09Processing Badge That Swaps to Static Text When a Reduced-motion Value Is Detected

<main class="stage">
<div class="ld" id="ld">
  <p class="ld__hint">
    <svg class="ld__ico" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 56v56a8 8 0 0 1-16 0V91.3l-25.6 25.7A80 80 0 1 1 174 60a8 8 0 1 1-9 13.2A64 64 0 1 0 179.7 128H216a8 8 0 0 1 0 16h-56a8 8 0 0 1-8-8V80a8 8 0 0 1 16 0v20.7L192.7 76A80.1 80.1 0 0 0 64 128a8 8 0 0 1-16 0a96 96 0 0 1 163.6-68.3L224 71.3V56a8 8 0 0 1 8 8" opacity=".2"/><path d="M224 48a8 8 0 0 0-8 8v15.3l-11.7-11.6a96 96 0 1 0 27.6 51.6a8 8 0 0 0-15.8 2.5a80 80 0 1 1-23-43l-25.7 25.7A8 8 0 0 0 173 112h56a8 8 0 0 0 8-8V56a8 8 0 0 0-13-8"/></g></svg>
    <span>Click or press the space bar to pause or restart</span>
  </p>
  <div class="ld__field" id="field" role="application" aria-label="Reduced-motion badge-switch test panel" tabindex="0">
    <div class="ld__scene">
      <div class="ld__dots" id="dots" aria-hidden="true">
        <i></i><i></i><i></i>
      </div>
      <div class="ld__badge" id="badge">
        <b class="ld__badgeDot" aria-hidden="true"></b>
        <span id="badgeText">Processing</span>
      </div>
    </div>
    <p class="ld__state" id="state">Reduced motion: off · moving</p>
  </div>
</div>
</main>

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

// reduced-motion-static-badge — 동작 줄임 설정 값을 감지해, 그 값이 켜져 있으면 애니메이션 없이
// '처리 중' 문구 배지가 즉시 나타나고, 꺼져 있을 때만 원래 속도로 움직인다. 이 항목 자체가
// 접근성 정지 프레임의 주제 — 루프 절반은 바운스 점(사인), 절반은 스프링 오버슛 배지. @keyframes 없음.

$duration: $dur-loop;
$easing: $ease-spring;
$color: $subject-cream;

@include stage($stage-ink);

.ld {
  --dot: #{$subject-blue-light};
  --badge-bg: #{$subject-cream};
  --badge-fg: #{$stage-ink};

  display: flex; flex-direction: column; gap: $sp-2;
  width: 100%; max-width: 424px;
}

.ld__hint {
  display: flex; align-items: center; gap: $sp-1; margin: 0;
  font-weight: 700; font-size: clamp(10px, 2.8vw, 12px); line-height: 1.35;
  color: $subject-cream;
}
.ld__ico { width: 16px; height: 16px; flex: 0 0 auto; color: $subject-cream; }

.ld__field {
  position: relative; height: 208px;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: $sp-3;
  border-radius: $r-card; overflow: hidden;
  background: rgba($subject-cream, .06);
  box-shadow: inset 0 0 0 1px rgba($subject-cream, .18);
  cursor: pointer;
}
.ld__field:focus-visible { outline: 2px solid $subject-cream; outline-offset: 2px; }

.ld__scene { position: relative; width: 100%; height: 64px; display: flex; align-items: center; justify-content: center; }

.ld__dots {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center; gap: $sp-2;
}
.ld__dots > i {
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--dot);
}

.ld__badge {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center; gap: $sp-2;
  opacity: 0; transform: scale(.7);
}
.ld__badgeDot { width: 10px; height: 10px; border-radius: 50%; background: var(--badge-fg); }
.ld__badge span {
  padding: $sp-2 $sp-4; border-radius: $r-pill;
  background: var(--badge-bg); color: var(--badge-fg);
  font-weight: 700; font-size: 15px;
}

.ld__state {
  margin: 0; font-size: 12px; font-weight: 600; color: rgba($subject-cream, .78);
}

