01Scan-line sweep — a scan-progress value moves top to bottom while the ridge-brightness value at each passed line rises in order

<main class="stage">
<div class="scan-wrap">
<button type="button" class="scan is-demo" id="scan" aria-pressed="false">
  <svg class="scan__icon" viewBox="0 0 120 130" aria-hidden="true">
    <path class="scan__ridge" data-apex="72" d="M10,118 A50 46 0 0 1 110,118"></path>
    <path class="scan__ridge" data-apex="77" d="M16,118 A44 41 0 0 1 104,118"></path>
    <path class="scan__ridge" data-apex="82" d="M22,118 A38 36 0 0 1 98,118"></path>
    <path class="scan__ridge" data-apex="87" d="M28,118 A32 31 0 0 1 92,118"></path>
    <path class="scan__ridge" data-apex="92" d="M34,118 A26 26 0 0 1 86,118"></path>
    <path class="scan__ridge" data-apex="97" d="M40,118 A20 21 0 0 1 80,118"></path>
    <path class="scan__ridge" data-apex="102" d="M46,118 A14 16 0 0 1 74,118"></path>
    <line class="scan__beam" id="beam" x1="6" x2="114" y1="6" y2="6"></line>
  </svg>
  <span class="scan__label">Fingerprint scan</span>
</button>
<p class="scan__status" id="status">Idle</p>
</div>
</main>

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

// 계산 겹은 index.html 의 apply() 에 있다 — 능선마다 정점(apex) y 와 스캔 라인 y 의 차를 GLOW_BAND 로
// 나눈 활성 값(act)을 opacity 에 매 프레임 반영한다. 여기는 무대·모양만 맡는다.
@include stage($stage-ink);

.scan-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
}

.scan {
  appearance: none;
  border: none;
  background: transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
  cursor: pointer;
  padding: $sp-4;
  border-radius: $r-card;

  &:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 4px; }
}

.scan__icon {
  width: clamp(120px, 30vw, 160px);
  height: auto;
  overflow: visible;
}

.scan__ridge {
  fill: none;
  stroke: $subject-blue-light;
  stroke-width: 3;
  stroke-linecap: round;
  opacity: .26;
}

.scan__beam {
  stroke: $subject-blue-light;
  stroke-width: 2;
  filter: drop-shadow(0 0 6px rgba($subject-blue-light, .9));
}

.scan__label {
  color: $subject-cream;
  font-weight: 600;
  font-size: 13px;
  line-height: 1.2;
  letter-spacing: .02em;
}

.scan__status {
  margin: 0;
  color: rgba($subject-cream, .58);
  font-weight: 500;
  font-size: 12px;
  line-height: 1.2;
}

@media (max-width: 340px) {
  .stage { padding: $sp-2; }
  .scan-wrap { gap: $sp-2; }
  .scan { padding: $sp-2 $sp-3; gap: $sp-2; }
  .scan__icon { width: 104px; }
  .scan__label { font-size: 12px; }
  .scan__status { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .scan__ridge, .scan__beam { 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);
}

.scan-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.scan {
  appearance: none;
  border: none;
  background: transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  padding: 16px;
  border-radius: 16px;
}
.scan:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 4px;
}

.scan__icon {
  width: clamp(120px, 30vw, 160px);
  height: auto;
  overflow: visible;
}

.scan__ridge {
  fill: none;
  stroke: #5b8cf8;
  stroke-width: 3;
  stroke-linecap: round;
  opacity: 0.26;
}

.scan__beam {
  stroke: #5b8cf8;
  stroke-width: 2;
  filter: drop-shadow(0 0 6px rgba(91, 140, 248, 0.9));
}

.scan__label {
  color: #fff7e6;
  font-weight: 600;
  font-size: 13px;
  line-height: 1.2;
  letter-spacing: 0.02em;
}

.scan__status {
  margin: 0;
  color: rgba(255, 247, 230, 0.58);
  font-weight: 500;
  font-size: 12px;
  line-height: 1.2;
}

@media (max-width: 340px) {
  .stage {
    padding: 8px;
  }
  .scan-wrap {
    gap: 8px;
  }
  .scan {
    padding: 8px 12px;
    gap: 8px;
  }
  .scan__icon {
    width: 104px;
  }
  .scan__label {
    font-size: 12px;
  }
  .scan__status {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .scan__ridge, .scan__beam {
    transition: none;
  }
}

