Imported from affaan-m/ecc (skills/motion-advanced/SKILL.md) via skills.sh. Install upstream with npx skills add affaan-m/ecc --skill motion-advanced. Copyright stays with the author.

Motion Advanced

Complex, interactive, and physics-based animation patterns. Requires motion-foundations to be set up first. Use these when motion-patterns is not enough.

When to Activate

• Building drag-to-dismiss sheets, swipe gestures, or reorderable lists
• Animating text word-by-word, character-by-character, or as a live counter
• Drawing SVG paths, morphing icons, or animating circular progress
• Writing a custom animation hook (useScrollReveal, magnetic button, cursor follower)
• Sequencing multi-step animations imperatively with useAnimate
• Building spinners, shimmer skeletons, pulse indicators, or loading button states

Outputs

This skill produces:

• Drag interactions: draggable cards, drag-to-dismiss sheets, Reorder.Group lists
• Gesture hooks: swipe detection, long press, pinch outline
• Text animation components: word reveal, character typewriter, number counter
• SVG animation: path draw-on, icon morph, stroke progress ring
• Custom hooks: useScrollReveal, useHoverScale, useNavigationDirection, useInViewOnce
• Imperative sequences via useAnimate with interrupt-safe async/await
• Loader components: spinner, shimmer, pulse dot, progress bar, button loading state

Principles

• Physics-based motion (useSpring, springs.*) always feels more natural than duration-based for direct manipulation.
• useMotionValue + useTransform computes derived values without triggering re-renders.
• useAnimate sequences are imperative and interrupt-safe — calling animate() mid-flight cancels the previous animation automatically.
• Motion values (useMotionValue, useSpring) are SSR-safe and do not cause hydration errors.

Rules

1. Drag interactions must be tested on touch devices, not just mouse. drag prop works on both but feel and threshold differ.
2. Infinite animations must pause when document.visibilityState === "hidden". Background tabs must not consume GPU/CPU.
3. Swipe threshold must be explicit. Never infer intent from velocity alone; combine offset + velocity checks.
4. useAnimate scope ref must be attached to a mounted DOM element. Calling animate() before mount throws silently.
5. Motion values must not be recreated on render. useMotionValue(0) inside a component body is correct; new MotionValue(0) in a render is not.
6. All token values are imported from motion-foundations. No inline numbers.
7. Custom hooks must handle cleanup. Every window.addEventListener needs a matching removeEventListener in the useEffect return.
8. SVG morphing requires equal path command counts. Paths with different command structures snap instead of interpolating.

Decision Guidance

Choosing the right advanced API

When to use useSpring vs a spring transition

Core Concepts

useMotionValue + useTransform

Reactive computation without re-renders:

const x = useMotionValue(0)
const opacity = useTransform(x, [-200, 0, 200], [0, 1, 0])
// opacity updates every frame as x changes — no setState, no re-render

useAnimate

Returns [scope, animate]. The scope ref must be attached to a DOM element. animate() calls are interrupt-safe — calling mid-flight cancels the previous run.

const [scope, animate] = useAnimate()

async function play() {
  await animate(".step-1", { opacity: 1 }, { duration: 0.3 })
  await animate(".step-2", { x: 0 },       { duration: 0.4 })
        animate(".step-3", { scale: 1 },    { duration: 0.25 })  // fire and forget
}

return <div ref={scope}>...</div>

Code Examples

Draggable card

"use client"
import { motion } from "motion/react"
import { springs, motionTokens } from "@/lib/motion-tokens"

<motion.div
  drag
  dragConstraints={{ left: -100, right: 100, top: -100, bottom: 100 }}
  dragElastic={0.1}
  whileDrag={{
    scale: motionTokens.scale.pop,
    boxShadow: "0 16px 40px rgba(0,0,0,0.2)",
  }}
  dragTransition={springs.release}
/>

