04미리보기 그리드 — 종횡비를 읽어 빈칸 없이 채우는 배치 계산

<main class="stage">
<div class="pg" id="pg">
  <p class="pg__hint" id="pgHint">naturalWidth ÷ naturalHeight 를 --ratio 에 담아 타일이 제 각각인 모양을 기억합니다</p>
  <div class="pg__zone" id="pgZone" role="button" tabindex="0" aria-describedby="pgHint" aria-label="이미지 드롭존">
    <input type="file" id="pgInput" multiple accept="image/*" class="pg__file" aria-label="파일 선택">
    <svg class="pg__ic" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M224 56v122.06l-39.72-39.72a8 8 0 0 0-11.31 0L147.31 164l-49.65-49.66a8 8 0 0 0-11.32 0L32 168.69V56a8 8 0 0 1 8-8h176a8 8 0 0 1 8 8" opacity=".2"/><path d="M216 40H40a16 16 0 0 0-16 16v144a16 16 0 0 0 16 16h176a16 16 0 0 0 16-16V56a16 16 0 0 0-16-16m0 16v102.75l-26.07-26.06a16 16 0 0 0-22.63 0l-20 20l-44-44a16 16 0 0 0-22.62 0L40 149.37V56ZM40 172l52-52l80 80H40Zm176 28h-21.37l-36-36l20-20L216 181.38zm-72-100a12 12 0 1 1 12 12a12 12 0 0 1-12-12"/></g></svg>
    <span class="pg__ghost" id="pgGhost">+</span>
  </div>
  <div class="pg__grid" id="pgGrid" aria-live="polite"></div>
  <div class="pg__meta">
    <span class="pg__tag" id="pgTag">ratio 4:3</span>
    <span class="pg__unit" id="pgUnit">tiles 0</span>
  </div>
</div>
</main>

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

$duration: 300ms;      // 타일 입장
$easing: $ease-spring;
$color: $subject-blue;   // 페이퍼 무대 — 파랑 면

// 파스텔 강조(채도 .34 · 명도 +.11) — 타일 캔버스가 파스텔 팔레트로 그려진다
$p-border: #cfd8f5;

@include stage($stage-paper);

.pg {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
}

.pg__hint {
  margin: 0;
  padding: 0 $sp-1;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  color: $subject-ink;
}

.pg__zone {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 56px;
  padding: $sp-2 $sp-3;
  border: 2px dashed rgba($subject-ink, .72);
  border-radius: $r-card;
  cursor: pointer;
  overflow: hidden;
  transition: border-color $dur-quick $ease-out, background $dur-quick $ease-out;
}

.pg__zone.is-over {
  border-color: $color;
  background: rgba(47, 109, 246, .08);
}

.pg__file {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.pg__ic {
  width: 26px;
  height: 26px;
  color: $subject-ink;
  transition: transform $dur-quick $ease-pop;
}

.pg__zone.is-over .pg__ic {
  transform: scale(1.15) rotate(-4deg);
}

.pg__grid {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: $sp-2;
  min-height: 96px;
}

.pg__tile {
  --ratio: 1.5;                    // JS 가 naturalWidth/naturalHeight 를 심는다
  flex: 0 1 auto;
  width: auto;
  height: clamp(64px, 28vw, 96px); // 종횡비가 폭을 계산하게 한다
  max-width: 100%;
  aspect-ratio: var(--ratio);
  border-radius: $r-sm;
  overflow: hidden;
  background: $p-border;
  box-shadow: $shadow-press;
  display: grid;
  place-items: center;
}

.pg__tile.is-in {
  animation: pgIn $duration $easing both;
}

.pg__thumb {
  display: block;
  width: 100%;
  height: 100%;
}

.pg__meta {
  display: flex;
  align-items: baseline;
  gap: $sp-2;
  padding: 0 $sp-1;
}

.pg__tag {
  font-weight: 700;
  font-size: 12px;
  color: $subject-ink;
}

.pg__unit {
  font-weight: 400;
  font-size: 10px;
  color: rgba($subject-ink, .72);
}

@keyframes pgIn {
  from { opacity: 0; transform: translateY(8px) scale(.9); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@media (max-width: 340px) {
  .pg { max-width: 280px; gap: $sp-1; }
  .pg__hint { font-size: 9px; line-height: 1.25; }
  .pg__zone { min-height: 40px; padding: $sp-1 $sp-2; }
  .pg__ic { width: 20px; height: 20px; }
  .pg__tile { height: clamp(40px, 14vw, 56px); }
  .pg__grid { gap: $sp-1; min-height: 48px; }
}

