[EraPartner]

Requested by EraPartner · project thread

Summary

First round of a static performance audit of the Swift frontend (apps/native/Sources/VisionNativeUI). Each change removes work SwiftUI or Core Animation did per pointer move or per composited frame. Nothing was measured: there is no Swift/SwiftUI toolchain for macOS in the cloud container, so every benefit below is reasoning from the code (inference), not a number.

Change	File	What it removes
Table hover band observes its own state (VisionTableHover, VisionTableHoverBand)	Components/VisionTable.swift	hoverY was @State on the table: every pointer move re-ran the table body, content() for every cell, updateCache (which drops the plan) and the full table layout
Row hover fill observes its own flag (RowHoverBand)	Components/LocalDataTable.swift	pointer entering or leaving a row rebuilt that row's cells (AnyView closures)
ChartSelectionScope owns chart hover state	Components/ChartSupport.swift, HomeView.swift	hover over the summary sparkline or monthly trends chart re-ran the whole HomeView body; three unused @State fields removed
Tooltip anchor view only while hovered	Components/VisionTooltip.swift	one AppKit view per tooltip'd control (74 call sites, one in each ledger row)
Rectangular clipShape instead of .mask on the detail column and the canvas	ShellRootView.swift	a mask view over the whole page (offscreen pass through the mask alpha)
No shadow cut-out mask under an opaque card fill	Components/VisionCardLayers.swift	one masked offscreen pass per card on the reduced tier and with Reduce Transparency
shadow-sm cast by the fill, only on variants that have one	Components/VisionButtonStyles.swift	a shadow effect (alpha 0) on every ghost, outline and secondary button
Topbar veil over opaque --card on the reduced tier and with Reduce Transparency	Components/NativeTopbar.swift	a backdrop blur of the page under the bar while scrolled; matches :root.fx-reduced .app-topbar (backdrop-filter: none; background: hsl(var(--card)))

Type of change

• fix — bug fix
• feat — new feature
• refactor — no behavior change
• perf — performance
• docs — documentation only
• chore / ci / test — tooling, build, or tests

Checklist

• Tests pass (bun run test) and lint is clean (bun run lint): not run locally; the CI swift job builds and tests the package
• Types check (bun run typecheck): no TypeScript changed
• Conventional Commit title (type(scope): subject)
• No leftover console.log / debug code
• Affected docs/ pages updated (docs/architecture/native-app.md, new section "Swift redraw and layer optimisations")
• i18n: no strings changed

Architecture & data

• No architectural change
• No API change
• No schema change

Verification

• swiftc -frontend -parse (swift:6.2-noble container) on the nine changed Swift files: exit 0. This checks syntax only; SwiftUI and AppKit do not exist on Linux, so type checking is left to the CI swift job.
• bun scripts/native-lint.ts: native-lint ok.
• Not run: the app itself. No visual check was possible from the cloud.

Residual risk & follow-ups

• Visible change, reduced tier or Reduce Transparency only: once the page has scrolled, the topbar is an opaque card colour under its gradient instead of a blur of the page. At scroll top nothing changes.
• Table hover band: after a table re-lays out under a parked pointer, the band keeps its old row until the pointer next moves.
• Tooltip: the anchor view is created on hover. With no open delay (another tooltip closed under 300 ms ago) the presenter waits up to about 100 ms for it to join the window.
• Card shadow without the cut-out (opaque fill only): the shadow now lies under the card's antialiased edge pixels; inference: not visible.
• Button shadow: cast by the fill shape instead of the composited label, fill and border; same silhouette (inference).

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