EPUB 3.3 Guide
Overview of EPUB 3.3 support in AozoraEpub3-JDK21.
What is EPUB 3.3?
EPUB (Electronic Publication) 3.3 is the international standard for e-book formats.
- Official Specification: IDPF EPUB 3.3 Standard
- Japanese Reference: Japanese Book Publishing Association EPUB 3 Production Guide
Enhanced Semantics
EPUB 3.3 emphasizes more detailed metadata and structured information.
- Expanded
epub:typeattributes (for chapters, footnotes, annotations, etc.) - Recommended use of HTML5 semantic elements (
<section>,<article>,<nav>, etc.)
Improved Media Queries
- Enhanced CSS media query support
- Better horizontal/vertical writing mode switching
- Recommended dark mode support
Enhanced Accessibility
- Expanded ARIA label recommendations
- Required alt text for images
- Improved table of contents and landmark structure
AozoraEpub3-JDK21 Support Status
✅ Implemented
- Basic EPUB 3.3 format generation
- CSS compliant with Japanese e-book guidelines
- Ruby (furigana) support
- Vertical text mode support
- Image embedding
- Character variation handling (IVS, gaiji, dakuten)
- Device-specific CSS presets (Kindle, Kobo, etc.)
📋 Planned / Under Development
- Enhanced accessibility metadata
- Advanced media overlay support
- Fixed layout EPUB support
❌ Not Supported
- EPUB 2.0 / KF8 output (EPUB 3.3 only)
- Interactive JavaScript content
- DRM (Digital Rights Management)
Key Features
Ruby (Furigana) Support
<ruby>
<rb>漢字</rb>
<rt>かんじ</rt>
</ruby>
Vertical Text Layout
Use CSS to enable vertical writing:
writing-mode: vertical-rl;
Device Presets
Pre-configured CSS for popular e-readers:
- Kindle Paperwhite
- Kobo Glo / Glo HD
- Sony Reader
How to Use
- Prepare your text file (UTF-8 format)
- Place images in the same directory (optional)
- Run AozoraEpub3 with your text file
- Specify device preset if needed
- The resulting EPUB file is ready for distribution