@media (max-width: 340px) {
  .ld { gap: $sp-1; }
  .ld__field { height: 124px; gap: $sp-2; }
  .ld__scene { height: 44px; }
  .ld__dots > i { width: 10px; height: 10px; }
  .ld__state { font-size: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field { cursor: default !important; }
  .ld.is-still .ld__badge { opacity: 1 !important; }
}

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);
}

.ld {
  --dot: #5b8cf8;
  --badge-bg: #fff7e6;
  --badge-fg: #17141a;
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
  max-width: 424px;
}

.ld__hint {
  display: flex;
  align-items: center;
  gap: 4px;
  margin: 0;
  font-weight: 700;
  font-size: clamp(10px, 2.8vw, 12px);
  line-height: 1.35;
  color: #fff7e6;
}

.ld__ico {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  color: #fff7e6;
}

.ld__field {
  position: relative;
  height: 208px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  border-radius: 16px;
  overflow: hidden;
  background: rgba(255, 247, 230, 0.06);
  box-shadow: inset 0 0 0 1px rgba(255, 247, 230, 0.18);
  cursor: pointer;
}

.ld__field:focus-visible {
  outline: 2px solid #fff7e6;
  outline-offset: 2px;
}

.ld__scene {
  position: relative;
  width: 100%;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.ld__dots {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.ld__dots > i {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--dot);
}

.ld__badge {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  opacity: 0;
  transform: scale(0.7);
}

.ld__badgeDot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--badge-fg);
}

.ld__badge span {
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--badge-bg);
  color: var(--badge-fg);
  font-weight: 700;
  font-size: 15px;
}

.ld__state {
  margin: 0;
  font-size: 12px;
  font-weight: 600;
  color: rgba(255, 247, 230, 0.78);
}

@media (max-width: 340px) {
  .ld {
    gap: 4px;
  }
  .ld__field {
    height: 124px;
    gap: 8px;
  }
  .ld__scene {
    height: 44px;
  }
  .ld__dots > i {
    width: 10px;
    height: 10px;
  }
  .ld__state {
    font-size: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field {
    cursor: default !important;
  }
  .ld.is-still .ld__badge {
    opacity: 1 !important;
  }
}

(function () {
  var LOOP = 2.0;
  var SWITCH_AT = LOOP * 0.5;   // 동작 줄임 값이 켜졌다고 보는 시각
  var SPRING_MS = 0.36;         // 배지가 나타날 때 스프링 오버슛 시간
  var BOUNCE_HZ = 2.4;          // 점 세 개 바운스 진동수

  var root = document.getElementById('ld');
  var field = document.getElementById('field');
  var dots = document.getElementById('dots').children;
  var badge = document.getElementById('badge');
  var stateEl = document.getElementById('state');
  var paused = false;
  var t0 = performance.now();
  var raf = 0;

  function reduced() { return window.matchMedia('(prefers-reduced-motion: reduce)').matches; }
  function clamp01(v) { return v < 0 ? 0 : v > 1 ? 1 : v; }

  // 임계 감쇠 스프링 근사(오버슛 포함): t=0 에서 0, t=1 부근에서 1을 살짝 넘겼다 정착
  function spring(t) {
    var x = clamp01(t);
    return 1 - Math.exp(-6 * x) * Math.cos(7 * x);
  }

  function draw(sec) {
    var t = sec % LOOP;
    var on = t >= SWITCH_AT;   // 동작 줄임 값(시뮬레이션)

    if (on) {
      var localT = (t - SWITCH_AT) / SPRING_MS;
      var s = spring(localT);
      badge.style.opacity = '1';
      badge.style.transform = 'scale(' + (0.7 + 0.3 * s).toFixed(3) + ')';
      dots.length && (root.querySelector('.ld__dots').style.opacity = '0');
      stateEl.textContent = 'Reduced motion: on · processing badge';
    } else {
      badge.style.opacity = '0';
      badge.style.transform = 'scale(.7)';
      root.querySelector('.ld__dots').style.opacity = '1';
      for (var i = 0; i < dots.length; i++) {
        var phase = i * (Math.PI * 2 / 3);
        var y = Math.sin(t * BOUNCE_HZ * Math.PI * 2 + phase);
        dots[i].style.transform = 'translateY(' + (y * 7).toFixed(1) + 'px)';
        dots[i].style.opacity = (0.55 + 0.45 * (0.5 + 0.5 * y)).toFixed(2);
      }
      stateEl.textContent = 'Reduced motion: off · moving';
    }
  }

