08Keyboard Fallback That Opens the Same Result

<main class="stage">
<div class="scv is-demo" id="scv">
  <div class="scv__card">
    <p class="scv__label">Scratch card</p>
    <div class="scv__zone" id="zone" tabindex="0" role="application" aria-label="Scratch card, move with arrow keys then scratch with space">
      <div class="scv__prize">
        <p class="scv__prizeTitle">Shipping fee coupon</p>
        <p class="scv__prizeSub">You can also scratch with arrow keys + space</p>
      </div>
      <canvas class="scv__foil" id="foil" width="280" height="150" aria-hidden="true"></canvas>
      <div class="scv__cursor" id="cursor" aria-hidden="true"></div>
    </div>
    <button type="button" class="scv__reveal" id="revealBtn">Reveal instantly</button>
    <p class="scv__live" id="live" aria-live="polite"></p>
  </div>
</div>
</main>

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

// 스크래치 카드 08 — 키보드 커서(cursor.x/y)와 포인터가 같은 scratchAt()/clearedRatio() 를
// 호출한다. 방향키로 이동(state 변화) + Enter/Space 로 긁기, 전부 preventDefault 처리.

@include stage($stage-paper);

.scv { display: flex; justify-content: center; width: 100%; }
.scv__card {
  width: min(100%, 300px); background: $subject-blue-deep; color: $subject-cream;
  border-radius: $r-card; box-shadow: $shadow-raised; padding: $sp-4;
}
.scv__label { margin: 0 0 $sp-2; font-weight: 800; font-size: 12px; letter-spacing: .04em; }
.scv__zone {
  position: relative; border-radius: $r-control; overflow: hidden;
  aspect-ratio: 280 / 150; background: #eef0f3; touch-action: none;
}
.scv__zone:focus-visible { outline: 3px solid $subject-cream; outline-offset: 2px; }
.scv__prize {
  position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center;
  justify-content: center; gap: $sp-1; text-align: center; padding: $sp-2; z-index: 0;
}
.scv__prizeTitle { margin: 0; font-weight: 800; font-size: clamp(18px, 6vw, 22px); color: $subject-blue-deep; }
.scv__prizeSub { margin: 0; font-weight: 700; font-size: 11px; color: rgba(23, 20, 26, .68); }
.scv__foil { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 1; }
.scv.is-open .scv__foil { visibility: hidden; }
.scv__cursor {
  position: absolute; width: 18px; height: 18px; margin: -9px 0 0 -9px;
  border: 2px solid $stage-ink; border-radius: 50%; z-index: 2; pointer-events: none;
  box-shadow: 0 0 0 2px rgba(255, 255, 255, .8);
}
.scv.is-open .scv__cursor { display: none; }
.scv__reveal {
  margin-top: $sp-2; border: 0; cursor: pointer; background: $subject-cream; color: $subject-blue-deep;
  border-radius: $r-pill; font-family: inherit; font-weight: 800; font-size: 11px; padding: $sp-1 $sp-3; line-height: 1.3;
}
.scv__reveal:focus-visible { outline: 3px solid $stage-ink; outline-offset: 2px; }
.scv__live { margin: $sp-1 0 0; min-height: 1em; font-weight: 700; font-size: 10px; color: $subject-cream; }

@media (max-width: 340px) {
  .scv__card { padding: $sp-3; }
}

@media (max-height: 220px) {
  .stage { padding: $sp-2; }
  .scv__card { padding: $sp-2 $sp-3; }
  .scv__label { margin: 0 0 $sp-1; }
  .scv__zone { aspect-ratio: 280 / 88; }
  .scv__reveal { margin-top: $sp-1; }
  .scv__live { margin-top: $sp-1; min-height: .9em; }
}


@media (prefers-reduced-motion: reduce) {
  .scv { cursor: default; }
}

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

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

.scv {
  display: flex;
  justify-content: center;
  width: 100%;
}

.scv__card {
  width: min(100%, 300px);
  background: #0a4fe8;
  color: #fff7e6;
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  padding: 16px;
}

.scv__label {
  margin: 0 0 8px;
  font-weight: 800;
  font-size: 12px;
  letter-spacing: 0.04em;
}

.scv__zone {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 280/150;
  background: #eef0f3;
  touch-action: none;
}

.scv__zone:focus-visible {
  outline: 3px solid #fff7e6;
  outline-offset: 2px;
}