Drag-to-dismiss sheet

"use client"
import { motion, useMotionValue, useTransform } from "motion/react"

export function BottomSheet({ onClose }: { onClose: () => void }) {
  const y = useMotionValue(0)
  const opacity = useTransform(y, [0, 200], [1, 0])

  return (
    <motion.div
      drag="y"
      dragConstraints={{ top: 0 }}
      style={{ y, opacity }}
      onDragEnd={(_, info) => {
        // Rule 3: combine offset + velocity
        if (info.offset.y > 120 || info.velocity.y > 500) onClose()
      }}
    />
  )
}

Reorderable list

"use client"
import { Reorder } from "motion/react"

export function SortableList() {
  const [items, setItems] = useState(initialItems)
  return (
    <Reorder.Group axis="y" values={items} onReorder={setItems}>
      {items.map((item) => (
        <Reorder.Item key={item.id} value={item}>
          {item.label}
        </Reorder.Item>
      ))}
    </Reorder.Group>
  )
}

Swipe detection

"use client"
import { motion } from "motion/react"

const OFFSET_THRESHOLD  = 50
const VELOCITY_THRESHOLD = 300

<motion.div
  drag="x"
  dragConstraints={{ left: 0, right: 0 }}
  onDragEnd={(_, info) => {
    const swipedRight = info.offset.x > OFFSET_THRESHOLD  || info.velocity.x > VELOCITY_THRESHOLD
    const swipedLeft  = info.offset.x < -OFFSET_THRESHOLD || info.velocity.x < -VELOCITY_THRESHOLD
    if (swipedRight) onSwipeRight()
    if (swipedLeft)  onSwipeLeft()
  }}
/>

Long press hook

import { useRef } from "react"

export function useLongPress(callback: () => void, ms = 600) {
  const timerRef = useRef<ReturnType<typeof setTimeout>>()
  return {
    onPointerDown:  () => { timerRef.current = setTimeout(callback, ms) },
    onPointerUp:    () => clearTimeout(timerRef.current),
    onPointerLeave: () => clearTimeout(timerRef.current),
  }
}

Word-by-word reveal

"use client"
import { motion } from "motion/react"
import { springs } from "@/lib/motion-tokens"

export function AnimatedText({ text }: { text: string }) {
  return (
    <motion.p
      variants={{ visible: { transition: { staggerChildren: 0.05 } } }}
      initial="hidden"
      animate="visible"
    >
      {text.split(" ").map((word, i) => (
        <motion.span
          key={i}
          className="inline-block mr-1"
          variants={{
            hidden:  { opacity: 0, y: 12 },
            visible: { opacity: 1, y: 0, transition: springs.gentle },
          }}
        >
          {word}
        </motion.span>
      ))}
    </motion.p>
  )
}

Number counter

"use client"
import { useRef, useEffect } from "react"
import { animate } from "motion"
import { motionTokens } from "@/lib/motion-tokens"

export function Counter({ to }: { to: number }) {
  const nodeRef = useRef<HTMLSpanElement>(null)

  useEffect(() => {
    const controls = animate(0, to, {
      duration: motionTokens.duration.crawl,
      ease: motionTokens.easing.smooth,
      onUpdate: (v) => {
        if (nodeRef.current) nodeRef.current.textContent = Math.round(v).toString()
      },
    })
    return controls.stop   // Rule 7: cleanup
  }, [to])

  return <span ref={nodeRef} />
}

SVG path draw-on

"use client"
import { motion } from "motion/react"
import { motionTokens } from "@/lib/motion-tokens"

<motion.path
  d="M 0 100 Q 50 0 100 100"
  initial={{ pathLength: 0, opacity: 0 }}
  animate={{ pathLength: 1, opacity: 1 }}
  transition={{ duration: motionTokens.duration.slow, ease: motionTokens.easing.smooth }}
/>

