Feature Request: Vertical Continuous Scroll Mode for EPUB

[bimemto]

Summary

Add support for vertical continuous scrolling in EPUB scroll mode, allowing users to scroll vertically through all chapters/spreads seamlessly without needing to swipe horizontally to change spreads.

Current Behavior

In EPUB scroll mode (EPUBPreferences.scroll = true):

• Each spread (chapter/resource) is still contained in a horizontal PaginationView
• Users can scroll vertically within each spread
• To move to the next spread, users must swipe horizontally
• This creates a jarring reading experience with mixed scroll directions

Current: Vertical scroll within spread + Horizontal swipe between spreads
┌─────────────┐
│  Spread 1   │ ← Vertical scroll works here
│             │
│  (scroll ↕) │
└─────────────┘
      ↓ Horizontal swipe required →
┌─────────────┐
│  Spread 2   │
│             │
└─────────────┘

Proposed Behavior

In vertical scroll mode, all spreads should be stacked vertically in PaginationView:

• Users scroll vertically through all content continuously
• Spreads transition seamlessly as user scrolls
• No horizontal swiping required
• Similar to modern web reading experiences (Medium, Substack, etc.)

Proposed: Pure vertical continuous scroll
┌─────────────┐
│  Spread 1   │
│             │ ↕ Vertical scroll through
│  Spread 2   │   all spreads continuously
│             │
│  Spread 3   │
└─────────────┘

Benefits

1. Better UX: Natural reading flow without direction changes
2. Consistency: Matches user expectations from web reading
3. Accessibility: Easier for users with motor difficulties
4. Modern: Aligns with contemporary reading apps (Apple Books scroll mode, Kindle app)