09一つのアンカーの周りで押し合って落ち着くポップオーバーの輪

<main class="stage">
<div class="pm is-demo" id="pm" data-demo="1">
  <p class="pm__live" data-r="live" aria-live="off" aria-atomic="true"></p>
  <div class="pm__btns"><button class="pm__btn" data-r="again" type="button">もう一度広げる</button><button class="pm__btn" data-r="more" type="button">個数を変える</button></div>
  <i class="pm__hub" data-r="hub"></i>
  <i class="pm__chip" data-r="chip">1</i><i class="pm__chip" data-r="chip">2</i><i class="pm__chip" data-r="chip">3</i><i class="pm__chip" data-r="chip">4</i><i class="pm__chip" data-r="chip">5</i><i class="pm__chip" data-r="chip">6</i><i class="pm__chip" data-r="chip">7</i>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// 핵심: 한 앵커 둘레에 같은 각도 간격으로 목표를 잡고, 사각형이 겹치면 서로 밀어내는 힘을 더해 몇 프레임 만에 겹침을 푼다.

@include stage($stage-ink);

.pm {
  position: relative;
  box-sizing: border-box;
  overflow: hidden;
  width: min(100%, 440px);
  height: min(252px, calc(100vh - 2 * clamp(8px, 4vw, 24px)));
  border-radius: $r-card;
  background: rgba($subject-cream, .07);
  color: $subject-cream;
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  user-select: none;
}
.pm b { font-weight: 800; font-variant-numeric: tabular-nums; }
.pm__live {
  position: absolute;
  left: $sp-3;
  top: $sp-2;
  margin: 0;
  z-index: 9;
  color: $tick-mute;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  pointer-events: none;
}
.pm button { font-family: inherit; }
.pm button:focus-visible { outline: 3px solid $subject-pink; outline-offset: 2px; }


.pm__btns {
  position: absolute;
  right: $sp-3;
  top: $sp-2;
  z-index: 8;
  display: flex;
  gap: $sp-1;
}
.pm__btn {
  height: 24px;
  padding: 0 $sp-3;
  border: 0;
  border-radius: $r-pill;
  background: rgba($subject-cream, .14);
  color: $subject-cream;
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  cursor: pointer;
}
.pm__hub {
  position: absolute;
  left: 0;
  top: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: $subject-sky;
  box-shadow: 0 0 0 4px rgba($subject-sky, .3);
}
.pm__chip {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  height: 26px;
  border-radius: $r-pill;
  background: $subject-pink;
  color: $subject-ink;
  font-style: normal;
  font-size: 12px;
  line-height: 26px;
  font-weight: 800;
  text-align: center;
  box-shadow: $shadow-press;
}
.pm__chip:nth-of-type(odd) { background: $subject-lilac; }
.pm__chip:nth-of-type(3n) { background: $subject-mint; }
@media (prefers-reduced-motion: reduce) {
  .pm__btn { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.pm {
  position: relative;
  box-sizing: border-box;
  overflow: hidden;
  width: min(100%, 440px);
  height: min(252px, 100vh - 2 * clamp(8px, 4vw, 24px));
  border-radius: 16px;
  background: rgba(255, 247, 230, 0.07);
  color: #fff7e6;
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  user-select: none;
}

.pm b {
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.pm__live {
  position: absolute;
  left: 12px;
  top: 8px;
  margin: 0;
  z-index: 9;
  color: #9a93a6;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  pointer-events: none;
}

.pm button {
  font-family: inherit;
}

.pm button:focus-visible {
  outline: 3px solid #ff9ebb;
  outline-offset: 2px;
}

.pm__btns {
  position: absolute;
  right: 12px;
  top: 8px;
  z-index: 8;
  display: flex;
  gap: 4px;
}

.pm__btn {
  height: 24px;
  padding: 0 12px;
  border: 0;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.14);
  color: #fff7e6;
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  cursor: pointer;
}

.pm__hub {
  position: absolute;
  left: 0;
  top: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #6ec8ff;
  box-shadow: 0 0 0 4px rgba(110, 200, 255, 0.3);
}

.pm__chip {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  height: 26px;
  border-radius: 999px;
  background: #ff9ebb;
  color: #17141a;
  font-style: normal;
  font-size: 12px;
  line-height: 26px;
  font-weight: 800;
  text-align: center;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.pm__chip:nth-of-type(odd) {
  background: #b9a0ff;
}

