scroll_spy 0.2.2

Compute focused items and a stable primary item in a scrollable viewport (feed/autoplay/analytics).

0.2.2 — 2025-12-20

Docs-only release with refreshed preview media.

Changed

• Updated demo gif.
• Adjusted README preview sizing.

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0.2.1 — 2025-12-20

Insets-aware viewport support plus metrics filtering.

Added

• viewportInsets and insetsAffectVisibility on ScrollSpyScope and all wrapper widgets.
• metricsNotificationPredicate to filter ScrollMetricsNotification signals.
• Geometry guard to skip entries from mismatched viewports (nested scrollables safety).
• Tests for viewport insets + metrics predicate behavior.

Changed

• Focus anchor and region evaluation now use the effective (insets-deflated) viewport.
• Debug overlay now visualizes the effective viewport bounds by default.

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0.2.0 — 2025-12-20

Performance-focused release with low-overhead per-item signals for large feeds.

Highlights

• Per-item boolean notifiers for primary/focused/visible state.
• ScrollSpyItemLite to rebuild only when those booleans toggle.
• Builder/listener widgets for boolean signals (no rebuild when unchanged).

Added

• ScrollSpyController.itemIsPrimaryOf(id).
• ScrollSpyController.itemIsFocusedOf(id).
• ScrollSpyController.itemIsVisibleOf(id).
• ScrollSpyItemLite<T>.
• ScrollSpyItemPrimaryBuilder / ScrollSpyItemFocusedBuilder / ScrollSpyItemVisibleBuilder.
• ScrollSpyItemPrimaryListener / ScrollSpyItemFocusedListener / ScrollSpyItemVisibleListener.

Changed

• Per-item notifier updates now iterate tracked listeners (O(listeners)) and use diff-based updates for boolean signals (behavior unchanged).

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0.1.0 — 2025-12-19

Initial public release of scroll_spy.

Highlights

• Compute focused items plus a single stable primary winner.
• Configurable focus region, selection policy, stability, and update cadence.
• Debug overlay for visualizing region, bounds, and per-item metrics.
• Convenience wrappers and builders for rapid integration.

Added

• Focus engine that computes focused items and a single stable primary item.
• ScrollSpyScope<T> to observe a scrollable subtree.
• ScrollSpyItem<T> for per-item registration + focused/primary rebuild isolation.
• ScrollSpyController<T> exposing primaryId, focusedIds, snapshot, and itemFocusOf(id).
• Focus regions:
  • line (anchor + optional thickness)
  • zone (anchor + extentPx)
  • custom (anchor + evaluator)
• Primary selection policies:
  • closestToAnchor
  • largestVisibleFraction
  • largestFocusOverlap
  • largestFocusProgress
  • custom comparator
• Stability controls:
  • hysteresisPx
  • minPrimaryDuration
  • preferCurrentPrimary
  • allowPrimaryWhenNoItemFocused
• Update policies:
  • perFrame
  • onScrollEnd (debounced)
  • hybrid (drag per-frame + throttled ballistic + final settle)
• Debug overlay (optional):
  • focus region visualization
  • primary/focused outlines
  • optional labels
  • optional rect inclusion (debug-only)
• Diagnostics hook: ScrollSpyDiagnostics.
• Convenience wrappers:
  • ScrollSpyListView / ScrollSpyGridView / ScrollSpyCustomScrollView / ScrollSpyPageView
• Builder/listener utilities:
  • ScrollSpyPrimaryBuilder / ScrollSpyPrimaryListener
  • ScrollSpyFocusedIdsBuilder
  • ScrollSpySnapshotBuilder
  • ScrollSpyItemFocusBuilder

Notes

• For best performance, keep the debug overlay disabled in release builds.
• When using nested scrollables, configure notificationDepth / notificationPredicate to filter signals.