07値が軌道を回る長さに変わるオービットダイヤルピッカー

<main class="stage">
<figure class="od is-demo" id="od">
  <div class="od__zone" id="zone">
    <svg class="od__chart" id="chart" viewBox="0 0 480 300" role="img" aria-label="円周を回るオービットダイヤル。つまみを回すと開始点から点まで続く軌道の弧の長さが毎瞬間描き直される。">
      <circle class="od__orbit" cx="240" cy="150" r="106"></circle>
      <path class="od__arc" id="arc"></path>
      <circle class="od__dot" id="dot" r="19"></circle>
    </svg>
    <button class="od__grab" id="grab" type="button" role="slider" aria-orientation="horizontal"
            aria-label="軌道の角度を選ぶ" aria-valuemin="1" aria-valuemax="99"
            aria-valuenow="35" aria-valuetext="軌道 126度">
      <svg class="od__ic" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><circle cx="128" cy="128" r="96" opacity=".2"/><path d="M128 24a104 104 0 1 0 104 104A104.11 104.11 0 0 0 128 24m0 192a88 88 0 1 1 88-88 88.1 88.1 0 0 1-88 88"/></g></svg>
    </button>
    <b class="od__badge" aria-hidden="true"><span id="od-val">126</span>°</b>
  </div>

  <p class="od__hint">つまみを引くか矢印キーで軌道弧の長さが再計算されます。</p>

  <div class="sr">
    <span aria-live="polite" id="od-live"></span>
  </div>
</figure>
</main>

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

// 오빗 다이얼 피커 — 손잡이를 돌린 각도(1~99, 도 단위)를 값으로 바꾸면, 원 둘레 위
// 점의 위치를 극좌표로 다시 계산하고 시작점(위쪽)부터 그 점까지 이어진 궤도 호의
// 길이(path d 속성)를 매 프레임 다시 그린다. 값은 관성 lerp(ARC_LERP)로 목표를 뒤따른다.
// CSS @keyframes 는 0개(각도가 매 프레임 실수로 바뀌어 선언형으로 못 담는다,
// 398-01~06 과 같은 이유).
// picker-graph-orbit-dial-arc-smoothing(JS, ARC_LERP)이 변형 07 의 조정 대상.

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

@include stage($stage-orange);

.sr {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip-path: inset(50%); white-space: nowrap;
}

.od {
  box-sizing: border-box;
  width: min(360px, 92vw);
  margin: 0; padding: $sp-1;
  display: flex; flex-direction: column; align-items: center; gap: $sp-1;
  border-radius: $r-card;
  background: $stage-paper;
  box-shadow: $shadow-raised;
  color: $subject-ink;
}

.od__zone {
  position: relative;
  width: min(352px, 100%);
  aspect-ratio: 480 / 300;
}

.od__chart { display: block; width: 100%; height: 100%; overflow: visible; }

.od__orbit { fill: none; stroke: rgba($subject-ink, .14); stroke-width: 2; }
.od__arc { fill: none; stroke: $subject-blue-deep; stroke-width: 40; stroke-linecap: round; }
.od__dot { fill: $subject-blue-deep; stroke: $stage-paper; stroke-width: 4; }

.od__grab {
  position: absolute; top: 0; left: 0;
  width: 30px; height: 30px;
  margin: 0; padding: 0; border: 0; border-radius: 50%;
  display: grid; place-items: center;
  background: transparent;
  color: $subject-blue-deep;
  transform: translate(-50%, -50%);
  cursor: grab;
  touch-action: none;
}
.od__grab:active { cursor: grabbing; }
.od__grab:focus-visible { outline: 2px solid $subject-blue-deep; outline-offset: 2px; border-radius: 50%; }
.od__ic { width: 15px; height: 15px; opacity: 0; }

.od__badge {
  position: absolute; top: $sp-2; right: $sp-2;
  padding: $sp-1 $sp-2;
  border-radius: $r-pill;
  background: rgba($subject-ink, .06);
  font-size: 13px; line-height: 18px; font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: $subject-blue-deep;
  pointer-events: none;
}

.od__hint { margin: 0; padding: 0 $sp-2; font-size: 11px; line-height: 16px; color: rgba($subject-ink, .62); text-align: center; }

@media (max-width: 340px) {
  .od { padding: $sp-1; gap: $sp-1; }
  .od__hint { display: none; }
  .od__badge { font-size: 12px; }
  .od__zone { width: min(210px, 100%); }
}

