03全角2・半角1で数える幅の重み付きカウント

<main class="stage">
<div class="cc is-demo" id="ccRoot">
  <label class="cc__label" for="ccText">メモ</label>
  <textarea class="cc__ta" id="ccText" aria-describedby="ccCount" placeholder="混ぜて入力してみて"></textarea>
  <div class="cc__bar" id="ccBar" aria-hidden="true"></div>
  <div class="cc__row">
    <div class="cc__big"><span class="cc__num" id="ccCount">0</span><span class="cc__unit">/ 80 幅</span></div>
    <div class="cc__legend"><span class="cc__chip cc__chip--half">半角 1</span><span class="cc__chip cc__chip--full">全角 2</span></div>
  </div>
  <p class="cc__sr" id="ccSr" aria-live="polite"></p>
</div>
</main>

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

// 핵심: 막대 칸 하나가 글자 하나이고, 칸의 너비가 폭 가중치다 (반각 1 · 전각 2).

@include stage($stage-ink);

.cc {
  width: min(100%, 420px);
  display: grid;
  gap: $sp-2;
  color: $stage-paper;
}

.cc__label {
  font-size: 12px;
  font-weight: 600;
  line-height: 16px;
  color: rgba($stage-paper, .82);
}

.cc__ta {
  box-sizing: border-box;
  width: 100%;
  height: 64px;
  resize: none;
  padding: $sp-2 $sp-3;
  border: 1px solid rgba($stage-paper, .28);
  border-radius: $r-sm;
  background: rgba($stage-paper, .08);
  color: $stage-paper;
  font-family: inherit;
  font-size: 13px;
  line-height: 18px;
}

.cc__ta::placeholder { color: rgba($stage-paper, .7); }
.cc__ta:focus-visible { outline: 2px solid $subject-sky; outline-offset: 2px; }

.cc__bar {
  position: relative;
  height: 28px;
  overflow: hidden;
  border-radius: $r-xs;
  background: rgba($stage-paper, .08);
}

.cc__cell {
  position: absolute;
  top: 0;
  bottom: 0;
  transform-origin: 50% 100%;
  border-radius: $r-xs;
}

.cc__cell.is-half { background: $subject-sky; }
.cc__cell.is-full { background: $subject-lilac; }
.cc__cell.is-over { background: $subject-pink; }
.cc__cell.is-space { opacity: .45; }

.cc__row { display: flex; align-items: baseline; justify-content: space-between; gap: $sp-3; }
.cc__big { display: flex; align-items: baseline; gap: $sp-1; }

.cc__num {
  font-size: 24px;
  line-height: 28px;
  font-weight: 700;
  color: $subject-sky;
  font-variant-numeric: tabular-nums;
}

.cc__unit { font-size: 12px; font-weight: 600; color: rgba($stage-paper, .82); }

.cc__legend { display: flex; gap: $sp-2; }

.cc__chip {
  padding: 0 $sp-2;
  border-radius: $r-xs;
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  color: $subject-ink;
}

.cc__chip--half { background: $subject-sky; }
.cc__chip--full { background: $subject-lilac; }

.cc__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .cc__legend { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .cc__cell { transform: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cc {
  width: min(100%, 420px);
  display: grid;
  gap: 8px;
  color: #ffffff;
}

.cc__label {
  font-size: 12px;
  font-weight: 600;
  line-height: 16px;
  color: rgba(255, 255, 255, 0.82);
}

.cc__ta {
  box-sizing: border-box;
  width: 100%;
  height: 64px;
  resize: none;
  padding: 8px 12px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
  font-family: inherit;
  font-size: 13px;
  line-height: 18px;
}

.cc__ta::placeholder {
  color: rgba(255, 255, 255, 0.7);
}

.cc__ta:focus-visible {
  outline: 2px solid #6ec8ff;
  outline-offset: 2px;
}

.cc__bar {
  position: relative;
  height: 28px;
  overflow: hidden;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.08);
}

.cc__cell {
  position: absolute;
  top: 0;
  bottom: 0;
  transform-origin: 50% 100%;
  border-radius: 4px;
}