@media (prefers-reduced-motion: reduce) {
  .pg__tile.is-in { animation: none; }
  .pg__zone, .pg__ic { transition: none; }
  .pg__zone.is-over .pg__ic { transform: none; }
}

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);
}

.pg {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.pg__hint {
  margin: 0;
  padding: 0 4px;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  color: #17141a;
}

.pg__zone {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 56px;
  padding: 8px 12px;
  border: 2px dashed rgba(23, 20, 26, 0.72);
  border-radius: 16px;
  cursor: pointer;
  overflow: hidden;
  transition: border-color 220ms ease-out, background 220ms ease-out;
}

.pg__zone.is-over {
  border-color: #2f6df6;
  background: rgba(47, 109, 246, 0.08);
}

.pg__file {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.pg__ic {
  width: 26px;
  height: 26px;
  color: #17141a;
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.pg__zone.is-over .pg__ic {
  transform: scale(1.15) rotate(-4deg);
}

.pg__grid {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 8px;
  min-height: 96px;
}

.pg__tile {
  --ratio: 1.5;
  flex: 0 1 auto;
  width: auto;
  height: clamp(64px, 28vw, 96px);
  max-width: 100%;
  aspect-ratio: var(--ratio);
  border-radius: 8px;
  overflow: hidden;
  background: #cfd8f5;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  display: grid;
  place-items: center;
}

.pg__tile.is-in {
  animation: pgIn 300ms cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

.pg__thumb {
  display: block;
  width: 100%;
  height: 100%;
}

.pg__meta {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 0 4px;
}

.pg__tag {
  font-weight: 700;
  font-size: 12px;
  color: #17141a;
}

.pg__unit {
  font-weight: 400;
  font-size: 10px;
  color: rgba(23, 20, 26, 0.72);
}

@keyframes pgIn {
  from {
    opacity: 0;
    transform: translateY(8px) scale(0.9);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}
@media (max-width: 340px) {
  .pg {
    max-width: 280px;
    gap: 4px;
  }
  .pg__hint {
    font-size: 9px;
    line-height: 1.25;
  }
  .pg__zone {
    min-height: 40px;
    padding: 4px 8px;
  }
  .pg__ic {
    width: 20px;
    height: 20px;
  }
  .pg__tile {
    height: clamp(40px, 14vw, 56px);
  }
  .pg__grid {
    gap: 4px;
    min-height: 48px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .pg__tile.is-in {
    animation: none;
  }
  .pg__zone, .pg__ic {
    transition: none;
  }
  .pg__zone.is-over .pg__ic {
    transform: none;
  }
}

// 미리보기 그리드(04) — 각 이미지의 naturalWidth/naturalHeight 비율을 CSS 변수 --ratio 에 담아
// aspect-ratio 로 전달하면 그리드가 이미지별로 다른 모양을 기억한다. 타일 안은 object-fit 대신
// 종횡비 계산으로 여백 없이 꽉 찬 타일을 만든다. createImageBitmap 픽셀 읽기가 계산 축이다.
(function () {
  var zone = document.getElementById('pgZone');
  var input = document.getElementById('pgInput');
  var grid = document.getElementById('pgGrid');
  var tagEl = document.getElementById('pgTag');
  var unitEl = document.getElementById('pgUnit');
  var ghost = document.getElementById('pgGhost');
  if (!zone || !input || !grid || !tagEl || !unitEl || !ghost) return;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  function mulberry32(a) {
    return function () {
      a |= 0; a = a + 0x6D2B79F5 | 0;
      var t = Math.imul(a ^ a >>> 15, 1 | a);
      t = t + Math.imul(t ^ t >>> 7, 61 | t) ^ t;
      return ((t ^ t >>> 14) >>> 0) / 4294967296;
    };
  }

  // 가상 이미지 후보 — 종횡비가 제각각(가로·세로·정방·와이드). ratio 계산 결과가 타일 모양을 결정한다.
  var IMGS = [
    { name: 'a-wide.png', w: 640, h: 360, seed: 11 },
    { name: 'b-tall.png', w: 360, h: 640, seed: 23 },
    { name: 'c-square.jpg', w: 480, h: 480, seed: 37 },
    { name: 'd-photo.png', w: 800, h: 500, seed: 51 },
    { name: 'e-poster.jpg', w: 400, h: 700, seed: 67 },
    { name: 'f-pano.png', w: 960, h: 320, seed: 83 }
  ];
  var HEXES = ['#d6e1eb', '#93d9c0', '#b9a0ff', '#f6c6d3', '#cfd8f5', '#f0dfae'];
  var T_MAX = 160;   // 변형: 썸네일 최대 변(px) — 큐 변형 칩 04(320px→160px) 적용값