(function () {
  // 계산 겹: 능선 stagger 순서 계산 — 능선마다 정점(apex) y 값이 다르고, 스캔 라인 y 값이 그 정점을
  // 지난 만큼(GLOW_BAND 로 나눈 비율)을 활성 값(act, 0~1)으로 써서 밝기를 매긴다. 정점이 위(작은 y)일수록
  // 먼저 활성되므로 "능선이 순서대로 밝아지는" 흐름이 실제 계산으로 나온다.
  var SWEEP_SPEED = 1.4; // 변형 01: SWEEP_SPEED 1.4 → 0.6 (스윕 속도)
  var BASE_MS = 1000; // 기준 스윕 시간 — 실제 소요는 BASE_MS / SWEEP_SPEED
  var GLOW_BAND = 16; // 스캔 라인이 능선 정점을 지난 뒤 완전히 밝아지기까지의 svg 단위 거리
  var HOLD_MS = 500; // Scan complete 뒤 전체 밝기를 유지하는 시간
  var GAP_MS = 700; // 다음 자동 스캔까지 대기하는 시간
  var TOP = 6, BOTTOM = 124;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var DUR = reduce ? 1 : (BASE_MS / SWEEP_SPEED);

  var root = document.getElementById('scan');
  var beam = document.getElementById('beam');
  var ridges = Array.prototype.slice.call(document.querySelectorAll('.scan__ridge'));
  var status = document.getElementById('status');
  var STRINGS = { idle: 'Idle', scanning: 'Scanning', done: 'Scan complete' };
  var isDemo = true;
  var running = false;
  var startTs = 0;

  function apply(scanY) {
    beam.setAttribute('y1', scanY.toFixed(2));
    beam.setAttribute('y2', scanY.toFixed(2));
    for (var i = 0; i < ridges.length; i++) {
      var apex = parseFloat(ridges[i].getAttribute('data-apex'));
      var act = Math.max(0, Math.min(1, (scanY - apex) / GLOW_BAND + 0.001));
      ridges[i].style.opacity = (0.26 + 0.74 * act).toFixed(3);
    }
  }

  function runScan(ts) {
    if (!startTs) startTs = ts;
    var t = ts - startTs;
    if (t <= DUR) {
      apply(TOP + (BOTTOM - TOP) * (t / DUR));
      status.textContent = STRINGS.scanning;
      requestAnimationFrame(runScan);
    } else if (t <= DUR + HOLD_MS) {
      apply(BOTTOM);
      status.textContent = STRINGS.done;
      requestAnimationFrame(runScan);
    } else {
      apply(TOP);
      status.textContent = STRINGS.idle;
      running = false;
      root.setAttribute('aria-pressed', 'false');
    }
  }

  function trigger() {
    if (running) return;
    running = true;
    startTs = 0;
    root.setAttribute('aria-pressed', 'true');
    requestAnimationFrame(runScan);
  }

  function human() { if (isDemo) { root.classList.remove('is-demo'); isDemo = false; } }

  root.addEventListener('click', function () { human(); trigger(); });
  root.addEventListener('keydown', function (e) {
    if (e.key === ' ' || e.key === 'Enter') { human(); }
  });

  apply(TOP);

  var cycleStart = 0;
  var PERIOD = DUR + HOLD_MS + GAP_MS;
  function loop(ts) {
    if (isDemo && !reduce) {
      if (!cycleStart) cycleStart = ts;
      var phase = (ts - cycleStart) % PERIOD;
      if (phase < 16 && !running) trigger();
    }
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

// ScanSweepLine — vanilla 판(run/371/demo/01-biometric-scan-sweep-line/index.html) 의 React 포트.
// 계산 겹(능선 stagger 순서 계산)은 useScanSweep 훅 안에 있다: 능선 정점(apex) y 와 스캔 라인 y 의
// 차를 GLOW_BAND 로 나눈 활성 값(act)을 매 프레임 svg style.opacity 에 반영한다.
import { useEffect, useRef, useState } from "react";
import styles from "./ScanSweepLine.module.scss";

type Box<T> = { current: T };

const RIDGES = [
  { apex: 72, d: "M10,118 A50 46 0 0 1 110,118" },
  { apex: 77, d: "M16,118 A44 41 0 0 1 104,118" },
  { apex: 82, d: "M22,118 A38 36 0 0 1 98,118" },
  { apex: 87, d: "M28,118 A32 31 0 0 1 92,118" },
  { apex: 92, d: "M34,118 A26 26 0 0 1 86,118" },
  { apex: 97, d: "M40,118 A20 21 0 0 1 80,118" },
  { apex: 102, d: "M46,118 A14 16 0 0 1 74,118" },
];

