Eunchurn Park f9b604f04e Add XTC/XTCH ebook format support (#135) ...

## Summary

* **What is the goal of this PR?**

Add support for XTC (XTeink X4 native) ebook format, which contains
pre-rendered 480x800 1-bit bitmap pages optimized for e-ink displays.

* **What changes are included?**

- New `lib/Xtc/` library with XtcParser for reading XTC files
- XtcReaderActivity for displaying XTC pages on e-ink display
- XTC file detection in FileSelectionActivity
- Cover BMP generation from first XTC page
- Correct XTG page header structure (22 bytes) and bit polarity handling

## Additional Context

- XTC files contain pre-rendered bitmap pages with embedded status bar
(page numbers, progress %)
- XTG page header: 22 bytes (magic + dimensions + reserved fields +
bitmap size)
- Bit polarity: 0 = black, 1 = white
- No runtime text rendering needed - pages display directly on e-ink
- Faster page display compared to EPUB since no parsing/rendering
required
- Memory efficient: loads one page at a time (48KB per page)
- Tested with XTC files generated from https://x4converter.rho.sh/
- Verified correct page alignment and color rendering
- Please report any issues if you test with XTC files from other
sources.

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

2025-12-29 01:56:05 +11:00

18 KiB

Raw Blame History

View Raw