From Lesson 4 of our Framer Motion Recipes course.
The useBoundedScroll(threshold) Hook returns the percentage of threshold pixels that the user has scrolled through. The percentage moves between 0 and 1 whenever the user changes scroll direction, regardless of the document's overall scroll position.
This demo uses an additional transform to delay the beginning of the animation.
Code
"use client";
import {
motion,
useMotionTemplate,
useMotionValue,
useScroll,
useTransform,
} from "framer-motion";
import { useEffect } from "react";
function useBoundedScroll(threshold: number) {
let { scrollY } = useScroll();
let scrollYBounded = useMotionValue(0);
let scrollYBoundedProgress = useTransform(
scrollYBounded,
[0, threshold],
[0, 1]
);
useEffect(() => {
return scrollY.on("change", (current) => {
let previous = scrollY.getPrevious();
let diff = current - previous;
let newScrollYBounded = scrollYBounded.get() + diff;
scrollYBounded.set(clamp(newScrollYBounded, 0, threshold));
});
}, [threshold, scrollY, scrollYBounded]);
return { scrollYBounded, scrollYBoundedProgress };
}
export default function Header() {
let { scrollYBoundedProgress } = useBoundedScroll(400);
let scrollYBoundedProgressDelayed = useTransform(
scrollYBoundedProgress,
[0, 0.75, 1],
[0, 0, 1]
);
return (
<div className="mx-auto flex w-full max-w-3xl flex-1 overflow-hidden text-slate-600">
<div className="z-0 flex-1 overflow-y-scroll">
<motion.header
style={{
height: useTransform(
scrollYBoundedProgressDelayed,
[0, 1],
[80, 50]
),
backgroundColor: useMotionTemplate`rgb(255 255 255 / ${useTransform(
scrollYBoundedProgressDelayed,
[0, 1],
[1, 0.1]
)})`,
}}
className="fixed inset-x-0 flex h-20 shadow backdrop-blur-md"
>
<div className="mx-auto flex w-full max-w-3xl items-center justify-between px-8">
<motion.p
style={{
scale: useTransform(
scrollYBoundedProgressDelayed,
[0, 1],
[1, 0.9]
),
}}
className="flex origin-left items-center text-xl font-semibold uppercase"
>
<span className="-ml-1.5 inline-block -rotate-90 text-[10px] leading-[0]">
The
</span>
<span className="-ml-1 text-2xl tracking-[-.075em]">
Daily Bugle
</span>
</motion.p>
<motion.nav
style={{
opacity: useTransform(
scrollYBoundedProgressDelayed,
[0, 1],
[1, 0]
),
}}
className="flex space-x-4 text-sm font-medium text-slate-400"
>
<a href="#">News</a>
<a href="#">Sports</a>
<a href="#">Culture</a>
</motion.nav>
</div>
</motion.header>
<main className="px-8 pt-28">
<h1 className="h-10 w-4/5 rounded bg-slate-200 text-2xl font-bold" />
<div className="mt-8 space-y-6">
{Array.from(Array(2).keys()).map((i) => (
<div key={i} className="space-y-2 text-sm">
<p className="h-4 w-5/6 rounded bg-slate-200" />
<p className="h-4 rounded bg-slate-200" />
<p className="h-4 w-4/6 rounded bg-slate-200" />
</div>
))}
<div className="h-64 rounded bg-slate-200"></div>
{Array.from(Array(90).keys()).map((i) => (
<div key={i} className="space-y-2 text-sm">
<p className="h-4 w-5/6 rounded bg-slate-200" />
<p className="h-4 rounded bg-slate-200" />
<p className="h-4 w-4/6 rounded bg-slate-200" />
</div>
))}
</div>
</main>
</div>
</div>
);
}
let clamp = (number: number, min: number, max: number) =>
Math.min(Math.max(number, min), max);