01Icon-morph check — a button that draws its success as a single stroke

<main class="stage">
<section class="panel">
  <button class="copyBtn" id="copyBtn" type="button" aria-pressed="false" aria-label="Copy code">
    <span class="iconSlot" id="iconSlot">
      <svg class="icon icon--sheet" id="sheetIcon" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M216 40v128h-48V88H88V40Z" opacity=".2"/><path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z"/></g></svg>
      <svg class="icon icon--check" id="checkIcon" viewBox="0 0 24 24" aria-hidden="true">
        <polyline id="checkStroke" points="4,13 9.5,18.5 20,6"></polyline>
      </svg>
    </span>
    <span class="label" id="label">Copy code</span>
  </button>
  <span class="sr" id="live" role="status" aria-live="polite"></span>
</section>
</main>

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

@include stage($stage-ink);

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-4;
}

.copyBtn {
  display: inline-flex;
  align-items: center;
  gap: $sp-2;
  padding: $sp-3 $sp-5;
  border: 0;
  border-radius: $r-pill;
  background: $subject-blue-deep;
  color: $subject-cream;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 15px;
  line-height: 1.3;
  cursor: pointer;
  box-shadow: $shadow-raised;
}

.iconSlot {
  position: relative;
  width: 22px;
  height: 22px;
  flex: none;
}

.icon {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.icon--sheet {
  color: $subject-cream;
}

.icon--check {
  opacity: 0;
  fill: none;
  stroke: $subject-cream;
  stroke-width: 2.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.label {
  white-space: nowrap;
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 340px) {
  .copyBtn {
    padding: $sp-2 $sp-4;
    font-size: 13px;
  }
  .iconSlot {
    width: 18px;
    height: 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .copyBtn * {
    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);
}

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.copyBtn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border: 0;
  border-radius: 999px;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 15px;
  line-height: 1.3;
  cursor: pointer;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.iconSlot {
  position: relative;
  width: 22px;
  height: 22px;
  flex: none;
}

.icon {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.icon--sheet {
  color: #fff7e6;
}

.icon--check {
  opacity: 0;
  fill: none;
  stroke: #fff7e6;
  stroke-width: 2.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.label {
  white-space: nowrap;
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 340px) {
  .copyBtn {
    padding: 8px 16px;
    font-size: 13px;
  }
  .iconSlot {
    width: 18px;
    height: 18px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .copyBtn * {
    transition: none;
  }
}

// 아이콘 모핑 체크 — 서류 아이콘이 사라지고 체크 폴리라인이 stroke-dashoffset 으로 그려진다.
// 체크 선의 실제 길이는 getTotalLength 로 재고, 그 길이만큼 오프셋을 0 까지 줄이며 그린다.
// 계산 겹: 선 길이 실측 → 경과 비율 → 오프셋 재계산. 자동 재생만, 실사용자 리스너 없음.
(function () {
  var sheet = document.getElementById('sheetIcon');
  var check = document.getElementById('checkIcon');
  var stroke = document.getElementById('checkStroke');
  var label = document.getElementById('label');
  var live = document.getElementById('live');
  if (!sheet || !check || !stroke || !label || !live) return;

  var length = stroke.getTotalLength();
  stroke.style.strokeDasharray = length.toFixed(2);

  var LABEL_IDLE = 'Copy code';
  var LABEL_DONE = 'Copied';
  var CYCLE_MS = 2000;
  var TRIGGER_AT = 0.08;
  var DRAW_MS = 640;
  var REVERT_AT = 0.62;

  function apply(t) {
    var drawStart = TRIGGER_AT * CYCLE_MS;
    var drawEnd = drawStart + DRAW_MS;
    var revertAt = REVERT_AT * CYCLE_MS;
    var success = t >= drawStart && t < revertAt;
    var drawT = Math.min(Math.max((t - drawStart) / DRAW_MS, 0), 1);
    var offset = success ? length * (1 - drawT) : length;
    stroke.style.strokeDashoffset = offset.toFixed(2);
    sheet.style.opacity = success ? '0' : '1';
    check.style.opacity = success ? '1' : '0';
    var done = success && drawT >= 1;
    label.textContent = done ? LABEL_DONE : LABEL_IDLE;
    live.textContent = done ? LABEL_DONE : '';
  }

  apply(0);
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (reduce) return;
  var start = null;
  function loop(ts) {
    if (start === null) start = ts;
    var t = (ts - start) % CYCLE_MS;
    apply(t);
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

import { useEffect, useRef } from "react";
import styles from "./CopyIconMorphCheck.module.scss";