.cc__cell.is-half {
  background: #6ec8ff;
}

.cc__cell.is-full {
  background: #b9a0ff;
}

.cc__cell.is-over {
  background: #ff9ebb;
}

.cc__cell.is-space {
  opacity: 0.45;
}

.cc__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.cc__big {
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.cc__num {
  font-size: 24px;
  line-height: 28px;
  font-weight: 700;
  color: #6ec8ff;
  font-variant-numeric: tabular-nums;
}

.cc__unit {
  font-size: 12px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.82);
}

.cc__legend {
  display: flex;
  gap: 8px;
}

.cc__chip {
  padding: 0 8px;
  border-radius: 4px;
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  color: #17141a;
}

.cc__chip--half {
  background: #6ec8ff;
}

.cc__chip--full {
  background: #b9a0ff;
}

.cc__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .cc__legend {
    display: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cc__cell {
    transform: none;
  }
}

(function () {
  // 기법: 글자마다 코드 포인트 범위로 폭 가중치를 매긴다. ASCII 와 반각 가타카나는 1, 나머지는 2.
  // 가중치를 모두 더한 값이 WIDTH_LIMIT 를 넘으면 그 뒤 칸은 핑크로 칠한다.
  // 막대 칸의 너비는 가중치 비율이고, 새 칸은 아래에서 스프링 오버슛으로 솟는다.
  var WIDTH_LIMIT = 80;
  var HALF_WEIGHT = 1;
  var FULL_WEIGHT = 2;
  var POP_MS = 420;
  var COUNT_LERP_RATE = 14;
  var START_MS = 200;
  var CHUNK_MS = 200;
  var HOLD_MS = 1500;

  var CHUNKS = ['Hello', 'こんにちは', 'World', 'カウンター', 'ABC', '文字数', '123', 'ｶﾀｶﾅ', 'ありがとう', 'Text', '全角と半角', 'mix', 'ＡＢＣ', '１２３', '日本語', 'kana', 'おわり'];
  var DEMO_TEXT = CHUNKS.join(' ');

  var root = document.getElementById('ccRoot');
  var ta = document.getElementById('ccText');
  var bar = document.getElementById('ccBar');
  var countEl = document.getElementById('ccCount');
  var sr = document.getElementById('ccSr');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var seg = (typeof Intl !== 'undefined' && Intl.Segmenter) ? new Intl.Segmenter(undefined, { granularity: 'grapheme' }) : null;
  function graphemes(s) {
    if (!seg) return Array.from(s);
    return Array.from(seg.segment(s), function (x) { return x.segment; });
  }
  function weightOf(g) {
    var cp = g.codePointAt(0);
    if (cp <= 0x7e || (cp >= 0xff61 && cp <= 0xff9f)) return HALF_WEIGHT;
    return FULL_WEIGHT;
  }

  var cells = [];
  var born = [];
  var total = 0;
  var shown = 0;
  var prevCount = 0;
  var stage = 0;
  var t0 = null;
  function perfNow() { return t0 === null ? 0 : performance.now() - t0; }

  function popScale(age) {
    if (age < 0 || age >= POP_MS) return 1;
    return 1 - Math.exp(-age / 70) * Math.cos(age / 55);
  }

  function update(nowMs) {
    var list = graphemes(ta.value);
    var cum = 0;
    for (var i = 0; i < list.length; i += 1) {
      if (!cells[i]) {
        var c = document.createElement('span');
        bar.appendChild(c);
        cells.push(c);
        born.push(-1);
      }
      var w = weightOf(list[i]);
      var el = cells[i];
      el.style.display = '';
      el.style.left = (cum / WIDTH_LIMIT * 100).toFixed(3) + '%';
      el.style.width = 'calc(' + (w / WIDTH_LIMIT * 100).toFixed(3) + '% - 1px)';
      var over = cum + w > WIDTH_LIMIT;
      el.className = 'cc__cell ' + (over ? 'is-over' : (w === FULL_WEIGHT ? 'is-full' : 'is-half')) + (list[i] === ' ' ? ' is-space' : '');
      if (i >= prevCount && !reduce) born[i] = nowMs;
      cum += w;
    }
    for (var j = list.length; j < cells.length; j += 1) cells[j].style.display = 'none';
    prevCount = list.length;
    total = cum;
    var next = total > WIDTH_LIMIT ? 2 : 0;
    if (next !== stage) {
      sr.textContent = next === 2 ? '幅の上限を超えました' : '';
      stage = next;
    }
    if (reduce) { shown = total; paintNumber(); }
  }