@media (prefers-reduced-motion: reduce) {
  .od.is-still .od__arc,
  .od.is-still .od__dot { 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: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.od {
  box-sizing: border-box;
  width: min(360px, 92vw);
  margin: 0;
  padding: 4px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  color: #17141a;
}

.od__zone {
  position: relative;
  width: min(352px, 100%);
  aspect-ratio: 480/300;
}

.od__chart {
  display: block;
  width: 100%;
  height: 100%;
  overflow: visible;
}

.od__orbit {
  fill: none;
  stroke: rgba(23, 20, 26, 0.14);
  stroke-width: 2;
}

.od__arc {
  fill: none;
  stroke: #0a4fe8;
  stroke-width: 40;
  stroke-linecap: round;
}

.od__dot {
  fill: #0a4fe8;
  stroke: #ffffff;
  stroke-width: 4;
}

.od__grab {
  position: absolute;
  top: 0;
  left: 0;
  width: 30px;
  height: 30px;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: transparent;
  color: #0a4fe8;
  transform: translate(-50%, -50%);
  cursor: grab;
  touch-action: none;
}

.od__grab:active {
  cursor: grabbing;
}

.od__grab:focus-visible {
  outline: 2px solid #0a4fe8;
  outline-offset: 2px;
  border-radius: 50%;
}

.od__ic {
  width: 15px;
  height: 15px;
  opacity: 0;
}

.od__badge {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.06);
  font-size: 13px;
  line-height: 18px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: #0a4fe8;
  pointer-events: none;
}

.od__hint {
  margin: 0;
  padding: 0 8px;
  font-size: 11px;
  line-height: 16px;
  color: rgba(23, 20, 26, 0.62);
  text-align: center;
}

@media (max-width: 340px) {
  .od {
    padding: 4px;
    gap: 4px;
  }
  .od__hint {
    display: none;
  }
  .od__badge {
    font-size: 12px;
  }
  .od__zone {
    width: min(210px, 100%);
  }
}
@media (prefers-reduced-motion: reduce) {
  .od.is-still .od__arc,
  .od.is-still .od__dot {
    transition: none !important;
  }
}

// 실제 동작: pointerdown/move/up 과 keydown 이 각도값(1~99, 度 단위로 환산)을 바꾸면,
// 원 둘레 위 점의 위치를 극좌표로 다시 계산하고, 시작점(위쪽)부터 그 점까지 이어진
// 軌道 호의 길이(path d 속성)를 매 프레임 다시 그린다. 값은 관성 lerp(ARC_LERP)로
// 목표를 뒤따른다. CSS @keyframes 없음(각도가 매 프레임 실수로 바뀌어 선언형으로
// 못 담는다, 398-01~06 과 같은 이유).
var root = document.getElementById('od');
var zone = document.getElementById('zone');
var arcEl = document.getElementById('arc');
var dotEl = document.getElementById('dot');
var grab = document.getElementById('grab');
var valEl = document.getElementById('od-val');
var live = document.getElementById('od-live');

var CX = 240, CY = 150, R = 106;        // picker-graph-orbit-radius — 軌道 반지름
var START = -90;
var MIN_V = 1, MAX_V = 99;
var ARC_LERP = 0.18;                    // picker-graph-orbit-dial-arc-smoothing — 변형 07 의 조정 대상
var AUTO_PERIOD = 1.5;
var STEP = 5;

var value = 35;
var current = 35;
var manual = false;
var autoT = 0;
var lastTs = 0;
var zoneRect = null;
var rafId = 0;

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

function polar(cx, cy, r, deg) {
  var rad = deg * Math.PI / 180;
  return { x: cx + r * Math.cos(rad), y: cy + r * Math.sin(rad) };
}

function arcPath(cx, cy, r, a0, a1) {
  if (a1 - a0 < 0.6) return '';
  var s = polar(cx, cy, r, a0), e = polar(cx, cy, r, a1);
  var large = (a1 - a0) > 180 ? 1 : 0;
  return 'M ' + s.x + ' ' + s.y + ' A ' + r + ' ' + r + ' 0 ' + large + ' 1 ' + e.x + ' ' + e.y;
}