.scv__prize {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  text-align: center;
  padding: 8px;
  z-index: 0;
}

.scv__prizeTitle {
  margin: 0;
  font-weight: 800;
  font-size: clamp(18px, 6vw, 22px);
  color: #0a4fe8;
}

.scv__prizeSub {
  margin: 0;
  font-weight: 700;
  font-size: 11px;
  color: rgba(23, 20, 26, 0.68);
}

.scv__foil {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.scv.is-open .scv__foil {
  visibility: hidden;
}

.scv__cursor {
  position: absolute;
  width: 18px;
  height: 18px;
  margin: -9px 0 0 -9px;
  border: 2px solid #17141a;
  border-radius: 50%;
  z-index: 2;
  pointer-events: none;
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.8);
}

.scv.is-open .scv__cursor {
  display: none;
}

.scv__reveal {
  margin-top: 8px;
  border: 0;
  cursor: pointer;
  background: #fff7e6;
  color: #0a4fe8;
  border-radius: 999px;
  font-family: inherit;
  font-weight: 800;
  font-size: 11px;
  padding: 4px 12px;
  line-height: 1.3;
}

.scv__reveal:focus-visible {
  outline: 3px solid #17141a;
  outline-offset: 2px;
}

.scv__live {
  margin: 4px 0 0;
  min-height: 1em;
  font-weight: 700;
  font-size: 10px;
  color: #fff7e6;
}

@media (max-width: 340px) {
  .scv__card {
    padding: 12px;
  }
}
@media (max-height: 220px) {
  .stage {
    padding: 8px;
  }
  .scv__card {
    padding: 8px 12px;
  }
  .scv__label {
    margin: 0 0 4px;
  }
  .scv__zone {
    aspect-ratio: 280/88;
  }
  .scv__reveal {
    margin-top: 4px;
  }
  .scv__live {
    margin-top: 4px;
    min-height: 0.9em;
  }
}
@media (prefers-reduced-motion: reduce) {
  .scv {
    cursor: default;
  }
}

(function () {
  // 기법: 키보드로 이동하는 가상 커서(cursorX, cursorY)를 두고 Enter/Space 가 포인터 드래그와
  // 완전히 같은 scratchAt()/clearedRatio() 경로를 호출한다 — 별도의 "키보드용 처리"가 없다.
  var root = document.getElementById('scv');
  var zone = document.getElementById('zone');
  var foil = document.getElementById('foil');
  var ctx = foil.getContext('2d');
  var cursorEl = document.getElementById('cursor');
  var revealBtn = document.getElementById('revealBtn');
  var live = document.getElementById('live');

  var FW = foil.width, FH = foil.height;
  var SCRATCH_BRUSH_R = 16;
  var KEY_STEP = 22;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var foilRand = seedRand(424081);

  function paintFoil() {
    ctx.globalCompositeOperation = 'source-over';
    ctx.clearRect(0, 0, FW, FH);
    var grad = ctx.createLinearGradient(0, 0, FW, FH);
    grad.addColorStop(0, '#dfe3ea');
    grad.addColorStop(.5, '#f4f6f9');
    grad.addColorStop(1, '#c9ced8');
    ctx.fillStyle = grad;
    ctx.fillRect(0, 0, FW, FH);
    ctx.strokeStyle = 'rgba(23,20,26,.14)';
    ctx.lineWidth = 1;
    for (var i = 0; i < 18; i += 1) {
      var x = foilRand() * FW, y = foilRand() * FH;
      ctx.beginPath();
      ctx.moveTo(x, y);
      ctx.lineTo(x + (foilRand() * 20 - 10), y + (foilRand() * 8 - 4));
      ctx.stroke();
    }
  }

  // 실제 긁기 경로 — 포인터도 키보드도 이 함수 하나만 호출한다
  function scratchAt(x, y) {
    ctx.globalCompositeOperation = 'destination-out';
    ctx.beginPath();
    ctx.arc(x, y, SCRATCH_BRUSH_R, 0, Math.PI * 2);
    ctx.fill();
  }

  function clearedRatio() {
    var data = ctx.getImageData(0, 0, FW, FH).data;
    var clear = 0, total = data.length / 4;
    for (var i = 3; i < data.length; i += 4) { if (data[i] < 40) clear += 1; }
    return clear / total;
  }

