08A Circular Mask with a Noisy Edge Blooming from the Anchor

<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>
  <i class="pm__ring" data-r="ring"></i>
  <div class="pm__card" data-r="card"><i class="pm__sun"></i><i class="pm__hill"></i><b class="pm__ttl">Preview</b></div>
  <button class="pm__anchor" data-r="anchor" type="button" aria-expanded="false" aria-label="Open image preview"></button>
</div>
</main>

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

// 핵심: 앵커 점에서 퍼지는 원형 마스크의 반지름을 각도마다 2차원 노이즈로 흔들어, 잉크가 번지듯 불규칙한 가장자리로 내용이 드러난다.

@include stage($stage-paper);

.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-ink, .07);
  color: $subject-ink;
  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: $sp-2;
  margin: 0;
  z-index: 9;
  color: rgba($subject-ink, .72);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  pointer-events: none;
}
.pm button { font-family: inherit; }
.pm button:focus-visible { outline: 3px solid $subject-ink; outline-offset: 2px; }


.pm__anchor {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: $r-control;
  background: linear-gradient(145deg, $subject-sky, $subject-lilac);
  box-shadow: $shadow-press;
  cursor: pointer;
  z-index: 5;
}
.pm__ring, .pm__card {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  border-radius: $r-card;
  visibility: hidden;
}
.pm__ring { background: $subject-lilac; z-index: 3; }
.pm__card {
  overflow: hidden;
  background: linear-gradient(170deg, $subject-sky 0%, $subject-pink 62%, $subject-lilac 100%);
  color: $subject-ink;
  box-shadow: $shadow-raised;
  z-index: 4;
}
.pm__sun {
  position: absolute;
  right: 18%;
  top: 16%;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: $subject-cream;
}
.pm__hill {
  position: absolute;
  left: -10%;
  right: -10%;
  bottom: -38%;
  height: 70%;
  border-radius: 50%;
  background: $subject-mint;
}
.pm__ttl { position: absolute; left: $sp-3; bottom: $sp-3; font-size: 13px; line-height: 20px; }
@media (prefers-reduced-motion: reduce) {
  .pm__anchor { cursor: default; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  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(23, 20, 26, 0.07);
  color: #17141a;
  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: rgba(23, 20, 26, 0.72);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  pointer-events: none;
}

.pm button {
  font-family: inherit;
}

.pm button:focus-visible {
  outline: 3px solid #17141a;
  outline-offset: 2px;
}

.pm__anchor {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: 12px;
  background: linear-gradient(145deg, #6ec8ff, #b9a0ff);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: pointer;
  z-index: 5;
}

.pm__ring, .pm__card {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  border-radius: 16px;
  visibility: hidden;
}

.pm__ring {
  background: #b9a0ff;
  z-index: 3;
}

.pm__card {
  overflow: hidden;
  background: linear-gradient(170deg, #6ec8ff 0%, #ff9ebb 62%, #b9a0ff 100%);
  color: #17141a;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  z-index: 4;
}

.pm__sun {
  position: absolute;
  right: 18%;
  top: 16%;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: #fff7e6;
}

.pm__hill {
  position: absolute;
  left: -10%;
  right: -10%;
  bottom: -38%;
  height: 70%;
  border-radius: 50%;
  background: #4cd4a6;
}

.pm__ttl {
  position: absolute;
  left: 12px;
  bottom: 12px;
  font-size: 13px;
  line-height: 20px;
}

@media (prefers-reduced-motion: reduce) {
  .pm__anchor {
    cursor: default;
  }
}

