bklit-studio-chart-performance

Studio chart performance

Use when a chart feels sluggish in Studio but similar charts (e.g. pie-chart) are fine.

One-line rule

Keep enter animation on paths if you need it, then drop Motion path subscriptions and isolate hover so Studio slider and legend updates don't replay expensive arc/path math across every series every frame.

1. Find what re-renders on every interaction

Studio updates displayState on every slider tick and on legend/slice hover. Trace:

• Does hover live in the same context as data, scales, and animation config?
• Does the preview recreate children (data.map, pattern defs, motion props) every render?
• Does the chart remount unnecessarily (key tied to motion signature vs manual replay)?

Pattern: Split context like cartesian / pie charts — stable slice (data, geometry, animation config) vs hover slice (hoveredIndex, tooltip). Consumers that don't need hover use only the stable hook (usePieStable, useRingStable, useChartStable, …).

Studio pan: Wrap chart render in StudioChartRender (packages/studio/src/components/studio-chart-render.tsx) so camera pan / FPS counter parent updates skip the chart tree when render props are unchanged.

2. Treat SVG path d animation as expensive

Animating d with Motion / useTransform + d3 arc (or similar) runs layout + paint every frame, per series.

Pattern: useMountProgress for enter → when progress ≥ 1 (useEnterComplete), render static paths and only animate hover with x/y/opacity/scale on a `motion.g` wrapper (not per-path scale on motion.path).

Shared hook: packages/ui/src/charts/use-enter-complete.ts

3. Memoize chart shell context

Unmemoized provider values force all children to reconcile on every parent render.

• Memoize the stable context object with explicit deps (data, arcs/radii, dimensions, callbacks).
• Memoize hover context on hoveredIndex + stable setHoveredIndex (useCallback in chart shell).
• Match `isLoaded` to ring/cartesian: useEffect + timeout, not a lazy useState initializer.

Reference: pie-context.tsx, ring-context.tsx, chart-context.tsx, PieChartCore / RingChartCore useMemo on provider value.

4. Studio preview–specific wins

Chart-agnostic; apply in packages/studio/src/components/charts/*-studio*.tsx:

Reference: pie-studio-preview.tsx, ring-studio-preview.tsx

5. Compare against a “fast” sibling in Studio

Diff the slow chart against one that feels smooth in the same editor (usually pie-chart):

6. Validation bar

Before opening a PR:

pnpm lint
pnpm --filter @bklitui/ui check-types
pnpm --filter @bklitui/studio check-types
# scoped production build when touching studio/web

Manual /studio?chart=<slug>:

• [ ] Enter animation
• [ ] Hover / legend sync
• [ ] Drag geometry sliders (no unnecessary remount)
• [ ] Canvas pan (space + drag) after enter — FPS near pie-chart baseline
• [ ] Pattern/gradient mode if supported

Chart status (bklit-ui)

Key files