CARTA

A catalog of more than 5,000 passages lives in Supabase Postgres. Decks are served by paginated RPCs that filter, de-duplicate, and rank on the server, with row-level security on every table. A bundled starter library and an on-device cache put the first card on screen instantly and keep the app readable offline.

Kept passages and custom decks persist locally in SwiftData and sync to an optional account. Per-deck state and a staged buffer keep rapid deck switching free of repeats, and For You re-ranks upcoming cards from what a reader keeps and skips.

The signature card-swipe interaction is powered by custom SwiftUI drag gestures tracking translation deltas, instantaneous velocity, and angular rotation transforms.

Dynamic release thresholds determine whether to snap the card back to center or dismiss it off-screen using damped spring physics. View rendering trees were profiled in Xcode Instruments to eliminate main-thread layout thrashing and maintain 120Hz animation fluidity.

Ambient soundscapes (rain, hearth, library, twilight wind) are managed via a dedicated audio coordinator configuring AVAudioSession with ambient mixing categories.

The system observes NotificationCenter events for audio route changes (e.g. AirPods disconnect) and system interruptions (incoming phone calls, alarms), smoothly fading playback volume and resuming state without audio clipping or memory leaks.