(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: 앵커 점에서 퍼지는 원형 마스크의 반지름을 각도마다 2차원 값 노이즈로 흔들어 다각형 clip-path 로 만든다. 뒤에 RING 만큼 큰 같은 모양을 깔아 잉크 가장자리를 낸다.
    const BLOOM_MS = 700;
    const NOISE_AMP = 0.24;
    const NOISE_FREQ = 2.2;
    const RING = 10;
    const POINTS = 48;
    const CYCLE_MS = 3200;
    const ANCHOR_SIZE = 44;
    const anchor = q("[data-r=anchor]");
    const card = q("[data-r=card]");
    const ring = q("[data-r=ring]");
    let want = reduce;
    let p = 0;
    let expanded = false;
    let radius = 0;
    let cw = 0;
    let ch = 0;
    let ox = 0;
    let oy = 0;
    function hash(ix, iy) {
        let h = (Math.imul(ix, 374761393) + Math.imul(iy, 668265263)) | 0;
        h = Math.imul(h ^ (h >>> 13), 1274126177);
        return (((h ^ (h >>> 16)) >>> 0) / 4294967296) * 2 - 1;
    }
    function noise2(x, y) {
        const ix = Math.floor(x);
        const iy = Math.floor(y);
        const fx = x - ix;
        const fy = y - iy;
        const ux = fx * fx * (3 - 2 * fx);
        const uy = fy * fy * (3 - 2 * fy);
        const a = hash(ix, iy);
        const b = hash(ix + 1, iy);
        const c = hash(ix, iy + 1);
        const d = hash(ix + 1, iy + 1);
        return a + (b - a) * ux + (c - a) * uy + (a - b - c + d) * ux * uy;
    }
    function mask(r, extra) {
        const pts = [];
        for (let i = 0; i < POINTS; i += 1) {
            const a = (i / POINTS) * Math.PI * 2;
            const n = noise2(Math.cos(a) * NOISE_FREQ + 7 + p * 0.8, Math.sin(a) * NOISE_FREQ + 3);
            const rr = Math.max(0, r * (1 + NOISE_AMP * n) + extra);
            pts.push((ox + Math.cos(a) * rr).toFixed(1) + "px " + (oy + Math.sin(a) * rr).toFixed(1) + "px");
        }
        return "polygon(" + pts.join(",") + ")";
    }
    function layout() {
        const w = root.clientWidth;
        const h = root.clientHeight;
        cw = Math.min(260, w - 96);
        ch = Math.min(150, h - 28);
        const ax = 20 + ANCHOR_SIZE / 2;
        const ay = h / 2;
        const cx = 80;
        const cy = (h - ch) / 2;
        ox = ax - cx;
        oy = ay - cy;
        for (const el of [card, ring]) {
            el.style.width = cw + "px";
            el.style.height = ch + "px";
            el.style.transform = "translate3d(" + cx + "px," + cy.toFixed(1) + "px,0)";
        }
        anchor.style.transform = "translate3d(20px," + (ay - ANCHOR_SIZE / 2).toFixed(1) + "px,0)";
        const far = Math.max(Math.hypot(ox, oy), Math.hypot(ox, oy - ch), Math.hypot(ox - cw, oy), Math.hypot(ox - cw, oy - ch));
        radius = (far * 1.05) / (1 - NOISE_AMP);
    }
    function tick(ms) {
        if (demo) {
            const t = ms % CYCLE_MS;
            want = t >= 250 && t < 1750;
        }
        const dp = 1000 / 60 / BLOOM_MS;
        p = clamp(p + (want ? dp : -dp), 0, 1);
    }
    function snap() {
        p = want ? 1 : 0;
    }
    function render() {
        layout();
        const e = 1 - Math.pow(1 - p, 3);
        const r = radius * e;
        const on = p > 0.004;
        card.style.visibility = on ? "visible" : "hidden";
        ring.style.visibility = on ? "visible" : "hidden";
        if (on) {
            card.style.clipPath = p >= 1 ? "none" : mask(r, 0);
            ring.style.clipPath = p >= 1 ? "none" : mask(r, RING);
            ring.style.opacity = p >= 1 ? "0" : "1";
        }
        if (want !== expanded) {
            expanded = want;
            anchor.setAttribute("aria-expanded", want ? "true" : "false");
        }
        say("r " + Math.round(r) + "  noise " + Math.round(NOISE_AMP * 100) + "%");
    }
    function toggle() {
        stopDemo();
        want = !want;
        sync();
    }
    on(anchor, "click", toggle);
    on(root, "keydown", (e) => {
        if (e.key !== "Escape" || !want)
            return;
        e.preventDefault();
        stopDemo();
        want = false;
        anchor.focus({ preventScroll: true });
        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();
    };
})();

// InkBloomReveal - vanilla 판(08-pm-ink-bloom-reveal) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./InkBloomReveal.module.scss";

export default function InkBloomReveal() {
  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: 앵커 점에서 퍼지는 원형 마스크의 반지름을 각도마다 2차원 값 노이즈로 흔들어 다각형 clip-path 로 만든다. 뒤에 RING 만큼 큰 같은 모양을 깔아 잉크 가장자리를 낸다.
    const BLOOM_MS = 700;
    const NOISE_AMP = 0.24;
    const NOISE_FREQ = 2.2;
    const RING = 10;
    const POINTS = 48;
    const CYCLE_MS = 3200;
    const ANCHOR_SIZE = 44;
    const anchor = q<HTMLElement>("[data-r=anchor]");
    const card = q<HTMLElement>("[data-r=card]");
    const ring = q<HTMLElement>("[data-r=ring]");
    let want = reduce;
    let p = 0;
    let expanded = false;
    let radius = 0;
    let cw = 0;
    let ch = 0;
    let ox = 0;
    let oy = 0;