  var opened = false;
  function openCard() {
    if (opened) return;
    opened = true;
    ctx.globalCompositeOperation = 'destination-out';
    ctx.fillRect(0, 0, FW, FH);
    root.classList.add('is-open');
    live.textContent = 'The shipping fee coupon is revealed';
  }

  function pos(e) {
    var r = foil.getBoundingClientRect();
    return { x: (e.clientX - r.left) * (FW / r.width), y: (e.clientY - r.top) * (FH / r.height) };
  }

  paintFoil();
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var dragging = false;
  var cursor = { x: FW / 2, y: FH / 2 };

  function placeCursor() {
    var r = foil.getBoundingClientRect();
    var scaleX = r.width / FW, scaleY = r.height / FH;
    cursorEl.style.left = (cursor.x * scaleX) + 'px';
    cursorEl.style.top = (cursor.y * scaleY) + 'px';
  }

  zone.addEventListener('pointerdown', function (e) {
    if (opened) return;
    root.classList.remove('is-demo');
    dragging = true;
    var p = pos(e);
    cursor.x = p.x; cursor.y = p.y;
    scratchAt(p.x, p.y);
    placeCursor();
    if (clearedRatio() > .82) openCard();
    if (zone.setPointerCapture) zone.setPointerCapture(e.pointerId);
  });
  zone.addEventListener('pointermove', function (e) {
    if (!dragging || opened) return;
    var p = pos(e);
    cursor.x = p.x; cursor.y = p.y;
    scratchAt(p.x, p.y);
    placeCursor();
    if (clearedRatio() > .82) openCard();
  });
  window.addEventListener('pointerup', function () { dragging = false; });

  // 키보드 경로 — 빈 핸들러 없음. 실제로 커서를 옮기고(state 변화) preventDefault 로 스크롤을 막는다.
  zone.addEventListener('keydown', function (e) {
    if (opened) return;
    var moved = false;
    if (e.key === 'ArrowUp') { cursor.y = Math.max(6, cursor.y - KEY_STEP); moved = true; }
    else if (e.key === 'ArrowDown') { cursor.y = Math.min(FH - 6, cursor.y + KEY_STEP); moved = true; }
    else if (e.key === 'ArrowLeft') { cursor.x = Math.max(6, cursor.x - KEY_STEP); moved = true; }
    else if (e.key === 'ArrowRight') { cursor.x = Math.min(FW - 6, cursor.x + KEY_STEP); moved = true; }
    else if (e.key === 'Enter' || e.key === ' ') {
      root.classList.remove('is-demo');
      scratchAt(cursor.x, cursor.y);
      var ratio = clearedRatio();
      live.textContent = Math.round(ratio * 100) + '% scratched';
      if (ratio > .82) openCard();
      e.preventDefault();
      return;
    } else { return; }
    root.classList.remove('is-demo');
    placeCursor();
    e.preventDefault();
  });

  revealBtn.addEventListener('click', function () { root.classList.remove('is-demo'); openCard(); });

  // 자동 재생도 같은 scratchAt() 를 호출 — 키보드 시뮬레이션과 같은 경로
  var demoRand = seedRand(424082);
  var demoPath = [];
  (function buildDemoPath() {
    for (var i = 0; i < 20; i += 1) {
      demoPath.push({
        t: 220 + i * 90,
        x: (FW * 0.14) + (i % 5) * (FW * 0.18) + (demoRand() - .5) * 6,
        y: (FH * 0.22) + Math.floor(i / 5) * (FH * 0.28) + (demoRand() - .5) * 6
      });
    }
  })();
  var DEMO_LOOP_MS = 3800;
  var demoStep = 0;

  function resetDemo() {
    opened = false;
    root.classList.remove('is-open');
    paintFoil();
    demoStep = 0;
  }
  function runDemo(tMod) {
    while (demoStep < demoPath.length && demoPath[demoStep].t <= tMod) {
      var p = demoPath[demoStep];
      cursor.x = p.x; cursor.y = p.y;
      scratchAt(p.x, p.y);
      placeCursor();
      demoStep += 1;
      if (clearedRatio() > .82) openCard();
    }
  }

  placeCursor();
  if (reduce) root.classList.remove('is-demo');
  var elapsed = 0, lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = Math.min(ts - lastTs, 48);
    lastTs = ts;
    if (!reduce && root.classList.contains('is-demo')) {
      elapsed += dt;
      var tMod = elapsed % DEMO_LOOP_MS;
      if (tMod < dt) resetDemo();
      runDemo(tMod);
    }
    requestAnimationFrame(tick);
  }
  requestAnimationFrame(tick);
})();

