README.md

Motion

motion.mp4

What Is Motion?

Motion is a simple Svelte animation library. Instead of being limited to animating CSS properties using a JavaScript animation library, or the Web Animations API, it uses values that change over time, to animate any property.

Installation

npm i @animotion/motion

API

• tween(value, options?) — create a tween that animates a value over time
• .to(value, options?) — animate to a new value, returns a promise
• .current — the current animated value
• .current.rounded rounds to integers
• .current.round(n) rounds to decimals
• .target = value — set the target value directly
• .sfx(sound, options?) — play a sound effect, returns the tween for chaining
• .reset() — reset to the initial value instantly
• all(...tweens) — wait for multiple tweens to complete

Example

<script>
	import { tween } from '@animotion/motion';

	const sfx = {
		transition: 'sfx/transition.mp3',
		tally: 'sfx/tally.mp3',
	};

	const camera = tween({ x: -2, y: -2, w: 24, h: 24 });
	const circle = tween({ x: 2.5, y: 2.5, r: 1.5, fill: '#00ffff' });
	const text = tween({ count: 0, opacity: 0 });

	async function animate() {
		await camera.sfx(sfx.transition).to({ x: 0, y: 0, w: 10, h: 10 });
		circle.sfx(sfx.transition).to({ x: 10, y: 10, r: 3, fill: '#ffff00' });
		camera.to({ x: 5, y: 5 });
		await text.to({ opacity: 1 }, { duration: 300 });
		text.sfx(sfx.tally).to({ count: 10_000 }, { duration: 600 });
	}
</script>

<svg viewBox="{camera.x} {camera.y} {camera.w} {camera.h}">
	{@render grid()}

	<circle cx={circle.x} cy={circle.y} r={circle.r} fill={circle.fill} />

	<text
		x={circle.x}
		y={circle.y}
		font-size={circle.r * 0.4}
		opacity={text.opacity}
		text-anchor="middle"
		dominant-baseline="middle"
		fill="#000"
	>
		{text.count}
	</text>
</svg>

<button onclick={animate}>Animate</button>