06ラチェット目盛り — 引いた距離の値が目盛りの値を通過するたびに位置が短く跳ねる表示

<main class="stage">
<div class="prtk is-demo" id="prtk">
  <div class="prtk__panel">
    <div class="prtk__track" id="prtkTrack">
      <span class="prtk__tick" style="bottom:22px"></span>
      <span class="prtk__tick" style="bottom:44px"></span>
      <span class="prtk__tick" style="bottom:66px"></span>
      <span class="prtk__tick" style="bottom:88px"></span>
      <span class="prtk__marker" id="prtkMarker"></span>
    </div>
    <div class="prtk__phone" id="prtkPhone">
      <div class="prtk__list" id="prtkList">
        <div class="prtk__row"></div>
        <div class="prtk__row"></div>
      </div>
    </div>
  </div>
  <span class="prtk__hint" id="prtkHint">下に引っぱってください</span>
</div>
</main>

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

// 계산 겹(감쇠 진동 burst)은 JS 에 있다 — 여기는 정적 배치만.
@include stage($stage-yellow);

.prtk {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
}

.prtk__panel {
  display: flex;
  align-items: flex-end;
  gap: $sp-4;
  padding: $sp-4;
  border-radius: $r-card;
  background: $stage-paper;
}

.prtk__track {
  position: relative;
  width: 20px;
  height: 110px;
  border-radius: $r-xs;
  background: $subject-cream;
}

.prtk__tick {
  position: absolute;
  left: -3px;
  right: -3px;
  height: 2px;
  background: rgba($subject-ink, .3);
}

.prtk__marker {
  position: absolute;
  left: 2px;
  right: 2px;
  bottom: 2px;
  height: 12px;
  border-radius: $r-xs;
  background: $subject-blue-deep;
}

.prtk__phone {
  position: relative;
  width: 156px;
  height: 108px;
  overflow: hidden;
  border-radius: $r-sm;
  background: $subject-cream;
  touch-action: none;
  cursor: grab;
}

.prtk__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
  padding: $sp-3;
}

.prtk__row {
  height: 18px;
  border-radius: $r-xs;
  background: $stage-paper;
}

.prtk__hint {
  color: $subject-ink;
  font-size: 12px;
  text-align: center;
}

@media (max-width: 340px) {
  .prtk__panel { padding: $sp-3; gap: $sp-2; }
  .prtk__track { height: 88px; }
  .prtk__phone { width: 128px; height: 88px; }
}

@media (prefers-reduced-motion: reduce) {
  .prtk__marker, .prtk__list { transition: none !important; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.prtk {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.prtk__panel {
  display: flex;
  align-items: flex-end;
  gap: 16px;
  padding: 16px;
  border-radius: 16px;
  background: #ffffff;
}

.prtk__track {
  position: relative;
  width: 20px;
  height: 110px;
  border-radius: 4px;
  background: #fff7e6;
}

.prtk__tick {
  position: absolute;
  left: -3px;
  right: -3px;
  height: 2px;
  background: rgba(23, 20, 26, 0.3);
}

.prtk__marker {
  position: absolute;
  left: 2px;
  right: 2px;
  bottom: 2px;
  height: 12px;
  border-radius: 4px;
  background: #0a4fe8;
}

.prtk__phone {
  position: relative;
  width: 156px;
  height: 108px;
  overflow: hidden;
  border-radius: 8px;
  background: #fff7e6;
  touch-action: none;
  cursor: grab;
}

.prtk__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px;
}

.prtk__row {
  height: 18px;
  border-radius: 4px;
  background: #ffffff;
}

.prtk__hint {
  color: #17141a;
  font-size: 12px;
  text-align: center;
}

@media (max-width: 340px) {
  .prtk__panel {
    padding: 12px;
    gap: 8px;
  }
  .prtk__track {
    height: 88px;
  }
  .prtk__phone {
    width: 128px;
    height: 88px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .prtk__marker, .prtk__list {
    transition: none !important;
  }
}

(function () {
  var phone = document.getElementById('prtkPhone');
  var marker = document.getElementById('prtkMarker');
  var list = document.getElementById('prtkList');
  var hint = document.getElementById('prtkHint');
  var root = document.getElementById('prtk');

