# 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>