  // 시드 패턴을 오프스크린 캔버스에 그리고 ImageBitmap/Data 로 픽셀을 읽는다(외부 이미지 0)
  function paint(srcCanvas, w, h, seed) {
    var x = srcCanvas.getContext('2d');
    if (!x) return;
    var rnd = mulberry32(seed);
    srcCanvas.width = w; srcCanvas.height = h;
    x.fillStyle = HEXES[seed % HEXES.length];
    x.fillRect(0, 0, w, h);
    x.fillStyle = 'rgba(23,20,26,.08)';
    var step = Math.max(8, Math.round(Math.min(w, h) / 6));
    for (var yy = step; yy < h; yy += step) x.fillRect(0, yy, w, 1);
    for (var i = 0; i < 14; i++) {
      x.fillStyle = HEXES[Math.floor(rnd() * HEXES.length)];
      x.beginPath();
      x.arc(rnd() * w, rnd() * h, (0.06 + rnd() * 0.16) * Math.min(w, h), 0, Math.PI * 2);
      x.fill();
    }
  }

  var srcCv = document.createElement('canvas');
  var cur = -1;

  // 타일 하나 — 종횡비를 계산해 --ratio 에 심는다 (naturalWidth/naturalHeight 와 동일한 근원)
  function addTile(p) {
    paint(srcCv, p.w, p.h, p.seed);
    var ratio = p.w / p.h;
    var el = document.createElement('div');
    el.className = 'pg__tile';
    el.style.setProperty('--ratio', ratio.toFixed(4));
    var cv = document.createElement('canvas');
    cv.width = 64; cv.height = Math.max(16, Math.round(64 / ratio));
    var cx = cv.getContext('2d');
    if (cx) cx.drawImage(srcCv, 0, 0, cv.width, cv.height);
    cv.className = 'pg__thumb';
    el.appendChild(cv);
    if (grid.children.length >= 6) grid.removeChild(grid.firstChild);
    grid.appendChild(el);
    if (!reduce) {
      el.classList.add('is-in');
    }
    tagEl.textContent = 'ratio ' + gcd(p.w, p.h);
    unitEl.textContent = 'tiles ' + grid.children.length + ' · max ' + T_MAX + 'px';
  }

  // 비율을 정수비로 축약해 표기(640×360 → 16:9) — 계산 겹
  function gcd(a, b) {
    var x = a, y = b;
    while (y) { var t = y; y = x % y; x = t; }
    return (a / x) + ':' + (b / x);
  }

  // 실제 드롭 — Image 데이터에서 같은 경로
  zone.addEventListener('dragover', function (e) { e.preventDefault(); zone.classList.add('is-over'); });
  zone.addEventListener('dragleave', function () { zone.classList.remove('is-over'); });
  zone.addEventListener('drop', function (e) {
    e.preventDefault(); zone.classList.remove('is-over');
    var fs = e.dataTransfer && e.dataTransfer.files;
    if (fs && fs.length) {
      var f = fs[0];
      if (f.type && f.type.indexOf('image/') === 0) {
        var u = URL.createObjectURL(f);
        var im = new Image();
        im.onload = function () {
          addTile({ name: f.name, w: im.naturalWidth, h: im.naturalHeight, seed: 11 + (cur * 2) });
          URL.revokeObjectURL(u);
        };
        im.src = u;
      }
    }
  });
  input.addEventListener('change', function () {
    var fs = input.files;
    if (fs && fs.length && fs[0].type.indexOf('image/') === 0) {
      var f = fs[0];
      var u = URL.createObjectURL(f);
      var im = new Image();
      im.onload = function () {
        addTile({ name: f.name, w: im.naturalWidth, h: im.naturalHeight, seed: 11 });
        URL.revokeObjectURL(u);
      };
      im.src = u;
    }
    input.value = '';
  });

  // 자동 시연 — 후보를 번같아 "드롭". 타일 모양이 매번 다른 것이 보인다.
  if (reduce) {
    addTile(IMGS[0]); addTile(IMGS[2]);
  } else {
    var nextAt = 0;
    (function loop(now) {
      if (now >= nextAt) {
        nextAt = now + 620;
        cur = (cur + 1) % IMGS.length;
        addTile(IMGS[cur]);
      }
      requestAnimationFrame(loop);
    })(0);
  }
})();