.pm__chip:nth-of-type(3n) {
  background: #4cd4a6;
}

@media (prefers-reduced-motion: reduce) {
  .pm__btn {
    transition: none;
  }
}

(function () {
    const root = document.getElementById("pm");
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let demo = !reduce;
    let raf = 0;
    let t0 = -1;
    let last = -1;
    let acc = 0;
    let clock = 0;
    const offs = [];
    const live = root.querySelector("[data-r=live]");
    function q(sel) {
        return root.querySelector(sel);
    }
    function clamp(v, lo, hi) {
        return Math.max(lo, Math.min(hi, v));
    }
    function seg(t, a, b) {
        const c = clamp((t - a) / (b - a), 0, 1);
        return c * c * (3 - 2 * c);
    }
    function on(el, type, fn) {
        el.addEventListener(type, fn);
        offs.push(() => el.removeEventListener(type, fn));
    }
    function stopDemo() {
        if (!demo)
            return;
        demo = false;
        root.removeAttribute("data-demo");
        root.classList.remove("is-demo");
        live.setAttribute("aria-live", "polite");
    }
    if (reduce)
        live.setAttribute("aria-live", "polite");
    let shown = "";
    function say(s) {
        if (s === shown)
            return;
        shown = s;
        live.textContent = s;
    }
    function makeRng(seed) {
        let s = seed >>> 0;
        return () => {
            s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
            return s / 4294967296;
        };
    }
    function local(e) {
        const r = root.getBoundingClientRect();
        return { x: e.clientX - r.left, y: e.clientY - r.top };
    }
    function sync() {
        if (reduce) {
            snap();
            render();
        }
    }
    // 기법: 팝오버를 앵커 둘레에 같은 각도 간격으로 목표를 잡고 PULL 로 끌어당기되, 사각형이 겹치면 얕게 겹친 축으로 REPEL 만큼 서로 밀어낸다. 겹침이 풀리고 속도가 SETTLE 아래로 내려가면 자리가 잡힌 것이다.
    const REPEL = 0.6;
    const RADIUS = 72;
    const SETTLE = 0.12;
    const ANGLE_OFFSET = -1.2;
    const PULL = 0.03;
    const DAMP = 0.82;
    const CHIP_H = 26;
    const MAX_N = 7;
    const CYCLE_MS = 3200;
    const hub = q("[data-r=hub]");
    const chips = Array.from(root.querySelectorAll("[data-r=chip]"));
    const againBtn = q("[data-r=again]");
    const moreBtn = q("[data-r=more]");
    const cw = [];
    const xs = [];
    const ys = [];
    const vxs = [];
    const vys = [];
    let count = 6;
    let age = 0;
    let restAt = -1;
    let clearAt = -1;
    let cycle = -2;
    let ov = 0;
    let diam = 0;
    let spawned = false;
    for (let i = 0; i < MAX_N; i += 1) {
        cw.push(58 + ((i * 17) % 26));
        xs.push(0);
        ys.push(0);
        vxs.push(0);
        vys.push(0);
    }
    function spawn(seed) {
        const rng = makeRng(seed + 11);
        const w = root.clientWidth;
        const h = root.clientHeight;
        for (let i = 0; i < MAX_N; i += 1) {
            const a = ANGLE_OFFSET + (i / count) * Math.PI * 2;
            xs[i] = w / 2 + Math.cos(a) * 20 + (rng() - 0.5) * 10;
            ys[i] = h / 2 + Math.sin(a) * 14 + (rng() - 0.5) * 10;
            vxs[i] = 0;
            vys[i] = 0;
        }
        age = 0;
        restAt = -1;
        clearAt = -1;
        spawned = true;
    }
    function advance() {
        const w = root.clientWidth;
        const h = root.clientHeight;
        const rx = Math.min(RADIUS * 1.45, w / 2 - 48);
        const ry = Math.min(RADIUS, h / 2 - 24);
        for (let i = 0; i < count; i += 1) {
            const a = ANGLE_OFFSET + (i / count) * Math.PI * 2;
            vxs[i] += (w / 2 + Math.cos(a) * rx - xs[i]) * PULL;
            vys[i] += (h / 2 + Math.sin(a) * ry - ys[i]) * PULL;