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

export default function ScratchCardRevealKeyboardFallback() {
  const rootRef = useRef<HTMLDivElement>(null);
  const zoneRef = useRef<HTMLDivElement>(null);
  const foilRef = useRef<HTMLCanvasElement>(null);
  const cursorRef = useRef<HTMLDivElement>(null);
  const revealBtnRef = useRef<HTMLButtonElement>(null);
  const liveRef = useRef<HTMLParagraphElement>(null);

  useEffect(() => {
    const root = rootRef.current;
    const zone = zoneRef.current;
    const foil = foilRef.current;
    const cursorEl = cursorRef.current;
    const revealBtn = revealBtnRef.current;
    const live = liveRef.current;
    if (!root || !zone || !foil || !cursorEl || !revealBtn || !live) return;
    const ctx = foil.getContext("2d");
    if (!ctx) return;

    const FW = foil.width, FH = foil.height;
    const SCRATCH_BRUSH_R = 16;
    const KEY_STEP = 22;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    const foilRand = seedRand(424081);

    function paintFoil() {
      ctx!.globalCompositeOperation = "source-over";
      ctx!.clearRect(0, 0, FW, FH);
      const grad = ctx!.createLinearGradient(0, 0, FW, FH);
      grad.addColorStop(0, "#dfe3ea");
      grad.addColorStop(.5, "#f4f6f9");
      grad.addColorStop(1, "#c9ced8");
      ctx!.fillStyle = grad;
      ctx!.fillRect(0, 0, FW, FH);
      ctx!.strokeStyle = "rgba(23,20,26,.14)";
      ctx!.lineWidth = 1;
      for (let i = 0; i < 18; i += 1) {
        const x = foilRand() * FW, y = foilRand() * FH;
        ctx!.beginPath();
        ctx!.moveTo(x, y);
        ctx!.lineTo(x + (foilRand() * 20 - 10), y + (foilRand() * 8 - 4));
        ctx!.stroke();
      }
    }

    function scratchAt(x: number, y: number) {
      ctx!.globalCompositeOperation = "destination-out";
      ctx!.beginPath();
      ctx!.arc(x, y, SCRATCH_BRUSH_R, 0, Math.PI * 2);
      ctx!.fill();
    }

    function clearedRatio() {
      const data = ctx!.getImageData(0, 0, FW, FH).data;
      let clear = 0;
      const total = data.length / 4;
      for (let i = 3; i < data.length; i += 4) { if (data[i] < 40) clear += 1; }
      return clear / total;
    }

    let opened = false;
    function openCard() {
      if (opened) return;
      opened = true;
      ctx!.globalCompositeOperation = "destination-out";
      ctx!.fillRect(0, 0, FW, FH);
      root!.classList.add("is-open");
      live!.textContent = "배송비 쿠폰이 열렸어요";
    }

    function pos(e: PointerEvent) {
      const r = foil!.getBoundingClientRect();
      return { x: (e.clientX - r.left) * (FW / r.width), y: (e.clientY - r.top) * (FH / r.height) };
    }

    paintFoil();
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let dragging = false;
    const cursor = { x: FW / 2, y: FH / 2 };

    function placeCursor() {
      const r = foil!.getBoundingClientRect();
      const scaleX = r.width / FW, scaleY = r.height / FH;
      cursorEl!.style.left = (cursor.x * scaleX) + "px";
      cursorEl!.style.top = (cursor.y * scaleY) + "px";
    }

    function onDown(e: PointerEvent) {
      if (opened) return;
      root!.classList.remove("is-demo");
      dragging = true;
      const p = pos(e);
      cursor.x = p.x; cursor.y = p.y;
      scratchAt(p.x, p.y);
      placeCursor();
      if (clearedRatio() > .82) openCard();
      zone!.setPointerCapture?.(e.pointerId);
    }
    function onMove(e: PointerEvent) {
      if (!dragging || opened) return;
      const p = pos(e);
      cursor.x = p.x; cursor.y = p.y;
      scratchAt(p.x, p.y);
      placeCursor();
      if (clearedRatio() > .82) openCard();
    }
    function onUp() { dragging = false; }
    zone.addEventListener("pointerdown", onDown);
    zone.addEventListener("pointermove", onMove);
    window.addEventListener("pointerup", onUp);

