01색상 값이 완료 쪽으로 도는 후광 링 AI 로딩

<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>클릭하거나 스페이스바를 누르면 멈추거나 다시 갑니다</span>
  </p>
  <div class="ld__field" id="field" role="application" aria-label="후광 링 색상 전환 실험판" tabindex="0">
    <div class="ld__ring" id="ring"></div>
    <div class="ld__core" id="core"></div>
    <b class="ld__badge" aria-hidden="true"><span class="ld__badgeNum" id="pct">0%</span><span class="ld__badgeUnit">진행</span></b>
  </div>
</div>
</main>

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

// halo-ring-hue-shift — conic-gradient 로 그린 후광 링이 회전하며, 진행 값이 전환 구간에 들어서면
// 남은 시간(AI_LOADER_HUE_TRANSITION_MS)에 걸쳐 링 색을 완료 색 쪽으로 서서히 섞는다.
// 움직임은 rAF 가 CSS 커스텀 속성을 매 프레임 고쳐 만든다 — @keyframes 없음.

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

@include stage($stage-ink);

.ld {
  --blue: #{$subject-blue};
  --done: #{$stage-yellow};
  --ring-size: 200px;
  --ring-band: 40px;

  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-blue-light; }

.ld__field {
  position: relative; height: 208px;
  display: flex; align-items: center; justify-content: center;
  border-radius: $r-card; overflow: hidden;
  background: $subject-ink;
  box-shadow: inset 0 0 0 1px rgba($subject-cream, .14);
  cursor: pointer;
}
.ld__field:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 2px; }

.ld__ring {
  position: relative;
  width: var(--ring-size); height: var(--ring-size);
  border-radius: $r-pill;
  background: conic-gradient(from var(--angle, 0deg), var(--c1, #{$subject-blue}), var(--c2, transparent), var(--c1, #{$subject-blue}));
  -webkit-mask: radial-gradient(circle, transparent calc(50% - var(--ring-band)), #000 calc(50% - var(--ring-band) + 1px));
  mask: radial-gradient(circle, transparent calc(50% - var(--ring-band)), #000 calc(50% - var(--ring-band) + 1px));
  filter: drop-shadow(0 0 14px rgba($subject-blue-light, .5));
}

.ld__core {
  position: absolute;
  width: 46px; height: 46px; border-radius: $r-pill;
  background: var(--core-c, #{$subject-blue});
  transform: scale(var(--core-scale, 1));
  box-shadow: 0 0 22px 4px rgba($subject-blue-light, .55);
}

.ld__badge {
  position: absolute; right: $sp-2; top: $sp-2;
  display: flex; align-items: baseline; gap: $sp-1;
  padding: $sp-1 $sp-2; border-radius: $r-pill;
  background: rgba($subject-cream, .12);
  color: $subject-cream; font-weight: 700; font-size: 11px;
}
.ld__badgeNum { font-size: 13px; color: $stage-yellow; }
.ld__badgeUnit { font-weight: 700; }

@media (max-width: 340px) {
  .ld { gap: $sp-1; }
  .ld__field { height: 124px; }
  .ld { --ring-size: 116px; --ring-band: 24px; }
  .ld__core { width: 28px; height: 28px; }
  .ld__badge { font-size: 10px; padding: 0 $sp-1; }
  .ld__badgeNum { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field { cursor: default !important; }
  .ld.is-still .ld__badge { opacity: .92 !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 {
  --blue: #2f6df6;
  --done: #ffd23f;
  --ring-size: 200px;
  --ring-band: 40px;
  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: #5b8cf8;
}

.ld__field {
  position: relative;
  height: 208px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  overflow: hidden;
  background: #17141a;
  box-shadow: inset 0 0 0 1px rgba(255, 247, 230, 0.14);
  cursor: pointer;
}

.ld__field:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.ld__ring {
  position: relative;
  width: var(--ring-size);
  height: var(--ring-size);
  border-radius: 999px;
  background: conic-gradient(from var(--angle, 0deg), var(--c1, #2f6df6), var(--c2, transparent), var(--c1, #2f6df6));
  -webkit-mask: radial-gradient(circle, transparent calc(50% - var(--ring-band)), #000 calc(50% - var(--ring-band) + 1px));
  mask: radial-gradient(circle, transparent calc(50% - var(--ring-band)), #000 calc(50% - var(--ring-band) + 1px));
  filter: drop-shadow(0 0 14px rgba(91, 140, 248, 0.5));
}