        }
        ov = 0;
        for (let i = 0; i < count; i += 1) {
            for (let j = i + 1; j < count; j += 1) {
                const dx = xs[j] - xs[i];
                const dy = ys[j] - ys[i];
                const gx = (cw[i] + cw[j]) / 2 - Math.abs(dx);
                const gy = CHIP_H - Math.abs(dy);
                if (gx <= 0 || gy <= 0)
                    continue;
                ov += 1;
                if (gx < gy) {
                    const f = gx * REPEL * 0.25 * (dx >= 0 ? 1 : -1);
                    vxs[i] -= f;
                    vxs[j] += f;
                }
                else {
                    const f = gy * REPEL * 0.25 * (dy >= 0 ? 1 : -1);
                    vys[i] -= f;
                    vys[j] += f;
                }
            }
        }
        let fast = 0;
        let lo = 99999;
        let hi = -99999;
        for (let i = 0; i < count; i += 1) {
            vxs[i] *= DAMP;
            vys[i] *= DAMP;
            xs[i] += vxs[i];
            ys[i] += vys[i];
            fast = Math.max(fast, Math.hypot(vxs[i], vys[i]));
            lo = Math.min(lo, xs[i] - cw[i] / 2);
            hi = Math.max(hi, xs[i] + cw[i] / 2);
        }
        diam = hi - lo;
        age += 1;
        if (clearAt < 0 && ov === 0)
            clearAt = age;
        if (restAt < 0 && ov === 0 && fast < SETTLE)
            restAt = age;
    }
    function tick(ms) {
        if (demo) {
            const c = Math.floor((ms - 200) / CYCLE_MS);
            if (c !== cycle && ms >= 200) {
                cycle = c;
                spawn(c);
            }
        }
        if (!spawned)
            spawn(0);
        advance();
    }
    function snap() {
        if (!spawned)
            spawn(0);
        for (let k = 0; k < 160; k += 1)
            advance();
    }
    function render() {
        const w = root.clientWidth;
        const h = root.clientHeight;
        hub.style.transform = "translate3d(" + (w / 2 - 14).toFixed(1) + "px," + (h / 2 - 14).toFixed(1) + "px,0)";
        for (let i = 0; i < MAX_N; i += 1) {
            const on = i < count;
            chips[i].style.visibility = on ? "visible" : "hidden";
            chips[i].style.width = cw[i] + "px";
            chips[i].style.transform = "translate3d(" + (xs[i] - cw[i] / 2).toFixed(1) + "px," + (ys[i] - CHIP_H / 2).toFixed(1) + "px,0)";
        }
        say("overlap " + ov + "  clear " + (clearAt < 0 ? "-" : clearAt + "f") + "  rest " + (restAt < 0 ? "-" : restAt + "f") + "  d " + Math.round(diam));
    }
    on(againBtn, "click", () => {
        stopDemo();
        spawn(age + count);
        sync();
    });
    on(moreBtn, "click", () => {
        stopDemo();
        count = 4 + ((count - 3) % 4);
        spawn(count);
        sync();
    });
    const FRAME_MS = 1000 / 60;
    function frame(ts) {
        if (t0 < 0) {
            t0 = ts;
            last = ts;
        }
        acc += Math.min(100, ts - last);
        last = ts;
        let n = 0;
        while (acc >= FRAME_MS && n < 6) {
            clock += FRAME_MS;
            tick(clock);
            acc -= FRAME_MS;
            n += 1;
        }
        if (n === 6)
            acc = 0;
        render();
        raf = requestAnimationFrame(frame);
    }
    const ro = new ResizeObserver(() => sync());
    ro.observe(root);
    if (reduce) {
        stopDemo();
        snap();
        render();
    }
    else {
        raf = requestAnimationFrame(frame);
    }
    return () => {
        cancelAnimationFrame(raf);
        offs.forEach((f) => f());
        ro.disconnect();
    };
})();