Stroke progress ring

"use client"
import { motion } from "motion/react"
import { motionTokens } from "@/lib/motion-tokens"

const CIRCUMFERENCE = 2 * Math.PI * 40   // r=40

export function ProgressRing({ progress }: { progress: number }) {
  return (
    <svg width="100" height="100" viewBox="0 0 100 100">
      <circle cx="50" cy="50" r="40" fill="none" stroke="#e5e7eb" strokeWidth="8" />
      <motion.circle
        cx="50" cy="50" r="40"
        fill="none" stroke="#6366f1" strokeWidth="8"
        strokeLinecap="round"
        strokeDasharray={CIRCUMFERENCE}
        animate={{ strokeDashoffset: CIRCUMFERENCE - (progress / 100) * CIRCUMFERENCE }}
        transition={{ duration: motionTokens.duration.normal, ease: motionTokens.easing.smooth }}
        style={{ rotate: -90, transformOrigin: "center" }}
      />
    </svg>
  )
}

useScrollReveal hook

"use client"
import { useRef } from "react"
import { useScroll, useTransform } from "motion/react"
import { motionTokens } from "@/lib/motion-tokens"

export function useScrollReveal() {
  const ref = useRef(null)
  const { scrollYProgress } = useScroll({ target: ref, offset: ["start end", "end start"] })
  const opacity = useTransform(scrollYProgress, [0, 0.3], [0, 1])
  const y       = useTransform(scrollYProgress, [0, 0.3], [motionTokens.distance.lg, 0])
  return { ref, style: { opacity, y } }
}

// Usage
const { ref, style } = useScrollReveal()
<motion.section ref={ref} style={style} />

Cursor follower

"use client"
import { useEffect } from "react"
import { motion, useMotionValue, useSpring } from "motion/react"
import { springs } from "@/lib/motion-tokens"

export function CursorFollower() {
  const x = useMotionValue(-100)
  const y = useMotionValue(-100)
  const sx = useSpring(x, springs.gentle)
  const sy = useSpring(y, springs.gentle)

  useEffect(() => {
    const move = (e: MouseEvent) => { x.set(e.clientX); y.set(e.clientY) }
    window.addEventListener("mousemove", move)
    return () => window.removeEventListener("mousemove", move)   // Rule 7
  }, [])

  return (
    <motion.div
      className="fixed top-0 left-0 w-6 h-6 rounded-full bg-indigo-500
                 pointer-events-none -translate-x-1/2 -translate-y-1/2 z-50"
      style={{ x: sx, y: sy }}
    />
  )
}

Shimmer skeleton

"use client"
import { useEffect } from "react"
import { motion, useAnimation } from "motion/react"
import { motionTokens } from "@/lib/motion-tokens"

export function ShimmerSkeleton({ className = "" }: { className?: string }) {
  const controls = useAnimation()

  useEffect(() => {
    const play = () =>
      controls.start({
        x: ["-100%", "100%"],
        transition: {
          repeat: Infinity,
          duration: motionTokens.duration.crawl,
          ease: motionTokens.easing.linear,
        },
      })

    const handleVisibility = () => {
      if (document.visibilityState === "hidden") controls.stop()
      else void play()
    }

    void play()
    document.addEventListener("visibilitychange", handleVisibility)
    return () => {
      controls.stop()
      document.removeEventListener("visibilitychange", handleVisibility)
    }
  }, [controls])

  return (
    <div className={`relative overflow-hidden bg-gray-200 rounded ${className}`}>
      <motion.div
        className="absolute inset-0 bg-gradient-to-r from-transparent via-white/60 to-transparent"
        initial={{ x: "-100%" }}
        animate={controls}
      />
    </div>
  )
}

Button loading state

"use client"
import { motion, AnimatePresence } from "motion/react"
import { motionTokens, springs } from "@/lib/motion-tokens"

export function LoadingButton({
  loading,
  label,
  onClick,
}: {
  loading: boolean
  label: string
  onClick: () => void
}) {
  return (
    <motion.button
      onClick={onClick}
      animate={{ opacity: loading ? 0.7 : 1 }}
      whileTap={loading ? {} : { scale: motionTokens.scale.press }}
      transition={springs.snappy}
      disabled={loading}
    >
      <AnimatePresence mode="wait">
        {loading ? (
          <motion.span
            key="loading"
            initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }}
            transition={{ duration: motionTokens.duration.fast }}
          >
            …
          </motion.span>
        ) : (
          <motion.span
            key="label"
            initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }}
            transition={{ duration: motionTokens.duration.fast }}
          >
            {label}
          </motion.span>
        )}
      </AnimatePresence>
    </motion.button>
  )
}

