## Summary
**What is the goal of this PR?**
Replaced manual 1-bit BMP header logic in `Xtc::generateCoverBmp()` and
`Xtc::generateThumbBmp()` with calls to the existing `createBmpHeader()`
utility. Added a `BmpRowOrder` enum and param to support the top-down
row order of XTC cover images.
---
### 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? _**PARTIALLY**_
## Summary
* **What is the goal of this PR?** (e.g., Fixes a bug in the user
authentication module,
Display the book cover image in the **"Continue Reading"** card on the
home screen, with fast navigation using framebuffer caching.
* **What changes are included?**
- Display book cover image in the "Continue Reading" card on home screen
- Load cover from cached BMP (same as sleep screen cover)
- Add framebuffer store/restore functions (`copyStoredBwBuffer`,
`freeStoredBwBuffer`) for fast navigation after initial render
- Fix `drawBitmap` scaling bug: apply scale to offset only, not to base
coordinates
- Add white text boxes behind title/author/continue reading label for
readability on cover
- Support both EPUB and XTC file cover images
- Increase HomeActivity task stack size from 2048 to 4096 for cover
image rendering
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
- Performance: First render loads cover from SD card (~800ms),
subsequent navigation uses cached framebuffer (~instant)
- Memory: Framebuffer cache uses ~48KB (6 chunks × 8KB) while on home
screen, freed on exit
- Fallback: If cover image is not available, falls back to standard
text-only display
- The `drawBitmap` fix corrects a bug where screenY = (y + offset) scale
was incorrectly scaling the base coordinates. Now correctly uses screenY
= y + (offset scale)
1. Refactor Bitmap.cpp/h to expose the options for FloydSteinberg and
brightness/gamma correction at runtime
2. Fine-tune the thresholds for Floyd Steiberg and simple quantization
to better match the display's colors
Turns out that 2 is enough to make the images render properly, so the
brightness boost and gamma adjustment doesn't seem necessary currently
(at least for my test image).
Zach Nelson
Eliz
Eunchurn Park
Jonas Diemer
