Casper

Personal firmware for Xteink X3/X4, based on CrossPoint Reader 1.5.0 & CrossInk. Huge thanks to everyone for all their hard work!

Casper keeps CrossPoint's stable reader core and CrossInk's excellent stat tracking, then adds a redesigned UI, a new layout engine (Rivulet), thoughtful long-press menus, fully customizable Reader UI, Synopsis Viewer, and StarDict Dictionary with multi-word selection and bilingual packs.

Home themes: Penumbra (X3 clock / X4 title) and Bare.

Themes

Home skins for different reading styles. Pick one under Settings → Display → Theme.

Penumbra (X3)	Penumbra (X4)	Bare

Note: Clock, weekday, and certain date/time features on Penumbra need the X3 RTC (the X4 has no real-time clock). Bare looks the same on both devices.

Penumbra Demo

Gallery

Penumbra Recents	Penumbra Book Stats	Penumbra Lifetime	Synopsis

Reading UI	Multi-Word Lookup	Dictionary Lookup	Reading Stats

Lifetime Stats	Controls	Dictionary Settings	Spanish Translation

Manage Fonts	Customize Reader UI	Settings

Full photo tour: docs/casper.md

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Features

Casper is a personal firmware for the Xteink X3 and X4 (one binary for both devices). It keeps CrossPoint’s solid reader core and CrossInk’s excellent stats system, then adds a redesigned UI, a new layout engine, and a bunch of quality-of-life improvements.

Rivulet Layout Engine

Brand-new EPUB layout engine built for e-ink and real books.

• Respects book CSS for font size, line height, and headings (scaled relative to your chosen size)
• Text wrapping around floated images
• Drop caps
• Much cleaner simple tables
• Stream-based (doesn’t load entire chapters into RAM)
• Full BiDi / right-to-left support retained

Themes

Two carefully designed home experiences under Settings → Display → Theme:

Penumbra
Text-first hub with side-button panels.

• X3: Large clock + weekday, then cycle Title · Recents · Book Stats · Lifetime
• X4: Last-read title/author on top + scrollable Recents list

Bare
Minimal cover-focused theme. Same clean layout on both X3 and X4 — just you and the book.

Reader & Typography

• Completely redesigned Manage Fonts with live 50/50 preview
• Built-in fonts: Source Serif 4 (default) + Lexend Deca
• Body sizes: 10 / 12 / 14 / 16 / 18 pt
• Text Anti-Aliasing with on-device preview
• Fully customizable Reader UI (status bar slots, progress bar, etc.)
• Independent status bars for system UI and reader (6 slots each)
• Battery display options (icon, percent, both, or hidden)

Clippings & Dictionary

• Multi-word selection and clippings (raised limits for small fonts)
• Offline StarDict dictionaries with multi-pack cascade
• Multi-word lookup and bilingual packs supported
• Long-press Select → Dictionary (press again for multi-word mode)

Navigation & Controls

• Fully remappable buttons
• Tabbed navigation (popular setup: side buttons as left/right tabs)
• Long-press menus throughout (Home, Library, Reader)
• Book quick menu (mark finished, synopsis, clear cache, etc.)
• Orient front buttons with reading orientation
• Configurable long-press side buttons (Chapter Skip / Change Orientation)

Progress, Stats & Library

• CrossInk-style reading stats and progress tracking (can be completely disabled)
• Book Stats and Lifetime Stats panels (Penumbra)
• Progress bars on Recents
• Book Synopsis viewer (from quick menu or library)
• Finished books handling (/read folder, hide from Library, Show Read Books in Recents)
• Smarter first-open (skips pure cover/title pages when possible)

Home & Sleep Experience

• Much snappier return to Home after reading
• Cleaner Home refresh (less residual ghosting)
• PNG wallpaper support (in addition to BMP)
• Sleep screen options (Casper Dark / Casper Light)

System

• One binary for X3 and X4
• Wi-Fi passwords stored in shared CrossPoint/CrossInk format
• Stats enable/disable + auto-backup
• Menu font size options
• Various stability improvements (low-memory book open, RTC timeouts, etc.)

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Docs

Doc	Contents
docs/casper.md	Visual showcase of Casper changes (photos)
CASPER.md	Scope, APIs, defaults, implementation notes
docs/dictionary.md	StarDict install and lookup behavior
dist/dictionaries/README.txt	Shipping dictionary packs

Credits & Acknowledgements

Casper is personal firmware for the Xteink X3/X4. It stands on the shoulders of these projects:

Required lineage

• CrossPoint Reader by Dave Allie and contributors — stable reader core, EPUB/TXT/XTC pipeline, dictionary/KOReader infrastructure, and the MIT-licensed base this firmware builds on (release/1.5.0).
• CrossInk by uxjulia — reading stats, progress tracking, and substantial UI/UX design influence.
• FreeInk SDK — shared X3/X4 hardware, display, storage, and device libraries (submodule).

Hardware / display ancestry (via FreeInk)

• Open X4 E-Paper Community SDK and community device ports — e-paper driver sequences and related work; FreeInk’s NOTICE retains the upstream MIT terms.
• CidVonHighwind — original e-ink display work in that lineage (also author of MicroReader, which Casper does not ship as source).

License

See LICENSE (MIT; upstream CrossPoint copyright retained) and FreeInk’s LICENSE / NOTICE for third-party attribution in the SDK.

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Casper’s UI, home themes (Penumbra / Bare), and Rivulet layout engine are original work on top of the stack above.