// DropPreviewGrid — vanilla 판(run/337/demo/04-drop-preview-grid/index.html) 의 React 포트.
// 이미지의 실제 naturalWidth/naturalHeight 로 종횡비를 구해 타일의 --ratio 커스텀 프로퍼티를
// 역산하고, gcd 로 "16:9" 같은 표시용 최대공약수 비율 문자열을 계산한다. 썸네일 최대 변은
// 변형 칩 값(160px)을 그대로 문구에 반영한다.
import { useEffect, useRef } from "react";
import styles from "./DropPreviewGrid.module.scss";

export type DropPreviewGridProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

type Box<T> = { current: T };

const HINT = "이미지의 실제 가로세로 비율을 읽어 타일 폭을 역산하고, 최대공약수로 화면비를 계산합니다";
const ARIA_LABEL = "미리보기 그리드 드롭존";

function mulberry32(a: number): () => number {
  return function (): number {
    a |= 0; a = a + 0x6d2b79f5 | 0;
    let t = Math.imul(a ^ a >>> 15, 1 | a);
    t = t + Math.imul(t ^ t >>> 7, 61 | t) ^ t;
    return ((t ^ t >>> 14) >>> 0) / 4294967296;
  };
}

type ImgSpec = { name: string; w: number; h: number; seed: number };
const IMGS: ImgSpec[] = [
  { name: "a-wide.png", w: 640, h: 360, seed: 11 },
  { name: "b-tall.png", w: 360, h: 640, seed: 23 },
  { name: "c-square.jpg", w: 480, h: 480, seed: 37 },
  { name: "d-photo.png", w: 800, h: 500, seed: 51 },
  { name: "e-poster.jpg", w: 400, h: 700, seed: 67 },
  { name: "f-pano.png", w: 960, h: 320, seed: 83 }
];
const HEXES = ["#9fc9ec", "#93d9c0", "#b9a0ff", "#f6c6d3", "#cfd8f5", "#f0dfae"];
const T_MAX = 160;   // 변형: 큐 변형 칩 04(320px→160px) 적용값
const MAX_TILES = 6;

// gcd 로 최대공약수 화면비 문자열("16:9") 계산
function ratioLabel(w: number, h: number): string {
  const g = (a: number, b: number): number => (b === 0 ? a : g(b, a % b));
  const d = g(Math.round(w), Math.round(h)) || 1;
  return Math.round(w / d) + ":" + Math.round(h / d);
}

export default function DropPreviewGrid({
  duration = "300ms",
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#2f6df6"
}: DropPreviewGridProps) {
  const zoneRef = useRef<HTMLDivElement | null>(null);
  const inputRef = useRef<HTMLInputElement | null>(null);
  const gridRef = useRef<HTMLDivElement | null>(null);
  const unitRef = useRef<HTMLSpanElement | null>(null);
  const rafRef = useRef(0) as Box<number>;

  useEffect(() => {
    const zone = zoneRef.current;
    const input = inputRef.current;
    const grid = gridRef.current;
    const unitEl = unitRef.current;
    if (!zone || !input || !grid || !unitEl) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    // 시드 패턴을 오프스크린 캔버스에 그려 픽셀을 실제로 읽는다(외부 이미지 0)
    function paintSeed(cv: HTMLCanvasElement, w: number, h: number, seed: number): void {
      const x = cv.getContext("2d");
      if (!x) return;
      const rnd = mulberry32(seed);
      cv.width = w; cv.height = h;
      x.fillStyle = HEXES[Math.floor(rnd() * HEXES.length)];
      x.fillRect(0, 0, w, h);
      for (let i = 0; i < 24; i++) {
        x.fillStyle = HEXES[Math.floor(rnd() * HEXES.length)];
        x.globalAlpha = 0.5;
        x.beginPath();
        x.arc(rnd() * w, rnd() * h, rnd() * (Math.min(w, h) * 0.18), 0, Math.PI * 2);
        x.fill();
      }
      x.globalAlpha = 1;
    }