  function togglePause() { paused = !paused; root.classList.toggle('is-paused', paused); }
  function restart() { t0 = performance.now(); draw(0); }
  function onKey(e) {
    if (e.key === ' ' || e.key === 'Enter') { e.preventDefault(); togglePause(); }
    else if (e.key === 'r' || e.key === 'R') { e.preventDefault(); restart(); }
  }
  field.addEventListener('click', togglePause);
  field.addEventListener('keydown', onKey);

  function onResize() {
    if (paused || reduced()) draw((performance.now() - t0) / 1000 % LOOP);
  }
  window.addEventListener('resize', onResize);

  function frame(now) {
    if (!paused) draw((now - t0) / 1000);
    raf = requestAnimationFrame(frame);
  }

  if (reduced()) {
    root.classList.add('is-still');
    draw(SWITCH_AT + SPRING_MS);   // 배지가 이미 자리 잡은 정지 프레임
  } else {
    raf = requestAnimationFrame(frame);
  }
})();

// ReduceBadge — vanilla 판(run/403/demo/09-ai-processing-loading-reduced-motion-static-badge/index.html) 의 React 포트.
// 동작 줄임 설정 값을 감지해, 그 값이 켜져 있으면 애니메이션 없이 '처리 중' 문구 배지가 즉시
// 나타나고, 꺼져 있을 때만 원래 속도로 움직인다. 이 항목 자체가 접근성 정지 프레임의 주제다.
import { useEffect, useRef } from "react";
import type { CSSProperties } from "react";
import styles from "./ReduceBadge.module.scss";

export type ReduceBadgeProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type Box<T> = { current: T };
type KeyEvt = { key: string; preventDefault(): void };

const LOOP = 2.0;
const SWITCH_AT = LOOP * 0.5;
const SPRING_MS = 0.36;
const BOUNCE_HZ = 2.4;
const FIELD_LABEL = "동작 줄임 배지 전환 실험판";

function clamp01(v: number): number { return v < 0 ? 0 : v > 1 ? 1 : v; }
function spring(t: number): number {
  const x = clamp01(t);
  return 1 - Math.exp(-6 * x) * Math.cos(7 * x);
}

export default function ReduceBadge({
  duration = "2s",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  color = "#fff7e6",
}: ReduceBadgeProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const fieldRef = useRef<HTMLDivElement | null>(null);
  const dotsWrapRef = useRef<HTMLDivElement | null>(null);
  const dotRefs = useRef<(HTMLElement | null)[]>([]) as Box<(HTMLElement | null)[]>;
  const badgeRef = useRef<HTMLDivElement | null>(null);
  const stateRef = useRef<HTMLParagraphElement | null>(null);
  const pausedRef = useRef(false) as Box<boolean>;
  const t0Ref = useRef(0) as Box<number>;
  const rafRef = useRef(0) as Box<number>;
  const vars: Vars = { "--duration": duration, "--easing": easing, "--color": color };

  function reduced(): boolean {
    return window.matchMedia("(prefers-reduced-motion: reduce)").matches;
  }

  function draw(sec: number): void {
    const dotsWrap = dotsWrapRef.current;
    const badge = badgeRef.current;
    const stateEl = stateRef.current;
    if (!dotsWrap || !badge) return;
    const t = sec % LOOP;
    const on = t >= SWITCH_AT;

