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That writes one file:compositions/components/motion-blur.html.
Source
motion-blur.html
motion-blur.html
<!--
Motion Blur — velocity-driven directional motion blur.
Usage: paste this snippet into your composition, then call
attachMotionBlur() with any element animated by your GSAP timeline.
The snippet hooks into the timeline's onUpdate callback, tracks the
GSAP x/y position of each target frame-by-frame, and applies:
1. Ghost copies of the element at increasing backward offsets with
decreasing opacity — inherently one-sided, no forward blur component.
2. A small Gaussian blur at the current position so the element looks
in-motion (blurry) rather than sharp on top of the trail.
3. An optional scaleX/Y stretch in the direction of travel (off by
default; enable via stretchMax > 0 if you want the effect).
Both effects clear automatically when the element decelerates to rest.
Requirements:
- Elements must be animated via GSAP x/y (transform), not left/top.
- Call attachMotionBlur() AFTER defining all tweens, before
window.__timelines registration.
- GSAP must be loaded before this snippet executes.
API:
attachMotionBlur(selector, timeline, options?)
Options:
blurScale — directional blur per px/s of velocity (default 0.008)
blurMax — max blur radius on the motion axis in px (default 20)
stretchScale — scaleX/Y added per px/s (default 0.0002)
stretchMax — max stretch factor above 1.0 (default 0, disabled)
axis — "x" | "y" | "both" (default "both")
-->
<script>
(function () {
if (!window._hfMbUid) window._hfMbUid = 0;
window.attachMotionBlur = function (selector, tl, opts) {
opts = opts || {};
var blurScale = opts.blurScale !== undefined ? opts.blurScale : 0.008;
var blurMax = opts.blurMax !== undefined ? opts.blurMax : 20;
var stretchScale = opts.stretchScale !== undefined ? opts.stretchScale : 0.0002;
var stretchMax = opts.stretchMax !== undefined ? opts.stretchMax : 0;
var axis = opts.axis || "both";
var items = Array.isArray(selector) ? selector : [selector];
var targets = items.reduce(function (acc, s) {
if (typeof s === "string") {
document.querySelectorAll(s).forEach(function (el) {
acc.push(el);
});
} else if (s instanceof Element) {
acc.push(s);
}
return acc;
}, []);
// One SVG filter per target. Ghost copies placed behind → inherently one-sided.
// Small top Gaussian makes element look blurry at current position, not sharp.
var ns = "http://www.w3.org/2000/svg";
var GHOST_CFG = [
{ frac: 0.25, slope: 0.55 },
{ frac: 0.55, slope: 0.28 },
{ frac: 1.0, slope: 0.1 },
];
var state = targets.map(function (el) {
var uid = "hf-mb-" + window._hfMbUid++;
var svg = document.createElementNS(ns, "svg");
svg.setAttribute("style", "position:absolute;width:0;height:0;overflow:hidden;");
var filter = document.createElementNS(ns, "filter");
filter.id = uid;
filter.setAttribute("x", "-110%");
filter.setAttribute("y", "-25%");
filter.setAttribute("width", "260%");
filter.setAttribute("height", "150%");
var ghosts = GHOST_CFG.map(function (cfg, gi) {
var feOff = document.createElementNS(ns, "feOffset");
feOff.setAttribute("in", "SourceGraphic");
feOff.setAttribute("dx", "0");
feOff.setAttribute("dy", "0");
feOff.setAttribute("result", "go" + gi);
