Xteink-X4-crosspoint-reader/lib/Xtc
Dave Allie 5e24895f6d
feat: Extract author from XTC/XTCH files (#563)
## Summary

* Extract author from XTC/XTCH files

## Additional Context

* Based on updated details in
https://gist.github.com/CrazyCoder/b125f26d6987c0620058249f59f1327d

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### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? No
2026-01-27 22:56:51 +11:00
..
Xtc feat: Extract author from XTC/XTCH files (#563) 2026-01-27 22:56:51 +11:00
README Add XTC/XTCH ebook format support (#135) 2025-12-29 01:56:05 +11:00
Xtc.cpp feat: Extract author from XTC/XTCH files (#563) 2026-01-27 22:56:51 +11:00
Xtc.h feat: Extract author from XTC/XTCH files (#563) 2026-01-27 22:56:51 +11:00

# XTC/XTCH Library

XTC ebook format support for CrossPoint Reader.

## Supported Formats

| Format | Extension | Description                                  |
|--------|-----------|----------------------------------------------|
| XTC    | `.xtc`    | Container with XTG pages (1-bit monochrome)  |
| XTCH   | `.xtch`   | Container with XTH pages (2-bit grayscale)   |

## Format Overview

XTC/XTCH are container formats designed for ESP32 e-paper displays. They store pre-rendered bitmap pages optimized for the XTeink X4 e-reader (480x800 resolution).

### Container Structure (XTC/XTCH)

- 56-byte header with metadata offsets
- Optional metadata (title, author, etc.)
- Page index table (16 bytes per page)
- Page data (XTG or XTH format)

### Page Formats

#### XTG (1-bit monochrome)

- Row-major storage, 8 pixels per byte
- MSB first (bit 7 = leftmost pixel)
- 0 = Black, 1 = White

#### XTH (2-bit grayscale)

- Two bit planes stored sequentially
- Column-major order (right to left)
- 8 vertical pixels per byte
- Grayscale: 0=White, 1=Dark Grey, 2=Light Grey, 3=Black

## Reference

Original format info: <https://gist.github.com/CrazyCoder/b125f26d6987c0620058249f59f1327d>