Infinite Gallery

npx shadcn@latest add @atelier/infinite-gallery

"use client"

import {
    Children,
    type ComponentRef,
    isValidElement,
    type ReactNode,
    useCallback,
    useEffect,
    useRef,
} from "react"
import { useFrameLoop } from "../../hooks/use-frame-loop"

const DEFAULT_SCROLL_STATE = {
    position: 0,
    target: 0,
    momentum: 0,
    prev: 0,
}

export type InfiniteGalleryProps = {
    children: ReactNode
    perView?: number
    gap?: number
    speed?: number
    inertia?: number
    dragMultiplier?: number
    className?: string
}

function lerp(start: number, end: number, factor: number) {
    return start + (end - start) * factor
}

function clamp(min: number, max: number, value: number) {
    return Math.min(max, Math.max(min, value))
}

export function InfiniteGallery({
    children,
    perView = 4,
    gap = 5,
    className,
    speed = 6,
    inertia = 0.6,
    dragMultiplier = 3,
}: InfiniteGalleryProps) {
    const sourceItems = Children.toArray(children).filter(isValidElement)
    const repeats = sourceItems.length ? Math.ceil((perView + 2) / sourceItems.length) : 0
    const items = Array.from({ length: repeats }, () => sourceItems).flat()

    const containerRef = useRef<ComponentRef<"div">>(null)
    const measureRef = useRef({ containerWidth: 0, itemWidth: 0 })
    const scrollRef = useRef({ ...DEFAULT_SCROLL_STATE }).current

    const calcItemsPositions = useCallback(
        (scrollOffset: number, velocity: number) => {
            const container = containerRef.current
            const { containerWidth, itemWidth } = measureRef.current

            if (!container) return

            const totalWidth = items.length * itemWidth

            for (let i = 0; i < items.length; i++) {
                const itemElement = container.children[i] as HTMLElement
                if (!itemElement) return

                const totalOffset = i * itemWidth + scrollOffset

                let xPos = ((totalOffset % totalWidth) + totalWidth) % totalWidth

                if (xPos > totalWidth - itemWidth) xPos -= totalWidth

                const itemInView = xPos > -itemWidth && xPos < containerWidth

                if (itemInView) {
                    const maxDeg = 85
                    const rotate = itemWidth
                        ? clamp(-maxDeg, maxDeg, (velocity / itemWidth) * 6)
                        : 0
                    const transform = `translate3d(${xPos - i * itemWidth}px, 0, 0) perspective(800px) rotateY(${rotate}deg)`

                    itemElement.style.transform = transform
                    itemElement.style.visibility = "visible"
                } else {
                    itemElement.style.visibility = "hidden"
                }
            }
        },
        [items],
    )

    const measure = useCallback(() => {
        const container = containerRef.current
        if (!container) return
        if (!container.children.length) return

        const firstChild = container.children[0] as HTMLElement
        const computedGap = parseFloat(getComputedStyle(container).gap) || 0

        measureRef.current = {
            containerWidth: container.getBoundingClientRect().width,
            itemWidth: firstChild.offsetWidth + computedGap,
        }
    }, [])

    useFrameLoop((_, delta) => {
        scrollRef.target += scrollRef.momentum
        scrollRef.momentum *= inertia

        const pos = scrollRef.position
        const target = scrollRef.target

        if (Math.abs(target - pos) > 0.01 || Math.abs(scrollRef.momentum) > 0.01) {
            const factor = 1 - Math.exp(-speed * delta)
            const next = lerp(pos, target, factor)
            scrollRef.position = next

            const frameDelta = (next - scrollRef.prev) * 60
            scrollRef.prev = next

            calcItemsPositions(next, frameDelta)
        }
    })

    useEffect(() => {
        const container = containerRef.current
        if (!container) return

        const resetScroll = () => {
            Object.assign(scrollRef, DEFAULT_SCROLL_STATE)
            measure()
            calcItemsPositions(0, 0)
        }

        resetScroll()

        const onWheel = (event: WheelEvent) => {
            event.preventDefault()
            scrollRef.momentum -= event.deltaY
        }

        const dragState = {
            startX: 0,
            isDragging: false,
            start: 0,
        }

        const onPointerDown = (event: PointerEvent) => {
            dragState.isDragging = true
            dragState.startX = event.clientX
            dragState.start = scrollRef.target
            scrollRef.momentum = 0
            container.setPointerCapture(event.pointerId)
        }

        const onPointerMove = (event: PointerEvent) => {
            if (!dragState.isDragging) return
            const delta = (event.clientX - dragState.startX) * dragMultiplier
            scrollRef.target = dragState.start + delta
        }

        const onPointerUp = () => {
            dragState.isDragging = false
        }

        const resizeObserver = new ResizeObserver(resetScroll)
        resizeObserver.observe(container)

        container.addEventListener("pointerdown", onPointerDown)
        container.addEventListener("pointermove", onPointerMove)
        container.addEventListener("pointerup", onPointerUp)
        container.addEventListener("wheel", onWheel, { passive: false })

        return () => {
            container.removeEventListener("pointerdown", onPointerDown)
            container.removeEventListener("pointermove", onPointerMove)
            container.removeEventListener("pointerup", onPointerUp)
            container.removeEventListener("wheel", onWheel)
            resizeObserver.disconnect()
        }
    }, [calcItemsPositions, perView, scrollRef, inertia, speed, dragMultiplier, measure])

    return (
        <div
            ref={containerRef}
            data-lenis-prevent
            style={{ gap: `${gap}px` }}
            className={`overflow-hidden touch-pan-y user-select-none ${className}`}
        >
            {items.map((item, index) => (
                <div
                    key={index}
                    className="shrink-0 will-change-transform"
                    style={{ width: `calc(${100 / perView}%)` }}
                >
                    {item}
                </div>
            ))}
        </div>
    )
}

import { useEffect, useRef } from "react"

const DELTA_MAX = 0.1

type FrameLoopCallback = (time: number, delta: number) => void

export function useFrameLoop(callback: FrameLoopCallback, interval?: number) {
    const ref = useRef(callback)
    ref.current = callback

    useEffect(() => {
        let frameId = 0
        let lastTime = 0
        let lastTick = 0

        const tick = (now: number) => {
            frameId = requestAnimationFrame(tick)

            if (interval && now - lastTick < interval) return
            if (interval) lastTick = now

            const time = now * 0.001
            const delta = lastTime ? Math.min(time - lastTime, DELTA_MAX) : 0
            lastTime = time

            ref.current(time, delta)
        }

        frameId = requestAnimationFrame(tick)

        return () => {
            cancelAnimationFrame(frameId)
        }
    }, [interval])
}

const IMAGES = [
    "https://picsum.photos/seed/atelier-1/1200/800",
    "https://picsum.photos/seed/atelier-2/1200/800",
]

<InfiniteGallery className="flex py-15" perView={4}>
    {IMAGES.map((src) => (
        <img key={src} src={src} alt="" className="h-80 w-auto object-cover" />
    ))}
</InfiniteGallery>