  // 계산 겹: 目盛り 경계(TICK 배수)를 새로 지날 때마다 감쇠 진동 AMP*e^(-t/TAU)*sin(t*W) 을
  // 기준 위치에 얹는다 — 릴리즈 때 한 번이 아니라 손가락이 칸을 지날 때마다 걸리는 래칫 튐이다.
  var TICK = 22, N = 5, TRACK_H = 110, MAX_TICK = TICK * N, RAW_MAX = 150;
  var AMP = 10, TAU = 0.15, W = 26;

  var raw = 0, lastTick = 0, burstActive = false, burstStart = 0;
  var dragging = false, startY = 0, startRaw = 0, released = true;

  function triggerBurst(now) { burstActive = true; burstStart = now; }

  function frame(now) {
    var clamped = Math.min(raw, MAX_TICK);
    var tickIndex = Math.floor(clamped / TICK);
    if (tickIndex > lastTick) { triggerBurst(now); }
    lastTick = tickIndex;

    var basePos = (clamped / MAX_TICK) * TRACK_H;
    var burst = 0;
    if (burstActive) {
      var t = (now - burstStart) / 1000;
      burst = AMP * Math.exp(-t / TAU) * Math.sin(t * W);
      if (t > 0.6) { burstActive = false; }
    }
    marker.style.transform = 'translateY(' + (-(basePos) + burst).toFixed(1) + 'px)';
    list.style.transform = 'translateY(' + (clamped * 0.35).toFixed(1) + 'px)';
    hint.textContent = raw > 4 ? ('目盛り ' + Math.min(tickIndex, N) + '/' + N) : '下に引っぱってください';
    requestAnimationFrame(frame);
  }
  requestAnimationFrame(frame);

  var committing = false, commitTimer = null;
  function commit() {
    committing = true;
    hint.textContent = '更新中';
    commitTimer = setTimeout(function () {
      committing = false;
      raw = 0; lastTick = 0;
      hint.textContent = '下に引っぱってください';
    }, 620);
  }

  function onDown(y) { if (committing) { return; } dragging = true; released = false; startY = y; startRaw = raw; }
  function onMove(y) {
    if (!dragging) { return; }
    raw = Math.max(0, Math.min(RAW_MAX, startRaw + (y - startY)));
  }
  function onUp() {
    if (!dragging) { return; }
    dragging = false; released = true;
    if (raw >= MAX_TICK) { commit(); } else { raw = 0; lastTick = 0; }
  }

  function wireReal() {
    phone.addEventListener('pointerdown', function (e) { root.classList.remove('is-demo'); stopAutoplay(); onDown(e.clientY); });
    window.addEventListener('pointermove', function (e) { onMove(e.clientY); });
    window.addEventListener('pointerup', onUp);
  }
  phone.style.touchAction = 'none';
  wireReal();

  var autoRaw = 0, autoTimer = null;
  function autoTick() {
    if (committing) { return; }
    autoRaw += 16;
    if (autoRaw >= MAX_TICK) { raw = MAX_TICK; autoRaw = 0; commit(); return; }
    raw = autoRaw;
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } if (commitTimer) { clearTimeout(commitTimer); } }
  if (!reduce) { autoTimer = setInterval(autoTick, 160); }
})();

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

export type PullRefreshRatchetTickSnapProps = {
  color?: string;
};

export default function PullRefreshRatchetTickSnap({
  color = "#0a4fe8",
}: PullRefreshRatchetTickSnapProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const phone = root.querySelector<HTMLDivElement>(`.${styles.phone}`);
    const marker = root.querySelector<HTMLSpanElement>(`.${styles.marker}`);
    const list = root.querySelector<HTMLDivElement>(`.${styles.list}`);
    const hint = root.querySelector<HTMLSpanElement>(`.${styles.hint}`);
    if (!phone || !marker || !list || !hint) return;