function angleOf(v) { return START + (v / 100) * 360; }

function paint() {
  var deg = angleOf(current);
  arcEl.setAttribute('d', arcPath(CX, CY, R, START, deg));
  var p = polar(CX, CY, R, deg);
  dotEl.setAttribute('cx', String(p.x));
  dotEl.setAttribute('cy', String(p.y));
  grab.style.left = (p.x / 480 * 100) + '%';
  grab.style.top = (p.y / 300 * 100) + '%';
  var rd = Math.round(deg - START);
  valEl.textContent = String(rd);
  grab.setAttribute('aria-valuenow', String(Math.round(current)));
  grab.setAttribute('aria-valuetext', '軌道 ' + rd + '度');
}

function announce() {
  live.textContent = '軌道 ' + Math.round(angleOf(current) - START) + '度に再計算されました';
}

function setValue(v, isManual) {
  value = Math.max(MIN_V, Math.min(MAX_V, v));
  if (isManual) { manual = true; root.classList.remove('is-demo'); }
}

function angleFromPointer(clientX, clientY) {
  if (!zoneRect) zoneRect = zone.getBoundingClientRect();
  var cx = zoneRect.left + zoneRect.width * (CX / 480);
  var cy = zoneRect.top + zoneRect.height * (CY / 300);
  var deg = Math.atan2(clientY - cy, clientX - cx) * 180 / Math.PI;
  while (deg < START) deg += 360;
  while (deg >= START + 360) deg -= 360;
  return deg;
}

function fromPointer(clientX, clientY) {
  var deg = angleFromPointer(clientX, clientY);
  var v = (deg - START) / 360 * 100;
  setValue(v, true);
}

function onDown(e) {
  zoneRect = zone.getBoundingClientRect();
  if (grab.setPointerCapture) { try { grab.setPointerCapture(e.pointerId); } catch (err) {} }
  fromPointer(e.clientX, e.clientY);
  if (reduced()) { current = value; paint(); announce(); }
}
function onMove(e) { fromPointer(e.clientX, e.clientY); if (reduced()) { current = value; paint(); announce(); } }
function onUp() { announce(); }
function onZoneDown(e) {
  zoneRect = zone.getBoundingClientRect();
  fromPointer(e.clientX, e.clientY);
  if (reduced()) { current = value; paint(); announce(); }
}

function onKey(e) {
  var map = { ArrowLeft: -STEP, ArrowDown: -STEP, ArrowRight: STEP, ArrowUp: STEP };
  if (e.key === 'Home') { setValue(MIN_V, true); e.preventDefault(); }
  else if (e.key === 'End') { setValue(MAX_V, true); e.preventDefault(); }
  else if (map[e.key] !== undefined) { setValue(value + map[e.key], true); e.preventDefault(); }
  else { return; }
  if (reduced()) { current = value; paint(); announce(); }
}

function onResize() { zoneRect = zone.getBoundingClientRect(); if (reduced()) paint(); }

function autoStep(dt) {
  autoT += dt;
  var omega = 2 * Math.PI / AUTO_PERIOD;
  value = 50 + 46 * Math.sin(autoT * omega);
}

function frame(ts) {
  if (!lastTs) lastTs = ts;
  var dt = Math.min(0.05, (ts - lastTs) / 1000);
  lastTs = ts;
  if (!manual) autoStep(dt);
  current += (value - current) * ARC_LERP;
  paint();
  rafId = requestAnimationFrame(frame);
}

grab.addEventListener('pointerdown', onDown);
grab.addEventListener('pointermove', onMove);
grab.addEventListener('pointerup', onUp);
grab.addEventListener('keydown', onKey);
zone.addEventListener('pointerdown', onZoneDown);
window.addEventListener('resize', onResize);

if (reduced()) {
  root.classList.add('is-still');
  current = value;
  paint();
} else {
  paint();
  rafId = requestAnimationFrame(frame);
}