// OrbitPopoverRing - vanilla 판(09-pm-orbit-popover-ring) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./OrbitPopoverRing.module.scss";

export default function OrbitPopoverRing() {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const rootEl = rootRef.current;
    if (!rootEl) return;
    const root: HTMLElement = rootEl;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let demo = !reduce;
    let raf = 0;
    let t0 = -1;
    let last = -1;
    let acc = 0;
    let clock = 0;
    const offs: Array<() => void> = [];
    const live = root.querySelector("[data-r=live]") as HTMLElement;

    function q<T extends Element>(sel: string): T {
      return root.querySelector(sel) as T;
    }
    function clamp(v: number, lo: number, hi: number): number {
      return Math.max(lo, Math.min(hi, v));
    }
    function seg(t: number, a: number, b: number): number {
      const c = clamp((t - a) / (b - a), 0, 1);
      return c * c * (3 - 2 * c);
    }
    function on(el: EventTarget, type: string, fn: (e: any) => void): void {
      el.addEventListener(type, fn);
      offs.push(() => el.removeEventListener(type, fn));
    }
    function stopDemo(): void {
      if (!demo) return;
      demo = false;
      root.removeAttribute("data-demo");
      root.classList.remove("is-demo");
      live.setAttribute("aria-live", "polite");
    }
    if (reduce) live.setAttribute("aria-live", "polite");
    let shown = "";
    function say(s: string): void {
      if (s === shown) return;
      shown = s;
      live.textContent = s;
    }
    function makeRng(seed: number): () => number {
      let s = seed >>> 0;
      return () => {
        s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
        return s / 4294967296;
      };
    }
    function local(e: PointerEvent): { x: number; y: number } {
      const r = root.getBoundingClientRect();
      return { x: e.clientX - r.left, y: e.clientY - r.top };
    }
    function sync(): void {
      if (reduce) {
        snap();
        render();
      }
    }

    // 기법: 팝오버를 앵커 둘레에 같은 각도 간격으로 목표를 잡고 PULL 로 끌어당기되, 사각형이 겹치면 얕게 겹친 축으로 REPEL 만큼 서로 밀어낸다. 겹침이 풀리고 속도가 SETTLE 아래로 내려가면 자리가 잡힌 것이다.
    const REPEL = 0.6;
    const RADIUS = 72;
    const SETTLE = 0.12;
    const ANGLE_OFFSET = -1.2;
    const PULL = 0.03;
    const DAMP = 0.82;
    const CHIP_H = 26;
    const MAX_N = 7;
    const CYCLE_MS = 3200;
    const hub = q<HTMLElement>("[data-r=hub]");
    const chips = Array.from(root.querySelectorAll("[data-r=chip]")) as HTMLElement[];
    const againBtn = q<HTMLElement>("[data-r=again]");
    const moreBtn = q<HTMLElement>("[data-r=more]");
    const cw: number[] = [];
    const xs: number[] = [];
    const ys: number[] = [];
    const vxs: number[] = [];
    const vys: number[] = [];
    let count = 6;
    let age = 0;
    let restAt = -1;
    let clearAt = -1;
    let cycle = -2;
    let ov = 0;
    let diam = 0;
    let spawned = false;
    for (let i = 0; i < MAX_N; i += 1) {
      cw.push(58 + ((i * 17) % 26));
      xs.push(0);
      ys.push(0);
      vxs.push(0);
      vys.push(0);
    }

