flutter-animation ยท diff
git:20260822.e519e06 to git:20260823.0ed4f99
3 added, 1 removed. Audit A to A.
---
name: flutter-animation
- description: Implement or diagnose Flutter motion with implicit, explicit, route, Hero, staggered, and physics-based animations. Use when motion behavior is requested or broken; route general layout and performance profiling to their specialists.
+ description: Implement or diagnose Flutter motion with implicit, explicit, route, Hero, staggered, and physics-based animations. Use when timing, transition, or motion behavior is requested or broken; route optical materials, shaders, general layout, and performance profiling to their specialists.
---
# Flutter Animation
Use motion to explain state change, hierarchy, or continuity. Keep it interruptible and accessible.
+
+ Own timing, interpolation, sequencing, stable identity, and interruption. Route blur, glass, refraction, shader uniforms, and optical layer composition to `flutter-visual-effects`; when both apply, animation state drives the effect rather than duplicating controller ownership inside the renderer.
## Choose the mechanism
- Use implicit animation for a small number of property changes controlled by state.
- Use an `AnimationController` when timing, sequencing, repetition, interruption, or multiple values require explicit ownership.
- Use `Hero` only when the same conceptual element persists across routes and tags remain unique.
- Use custom painters or lower-level animation only when widget composition cannot express the result efficiently.
- Preserve animation controllers in the state lifecycle that owns them and dispose them correctly.
Do not animate layout-heavy properties across large subtrees without profiling. Avoid stacking unrelated implicit animations that make timing hard to reason about.
## Reduced motion
Read platform accessibility preferences through the project-compatible Flutter API. Replace nonessential motion with an immediate or low-motion transition while preserving meaning and task completion.
## Verification
Test initial, in-progress, completed, reversed, interrupted, and reduced-motion states where relevant. Check for ticker leaks and profile complex motion in profile mode on a representative device.
## Sources
- [Flutter animations](https://docs.flutter.dev/ui/animations)
- [Animation accessibility](https://docs.flutter.dev/ui/accessibility-and-internationalization/accessibility)