Observer & Gesture

Respond to pointer, touch, wheel, and scroll gestures with 21 callback events.

.onGesture() turns any timeline into a gesture-driven animation. It listens to pointer, touch, wheel, and scroll inputs and fires one of 21 callback events — letting you map gestures to animation actions like play, reverse, progressUp, or playNext.

Basic Usage

import { Motion } from "@motion.page/sdk";

Motion("swipe-panel", ".panel", {
  to: { x: "-100%" },
  duration: 0.4,
  ease: "power2.inOut",
}).onGesture({
  types: ["pointer", "touch"],
  events: {
    LeftComplete: "play",
    RightComplete: "reverse",
  },
});

Options

stopDelay is in milliseconds, not seconds. The default 150 means 150ms of inactivity triggers Stop. This is unlike other time values in the SDK which use seconds.

Gesture Types

You can combine multiple types in one trigger:

// Respond to both touch and pointer with the same callbacks
.onGesture({
  types: ["pointer", "touch"],
  events: { Up: "play", Down: "reverse" },
})

Event Reference

Events are the keys in the events map. They describe what gesture was detected and when within the gesture lifecycle.

Direction Events

These fire continuously while the gesture moves in that direction.

Direction Complete Events

These fire once on release if that direction was the dominant movement.

Change Events

Toggle Events

Toggle events fire once per direction change — when the gesture switches from moving in one direction to another.

Press & Drag Events

Stop & Hover Events

Action Reference

Actions are the values in the events map. They control what the timeline does when that event fires.

Observer vs. ScrollTrigger

Both .onGesture() and .onScroll() can react to scrolling, but they work very differently:

Use .onGesture() when you care about which way the user is moving. Use Scroll Trigger when you care about where they’ve scrolled to.

Swipe Detection

Detect completed swipe gestures using the *Complete events. These fire once per swipe when the finger or pointer lifts — not continuously during movement.

import { Motion } from "@motion.page/sdk";

// Slide a panel in/out with swipe gestures
Motion("drawer", ".drawer", {
from: { x: "100%" },
duration: 0.4,
ease: "power2.inOut",
}).onGesture({
target: ".drawer-area",
types: ["pointer", "touch"],
events: {
  LeftComplete: "play",    // Swipe left → open drawer
  RightComplete: "reverse", // Swipe right → close drawer
},
tolerance: 20,       // Require 20px movement before recognizing gesture
dragMinimum: 30,     // Require 30px drag before firing drag events
preventDefault: true, // Block default touch scroll during gesture
});

Wheel-Driven Animation Progress

Use progressUp / progressDown with the 'wheel' type to scrub a timeline with the mouse wheel — without locking the page scroll position the way onScroll with scrub does.

import { Motion } from "@motion.page/sdk";

// Step through a multi-frame animation with the wheel
Motion("frames", ".illustration", {
to: { backgroundPosition: "0% 100%" },
duration: 1,
}).onGesture({
types: ["wheel"],
events: {
  Up: "progressUp",
  Down: "progressDown",
},
animationStep: 0.05, // Advance 5% of timeline per wheel tick
wheelSpeed: 1.5,     // Slightly more sensitive
});

Per-event step sizes let you make one direction faster than the other:

.onGesture({
  types: ["wheel"],
  events: { Up: "progressUp", Down: "progressDown" },
  animationStep: { Up: 0.15, Down: 0.05 },
})

Touch Swipe with Live Demo

Slide Gallery with playNext / playPrevious

playNext and playPrevious advance or retreat through a set of per-element timelines. They require each: true — the gesture drives each element’s own timeline in sequence.

import { Motion } from "@motion.page/sdk";

// Each slide has its own timeline; gestures step through them in order
Motion("slides", ".slide", {
from: { opacity: 0, x: 80 },
duration: 0.5,
ease: "power2.out",
}).onGesture({
types: ["pointer", "touch", "wheel"],
each: true,
events: {
  LeftComplete: "playNext",
  RightComplete: "playPrevious",
  Up: "progressUp",
  Down: "progressDown",
},
animationStep: 0.08,
lockAxis: true, // Prevent diagonal gesture ambiguity
});

Scroll Direction Reactions

Use the 'scroll' type to fire animations based on the direction the user scrolls — not their scroll position. A common pattern: hide a navbar on scroll down, reveal it on scroll up.

import { Motion } from "@motion.page/sdk";

// Hide navbar on scroll down, reveal on scroll up
Motion("navbar", ".navbar", {
to: { y: "-100%", opacity: 0 },
duration: 0.35,
ease: "power2.inOut",
}).onGesture({
types: ["scroll"],
events: {
  Down: "play",      // Scrolling down → hide
  Up: "reverse",     // Scrolling up → reveal
},
tolerance: 5,
smooth: 0.1,
});

Stop Event — Idle Reset

The Stop event fires once after stopDelay milliseconds of inactivity. Use it to reset the animation when the user stops interacting.

Motion("progress-bar", ".bar", {
  to: { scaleX: 1 },
  duration: 1,
  ease: "none",
}).onGesture({
  types: ["wheel"],
  events: {
    Up: "progressUp",
    Down: "progressDown",
    Stop: "reverse",   // Rewind bar when wheel stops
  },
  stopDelay: 800,      // Wait 800ms of stillness before firing Stop
  animationStep: 0.04,
});

Hover Gestures on Elements

Hover and HoverEnd fire when the pointer enters and leaves the target element. They silently do nothing if target is window.

Motion("card-glow", ".card", {
  to: { boxShadow: "0 0 32px rgba(102, 51, 238, 0.6)", y: -6 },
  duration: 0.3,
  ease: "power2.out",
}).onGesture({
  target: ".card",
  types: ["pointer"],
  events: {
    Hover: "play",
    HoverEnd: "reverse",
  },
});

For hover effects this simple, .onHover() is a cleaner choice. Use gesture Hover/HoverEnd events when you need them alongside other gesture callbacks in one config.

each — Independent Per-Element Instances

Without each, all matched elements share one timeline. With each: true, every element gets its own independent instance — essential for gallery navigation with playNext/playPrevious.

// Without each — all cards animate together on any swipe
Motion("cards", ".card", {
  from: { opacity: 0, x: 60 },
  duration: 0.5,
}).onGesture({
  types: ["touch"],
  events: { LeftComplete: "play" },
});

// With each — every card has its own state
Motion("cards", ".card", {
  from: { opacity: 0, x: 60 },
  duration: 0.5,
}).onGesture({
  each: true,
  types: ["touch"],
  events: {
    LeftComplete: "playNext",
    RightComplete: "playPrevious",
  },
});

Tips & Gotchas

stopDelay is in milliseconds. The default 150 means 150ms. Do not pass 1.5 expecting 1.5 seconds — pass 1500.

Hover / HoverEnd require a target element. They silently do nothing when target is omitted (which defaults to window). Always provide a target selector for hover events.

preventDefault: true makes listeners non-passive. Required to block native browser scroll when using wheel or touch types. Without it, calling event.preventDefault() would throw a warning in modern browsers.

lockAxis: true prevents diagonal gestures. The first axis of movement is locked in. Useful for sliders and galleries where you want clean horizontal or vertical gestures only.

playNext / playPrevious only work with each: true. Without per-element timelines, there is no concept of “next” or “previous” to step through.

Related

• Scroll Trigger — position-based scroll animations with scrub, pin, and snap
• Scroll Trigger Advanced — pinning, horizontal scroll, and snap
• Click Trigger — toggle animations on click