03Rotate Handle Stemming From the Selection Box's Top

<main class="stage">
<div class="scene is-demo" id="scene">
  <div class="frame" id="frame">
    <div class="rotator" id="rotator">
      <div class="subjectShape"></div>
      <div class="stick" aria-hidden="true"></div>
      <div class="handle" id="handle" tabindex="0" role="slider" aria-label="Rotate handle, drag to rotate" aria-valuemin="0" aria-valuemax="360" aria-valuenow="0"></div>
    </div>
  </div>
  <div class="readout" id="readout" aria-hidden="true"><span id="rd">0</span>°</div>
</div>
</main>

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

// 변수 3개
$duration: $dur-enter;
$easing: $ease-out;
$color: $subject-pink;

// 계산 겹: index.html 의 angleFromPointer() 가 프레임 중심→포인터 벡터의 atan2 로 절대 각도를 구하고
// ROTATE_SNAP_DEG 배수로 반올림해 rotator 에 rotate() 로 준다 — 트윈이 아니라 매 프레임 산술.
@include stage($stage-orange);

.scene {
  position: relative;
  width: 320px;
  height: 180px;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
  background: linear-gradient(160deg, #ffd9c4, $stage-orange 90%);
}

.frame {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 84px;
  height: 84px;
  margin: -42px;
}

.rotator {
  position: relative;
  width: 100%;
  height: 100%;
  transform-origin: 50% 50%;
  will-change: transform;
}

.subjectShape {
  position: absolute;
  inset: 8px;
  border-radius: $r-sm;
  background: linear-gradient(135deg, $subject-lilac, $subject-pink);
  box-shadow: $shadow-press;
}

.stick {
  position: absolute;
  left: 50%;
  top: -22px;
  width: 2px;
  height: 22px;
  margin-left: -1px;
  background: rgba($subject-ink, .55);
}

.handle {
  position: absolute;
  left: 50%;
  top: -30px;
  width: 16px;
  height: 16px;
  margin: -8px 0 0 -8px;
  border-radius: $r-pill;
  background: $subject-cream;
  border: 3px solid $subject-ink;
  cursor: grab;
  touch-action: none;

  &:active { cursor: grabbing; }
  &:focus-visible { outline: 2px solid $color; outline-offset: 3px; }
}

.readout {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  padding: $sp-1 $sp-2;
  border-radius: $r-pill;
  background: rgba($subject-ink, .78);
  color: $subject-cream;
  font-size: 10px;
  font-variant-numeric: tabular-nums;
}

@media (max-width: 340px) {
  .scene { width: 220px; height: 124px; }
  .frame { width: 62px; height: 62px; margin: -31px; }
  .stick { top: -16px; height: 16px; }
  .handle { top: -22px; width: 13px; height: 13px; margin: -6px 0 0 -6px; }
  .readout { font-size: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  // 실사용 경로 적용 — 핸들 드래그·키보드는 index.html 이 트윈 없이 즉시 반영한다.
  // scss 만: 핸들 포커스 아웃라인 전환만 꺼서 잔여 트랜지션을 없앤다.
  .handle { transition: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.scene {
  position: relative;
  width: 320px;
  height: 180px;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: linear-gradient(160deg, #ffd9c4, #ff4d1f 90%);
}

.frame {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 84px;
  height: 84px;
  margin: -42px;
}

.rotator {
  position: relative;
  width: 100%;
  height: 100%;
  transform-origin: 50% 50%;
  will-change: transform;
}

.subjectShape {
  position: absolute;
  inset: 8px;
  border-radius: 8px;
  background: linear-gradient(135deg, #b9a0ff, #ff9ebb);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.stick {
  position: absolute;
  left: 50%;
  top: -22px;
  width: 2px;
  height: 22px;
  margin-left: -1px;
  background: rgba(23, 20, 26, 0.55);
}

.handle {
  position: absolute;
  left: 50%;
  top: -30px;
  width: 16px;
  height: 16px;
  margin: -8px 0 0 -8px;
  border-radius: 999px;
  background: #fff7e6;
  border: 3px solid #17141a;
  cursor: grab;
  touch-action: none;
}
.handle:active {
  cursor: grabbing;
}
.handle:focus-visible {
  outline: 2px solid #ff9ebb;
  outline-offset: 3px;
}

.readout {
  position: absolute;
  left: 12px;
  bottom: 12px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.78);
  color: #fff7e6;
  font-size: 10px;
  font-variant-numeric: tabular-nums;
}

@media (max-width: 340px) {
  .scene {
    width: 220px;
    height: 124px;
  }
  .frame {
    width: 62px;
    height: 62px;
    margin: -31px;
  }
  .stick {
    top: -16px;
    height: 16px;
  }
  .handle {
    top: -22px;
    width: 13px;
    height: 13px;
    margin: -6px 0 0 -6px;
  }
  .readout {
    font-size: 9px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .handle {
    transition: none;
  }
}