    if (on) {
      const localT = (t - SWITCH_AT) / SPRING_MS;
      const s = spring(localT);
      badge.style.opacity = "1";
      badge.style.transform = "scale(" + (0.7 + 0.3 * s).toFixed(3) + ")";
      dotsWrap.style.opacity = "0";
      if (stateEl) stateEl.textContent = "동작 줄임: 켜짐 · 처리 중 배지";
    } else {
      badge.style.opacity = "0";
      badge.style.transform = "scale(.7)";
      dotsWrap.style.opacity = "1";
      for (let i = 0; i < dotRefs.current.length; i++) {
        const phase = i * (Math.PI * 2 / 3);
        const y = Math.sin(t * BOUNCE_HZ * Math.PI * 2 + phase);
        const el = dotRefs.current[i];
        if (el) {
          el.style.transform = "translateY(" + (y * 7).toFixed(1) + "px)";
          el.style.opacity = (0.55 + 0.45 * (0.5 + 0.5 * y)).toFixed(2);
        }
      }
      if (stateEl) stateEl.textContent = "동작 줄임: 꺼짐 · 움직이는 중";
    }
  }

  function togglePause(): void {
    pausedRef.current = !pausedRef.current;
    const root = rootRef.current;
    if (root) root.classList.toggle("is-paused", pausedRef.current);
  }
  function restart(): void { t0Ref.current = performance.now(); draw(0); }
  function onKey(e: KeyEvt): void {
    if (e.key === " " || e.key === "Enter") { e.preventDefault(); togglePause(); }
    else if (e.key === "r" || e.key === "R") { e.preventDefault(); restart(); }
  }
  function onClick(): void { togglePause(); }
  function onResize(): void {
    if (pausedRef.current || reduced()) draw((performance.now() - t0Ref.current) / 1000 % LOOP);
  }
  function frame(now: number): void {
    if (!pausedRef.current) draw((now - t0Ref.current) / 1000);
    rafRef.current = requestAnimationFrame(frame);
  }

  useEffect(() => {
    t0Ref.current = performance.now();
    window.addEventListener("resize", onResize);
    if (reduced()) {
      const root = rootRef.current;
      if (root) root.classList.add("is-still");
      draw(SWITCH_AT + SPRING_MS);
    } else {
      rafRef.current = requestAnimationFrame(frame);
    }
    return () => {
      window.removeEventListener("resize", onResize);
      cancelAnimationFrame(rafRef.current);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.root} ref={rootRef} style={vars}>
        <p className={styles.hint}>
          <svg className={styles.ico} viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 56v56a8 8 0 0 1-16 0V91.3l-25.6 25.7A80 80 0 1 1 174 60a8 8 0 1 1-9 13.2A64 64 0 1 0 179.7 128H216a8 8 0 0 1 0 16h-56a8 8 0 0 1-8-8V80a8 8 0 0 1 16 0v20.7L192.7 76A80.1 80.1 0 0 0 64 128a8 8 0 0 1-16 0a96 96 0 0 1 163.6-68.3L224 71.3V56a8 8 0 0 1 8 8" opacity=".2"/><path d="M224 48a8 8 0 0 0-8 8v15.3l-11.7-11.6a96 96 0 1 0 27.6 51.6a8 8 0 0 0-15.8 2.5a80 80 0 1 1-23-43l-25.7 25.7A8 8 0 0 0 173 112h56a8 8 0 0 0 8-8V56a8 8 0 0 0-13-8"/></g></svg>
          <span>클릭하거나 스페이스바를 누르면 멈추거나 다시 갑니다</span>
        </p>
        <div
          className={styles.field}
          ref={fieldRef}
          role="application"
          aria-label={FIELD_LABEL}
          tabIndex={0}
          onClick={onClick}
          onKeyDown={onKey}
        >
          <div className={styles.scene}>
            <div className={styles.dots} ref={dotsWrapRef} aria-hidden="true">
              <i ref={(el: HTMLElement | null) => { dotRefs.current[0] = el; }}></i>
              <i ref={(el: HTMLElement | null) => { dotRefs.current[1] = el; }}></i>
              <i ref={(el: HTMLElement | null) => { dotRefs.current[2] = el; }}></i>
            </div>
            <div className={styles.badge} ref={badgeRef}>
              <b className={styles.badgeDot} aria-hidden="true"></b>
              <span>처리 중</span>
            </div>
          </div>
          <p className={styles.state} ref={stateRef}>동작 줄임: 꺼짐 · 움직이는 중</p>
        </div>
      </div>
    </main>
  );
}