## Desktop
https://github.com/user-attachments/assets/87999ff5-9257-4fed-90e0-781322b1db98
## Mobile
https://github.com/user-attachments/assets/0d115cb6-7bca-4229-8fde-0f188e862b00
Greets the user the moment they finish onboarding: a halftone Twenty
mark (brand purple) assembles from scattered particles, shimmers, then
bursts outward to reveal the freshly loaded workspace behind it. Plays
once, ~3s, with a reduced-motion fallback.
`PageChangeEffect` sets a transient `isWelcomeAnimationVisibleState`
atom at the onboarding to workspace redirect seam (gated by
`shouldShowWelcomeAnimationOnNavigate`); `WelcomeOverlay`, mounted in
`WorkspaceAppProviders`, plays it and clears it. Transient by design, so
it never replays on reload.
## Why a canvas rendered on another thread
The overlay plays at the exact moment the workspace mounts behind it,
which is one of the heaviest main-thread stretches in the app (metadata,
providers, first data fetch). Anything animating on the main thread
competes with that work:
- framer-motion and plain main-thread `requestAnimationFrame` visibly
stuttered and froze during the mount, because long tasks starve rAF.
- CSS keyframes stay smooth (they run on the compositor), but can't
drive a ~2900-particle halftone with per-particle physics (staggered
assemble, moving shimmer band, directional burst).
So the halftone runs as a Canvas 2D particle system inside a Web Worker,
drawing to an `OffscreenCanvas` transferred from the main thread. The
whole render loop lives off the main thread, so app-mount jank can't
reach it. A main-thread path is kept as a fallback for browsers without
`OffscreenCanvas` / `transferControlToOffscreen`, and Safari workers
(which lack rAF) fall back to a fixed-interval loop. The renderer is a
pure, DOM-free module so it bundles cleanly into the worker; dot colors
come from CSS vars read on the main thread and passed in.
Also fires for every onboarding completion path and skips the billing
`PlanRequired` detour.
<!-- This is an auto-generated description by cubic. -->
<a
href="https://cubic.dev/pr/twentyhq/twenty/pull/22622?utm_source=github"
target="_blank" rel="noopener noreferrer"
data-no-image-dialog="true"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source
media="(prefers-color-scheme: light)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img
alt="Review in cubic"
src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>
<!-- End of auto-generated description by cubic. -->
Raphaël Bosi
e38d587602
