SKILL.md
Mobile Touch Animation
Apply Disney's 12 animation principles to mobile gestures, haptics, and native app motion.
Quick Reference
Principle
Mobile Implementation
Squash & Stretch
Rubber-banding, bounce on scroll limits
Anticipation
Peek before reveal, long-press preview
Staging
Sheet presentations, focus states
Straight Ahead / Pose to Pose
Gesture-driven vs preset transitions
Follow Through / Overlapping
Momentum scrolling, trailing elements
Slow In / Slow Out
iOS spring animations, Material easing
Arc
Swipe-to-dismiss curves, card throws
Secondary Action
Haptic pulse with visual feedback
Timing
Touch response <100ms, transitions 250-350ms
Exaggeration
Bounce amplitude, haptic intensity
Solid Drawing
Respect safe areas, consistent anchors
Appeal
60fps minimum, gesture continuity
Principle Applications
Squash & Stretch: Implement rubber-band effect at scroll boundaries. Pull-to-refresh should stretch content naturally. Buttons compress on touch.
Anticipation: Long-press shows preview before full action. Drag threshold provides visual hint before item lifts. Swipe shows edge of destination content.
Staging: Use sheet presentations to maintain context. Dim and scale background during modal focus. Hero transitions connect views meaningfully.
Straight Ahead vs Pose to Pose: Gesture-following animations (drag, pinch) are straight ahead—driven by touch input. System transitions (push, present) are pose to pose—predefined keyframes.
Follow Through & Overlapping: Content continues moving after finger lifts (momentum). Navigation bar elements animate slightly after main content. Lists items settle with stagger.
Slow In / Slow Out: iOS uses spring physics—configure mass, stiffness, damping. Android Material uses standard easing: FastOutSlowIn. Never use linear for user-initiated motion.
Arc: Thrown cards follow parabolic arcs. Swipe-to-dismiss curves based on velocity vector. FAB expand/collapse follows natural arc path.
Secondary Action: Pair haptic feedback with visual response. Button ripple accompanies press. Success checkmark triggers light haptic.
Timing: Touch acknowledgment: <100ms. Quick actions: 150-250ms. View transitions: 250-350ms. Complex animations: 350-500ms. Haptic should sync precisely with visual.
Exaggeration: Pull-to-refresh stretches beyond natural—makes feedback clear. Error shake is pronounced. Success animations celebrate appropriately.
Solid Drawing: Respect device safe areas during animation. Maintain consistent transform origins. Account for notch/dynamic island in motion paths.
Appeal: Minimum 60fps, target 120fps on ProMotion displays. Gesture-driven animation must feel connected to finger. Interruptible animations essential.
Platform Patterns
iOS
// Spring animation with follow-through
UIView.animate(withDuration: 0.5,
delay: 0,
usingSpringWithDamping: 0.7,
initialSpringVelocity: 0.5,
options: .curveEaseOut)
// Haptic pairing
let feedback = UIImpactFeedbackGenerator(style: .medium)
feedback.impactOccurred()
Android
// Material spring animation
SpringAnimation(view, DynamicAnimation.TRANSLATION_Y)
.setSpring(SpringForce()
.setStiffness(SpringForce.STIFFNESS_MEDIUM)
.setDampingRatio(SpringForce.DAMPING_RATIO_MEDIUM_BOUNCY))
.start()
Haptic Guidelines
Action
iOS
Android
Selection
.selection
EFFECT_TICK
Success
.success
EFFECT_CLICK
Warning
.warning
EFFECT_DOUBLE_CLICK
Error
.error
EFFECT_HEAVY_CLICK
Haptics are secondary action—always pair with visual confirmation.