// 아이콘 모핑 체크 — 서류 아이콘이 사라지고 체크 폴리라인이 stroke-dashoffset 으로 그려진다.
// 체크 선의 실제 길이는 getTotalLength 로 재고, 그 길이만큼 오프셋을 0 까지 줄이며 그린다.
// 계산 겹: 선 길이 실측 → 경과 비율 → 오프셋 재계산. 자동 재생만, 실사용자 리스너 없음.
const LABEL_IDLE = "코드 복사";
const LABEL_DONE = "복사됨";
const CYCLE_MS = 2000;
const TRIGGER_AT = 0.08;
const DRAW_MS = 640;
const REVERT_AT = 0.62;

export default function CopyIconMorphCheck() {
  const sheetRef = useRef<SVGSVGElement>(null);
  const checkRef = useRef<SVGSVGElement>(null);
  const strokeRef = useRef<SVGPolylineElement>(null);
  const labelRef = useRef<HTMLSpanElement>(null);
  const liveRef = useRef<HTMLSpanElement>(null);

  useEffect(() => {
    const sheet = sheetRef.current;
    const check = checkRef.current;
    const stroke = strokeRef.current;
    const label = labelRef.current;
    const live = liveRef.current;
    if (!sheet || !check || !stroke || !label || !live) return;

    const length = stroke.getTotalLength();
    stroke.style.strokeDasharray = length.toFixed(2);

    function apply(t: number) {
      const drawStart = TRIGGER_AT * CYCLE_MS;
      const revertAt = REVERT_AT * CYCLE_MS;
      const success = t >= drawStart && t < revertAt;
      const drawT = Math.min(Math.max((t - drawStart) / DRAW_MS, 0), 1);
      const offset = success ? length * (1 - drawT) : length;
      stroke!.style.strokeDashoffset = offset.toFixed(2);
      sheet!.style.opacity = success ? "0" : "1";
      check!.style.opacity = success ? "1" : "0";
      const done = success && drawT >= 1;
      label!.textContent = done ? LABEL_DONE : LABEL_IDLE;
      live!.textContent = done ? LABEL_DONE : "";
    }

    apply(0);
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (reduce) return;

    let start: number | null = null;
    let raf = 0;
    function loop(ts: number) {
      if (start === null) start = ts;
      const t = (ts - start) % CYCLE_MS;
      apply(t);
      raf = requestAnimationFrame(loop);
    }
    raf = requestAnimationFrame(loop);
    return () => cancelAnimationFrame(raf);
  }, []);

  return (
    <div className={styles.stage}>
      <section className={styles.panel}>
        <button className={styles.copyBtn} type="button" aria-pressed="false" aria-label="코드 복사">
          <span className={styles.iconSlot}>
            <svg ref={sheetRef} className={`${styles.icon} ${styles.iconSheet}`} viewBox="0 0 256 256" aria-hidden="true">
              <g fill="currentColor">
                <path d="M216 40v128h-48V88H88V40Z" opacity=".2" />
                <path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z" />
              </g>
            </svg>
            <svg ref={checkRef} className={`${styles.icon} ${styles.iconCheck}`} viewBox="0 0 24 24" aria-hidden="true">
              <polyline ref={strokeRef} points="4,13 9.5,18.5 20,6" />
            </svg>
          </span>
          <span ref={labelRef} className={styles.label}>코드 복사</span>
        </button>
        <span ref={liveRef} className={styles.sr} role="status" aria-live="polite" />
      </section>
    </div>
  );
}