(function () {
  var ROTATE_SNAP_DEG = 15; // 변형 03 이 5 로 좁힌다
  var LOOP_SEQUENCE = [70, 200, 320, 360];
  var HOP_MS = 560;
  var HOLD_MS = 260;

  var scene = document.getElementById('scene');
  var frame = document.getElementById('frame');
  var rotator = document.getElementById('rotator');
  var handle = document.getElementById('handle');
  var rd = document.getElementById('rd');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var angle = 0;
  var dragging = false;
  var timers = [];

  function clamp(v, lo, hi) { return Math.min(hi, Math.max(lo, v)); }
  function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }
  function mod360(v) { return ((v % 360) + 360) % 360; }

  function applyRotate(deg) {
    angle = mod360(deg);
    rotator.style.transform = 'rotate(' + angle.toFixed(1) + 'deg)';
    rd.textContent = Math.round(angle);
    handle.setAttribute('aria-valuenow', String(Math.round(angle)));
  }

  function human() {
    if (scene.classList.contains('is-demo')) {
      scene.classList.remove('is-demo');
      timers.forEach(function (t) { clearTimeout(t); clearInterval(t); });
      timers = [];
    }
  }

  // 회전 핸들 = atan2 각 → rotate. 프레임 중심(회전하지 않는 고정 요소)에서 포인터까지의 벡터로
  // 절대 각도를 매 프레임 구하고, ROTATE_SNAP_DEG 배수로 반올림해 스냅한다.
  function angleFromPointer(e) {
    var r = frame.getBoundingClientRect();
    var cx = r.left + r.width / 2;
    var cy = r.top + r.height / 2;
    var raw = Math.atan2(e.clientY - cy, e.clientX - cx) * 180 / Math.PI;
    return mod360(raw + 90);
  }

  handle.addEventListener('pointerdown', function (e) {
    human();
    dragging = true;
    handle.setPointerCapture(e.pointerId);
  });
  handle.addEventListener('pointermove', function (e) {
    if (!dragging) return;
    var a = angleFromPointer(e);
    var snapped = Math.round(a / ROTATE_SNAP_DEG) * ROTATE_SNAP_DEG;
    applyRotate(snapped);
  });
  function end(e) {
    if (!dragging) return;
    dragging = false;
    try { handle.releasePointerCapture(e.pointerId); } catch (err) {}
  }
  handle.addEventListener('pointerup', end);
  handle.addEventListener('pointercancel', end);
  handle.addEventListener('keydown', function (e) {
    if (e.key === 'ArrowRight' || e.key === 'ArrowUp') { human(); applyRotate(angle + ROTATE_SNAP_DEG); e.preventDefault(); }
    else if (e.key === 'ArrowLeft' || e.key === 'ArrowDown') { human(); applyRotate(angle - ROTATE_SNAP_DEG); e.preventDefault(); }
  });

  // reduce: 실사용 경로 적용 — 핸들 pointer·keydown 은 위에서 즉시 반영한다.
  // 아래 hopRotate()·cycle() 은 시연 게이트만(연속 각도, 스냅 없이 부드럽게 돈다) — reduce 에서는 정지.
  function hopRotate(target, onDone) {
    var from = angle;
    var start = performance.now();
    function frame(now) {
      if (!scene.classList.contains('is-demo')) return;
      var p = clamp((now - start) / HOP_MS, 0, 1);
      applyRotate(from + (target - from) * easeOutCubic(p));
      if (p < 1) requestAnimationFrame(frame);
      else if (onDone) onDone();
    }
    requestAnimationFrame(frame);
  }

  function cycle(i) {
    if (!scene.classList.contains('is-demo')) return;
    var target = LOOP_SEQUENCE[i % LOOP_SEQUENCE.length];
    hopRotate(target, function () {
      timers.push(setTimeout(function () { cycle(i + 1); }, HOLD_MS));
    });
  }

  if (!reduce) {
    cycle(0);
  }
})();

import { useEffect, useRef } from 'react';
import styles from './XfRotateHandle.module.scss';

const ROTATE_SNAP_DEG = 15; // 변형 03 이 5 로 좁힌다 — 드래그 중 붙는 회전 스냅 각도
const HOP_MS = 620;
const HOLD_MS = 340;
const LOOP_SEQUENCE = [70, 200, 320, 360];

export default function XfRotateHandle() {
  const sceneRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const scene0 = sceneRef.current;
    if (!scene0) return undefined;
    const scene = scene0;
    const frame0 = scene.querySelector<HTMLDivElement>('#frame');
    const rotator0 = scene.querySelector<HTMLDivElement>('#rotator');
    const handle0 = scene.querySelector<HTMLDivElement>('#handle');
    const rd0 = scene.querySelector<HTMLSpanElement>('#rd');
    if (!frame0 || !rotator0 || !handle0 || !rd0) return undefined;
    const frame = frame0;
    const rotator = rotator0;
    const handle = handle0;
    const rd = rd0;

