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Stop 20 Hz playback ticks from re-rendering the full-screen backdrop - #88
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sanylax0 merged 1 commit intoJul 18, 2026
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The jetsam RCA's second finding: Player.tick() writes position at 20 Hz and NowPlayingView's body read it (progress ring, scrubber), so the whole page — including AlbumBackdrop's full-screen .blur(radius:60, opaque:true), a ~14 MB offscreen rasterization with an implicit 0.6 s crossfade — re-evaluated twenty times a second while playing. Two changes: - All player.position reads move into tiny leaf views (TrackProgressRing, ScrubberBar, MiniProgressLine); @observable tracks per-body, so the ticks now invalidate only those leaves. - AlbumBackdrop no longer live-blurs: artwork is downscaled once to a ~40 px bitmap (cached per URL) and upscaled by the compositor — visually identical to the radius-60 blur, zero per-frame offscreen rendering; track changes crossfade between two cached bitmaps.
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What
PR 4 of the jetsam RCA plan — the UI-render branch of the RCA. While playing,
Player.tick()writesposition20×/s;NowPlayingView.body(andMiniPlayerView.bodyin the always-mounted library page) read it, so entire pages re-evaluated at 20 Hz — includingAlbumBackdrop's full-screen.blur(radius: 60, opaque: true), a ~14 MB offscreen rasterization carrying an implicit 0.6 s crossfade animation. Constant invalidation of an offscreen-rendered layer with in-flight animation snapshots is a memory ramp.How
player.positionread moves into tiny dedicated views —TrackProgressRing,ScrubberBar(NowPlayingView),MiniProgressLine(MiniPlayerView).@Observabletracks dependencies per view body, so the 20 Hz ticks now invalidate only those leaves; the backdrop and page chrome never re-evaluate on tick. Visuals unchanged.AlbumBackdropno longer live-blurs. Artwork is downscaled once to a ~40 px bitmap (BackdropRenderer,NSCacheper URL, rendered off-main) and upscaled by the compositor with high interpolation — visually equivalent to a radius-60 gaussian, with zero per-frame offscreen rendering and no 14 MB backing store. Track changes crossfade between two cached bitmaps via an opacity transition; the scrim/vignette overlay is unchanged.Testing
On device: Now Playing should look the same (soft blurred art, crossfade on track change; tweak the 40 px constant in
BackdropRendererif you want it softer/sharper). With Instruments → Core Animation "Color Offscreen-Rendered Yellow", the backdrop should no longer glow yellow, and Allocations should show flat memory during plain playback.🤖 Generated with Claude Code
https://claude.ai/code/session_013TJoWkqg8bzkGdzxWhWjWP
Generated by Claude Code