Rito

A Rust-backed EPUB reader core with TypeScript package bindings.

Rito is an EPUB-focused reader engine. It opens EPUB archives, resolves a book-oriented CSS subset, creates layout revisions, builds paint-ready frames, and renders pages or spreads through the browser package facade.

The repository also includes:

• @ritojs/core — the Rust-backed core reader package
• @ritojs/kit — a framework-agnostic controller layer with transitions and overlays
• @ritojs/react — React hooks and components on top of the core packages

Install

pnpm add @ritojs/core

Quick Start

import { createReader } from '@ritojs/core';

const response = await fetch('book.epub');
const canvas = document.querySelector('canvas')!;

// The engine shapes text with pinned font bytes (no system font is
// reachable inside the WASM runtime) — a pinnedFontPolicy is required.
// See docs/getting-started.md for a complete loader.
const reader = await createReader(await response.arrayBuffer(), canvas, {
  width: 800,
  height: 600,
  margin: 40,
  spread: 'double',
  pinnedFontPolicy: await loadPinnedFontPolicy(),
});

reader.renderSpread(0);
console.log(`${reader.totalSpreads} spreads, ${reader.toc.length} TOC entries`);

reader.dispose();

Documentation

• Documentation Index
• Getting Started
• Reader API
• Reference Primitives
• Advanced Entry
• Specialized Subpaths
• Capabilities
• Limitations
• Using @ritojs/kit
• Using @ritojs/react
• Development Docs

Release Scope

Rito is optimized for EPUB book layout, not browser-equivalent web layout.

• EPUB-first rendering model
• small, stable reader API on the main @ritojs/core entry
• source-only TypeScript reference implementation for golden and parity work
• optional higher-level integration packages for controllers and React
• deliberate CSS/layout subset focused on book pagination

See the detailed scope in Capabilities and Limitations.

Development

pnpm install
pnpm run check