var feGB = document.createElementNS(ns, "feGaussianBlur");
feGB.setAttribute("in", "go" + gi);
feGB.setAttribute("stdDeviation", "0 0");
feGB.setAttribute("result", "gb" + gi);
var feCT = document.createElementNS(ns, "feComponentTransfer");
feCT.setAttribute("in", "gb" + gi);
feCT.setAttribute("result", "gf" + gi);
var feFuncA = document.createElementNS(ns, "feFuncA");
feFuncA.setAttribute("type", "linear");
feFuncA.setAttribute("slope", String(cfg.slope));
feCT.appendChild(feFuncA);
filter.appendChild(feOff);
filter.appendChild(feGB);
filter.appendChild(feCT);
return { feOff: feOff, feGB: feGB, frac: cfg.frac };
});
var feTopBlur = document.createElementNS(ns, "feGaussianBlur");
feTopBlur.setAttribute("in", "SourceGraphic");
feTopBlur.setAttribute("stdDeviation", "0 0");
feTopBlur.setAttribute("result", "top");
filter.appendChild(feTopBlur);
var feMerge = document.createElementNS(ns, "feMerge");
for (var mi = GHOST_CFG.length - 1; mi >= 0; mi--) {
var mn = document.createElementNS(ns, "feMergeNode");
mn.setAttribute("in", "gf" + mi);
feMerge.appendChild(mn);
}
var mnTop = document.createElementNS(ns, "feMergeNode");
mnTop.setAttribute("in", "top");
feMerge.appendChild(mnTop);
filter.appendChild(feMerge);
svg.appendChild(filter);
document.body.appendChild(svg);
return {
el: el,
ghosts: ghosts,
feTopBlur: feTopBlur,
filterId: uid,
prevX: parseFloat(gsap.getProperty(el, "x")) || 0,
prevY: parseFloat(gsap.getProperty(el, "y")) || 0,
prevTime: tl.time(),
};
});
// tl.eventCallback("onUpdate") is not available in the HyperFrames renderer —
// the runtime proxies the timeline object. Tween onUpdate fires on every seek.
var _proxy = { t: 0 };
tl.to(
_proxy,
{
t: 1,
duration: Math.max(tl.duration(), 0.1),
ease: "none",
onUpdate: function () {
var time = tl.time();
state.forEach(function (s) {
var x = parseFloat(gsap.getProperty(s.el, "x")) || 0;
var y = parseFloat(gsap.getProperty(s.el, "y")) || 0;
var dt = time - s.prevTime;
if (dt > 0.0005) {
var vx = axis !== "y" ? (x - s.prevX) / dt : 0;
var vy = axis !== "x" ? (y - s.prevY) / dt : 0;
var bx = Math.min(Math.abs(vx) * blurScale, blurMax);
var by = Math.min(Math.abs(vy) * blurScale, blurMax);
var bxFinal = axis !== "y" ? bx : Math.max(by * 0.08, 0.4);
var byFinal = axis !== "x" ? by : Math.max(bx * 0.08, 0.4);
var active = bx > 0.3 || by > 0.3;
if (active) {
s.el.style.filter = "url(#" + s.filterId + ")";
s.ghosts.forEach(function (g) {
var dx = axis !== "y" ? (vx >= 0 ? -bxFinal * g.frac : bxFinal * g.frac) : 0;
var dy = axis !== "x" ? (vy >= 0 ? -byFinal * g.frac : byFinal * g.frac) : 0;
g.feOff.setAttribute("dx", dx.toFixed(2));
g.feOff.setAttribute("dy", dy.toFixed(2));
var gbx =
axis !== "y"
? (bxFinal * g.frac * 0.5).toFixed(2)
: Math.max(byFinal * g.frac * 0.04, 0.4).toFixed(2);
var gby =
axis !== "x"
? (byFinal * g.frac * 0.5).toFixed(2)
: Math.max(bxFinal * g.frac * 0.04, 0.4).toFixed(2);
g.feGB.setAttribute("stdDeviation", gbx + " " + gby);
});
s.feTopBlur.setAttribute(
"stdDeviation",
(bxFinal * 0.15).toFixed(2) + " " + (byFinal * 0.15).toFixed(2),
);
if (stretchMax > 0) {
var sx = 1 + Math.min(Math.abs(vx) * stretchScale, stretchMax);
var sy = 1 + Math.min(Math.abs(vy) * stretchScale, stretchMax);
