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Jetpack Compose animation foundations - animate*AsState, AnimatedVisibility, Crossfade, updateTransition, SharedTransitionLayout, gestures.
Passed 19 of 22 test cases with the skill, and 18 of 22 without it.
1 fixed18 passed either way3 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
A test case the skill fixed. Same model, same prompt, with and without the skill.
Can you write a Jetpack Compose button component in Kotlin that animates a subtle press-and-release feedback scale effect? Please provide the full composable code configured with spring physics for a tactile feel, ensuring it modifies composite graphics transformations rather than triggering layout passes on every frame.
| Checked | Without skill | With skill |
|---|---|---|
| The spring spec uses StiffnessMedium. | Missed | Passed |
| The spring spec uses a damping ratio of 0.85f. | Missed | Passed |
| The scale effect is applied using graphicsLayer. | Passed | Passed |
The instructions your model reads when the skill loads.
Version-sensitive. Every API name, SDK gate and browser-support claim below was verified on 2026-09-08 against primary sources. What against, and when, is in
_jutsu/VERSIONS.md. If that date is old, re-verify before acting on a version number.
Jetpack Compose animation core. Loaded for Android Compose and Compose Multiplatform projects. Concise rules here. Deep-dive in
references/. Baseline: Jetpack Compose 1.12.0 (current stable, Aug 2026) - i.e. Compose BOM 2026.08.x. Modern stable APIs only - noswipeable, noanimateContentSizehacks whereAnimatedContentis correct. Anything below flagged 'Compose 1.x+' is a since marker, not the target.
| Need | API |
|---|---|
| Single value over time | animateFloatAsState, animateDpAsState, animateColorAsState, etc. |
| Visibility / mount-unmount | AnimatedVisibility(visible) { ... } |
| Crossfade between states | Crossfade(target) { state -> ... } |
| Multi-state coordinated | updateTransition(target).animateFloat { ... } |
| Manual control / interruption | Animatable(initialValue) + animateTo(...) |
| Looping / infinite | rememberInfiniteTransition().animateFloat(...) |
| Shared elements | SharedTransitionLayout + Modifier.sharedElement(...) (Compose 1.7+) |
| Layout swap with anim | AnimatedContent(target) { ... } |
| Drag / swipe | Modifier.draggable + Animatable.snapTo/animateTo, or Modifier.anchoredDraggable for snap-points |
Rule: climb the ladder only when needed. animate*AsState covers 70% of cases. Reach for Animatable only when you need to interrupt, chain, or read velocity.
| Use | Spec |
|---|---|
| UI snap (modal, drawer, tab) | spring(stiffness = Spring.StiffnessMediumLow, dampingRatio = Spring.DampingRatioNoBouncy) |
| Tactile (button press release, toggle) | spring(stiffness = Spring.StiffnessMedium, dampingRatio = 0.85f) |
| Bouncy reveal (toast, FAB, success) | spring(stiffness = Spring.StiffnessLow, dampingRatio = Spring.DampingRatioMediumBouncy) |
| Drag follow (1:1 finger tracking) | spring(stiffness = Spring.StiffnessHigh, dampingRatio = 1f) |
Stiffness constants (androidx.compose.animation.core.Spring): StiffnessVeryLow 50f, StiffnessLow 200f, StiffnessMediumLow 400f, StiffnessMedium 1500f (the spring() default), StiffnessHigh 10000f. Higher = faster settle. Damping constants: DampingRatioHighBouncy 0.2f, DampingRatioMediumBouncy 0.5f, DampingRatioLowBouncy 0.75f, DampingRatioNoBouncy 1.0f (the default). Below 1.0 overshoots. Springs ignore durationMillis; if you need a deterministic duration, use tween(...) instead.
test cases passed, vs 18 / 22 without
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