// OrbitDialArcLength — vanilla 판(run/398/demo/07-picker-graph-orbit-dial-arc-length/index.html) 의
// React 포트. 손잡이를 돌린 각도를 값으로 바꾸면, 원 둘레 위 점의 위치를 극좌표로 다시
// 계산하고 시작점(위쪽)부터 그 점까지 이어진 궤도 호의 길이를 매 프레임 값에 맞춰 다시 그린다.
import { useEffect, useRef } from "react";
import styles from "./OrbitDialArcLength.module.scss";

type Box<T> = { current: T };
type KeyEvt = { key: string; preventDefault(): void };
type PtrEvt = { clientX: number; clientY: number; pointerId: number };

const CX = 240, CY = 150, R = 106;   // picker-graph-orbit-radius — 궤도 반지름
const START = -90;
const MIN_V = 1, MAX_V = 99;
const ARC_LERP = 0.18;               // picker-graph-orbit-dial-arc-smoothing — 변형 07 의 조정 대상
const AUTO_PERIOD = 1.5;
const STEP = 5;

function polar(cx: number, cy: number, r: number, deg: number): { x: number; y: number } {
  const rad = (deg * Math.PI) / 180;
  return { x: cx + r * Math.cos(rad), y: cy + r * Math.sin(rad) };
}

function arcPath(cx: number, cy: number, r: number, a0: number, a1: number): string {
  if (a1 - a0 < 0.6) return "";
  const s = polar(cx, cy, r, a0);
  const e = polar(cx, cy, r, a1);
  const large = a1 - a0 > 180 ? 1 : 0;
  return "M " + s.x + " " + s.y + " A " + r + " " + r + " 0 " + large + " 1 " + e.x + " " + e.y;
}

function angleOf(v: number): number {
  return START + (v / 100) * 360;
}

export default function OrbitDialArcLength() {
  const rootRef = useRef<HTMLElement | null>(null);
  const zoneRef = useRef<HTMLDivElement | null>(null);
  const arcRef = useRef<SVGPathElement | null>(null);
  const dotRef = useRef<SVGCircleElement | null>(null);
  const grabRef = useRef<HTMLButtonElement | null>(null);
  const valRef = useRef<HTMLElement | null>(null);
  const liveRef = useRef<HTMLSpanElement | null>(null);

  const value = useRef(35) as Box<number>;
  const current = useRef(35) as Box<number>;
  const manual = useRef(false) as Box<boolean>;
  const autoT = useRef(0) as Box<number>;
  const lastTs = useRef(0) as Box<number>;
  const zoneRect = useRef<DOMRect | null>(null) as Box<DOMRect | null>;
  const rafId = useRef(0) as Box<number>;

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

  function paint(): void {
    const deg = angleOf(current.current);
    arcRef.current?.setAttribute("d", arcPath(CX, CY, R, START, deg));
    const p = polar(CX, CY, R, deg);
    dotRef.current?.setAttribute("cx", String(p.x));
    dotRef.current?.setAttribute("cy", String(p.y));
    const grab = grabRef.current;
    if (grab) {
      grab.style.left = (p.x / 480) * 100 + "%";
      grab.style.top = (p.y / 300) * 100 + "%";
      grab.setAttribute("aria-valuenow", String(Math.round(current.current)));
      grab.setAttribute("aria-valuetext", "궤도 " + Math.round(deg - START) + "도");
    }
    const rd = Math.round(deg - START);
    if (valRef.current) valRef.current.textContent = String(rd);
  }

  function announce(): void {
    if (liveRef.current) {
      liveRef.current.textContent = "궤도 " + Math.round(angleOf(current.current) - START) + "도로 다시 계산됨";
    }
  }

  function setValue(v: number, isManual: boolean): void {
    value.current = Math.max(MIN_V, Math.min(MAX_V, v));
    if (isManual) {
      manual.current = true;
      rootRef.current?.classList.remove("is-demo");
    }
  }

  function angleFromPointer(clientX: number, clientY: number): number {
    if (!zoneRect.current && zoneRef.current) zoneRect.current = zoneRef.current.getBoundingClientRect();
    const rect = zoneRect.current;
    if (!rect) return START;
    const cx = rect.left + rect.width * (CX / 480);
    const cy = rect.top + rect.height * (CY / 300);
    let deg = (Math.atan2(clientY - cy, clientX - cx) * 180) / Math.PI;
    while (deg < START) deg += 360;
    while (deg >= START + 360) deg -= 360;
    return deg;
  }

  function fromPointer(clientX: number, clientY: number): void {
    const deg = angleFromPointer(clientX, clientY);
    const v = ((deg - START) / 360) * 100;
    setValue(v, true);
  }

  function reflectNow(): void {
    current.current = value.current;
    paint();
    announce();
  }

