[biering]

Summary

• Add a maxFps rendering cap (default 60) — excess rAF frames are skipped with the loop kept alive and skipped time folded into the next delta.
• Park the render loop entirely when the active animation's speed is 0 — one frame is drawn, then the rAF chain stops until the next update()/visibility change.

Why

Benchmarked on a real wallpaper deployment (Apple powermetrics, M4 Pro): the uncapped loop runs at 120Hz on ProMotion displays for a field that moves imperceptibly per frame, and a paused (speed-0) field kept repainting identical frames at full rate — ~46% of one core while visible.

Benefits

• ProMotion/120Hz embedders halve their render cost with zero visual change for ambient speeds.
• speed: 0 now costs ~0 CPU instead of a full render loop — hosts can implement "pause" for free.

How

• Throttle uses a separate lastDrawTime so lastFrameTime keeps accumulating delta across skipped frames (the random animation integrates deltaMs); drift correction keeps average fps ≈ target; update()/resize draws bypass the throttle and reset its window.
• Static predicate is resolved[animation].speed === 0 (strict — negative speeds animate backwards), verified time-invariant per animation in new field tests (incl. arc breathe / ribbon bloom / random's post-init behavior). It funnels into the existing idleDrawn park machinery via shouldAnimate(), so visibility gates, resize, and update() re-wake paths all behave as before.
• Companion fix: update() pins lastFrameTime when resuming from a park, so delta-based animations don't integrate the whole parked stretch in one frame.
• bump-minor-pre-major added to release-please config → this releases as 0.7.0.

BREAKING: rendering is now capped at 60fps by default; pass maxFps: 0 for the old uncapped behavior.

Test plan

• 6 new loop tests (fps band under cap, uncapped, static park + rAF stop, resume via update, static random init frame, update-inside-throttle-window) on the existing fake-rAF harness.
• 4 new resolveConfig maxFps tests; 5 new field time-invariance tests.
• pnpm --filter wavedance test — 68/68 green; typecheck + build green.

🤖 Generated with Claude Code

https://claude.ai/code/session_015oFoSH9ZnH1mheL8R7wNQY