const STRINGS: Record<string, string> = { idle: "대기 중", scanning: "스캔 중", done: "스캔 완료" };

function useScanSweep(
  rootRef: Box<HTMLButtonElement>,
  beamRef: Box<SVGLineElement>,
  ridgeRefs: Box<SVGPathElement[]>,
  setStatus: (s: string) => void,
  setPressed: (b: boolean) => void
) {
  useEffect(() => {
    const SWEEP_SPEED = 1.4; // 변형 01: SWEEP_SPEED 1.4 → 0.6
    const BASE_MS = 1000;
    const GLOW_BAND = 16;
    const HOLD_MS = 500;
    const GAP_MS = 700;
    const TOP = 6, BOTTOM = 124;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const DUR = reduce ? 1 : BASE_MS / SWEEP_SPEED;

    const root = rootRef.current;
    const beam = beamRef.current;
    const ridges = ridgeRefs.current;
    if (!root || !beam || ridges.length === 0) return;

    let isDemo = true;
    let running = false;
    let startTs = 0;
    let rafId = 0;

    function apply(scanY: number) {
      beam.setAttribute("y1", scanY.toFixed(2));
      beam.setAttribute("y2", scanY.toFixed(2));
      for (let i = 0; i < ridges.length; i++) {
        const apex = RIDGES[i].apex;
        const act = Math.max(0, Math.min(1, (scanY - apex) / GLOW_BAND + 0.001));
        ridges[i].style.opacity = (0.26 + 0.74 * act).toFixed(3);
      }
    }

    function runScan(ts: number) {
      if (!startTs) startTs = ts;
      const t = ts - startTs;
      if (t <= DUR) {
        apply(TOP + (BOTTOM - TOP) * (t / DUR));
        setStatus(STRINGS.scanning);
        rafId = requestAnimationFrame(runScan);
      } else if (t <= DUR + HOLD_MS) {
        apply(BOTTOM);
        setStatus(STRINGS.done);
        rafId = requestAnimationFrame(runScan);
      } else {
        apply(TOP);
        setStatus(STRINGS.idle);
        running = false;
        setPressed(false);
      }
    }

    function trigger() {
      if (running) return;
      running = true;
      startTs = 0;
      setPressed(true);
      rafId = requestAnimationFrame(runScan);
    }

    function human() { if (isDemo) { root.classList.remove(styles.isDemo); isDemo = false; } }
    function onClick() { human(); trigger(); }
    function onKeyDown(e: KeyboardEvent) { if (e.key === " " || e.key === "Enter") human(); }
    root.addEventListener("click", onClick);
    root.addEventListener("keydown", onKeyDown);

    apply(TOP);

    let cycleStart = 0;
    const PERIOD = DUR + HOLD_MS + GAP_MS;
    function loop(ts: number) {
      if (isDemo && !reduce) {
        if (!cycleStart) cycleStart = ts;
        const phase = (ts - cycleStart) % PERIOD;
        if (phase < 16 && !running) trigger();
      }
      rafId = requestAnimationFrame(loop);
    }
    rafId = requestAnimationFrame(loop);

    return () => {
      root.removeEventListener("click", onClick);
      root.removeEventListener("keydown", onKeyDown);
      cancelAnimationFrame(rafId);
    };
  }, []);
}

export default function ScanSweepLine() {
  const rootRef = useRef(null) as unknown as Box<HTMLButtonElement>;
  const beamRef = useRef(null) as unknown as Box<SVGLineElement>;
  const ridgeRefs = useRef([]) as unknown as Box<SVGPathElement[]>;
  const [status, setStatus] = useState(STRINGS.idle);
  const [pressed, setPressed] = useState(false);

  useScanSweep(rootRef, beamRef, ridgeRefs, setStatus, setPressed);

  return (
    <main className={styles.stage}>
      <div className={styles.scanWrap}>
        <button
          type="button"
          className={styles.scan + " " + styles.isDemo}
          ref={rootRef}
          aria-pressed={pressed}
        >
          <svg className={styles.scanIcon} viewBox="0 0 120 130" aria-hidden="true">
            {RIDGES.map((r, i) => (
              <path
                key={i}
                className={styles.scanRidge}
                d={r.d}
                ref={(el: SVGPathElement | null) => { if (el) ridgeRefs.current[i] = el; }}
              />
            ))}
            <line className={styles.scanBeam} ref={beamRef} x1={6} x2={114} y1={6} y2={6} />
          </svg>
          <span className={styles.scanLabel}>지문 스캔</span>
        </button>
        <p className={styles.scanStatus}>{status}</p>
      </div>
    </main>
  );
}