Reader support
A feature-by-feature integration guide for reading applications that support ADT WebPub and EPUB exports.
This section is for developers of reading applications. An ADT — an Accessible Digital Textbook — is a publication enriched with narration, language variants, image descriptions, sign language, glossary data, and activities. This guide explains how a reader can make those capabilities available.
The integration model
An ADT export has two layers: a standard WebPub or EPUB that a conforming reader can open, and a compact ADT data layer that enriches the rendered content. Your reader can adopt one feature at a time.
What works without ADT support
| Capability | EPUB | WebPub |
|---|---|---|
| Open, navigation, TOC and page numbers | Native | Native |
| Read-aloud | Native Media Overlays when present; otherwise ADT data | ADT data |
| Glossary | Native EPUB glossary markup | ADT data |
| Language switching and Easy Read | ADT data | ADT data |
| Image descriptions, sign language, activities | ADT data | ADT data |
EPUB offers the most to an unmodified reader. It can carry SMIL Media Overlays and EPUB-native glossary markup. WebPub keeps the feature data as sidecars, so the host reader owns the interface and behaviour.
Start in this order
Open and identify the package
Locate assets/config.json, resolve the package base path, and use the feature flags to decide which controls exist. See Package and startup.
Render the text layer
Apply the active language’s texts.json map to the elements on the rendered page. This establishes the join between the publication and the ADT data. See Text and language.
Add the features your reader can support
Read-aloud, glossary, image descriptions, sign language, and activities are independent additions. Each guide includes the real exported data it consumes.
Integrate with your reader shell
Keep data loading, page injection, controls, cleanup, and validation in clear layers. See Reader integration.