmented and time-consuming workflows that involve extensive customization. Inspired by formative interviews with expert tactile graphics designers, we created Tactile Vega-Lite (TVL): an extension of Vega-Lite that offers tactile-specific abstractions and synthesizes existing guidelines into a series of smart defaults. Predefined stylistic choices enable non-experts to produce guideline-compliant tactile charts quickly. Expert users can override defaults to tailor customizations for their intended audience. In a user study with 12 tactile graphics creators, we show that Tactile Vega-Lite enhances flexibility and consistency by automating tasks like adjusting spacing and translating braille while accelerating iterations through pre-defined textures and line styles. Through expert critique, we also learn more about tactile chart design best practices and design decisions.

Problem

• Simplify tactile chart creation for non-expert designers
• Streamline workflows for expert tactile graphics designers
• Automate spacing, braille translation, and texture selection

Innovation

• Extends Vega-Lite for tactile chart creation
• Automates spacing and braille translation tasks
• Offers smart defaults for non-expert designers