  function onDown(e: PtrEvt): void {
    if (zoneRef.current) zoneRect.current = zoneRef.current.getBoundingClientRect();
    const grab = grabRef.current;
    if (grab && typeof grab.setPointerCapture === "function") {
      try { grab.setPointerCapture(e.pointerId); } catch { /* 캡처 실패는 치명적이지 않다 */ }
    }
    fromPointer(e.clientX, e.clientY);
    if (reduced()) reflectNow();
  }
  function onMove(e: PtrEvt): void {
    fromPointer(e.clientX, e.clientY);
    if (reduced()) reflectNow();
  }
  function onUp(): void {
    announce();
  }
  function onZoneDown(e: PtrEvt): void {
    if (zoneRef.current) zoneRect.current = zoneRef.current.getBoundingClientRect();
    fromPointer(e.clientX, e.clientY);
    if (reduced()) reflectNow();
  }

  function onKey(e: KeyEvt): void {
    const map: Record<string, number> = { ArrowLeft: -STEP, ArrowDown: -STEP, ArrowRight: STEP, ArrowUp: STEP };
    if (e.key === "Home") { setValue(MIN_V, true); e.preventDefault(); }
    else if (e.key === "End") { setValue(MAX_V, true); e.preventDefault(); }
    else if (map[e.key] !== undefined) { setValue(value.current + map[e.key], true); e.preventDefault(); }
    else { return; }
    if (reduced()) reflectNow();
  }

  function onResize(): void {
    if (zoneRef.current) zoneRect.current = zoneRef.current.getBoundingClientRect();
    if (reduced()) paint();
  }

  function autoStep(dt: number): void {
    autoT.current += dt;
    const omega = (2 * Math.PI) / AUTO_PERIOD;
    value.current = 50 + 46 * Math.sin(autoT.current * omega);
  }

  function frame(ts: number): void {
    if (!lastTs.current) lastTs.current = ts;
    const dt = Math.min(0.05, (ts - lastTs.current) / 1000);
    lastTs.current = ts;
    if (!manual.current) autoStep(dt);
    current.current += (value.current - current.current) * ARC_LERP;
    paint();
    rafId.current = requestAnimationFrame(frame);
  }

  useEffect(() => {
    window.addEventListener("resize", onResize);
    if (reduced()) {
      rootRef.current?.classList.add("is-still");
      reflectNow();
    } else {
      paint();
      rafId.current = requestAnimationFrame(frame);
    }
    return () => {
      window.removeEventListener("resize", onResize);
      cancelAnimationFrame(rafId.current);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <figure className={styles.od + " is-demo"} ref={rootRef}>
        <div className={styles.zone} ref={zoneRef} onPointerDown={onZoneDown}>
          <svg
            className={styles.chart}
            viewBox="0 0 480 300"
            role="img"
            aria-label="원 둘레를 도는 오빗 다이얼, 손잡이를 돌리면 시작점부터 점까지 이어진 궤도 호의 길이가 매 순간 다시 그려진다"
          >
            <circle className={styles.orbit} cx={CX} cy={CY} r={R} />
            <path className={styles.arc} ref={arcRef} />
            <circle className={styles.dot} ref={dotRef} r={19} />
          </svg>
          <button
            className={styles.grab}
            ref={grabRef}
            type="button"
            role="slider"
            aria-orientation="horizontal"
            aria-label="궤도 각도 고르기"
            aria-valuemin={MIN_V}
            aria-valuemax={MAX_V}
            aria-valuenow={35}
            aria-valuetext="궤도 126도"
            onPointerDown={onDown}
            onPointerMove={onMove}
            onPointerUp={onUp}
            onKeyDown={onKey}
          >
            <svg className={styles.ic} viewBox="0 0 256 256" aria-hidden="true">
              <g fill="currentColor">
                <circle cx={128} cy={128} r={96} opacity={0.2} />
                <path d="M128 24a104 104 0 1 0 104 104A104.11 104.11 0 0 0 128 24m0 192a88 88 0 1 1 88-88 88.1 88.1 0 0 1-88 88" />
              </g>
            </svg>
          </button>
          <b className={styles.badge} aria-hidden="true"><span ref={valRef}>126</span>°</b>
        </div>

        <p className={styles.hint}>손잡이를 끌거나 화살표키를 누르면 궤도 호의 길이가 다시 계산됩니다</p>

        <div className={styles.sr}>
          <span aria-live="polite" ref={liveRef} />
        </div>
      </figure>
    </main>
  );
}