    function spawn(seed: number): void {
      const rng = makeRng(seed + 11);
      const w = root.clientWidth;
      const h = root.clientHeight;
      for (let i = 0; i < MAX_N; i += 1) {
        const a = ANGLE_OFFSET + (i / count) * Math.PI * 2;
        xs[i] = w / 2 + Math.cos(a) * 20 + (rng() - 0.5) * 10;
        ys[i] = h / 2 + Math.sin(a) * 14 + (rng() - 0.5) * 10;
        vxs[i] = 0;
        vys[i] = 0;
      }
      age = 0;
      restAt = -1;
      clearAt = -1;
      spawned = true;
    }
    function advance(): void {
      const w = root.clientWidth;
      const h = root.clientHeight;
      const rx = Math.min(RADIUS * 1.45, w / 2 - 48);
      const ry = Math.min(RADIUS, h / 2 - 24);
      for (let i = 0; i < count; i += 1) {
        const a = ANGLE_OFFSET + (i / count) * Math.PI * 2;
        vxs[i] += (w / 2 + Math.cos(a) * rx - xs[i]) * PULL;
        vys[i] += (h / 2 + Math.sin(a) * ry - ys[i]) * PULL;
      }
      ov = 0;
      for (let i = 0; i < count; i += 1) {
        for (let j = i + 1; j < count; j += 1) {
          const dx = xs[j] - xs[i];
          const dy = ys[j] - ys[i];
          const gx = (cw[i] + cw[j]) / 2 - Math.abs(dx);
          const gy = CHIP_H - Math.abs(dy);
          if (gx <= 0 || gy <= 0) continue;
          ov += 1;
          if (gx < gy) {
            const f = gx * REPEL * 0.25 * (dx >= 0 ? 1 : -1);
            vxs[i] -= f;
            vxs[j] += f;
          } else {
            const f = gy * REPEL * 0.25 * (dy >= 0 ? 1 : -1);
            vys[i] -= f;
            vys[j] += f;
          }
        }
      }
      let fast = 0;
      let lo = 99999;
      let hi = -99999;
      for (let i = 0; i < count; i += 1) {
        vxs[i] *= DAMP;
        vys[i] *= DAMP;
        xs[i] += vxs[i];
        ys[i] += vys[i];
        fast = Math.max(fast, Math.hypot(vxs[i], vys[i]));
        lo = Math.min(lo, xs[i] - cw[i] / 2);
        hi = Math.max(hi, xs[i] + cw[i] / 2);
      }
      diam = hi - lo;
      age += 1;
      if (clearAt < 0 && ov === 0) clearAt = age;
      if (restAt < 0 && ov === 0 && fast < SETTLE) restAt = age;
    }
    function tick(ms: number): void {
      if (demo) {
        const c = Math.floor((ms - 200) / CYCLE_MS);
        if (c !== cycle && ms >= 200) {
          cycle = c;
          spawn(c);
        }
      }
      if (!spawned) spawn(0);
      advance();
    }
    function snap(): void {
      if (!spawned) spawn(0);
      for (let k = 0; k < 160; k += 1) advance();
    }
    function render(): void {
      const w = root.clientWidth;
      const h = root.clientHeight;
      hub.style.transform = "translate3d(" + (w / 2 - 14).toFixed(1) + "px," + (h / 2 - 14).toFixed(1) + "px,0)";
      for (let i = 0; i < MAX_N; i += 1) {
        const on = i < count;
        chips[i].style.visibility = on ? "visible" : "hidden";
        chips[i].style.width = cw[i] + "px";
        chips[i].style.transform = "translate3d(" + (xs[i] - cw[i] / 2).toFixed(1) + "px," + (ys[i] - CHIP_H / 2).toFixed(1) + "px,0)";
      }
      say("overlap " + ov + "  clear " + (clearAt < 0 ? "-" : clearAt + "f") + "  rest " + (restAt < 0 ? "-" : restAt + "f") + "  d " + Math.round(diam));
    }
    on(againBtn, "click", () => {
      stopDemo();
      spawn(age + count);
      sync();
    });
    on(moreBtn, "click", () => {
      stopDemo();
      count = 4 + ((count - 3) % 4);
      spawn(count);
      sync();
    });

    const FRAME_MS = 1000 / 60;
    function frame(ts: number): void {
      if (t0 < 0) {
        t0 = ts;
        last = ts;
      }
      acc += Math.min(100, ts - last);
      last = ts;
      let n = 0;
      while (acc >= FRAME_MS && n < 6) {
        clock += FRAME_MS;
        tick(clock);
        acc -= FRAME_MS;
        n += 1;
      }
      if (n === 6) acc = 0;
      render();
      raf = requestAnimationFrame(frame);
    }
    const ro = new ResizeObserver(() => sync());
    ro.observe(root);
    if (reduce) {
      stopDemo();
      snap();
      render();
    } else {
      raf = requestAnimationFrame(frame);
    }
    return () => {
      cancelAnimationFrame(raf);
      offs.forEach((f) => f());
      ro.disconnect();
    };

  }, []);

  return (
    <main className={styles["stage"]}>
      <div ref={rootRef} className={styles["pm"] + " is-demo"} data-demo="1">
        <p className={styles["pm__live"]} data-r="live" aria-live="off" aria-atomic="true"></p>
        <div className={styles["pm__btns"]}><button className={styles["pm__btn"]} data-r="again" type="button">다시 펼치기</button><button className={styles["pm__btn"]} data-r="more" type="button">개수 바꾸기</button></div>
        <i className={styles["pm__hub"]} data-r="hub"></i>
        <i className={styles["pm__chip"]} data-r="chip">1</i><i className={styles["pm__chip"]} data-r="chip">2</i><i className={styles["pm__chip"]} data-r="chip">3</i><i className={styles["pm__chip"]} data-r="chip">4</i><i className={styles["pm__chip"]} data-r="chip">5</i><i className={styles["pm__chip"]} data-r="chip">6</i><i className={styles["pm__chip"]} data-r="chip">7</i>
      </div>
    </main>
  );
}