    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

    let deg = 0;
    let dragging = false;
    let rafId = 0;
    let timers: number[] = [];

    function clamp(v: number, lo: number, hi: number) { return Math.min(hi, Math.max(lo, v)); }
    function easeOutCubic(t: number) { return 1 - Math.pow(1 - t, 3); }
    function mod360(raw: number) { return ((raw % 360) + 360) % 360; }

    // 프레임 중심→포인터 벡터의 atan2 로 절대 각도를 구한다 — 0° 가 위를 향하도록 +90 보정.
    function angleFromPointer(e: PointerEvent) {
      const r = frame.getBoundingClientRect();
      const cx = r.left + r.width / 2;
      const cy = r.top + r.height / 2;
      const dx = e.clientX - cx;
      const dy = e.clientY - cy;
      return mod360((Math.atan2(dy, dx) * 180) / Math.PI + 90);
    }

    function applyRotate(a: number) {
      deg = mod360(a);
      rotator.style.transform = 'rotate(' + deg.toFixed(1) + 'deg)';
      rd.textContent = String(Math.round(deg));
      handle.setAttribute('aria-valuenow', String(Math.round(deg)));
    }

    function human() {
      if (scene.classList.contains(styles['is-demo'])) {
        scene.classList.remove(styles['is-demo']);
        timers.forEach((t) => window.clearTimeout(t));
        timers = [];
      }
    }

    function onPointerDown(e: PointerEvent) {
      human();
      dragging = true;
      handle.setPointerCapture(e.pointerId);
    }
    function onPointerMove(e: PointerEvent) {
      if (!dragging) return;
      // 실 드래그는 ROTATE_SNAP_DEG 배수로 반올림해 붙는다.
      const a = angleFromPointer(e);
      applyRotate(Math.round(a / ROTATE_SNAP_DEG) * ROTATE_SNAP_DEG);
    }
    function onPointerUp(e: PointerEvent) {
      if (!dragging) return;
      dragging = false;
      try { handle.releasePointerCapture(e.pointerId); } catch { /* 캡처가 이미 풀린 경우 */ }
    }
    function onKeyDown(e: KeyboardEvent) {
      if (e.key === 'ArrowLeft' || e.key === 'ArrowDown') { human(); applyRotate(deg - ROTATE_SNAP_DEG); e.preventDefault(); }
      else if (e.key === 'ArrowRight' || e.key === 'ArrowUp') { human(); applyRotate(deg + ROTATE_SNAP_DEG); e.preventDefault(); }
    }

    handle.addEventListener('pointerdown', onPointerDown);
    handle.addEventListener('pointermove', onPointerMove);
    handle.addEventListener('pointerup', onPointerUp);
    handle.addEventListener('pointercancel', onPointerUp);
    handle.addEventListener('keydown', onKeyDown);
    applyRotate(0);

    // reduce: 실사용 경로 적용 — 핸들 드래그·키보드는 위에서 즉시 반영한다.
    // 아래 자동 루프는 시연 게이트만 — 스냅 없이 연속 회전하며 reduce 에서는 돌지 않는다.
    function hopRotate(target: number, onDone: () => void) {
      const from = deg;
      const delta = target - from;
      const start = performance.now();
      function frame(now: number) {
        if (!scene.classList.contains(styles['is-demo'])) return;
        const p = clamp((now - start) / HOP_MS, 0, 1);
        applyRotate(from + delta * easeOutCubic(p));
        if (p < 1) rafId = requestAnimationFrame(frame);
        else onDone();
      }
      rafId = requestAnimationFrame(frame);
    }

    function cycle(i: number) {
      if (!scene.classList.contains(styles['is-demo'])) return;
      const target = LOOP_SEQUENCE[i % LOOP_SEQUENCE.length];
      hopRotate(target, () => {
        timers.push(window.setTimeout(() => cycle(i + 1), HOLD_MS));
      });
    }

    if (!reduce) {
      cycle(0);
    }

    return () => {
      handle.removeEventListener('pointerdown', onPointerDown);
      handle.removeEventListener('pointermove', onPointerMove);
      handle.removeEventListener('pointerup', onPointerUp);
      handle.removeEventListener('pointercancel', onPointerUp);
      handle.removeEventListener('keydown', onKeyDown);
      timers.forEach((t) => window.clearTimeout(t));
      cancelAnimationFrame(rafId);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.scene + ' ' + styles['is-demo']} ref={sceneRef}>
        <div id="frame" className={styles.frame}>
          <div id="rotator" className={styles.rotator}>
            <span className={styles.subjectShape} aria-hidden="true"></span>
            <span className={styles.stick} aria-hidden="true"></span>
            <div
              id="handle"
              className={styles.handle}
              role="slider"
              tabIndex={0}
              aria-label="회전 핸들, 드래그하여 회전"
              aria-valuemin={0}
              aria-valuemax={360}
              aria-valuenow={0}
            ></div>
          </div>
        </div>
        <div className={styles.readout} aria-hidden="true"><span id="rd">0</span>°</div>
      </div>
    </main>
  );
}