Portable EPUBs

Original Article ↗ Hacker News Discussion ↗

Efforts to make EPUB a viable replacement for PDF are drawing both enthusiasm and skepticism. Supporters argue that HTML-based, self-contained “portable EPUBs” could offer reflowable text, better accessibility, and interactive features while remaining offline-capable, but critics worry about JavaScript, remote assets, inconsistent rendering across readers, and the complexity of HTML/CSS compared to PDF’s fixed layout. Many participants converge on a compromise: keep EPUBs as inert, zip-packaged HTML with strong typography and annotation support, but clearly separate use cases that demand fixed, print-like layout from those that benefit from flexible, device-adaptive reading.

Motivation: PDFs vs EPUBs

  • Many agree PDFs are poor for reading on phones/e‑readers due to fixed layout and zoom/scroll friction.
  • Others value PDFs’ stable, author-controlled layout, good for technical manuals, specs, and printing.
  • Several want a format that keeps PDF’s reliability but adds reflow and better accessibility.

EPUB3, “Portable EPUB,” and subsets

  • Multiple commenters note EPUB3 already supports most proposed features (fixed layout, reflow, MathML, media overlays).
  • Implementations are inconsistent; different readers support different slices of the spec, so a constrained “portable” subset is seen as useful by some, unnecessary or regressive by others.
  • Concern: requiring full JS support may hurt portability and exclude popular e‑ink readers that disable JS.

Layout, typography, and pagination

  • Debate over how closely EPUB/HTML should match PDF typography.
  • Some say HTML+CSS were designed for adaptive layout and authors should surrender perfect control.
  • Others highlight CSS’s weak typography (e.g., line-breaking, baseline alignment) and want better tools or dedicated readers with high-end layout engines.
  • Ideas: fixed-layout renditions as defaults, multiple stylesheets for different screen sizes, or precomputed line breaks.

Interactivity, JS, and security

  • Enthusiasts want “living documents” with interactive tables, graphs, and teaching materials.
  • Many oppose JS in ebooks entirely, preferring inert, offline documents; they associate JS with bloat, bugs, tracking, and attack surface.
  • Middle-ground view: JS should be optional enhancement; books must remain usable with JS disabled.

Networking, privacy, and offline use

  • Strong pushback against remote resources in ebooks: breaks offline use and enables reader surveillance (e.g., tracking via pixels).
  • Others argue loading network assets is HTML’s strength and removing it hurts adoption; several readers disagree, valuing immutability and offline reliability.

Annotations and note‑taking

  • Multiple people see rich, portable annotations as a major missing piece for EPUB compared to PDF.
  • Desired features: highlights with precise locations, exportable notes, inline handwritten annotations, and standardized formats (e.g., Web Annotation) so notes travel between readers.
  • Current reality: annotations are app-specific; some users convert EPUB → PDF just to keep handwritten notes.

Tooling, browsers, and complexity

  • Some think EPUB adoption is hampered because browsers don’t natively open .epub, unlike PDFs; others note browser extensions and in-app viewers already exist.
  • Implementing a full HTML/CSS engine is seen as heavy; proposals include using WebViews, drastically restricting the HTML/CSS subset, or even alternative lightweight markup formats.
  • A minority argues EPUB should stay as simple and static as possible to keep readers and DIY devices easy to implement.