    // 계산 겹: 칸 경계(TICK 배수)를 새로 지날 때마다 감쇠 진동 AMP*e^(-t/TAU)*sin(t*W) 을
    // 기준 위치에 얹는다 — 릴리즈 때 한 번이 아니라 손가락이 칸을 지날 때마다 걸리는 래칫 튐이다.
    const TICK = 22, N = 5, TRACK_H = 110, MAX_TICK = TICK * N, RAW_MAX = 150;
    const AMP = 10, TAU = 0.15, W = 26;

    let raw = 0, lastTick = 0, burstActive = false, burstStart = 0;
    let dragging = false, startY = 0, startRaw = 0;
    let rafId: number | null = null;

    function triggerBurst(now: number) { burstActive = true; burstStart = now; }

    function frame(now: number) {
      const clamped = Math.min(raw, MAX_TICK);
      const tickIndex = Math.floor(clamped / TICK);
      if (tickIndex > lastTick) triggerBurst(now);
      lastTick = tickIndex;

      const basePos = (clamped / MAX_TICK) * TRACK_H;
      let burst = 0;
      if (burstActive) {
        const t = (now - burstStart) / 1000;
        burst = AMP * Math.exp(-t / TAU) * Math.sin(t * W);
        if (t > 0.6) burstActive = false;
      }
      marker!.style.transform = "translateY(" + (-(basePos) + burst).toFixed(1) + "px)";
      list!.style.transform = "translateY(" + (clamped * 0.35).toFixed(1) + "px)";
      hint!.textContent = raw > 4 ? ("칸 " + Math.min(tickIndex, N) + "/" + N) : "아래로 당기세요";
      rafId = requestAnimationFrame(frame);
    }
    rafId = requestAnimationFrame(frame);

    let committing = false, commitTimer: number | null = null;
    function commit() {
      committing = true;
      hint!.textContent = "새로고침 중";
      commitTimer = window.setTimeout(() => {
        committing = false;
        raw = 0; lastTick = 0;
        hint!.textContent = "아래로 당기세요";
      }, 620);
    }

    function onDown(y: number) {
      if (committing) return;
      dragging = true; startY = y; startRaw = raw;
    }
    function onMove(y: number) {
      if (!dragging) return;
      raw = Math.max(0, Math.min(RAW_MAX, startRaw + (y - startY)));
    }
    function onUp() {
      if (!dragging) return;
      dragging = false;
      if (raw >= MAX_TICK) { commit(); } else { raw = 0; lastTick = 0; }
    }

    function onPointerDown(e: PointerEvent) { stopAutoplay(); onDown(e.clientY); }
    function onPointerMove(e: PointerEvent) { onMove(e.clientY); }
    phone.style.touchAction = "none";
    phone.addEventListener("pointerdown", onPointerDown);
    window.addEventListener("pointermove", onPointerMove);
    window.addEventListener("pointerup", onUp);

    let autoRaw = 0, autoTimer: number | null = null;
    function autoTick() {
      if (committing) return;
      autoRaw += 16;
      if (autoRaw >= MAX_TICK) { raw = MAX_TICK; autoRaw = 0; commit(); return; }
      raw = autoRaw;
    }
    function stopAutoplay() {
      if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; }
      if (commitTimer !== null) { window.clearTimeout(commitTimer); }
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, 160); }

    return () => {
      stopAutoplay();
      if (rafId !== null) cancelAnimationFrame(rafId);
      phone.removeEventListener("pointerdown", onPointerDown);
      window.removeEventListener("pointermove", onPointerMove);
      window.removeEventListener("pointerup", onUp);
    };
  }, []);

  return (
    <div ref={rootRef} className={styles.stage}>
      <div className={styles.prtk}>
        <div className={styles.panel}>
          <div className={styles.track}>
            <span className={styles.tick} style={{ bottom: "22px" }} />
            <span className={styles.tick} style={{ bottom: "44px" }} />
            <span className={styles.tick} style={{ bottom: "66px" }} />
            <span className={styles.tick} style={{ bottom: "88px" }} />
            <span className={styles.marker} style={{ "--accent": color } as any} />
          </div>
          <div className={styles.phone}>
            <div className={styles.list}>
              <div className={styles.row} />
              <div className={styles.row} />
            </div>
          </div>
        </div>
        <span className={styles.hint}>아래로 당기세요</span>
      </div>
    </div>
  );
}