.ld__core {
  position: absolute;
  width: 46px;
  height: 46px;
  border-radius: 999px;
  background: var(--core-c, #2f6df6);
  transform: scale(var(--core-scale, 1));
  box-shadow: 0 0 22px 4px rgba(91, 140, 248, 0.55);
}

.ld__badge {
  position: absolute;
  right: 8px;
  top: 8px;
  display: flex;
  align-items: baseline;
  gap: 4px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.12);
  color: #fff7e6;
  font-weight: 700;
  font-size: 11px;
}

.ld__badgeNum {
  font-size: 13px;
  color: #ffd23f;
}

.ld__badgeUnit {
  font-weight: 700;
}

@media (max-width: 340px) {
  .ld {
    gap: 4px;
  }
  .ld__field {
    height: 124px;
  }
  .ld {
    --ring-size: 116px;
    --ring-band: 24px;
  }
  .ld__core {
    width: 28px;
    height: 28px;
  }
  .ld__badge {
    font-size: 10px;
    padding: 0 4px;
  }
  .ld__badgeNum {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field {
    cursor: default !important;
  }
  .ld.is-still .ld__badge {
    opacity: 0.92 !important;
  }
}

(function () {
  var LOOP = 2.0;                          // 캡처 창(초) — S.초 와 동일
  var ROTATE_SPEED = 128;                  // 링 회전 속도(도/초)
  var AI_LOADER_HUE_TRANSITION_MS = 640;   // 후광 링 색상 전환 속도 값(전) — 남은 구간에서 완료 색으로 옮겨가는 창 길이
  var root = document.getElementById('ld');
  var field = document.getElementById('field');
  var ring = document.getElementById('ring');
  var core = document.getElementById('core');
  var pctEl = document.getElementById('pct');
  var paused = false;
  var t0 = performance.now();
  var raf = 0;

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

  function hexToRgb(hex) {
    var h = hex.replace('#', '').trim();
    if (h.length === 3) h = h[0]+h[0]+h[1]+h[1]+h[2]+h[2];
    var n = parseInt(h, 16);
    return [(n >> 16) & 255, (n >> 8) & 255, n & 255];
  }
  function mix(a, b, t) {
    return [
      Math.round(a[0] + (b[0] - a[0]) * t),
      Math.round(a[1] + (b[1] - a[1]) * t),
      Math.round(a[2] + (b[2] - a[2]) * t)
    ];
  }
  function smooth(t) { return t * t * (3 - 2 * t); }
  function rgbStr(c, a) { return 'rgba(' + c[0] + ',' + c[1] + ',' + c[2] + ',' + a + ')'; }

  var cs = getComputedStyle(root);
  var BLUE = hexToRgb(cs.getPropertyValue('--blue').trim());
  var DONE = hexToRgb(cs.getPropertyValue('--done').trim());

  function draw(sec) {
    var angle = (sec * ROTATE_SPEED) % 360;
    var p = (sec % LOOP) / LOOP;
    var winStart = 1 - (AI_LOADER_HUE_TRANSITION_MS / 1000) / LOOP;
    var mixT = p <= winStart ? 0 : smooth((p - winStart) / (1 - winStart));
    var col = mix(BLUE, DONE, mixT);
    var col2 = mix(BLUE, DONE, mixT * 0.6);

    ring.style.setProperty('--angle', angle + 'deg');
    ring.style.setProperty('--c1', rgbStr(col, 1));
    ring.style.setProperty('--c2', rgbStr(col2, .35));
    var corePulse = 1 + 0.08 * Math.sin(sec * Math.PI * 2 / LOOP * 3);
    core.style.setProperty('--core-scale', corePulse.toFixed(3));
    core.style.setProperty('--core-c', rgbStr(col, 1));

    var pct = Math.round(p * 100);
    pctEl.textContent = pct + '%';
  }

  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);
  }
  window.addEventListener('resize', onResize);

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

  if (reduced()) {
    root.classList.add('is-still');
    draw(LOOP * 0.62);
  } else {
    raf = requestAnimationFrame(frame);
  }
})();

