Meck/TXT Reader Guide.md

Text Reader Integration for Meck Firmware

Overview

This adds a text reader accessible via the R key from the home screen.

Features:

• Browse .txt files from /books/ folder on SD card
• Word-wrapped text rendering using tiny font (maximum text density)
• Page navigation with W/S/A/D keys
• Automatic reading position resume (persisted to SD card)
• Index files cached to SD for instant re-opens
• Bookmark indicator (*) on files with saved positions
• Compose mode (C) still accessible from within reader

Key Mapping:

Context	Key	Action
Home screen	R	Open text reader
File list	W/S	Navigate up/down
File list	Enter	Open selected file
File list	Q	Back to home screen
Reading	W/A	Previous page
Reading	S/D/Space/Enter	Next page
Reading	Q	Close book → file list
Reading	C	Enter compose mode

---

SD Card Setup

Place .txt files in a /books/ folder on the SD card root. The reader will:

• Auto-create /books/ if it doesn't exist
• Auto-create /.indexes/ for page index cache files
• Skip macOS hidden files (._*, .DS_Store)
• Support up to 50 files

Index format is compatible with the standalone reader (version 3), so if you've used the standalone reader previously, bookmarks and indexes will carry over.

---

Architecture Notes

• The reader renders through the standard UIScreen::render() framework, so no special bypass is needed in the main loop (unlike compose mode)
• SD card uses the same HSPI bus as e-ink display and LoRa radio — CS pin management handles contention
• Page content is pre-read from SD into a memory buffer during handleInput(), then rendered from buffer during render() — this avoids SPI bus conflicts during display refresh
• Layout metrics (chars per line, lines per page) are calculated dynamically from the display driver's font metrics on first entry