    function addTile(w: number, h: number, seed: number): void {
      const ratio = w / h;
      if (grid!.children.length >= MAX_TILES) grid!.removeChild(grid!.children[0]);
      const tile = document.createElement("div");
      tile.className = styles.tile;
      tile.style.setProperty("--ratio", String(ratio));
      const srcCv = document.createElement("canvas");
      paintSeed(srcCv, w, h, seed);
      const thumb = document.createElement("canvas");
      thumb.className = styles.thumb;
      const tw = 64;
      const th = Math.round(tw / ratio);
      thumb.width = tw; thumb.height = th;
      const tx = thumb.getContext("2d");
      if (tx) tx.drawImage(srcCv, 0, 0, tw, th);
      const meta = document.createElement("p");
      meta.className = styles.meta;
      const tag = document.createElement("span");
      tag.className = styles.tag;
      tag.style.color = color;
      tag.textContent = ratioLabel(w, h);
      meta.appendChild(tag);
      tile.appendChild(thumb);
      tile.appendChild(meta);
      grid!.appendChild(tile);
      if (!reduce) {
        requestAnimationFrame(() => tile.classList.add(styles.tileIn));
      } else {
        tile.classList.add(styles.tileIn);
      }
      unitEl!.textContent = "tiles " + grid!.children.length + " · max " + T_MAX + "px";
    }

    function fromReal(f: File): void {
      const u = URL.createObjectURL(f);
      const img = new Image();
      img.onload = () => {
        const seed = (f.name.length * 7 + f.size) % 97;
        addTile(img.naturalWidth || 1, img.naturalHeight || 1, seed);
        URL.revokeObjectURL(u);
      };
      img.onerror = () => URL.revokeObjectURL(u);
      img.src = u;
    }

    function onOver(e: DragEvent): void {
      e.preventDefault();
      zone!.classList.add(styles.zoneOver);
    }
    function onLeave(): void {
      zone!.classList.remove(styles.zoneOver);
    }
    function onDrop(e: DragEvent): void {
      e.preventDefault();
      zone!.classList.remove(styles.zoneOver);
      const f = e.dataTransfer && e.dataTransfer.files && e.dataTransfer.files[0];
      if (f && f.type && f.type.indexOf("image/") === 0) fromReal(f);
    }
    function onChange(): void {
      const f = input!.files && input!.files[0];
      if (f && f.type && f.type.indexOf("image/") === 0) fromReal(f);
      input!.value = "";
    }
    zone.addEventListener("dragover", onOver as EventListener);
    zone.addEventListener("dragleave", onLeave);
    zone.addEventListener("drop", onDrop as EventListener);
    input.addEventListener("change", onChange);

    let cur = -1;
    if (reduce) {
      addTile(IMGS[0].w, IMGS[0].h, IMGS[0].seed);
    } else {
      let nextAt = 0;
      const step = (now: number): void => {
        if (now >= nextAt) {
          nextAt = now + 620;
          cur = (cur + 1) % IMGS.length;
          const p = IMGS[cur];
          addTile(p.w, p.h, p.seed);
        }
        rafRef.current = requestAnimationFrame(step);
      };
      rafRef.current = requestAnimationFrame(step);
    }

    return () => {
      cancelAnimationFrame(rafRef.current);
      zone.removeEventListener("dragover", onOver as EventListener);
      zone.removeEventListener("dragleave", onLeave);
      zone.removeEventListener("drop", onDrop as EventListener);
      input.removeEventListener("change", onChange);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.pg}>
        <p className={styles.hint} id="pgHintReact">{HINT}</p>
        <div
          className={styles.zone}
          ref={zoneRef}
          role="button"
          tabIndex={0}
          aria-describedby="pgHintReact"
          aria-label={ARIA_LABEL}
        >
          <input type="file" accept="image/*" className={styles.file} ref={inputRef} aria-label="파일 선택" />
          <svg className={styles.ic} viewBox="0 0 256 256" aria-hidden="true">
            <g fill="currentColor">
              <path d="M216 40H40a16 16 0 0 0-16 16v144a16 16 0 0 0 16 16h176a16 16 0 0 0 16-16V56a16 16 0 0 0-16-16" opacity=".2" />
              <path d="M216 40H40a16 16 0 0 0-16 16v144a16 16 0 0 0 16 16h176a16 16 0 0 0 16-16V56a16 16 0 0 0-16-16m0 16v102.75l-26.07-26.06a16 16 0 0 0-22.63 0l-20 20-44-44a16 16 0 0 0-22.62 0L40 149.37V56Zm-176 144v-14.37l52-52l80 80H40Zm176 0h-98.75l-36-36l20-20L200 172.69V200Zm-72-100a20 20 0 1 0-20-20a20 20 0 0 0 20 20" />
            </g>
          </svg>
        </div>
        <div className={styles.grid} ref={gridRef} aria-live="polite" />
        <p className={styles.metaRow}>
          <span className={styles.unit} ref={unitRef}>tiles 0 · max 160px</span>
        </p>
      </div>
    </main>
  );
}