    function hash(ix: number, iy: number): number {
      let h = (Math.imul(ix, 374761393) + Math.imul(iy, 668265263)) | 0;
      h = Math.imul(h ^ (h >>> 13), 1274126177);
      return (((h ^ (h >>> 16)) >>> 0) / 4294967296) * 2 - 1;
    }
    function noise2(x: number, y: number): number {
      const ix = Math.floor(x);
      const iy = Math.floor(y);
      const fx = x - ix;
      const fy = y - iy;
      const ux = fx * fx * (3 - 2 * fx);
      const uy = fy * fy * (3 - 2 * fy);
      const a = hash(ix, iy);
      const b = hash(ix + 1, iy);
      const c = hash(ix, iy + 1);
      const d = hash(ix + 1, iy + 1);
      return a + (b - a) * ux + (c - a) * uy + (a - b - c + d) * ux * uy;
    }
    function mask(r: number, extra: number): string {
      const pts: string[] = [];
      for (let i = 0; i < POINTS; i += 1) {
        const a = (i / POINTS) * Math.PI * 2;
        const n = noise2(Math.cos(a) * NOISE_FREQ + 7 + p * 0.8, Math.sin(a) * NOISE_FREQ + 3);
        const rr = Math.max(0, r * (1 + NOISE_AMP * n) + extra);
        pts.push((ox + Math.cos(a) * rr).toFixed(1) + "px " + (oy + Math.sin(a) * rr).toFixed(1) + "px");
      }
      return "polygon(" + pts.join(",") + ")";
    }
    function layout(): void {
      const w = root.clientWidth;
      const h = root.clientHeight;
      cw = Math.min(260, w - 96);
      ch = Math.min(150, h - 28);
      const ax = 20 + ANCHOR_SIZE / 2;
      const ay = h / 2;
      const cx = 80;
      const cy = (h - ch) / 2;
      ox = ax - cx;
      oy = ay - cy;
      for (const el of [card, ring]) {
        el.style.width = cw + "px";
        el.style.height = ch + "px";
        el.style.transform = "translate3d(" + cx + "px," + cy.toFixed(1) + "px,0)";
      }
      anchor.style.transform = "translate3d(20px," + (ay - ANCHOR_SIZE / 2).toFixed(1) + "px,0)";
      const far = Math.max(Math.hypot(ox, oy), Math.hypot(ox, oy - ch), Math.hypot(ox - cw, oy), Math.hypot(ox - cw, oy - ch));
      radius = (far * 1.05) / (1 - NOISE_AMP);
    }
    function tick(ms: number): void {
      if (demo) {
        const t = ms % CYCLE_MS;
        want = t >= 250 && t < 1750;
      }
      const dp = 1000 / 60 / BLOOM_MS;
      p = clamp(p + (want ? dp : -dp), 0, 1);
    }
    function snap(): void {
      p = want ? 1 : 0;
    }
    function render(): void {
      layout();
      const e = 1 - Math.pow(1 - p, 3);
      const r = radius * e;
      const on = p > 0.004;
      card.style.visibility = on ? "visible" : "hidden";
      ring.style.visibility = on ? "visible" : "hidden";
      if (on) {
        card.style.clipPath = p >= 1 ? "none" : mask(r, 0);
        ring.style.clipPath = p >= 1 ? "none" : mask(r, RING);
        ring.style.opacity = p >= 1 ? "0" : "1";
      }
      if (want !== expanded) {
        expanded = want;
        anchor.setAttribute("aria-expanded", want ? "true" : "false");
      }
      say("r " + Math.round(r) + "  noise " + Math.round(NOISE_AMP * 100) + "%");
    }
    function toggle(): void {
      stopDemo();
      want = !want;
      sync();
    }
    on(anchor, "click", toggle);
    on(root, "keydown", (e: KeyboardEvent) => {
      if (e.key !== "Escape" || !want) return;
      e.preventDefault();
      stopDemo();
      want = false;
      anchor.focus({ preventScroll: true });
      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>
        <i className={styles["pm__ring"]} data-r="ring"></i>
        <div className={styles["pm__card"]} data-r="card"><i className={styles["pm__sun"]}></i><i className={styles["pm__hill"]}></i><b className={styles["pm__ttl"]}>미리보기</b></div>
        <button className={styles["pm__anchor"]} data-r="anchor" type="button" aria-expanded="false" aria-label="이미지 미리보기 열기"></button>
      </div>
    </main>
  );
}