Infinite animation with visibility pause

"use client"
import { useEffect } from "react"
import { motion, useAnimation } from "motion/react"
import { motionTokens } from "@/lib/motion-tokens"

export function PulseDot() {
  const controls = useAnimation()

  useEffect(() => {
    const pulse = () =>
      controls.start({
        scale: [1, 1.4, 1],
        opacity: [1, 0.6, 1],
        transition: { repeat: Infinity, duration: motionTokens.duration.crawl },
      })

    // Rule 2: pause when tab is hidden
    const handleVisibility = () => {
      if (document.visibilityState === "hidden") controls.stop()
      else void pulse()
    }

    void pulse()
    document.addEventListener("visibilitychange", handleVisibility)
    // Rule 7: stop controls and remove listeners on unmount.
    return () => {
      controls.stop()
      document.removeEventListener("visibilitychange", handleVisibility)
    }
  }, [controls])

  return <motion.span className="w-2 h-2 rounded-full bg-green-400" animate={controls} />
}

End-to-End Example

Drag-to-dismiss sheet with shimmer content, loading state, and reduced motion support — combining useMotionValue, useTransform, useSafeMotion, AnimatePresence, and tokens from motion-foundations:

"use client"
import { useState } from "react"
import { motion, AnimatePresence, useMotionValue, useTransform } from "motion/react"
import { springs, motionTokens } from "@/lib/motion-tokens"
import { useSafeMotion } from "@/hooks/use-reduced-motion"
import { ShimmerSkeleton } from "./shimmer-skeleton"

export function DismissibleSheet({
  isOpen,
  onClose,
  loading,
  children,
}: {
  isOpen: boolean
  onClose: () => void
  loading: boolean
  children: React.ReactNode
}) {
  const safe = useSafeMotion(motionTokens.distance.xl)
  const y = useMotionValue(0)
  const opacity = useTransform(y, [0, 200], [1, 0])

  return (
    <AnimatePresence>
      {isOpen && (
        <>
          {/* Backdrop */}
          <motion.div
            key="backdrop"
            className="fixed inset-0 bg-black/40"
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            onClick={onClose}
          />

          {/* Sheet — drag-to-dismiss */}
          <motion.div
            key="sheet"
            className="fixed bottom-0 inset-x-0 rounded-t-2xl bg-white p-6"
            drag="y"
            dragConstraints={{ top: 0 }}
            style={{ y, opacity }}
            onDragEnd={(_, info) => {
              if (info.offset.y > 120 || info.velocity.y > 500) onClose()
            }}
            initial={safe.initial}
            animate={safe.animate}
            exit={safe.exit}
            transition={springs.gentle}
          >
            {loading ? (
              <div className="space-y-3">
                <ShimmerSkeleton className="h-4 w-3/4" />
                <ShimmerSkeleton className="h-4 w-1/2" />
                <ShimmerSkeleton className="h-20 w-full" />
              </div>
            ) : children}
          </motion.div>
        </>
      )}
    </AnimatePresence>
  )
}

Constraints / Non-Goals

This skill does not cover:

• Token and spring definitions → see motion-foundations
• Standard UI patterns (button, modal, stagger, page transitions) → see motion-patterns
• CSS-only animations or Tailwind animate-* without motion/react
• Canvas or WebGL-based animation (Three.js, Pixi, etc.)
• Full drag-and-drop systems with external state managers (dnd-kit, react-beautiful-dnd)
• Game-loop or frame-by-frame animation

Anti-Patterns

Related Skills

• motion-foundations — defines all tokens, springs, useSafeMotion, and SSR guards imported here. Must be set up before using this skill.
• motion-patterns — handles standard UI patterns (button, modal, stagger, page transitions, scroll reveals). Use it before reaching for the advanced patterns here.