## Summary
* **What is the goal of this PR?** This PR introduces a new "Status Bar"
mode that displays a visual progress bar at the bottom of the screen,
providing readers with a graphical indication of their position within
the book.
* **What changes are included?**
* **Settings**: Updated SettingsActivity to expand the "Status Bar"
configuration with a new option: Full w/ Progress Bar.
* **EPUB Reader**: Modified EpubReaderActivity to calculate the global
book progress and render a progress bar at the bottom of the viewable
area when the new setting is active.
* **TXT Reader**: Modified TxtReaderActivity to implement similar
progress bar rendering logic based on the current page and total page
count.
## Additional Context
* The progress bar is rendered with a height of 4 pixels at the very
bottom of the screen (adjusted for margins).
* The feature reuses the existing renderStatusBar logic but
conditionally draws the bar instead of (or in addition to) other
elements depending on the specific implementation details in each
reader.
* Renamed existing 'Full' mode to 'Full w/ Percentage'
* Added new 'Full w/ Progress Bar' option
<img
src="https://github.com/user-attachments/assets/08c0dd49-c64c-4d4d-9fbb-f576c02d05d9"
width="500">
---
### 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**_
## Summary
* **What is the goal of this PR?**
Add support for reading plain text (.txt) files, enabling users to
browse, read, and track progress in TXT documents alongside existing
EPUB and XTC formats.
* **What changes are included?**
- New Txt library for loading and parsing plain text files
- New TxtReaderActivity with streaming page rendering using 8KB chunks
to handle large files without memory issues on ESP32-C3
- Page index caching system (index.bin) for instant re-open after sleep
or app restart
- Progress bar UI during initial file indexing (matching EPUB style)
- Word wrapping with proper UTF-8 support
- Cover image support for TXT files:
- Primary: image with same filename as TXT (e.g., book.jpg for book.txt)
- Fallback: cover.bmp/jpg/jpeg in the same folder
- JPG to BMP conversion using existing converter
- Sleep screen cover mode now works with TXT files
- File browser now shows .txt files
## Additional Context
* Add any other information that might be helpful for the reviewer
* Memory constraints: The streaming approach was necessary because
ESP32-C3 only has 320KB RAM. A 700KB TXT file cannot be loaded entirely
into memory, so we read 8KB chunks and build a page offset index
instead.
* Cache invalidation: The page index cache automatically invalidates
when file size, viewport width, or lines per page changes (e.g., font
size or orientation change).
* Performance: First open requires indexing (with progress bar),
subsequent opens load from cache instantly.
* Cover image format: PNG is detected but not supported for conversion
(no PNG decoder available). Only BMP and JPG/JPEG work.