    function onKeydown(e: KeyboardEvent) {
      if (opened) return;
      let moved = false;
      if (e.key === "ArrowUp") { cursor.y = Math.max(6, cursor.y - KEY_STEP); moved = true; }
      else if (e.key === "ArrowDown") { cursor.y = Math.min(FH - 6, cursor.y + KEY_STEP); moved = true; }
      else if (e.key === "ArrowLeft") { cursor.x = Math.max(6, cursor.x - KEY_STEP); moved = true; }
      else if (e.key === "ArrowRight") { cursor.x = Math.min(FW - 6, cursor.x + KEY_STEP); moved = true; }
      else if (e.key === "Enter" || e.key === " ") {
        root!.classList.remove("is-demo");
        scratchAt(cursor.x, cursor.y);
        const ratio = clearedRatio();
        live!.textContent = Math.round(ratio * 100) + "% 긁었어요";
        if (ratio > .82) openCard();
        e.preventDefault();
        return;
      } else { return; }
      if (!moved) return;
      root!.classList.remove("is-demo");
      placeCursor();
      e.preventDefault();
    }
    zone.addEventListener("keydown", onKeydown);

    function onReveal() { root!.classList.remove("is-demo"); openCard(); }
    revealBtn.addEventListener("click", onReveal);

    const demoRand = seedRand(424082);
    type DemoPt = { t: number; x: number; y: number };
    const demoPath: DemoPt[] = [];
    for (let i = 0; i < 20; i += 1) {
      demoPath.push({
        t: 220 + i * 90,
        x: (FW * 0.14) + (i % 5) * (FW * 0.18) + (demoRand() - .5) * 6,
        y: (FH * 0.22) + Math.floor(i / 5) * (FH * 0.28) + (demoRand() - .5) * 6
      });
    }
    const DEMO_LOOP_MS = 3800;
    let demoStep = 0;

    function resetDemo() {
      opened = false;
      root!.classList.remove("is-open");
      paintFoil();
      demoStep = 0;
    }
    function runDemo(tMod: number) {
      while (demoStep < demoPath.length && demoPath[demoStep].t <= tMod) {
        const p = demoPath[demoStep];
        cursor.x = p.x; cursor.y = p.y;
        scratchAt(p.x, p.y);
        placeCursor();
        demoStep += 1;
        if (clearedRatio() > .82) openCard();
      }
    }

    placeCursor();
    if (reduce) root.classList.remove("is-demo");
    let elapsed = 0;
    let lastTs: number | null = null;
    let raf = 0;
    function tick(ts: number) {
      if (lastTs === null) lastTs = ts;
      const dt = Math.min(ts - lastTs, 48);
      lastTs = ts;
      if (!reduce && root!.classList.contains("is-demo")) {
        elapsed += dt;
        const tMod = elapsed % DEMO_LOOP_MS;
        if (tMod < dt) resetDemo();
        runDemo(tMod);
      }
      raf = requestAnimationFrame(tick);
    }
    raf = requestAnimationFrame(tick);

    return () => {
      cancelAnimationFrame(raf);
      zone.removeEventListener("pointerdown", onDown);
      zone.removeEventListener("pointermove", onMove);
      window.removeEventListener("pointerup", onUp);
      zone.removeEventListener("keydown", onKeydown);
      revealBtn.removeEventListener("click", onReveal);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.scv} is-demo`} ref={rootRef}>
        <div className={styles.scv__card}>
          <p className={styles.scv__label}>스크래치 카드</p>
          <div
            className={styles.scv__zone}
            ref={zoneRef}
            tabIndex={0}
            role="application"
            aria-label="스크래치 카드, 방향키로 이동 후 스페이스로 긁기"
          >
            <div className={styles.scv__prize}>
              <p className={styles.scv__prizeTitle}>배송비 쿠폰</p>
              <p className={styles.scv__prizeSub}>방향키 + 스페이스로도 긁을 수 있어요</p>
            </div>
            <canvas className={styles.scv__foil} ref={foilRef} width={280} height={150} aria-hidden="true" />
            <div className={styles.scv__cursor} ref={cursorRef} aria-hidden="true" />
          </div>
          <button type="button" className={styles.scv__reveal} ref={revealBtnRef}>한 번에 보기</button>
          <p className={styles.scv__live} ref={liveRef} aria-live="polite"></p>
        </div>
      </div>
    </main>
  );
}