var ox = axis !== "y" ? (vx >= 0 ? "100% 50%" : "0% 50%") : "50% 50%";
var oy = axis !== "x" ? (vy >= 0 ? "50% 100%" : "50% 0%") : "50% 50%";
gsap.set(s.el, {
scaleX: axis !== "y" ? sx : 1,
scaleY: axis !== "x" ? sy : 1,
transformOrigin: axis === "x" ? ox : axis === "y" ? oy : "50% 50%",
});
}
} else {
s.el.style.filter = "";
s.ghosts.forEach(function (g) {
g.feOff.setAttribute("dx", "0");
g.feOff.setAttribute("dy", "0");
g.feGB.setAttribute("stdDeviation", "0 0");
});
s.feTopBlur.setAttribute("stdDeviation", "0 0");
if (stretchMax > 0) {
gsap.set(s.el, { scaleX: 1, scaleY: 1, transformOrigin: "50% 50%" });
}
}
s.prevX = x;
s.prevY = y;
s.prevTime = time;
} else if (dt < -0.0005) {
s.el.style.filter = "";
s.ghosts.forEach(function (g) {
g.feOff.setAttribute("dx", "0");
g.feOff.setAttribute("dy", "0");
g.feGB.setAttribute("stdDeviation", "0 0");
});
s.feTopBlur.setAttribute("stdDeviation", "0 0");
if (stretchMax > 0) {
gsap.set(s.el, { scaleX: 1, scaleY: 1, transformOrigin: "50% 50%" });
}
s.prevX = x;
s.prevY = y;
s.prevTime = time;
}
// dt ≈ 0: double-fire — skip.
});
},
},
0,
);
};
})();
</script>
<!--
Timeline integration example:
const tl = gsap.timeline({ paused: true });
tl.fromTo("#my-box", { x: -100 }, { x: 1700, duration: 1.2, ease: "power3.inOut" }, 0.5);
// Extend to data-duration so seeks past the last tween reach the blur callback.
tl.set(document.body, {}, DATA_DURATION);
// Call AFTER tweens, BEFORE window.__timelines registration.
// attachMotionBlur adds a tracking tween with onUpdate — must be called after
// tl.set()/tl.to() have established the final timeline duration.
attachMotionBlur("#my-box", tl, { axis: "x" });
window.__timelines = window.__timelines || {};
window.__timelines["my-composition"] = tl;
-->
Usage
Paste the snippet into your composition, then callattachMotionBlur() after your GSAP tweens and before registering window.__timelines.
<!-- Extend the timeline to data-duration before calling attachMotionBlur -->
tl.set(document.body, {}, DATA_DURATION);
attachMotionBlur("#my-box", tl, {
axis: "x", // "x" | "y" | "both"
blurMax: 40, // max blur radius in px (default 20)
});
window.__timelines = window.__timelines || {};
window.__timelines["my-composition"] = tl;
How it works
Each target element gets its own SVG filter. On every timeline seek,attachMotionBlur samples the element’s GSAP x/y position, computes velocity, and drives three SVG filter primitives:
- Ghost copies — three faded, blurred copies of the element placed behind it at increasing offsets proportional to speed. Inherently one-sided: no forward blur.
- Top blur — a small symmetric Gaussian at the current position so the element looks in-motion rather than crisp on top of the trail.
blurMax. Both the ghost trail and top blur clear automatically when the element decelerates to rest.
Options
| Option | Default | Description |
|---|---|---|
axis | "both" | Motion axis — "x", "y", or "both" |
blurScale | 0.008 | Blur per px/s of velocity |
blurMax | 20 | Max blur radius on the motion axis (px) |
stretchScale | 0.0002 | scaleX/Y added per px/s (requires stretchMax > 0) |
stretchMax | 0 | Max stretch above 1.0 — disabled by default |
effect motion-blur velocity animation physics.