// HaloRing — vanilla 판(run/403/demo/01-ai-processing-loading-halo-ring-hue-shift/index.html) 의 React 포트.
// conic-gradient 링을 rAF 로 회전시키고, 진행 값이 전환 구간에 들면 링 색을 완료 색 쪽으로 섞는다.
// 움직임은 CSS 커스텀 속성 갱신이 전부 맡는다 — @keyframes 없음.
import { useEffect, useRef } from "react";
import type { CSSProperties } from "react";
import styles from "./HaloRing.module.scss";

export type HaloRingProps = {
  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 ROTATE_SPEED = 128;
const AI_LOADER_HUE_TRANSITION_MS = 640;
const FIELD_LABEL = "후광 링 색상 전환 실험판";

function hexToRgb(hex: string): [number, number, number] {
  let h = hex.replace("#", "").trim();
  if (h.length === 3) h = h[0] + h[0] + h[1] + h[1] + h[2] + h[2];
  const n = parseInt(h, 16);
  return [(n >> 16) & 255, (n >> 8) & 255, n & 255];
}
function mix(a: [number, number, number], b: [number, number, number], t: number): [number, number, number] {
  return [
    Math.round(a[0] + (b[0] - a[0]) * t),
    Math.round(a[1] + (b[1] - a[1]) * t),
    Math.round(a[2] + (b[2] - a[2]) * t),
  ];
}
function smooth(t: number): number { return t * t * (3 - 2 * t); }
function rgbStr(c: [number, number, number], a: number): string { return "rgba(" + c[0] + "," + c[1] + "," + c[2] + "," + a + ")"; }

export default function HaloRing({
  duration = "2s",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  color = "#2f6df6",
}: HaloRingProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const fieldRef = useRef<HTMLDivElement | null>(null);
  const ringRef = useRef<HTMLDivElement | null>(null);
  const coreRef = useRef<HTMLDivElement | null>(null);
  const pctRef = useRef<HTMLSpanElement | null>(null);
  const pausedRef = useRef(false) as Box<boolean>;
  const t0Ref = useRef(0) as Box<number>;
  const rafRef = useRef(0) as Box<number>;
  const bluRef = useRef<[number, number, number]>([47, 109, 246]) as Box<[number, number, number]>;
  const doneRef = useRef<[number, number, number]>([255, 210, 63]) as Box<[number, number, 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 ring = ringRef.current;
    const core = coreRef.current;
    const pctEl = pctRef.current;
    if (!ring || !core) return;
    const angle = (sec * ROTATE_SPEED) % 360;
    const p = (sec % LOOP) / LOOP;
    const winStart = 1 - (AI_LOADER_HUE_TRANSITION_MS / 1000) / LOOP;
    const mixT = p <= winStart ? 0 : smooth((p - winStart) / (1 - winStart));
    const col = mix(bluRef.current, doneRef.current, mixT);
    const col2 = mix(bluRef.current, doneRef.current, mixT * 0.6);

    ring.style.setProperty("--angle", angle + "deg");
    ring.style.setProperty("--c1", rgbStr(col, 1));
    ring.style.setProperty("--c2", rgbStr(col2, .35));
    const corePulse = 1 + 0.08 * Math.sin((sec * Math.PI * 2 / LOOP) * 3);
    core.style.setProperty("--core-scale", corePulse.toFixed(3));
    core.style.setProperty("--core-c", rgbStr(col, 1));

    if (pctEl) pctEl.textContent = Math.round(p * 100) + "%";
  }

  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);
  }
  function frame(now: number): void {
    if (!pausedRef.current) draw((now - t0Ref.current) / 1000);
    rafRef.current = requestAnimationFrame(frame);
  }

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const cs = getComputedStyle(root);
    bluRef.current = hexToRgb(cs.getPropertyValue("--blue").trim() || "#2f6df6");
    doneRef.current = hexToRgb(cs.getPropertyValue("--done").trim() || "#ffd23f");
    t0Ref.current = performance.now();
    window.addEventListener("resize", onResize);
    if (reduced()) {
      root.classList.add("is-still");
      draw(LOOP * 0.62);
    } 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.ring} ref={ringRef}></div>
          <div className={styles.core} ref={coreRef}></div>
          <b className={styles.badge} aria-hidden="true"><span className={styles.badgeNum} ref={pctRef}>0%</span><span className={styles.badgeUnit}>진행</span></b>
        </div>
      </div>
    </main>
  );
}