  function paintNumber() {
    countEl.textContent = String(Math.round(shown));
    countEl.style.color = Math.round(shown) > WIDTH_LIMIT ? 'rgb(255,158,187)' : '';
  }

  function stopDemo() { root.classList.remove('is-demo'); }
  ta.addEventListener('focus', stopDemo);
  ta.addEventListener('keydown', stopDemo);
  ta.addEventListener('paste', stopDemo);
  ta.addEventListener('input', function () { stopDemo(); update(perfNow()); });

  var lastDemoN = -1;
  var lastTs = null;
  function tick(ts) {
    if (t0 === null) t0 = ts;
    var now = ts - t0;
    var dt = lastTs === null ? 0.016 : Math.min(0.05, (ts - lastTs) / 1000);
    lastTs = ts;
    if (root.classList.contains('is-demo')) {
      var cyc = (now - START_MS) % (CHUNKS.length * CHUNK_MS + HOLD_MS);
      var n = now < START_MS ? 0 : Math.min(CHUNKS.length, Math.floor(cyc / CHUNK_MS) + 1);
      if (n !== lastDemoN) {
        if (n === 1) prevCount = 0;
        lastDemoN = n;
        ta.value = CHUNKS.slice(0, n).join(' ');
        update(now);
      }
    }
    shown += (total - shown) * (1 - Math.exp(-dt * COUNT_LERP_RATE));
    paintNumber();
    for (var m = 0; m < born.length; m += 1) {
      if (born[m] < 0) continue;
      var s = popScale(now - born[m]);
      cells[m].style.transform = s === 1 ? '' : 'scaleY(' + s.toFixed(3) + ')';
      if (s === 1) born[m] = -1;
    }
    requestAnimationFrame(tick);
  }

  if (reduce) {
    stopDemo();
    ta.value = DEMO_TEXT;
    update(0);
  } else {
    requestAnimationFrame(tick);
  }
})();

// WeightedWidthCounter — vanilla 판(03-weighted-width-count-full-half-width) 의 React 포트.
// 글자마다 코드 포인트 범위로 폭 가중치(반각 1·전각 2)를 매겨 합산하고, 칸 너비로 그린다.
import { useEffect, useRef } from "react";
import styles from "./WeightedWidthCounter.module.scss";

type Box<T> = { current: T };
type SegmenterLike = { segment(s: string): Iterable<{ segment: string }> };
type SegmenterCtor = new (locale: string | undefined, options: { granularity: string }) => SegmenterLike;

const WIDTH_LIMIT = 80;
const HALF_WEIGHT = 1;
const FULL_WEIGHT = 2;
const POP_MS = 420;
const COUNT_LERP_RATE = 14;
const START_MS = 200;
const CHUNK_MS = 200;
const HOLD_MS = 1500;

const CHUNKS = ["Hello", "こんにちは", "World", "カウンター", "ABC", "文字数", "123", "ｶﾀｶﾅ", "ありがとう", "Text", "全角と半角", "mix", "ＡＢＣ", "１２３", "日本語", "kana", "おわり"];
const DEMO_TEXT = CHUNKS.join(" ");

function makeSegmenter(): SegmenterLike | null {
  const C = (Intl as unknown as { Segmenter?: SegmenterCtor }).Segmenter;
  return C ? new C(undefined, { granularity: "grapheme" }) : null;
}

function weightOf(g: string): number {
  const cp = g.codePointAt(0) || 0;
  if (cp <= 0x7e || (cp >= 0xff61 && cp <= 0xff9f)) return HALF_WEIGHT;
  return FULL_WEIGHT;
}

function popScale(age: number): number {
  if (age < 0 || age >= POP_MS) return 1;
  return 1 - Math.exp(-age / 70) * Math.cos(age / 55);
}

export default function WeightedWidthCounter() {
  const taRef = useRef<HTMLTextAreaElement | null>(null) as Box<HTMLTextAreaElement | null>;
  const barRef = useRef<HTMLDivElement | null>(null) as Box<HTMLDivElement | null>;
  const countRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const srRef = useRef<HTMLParagraphElement | null>(null) as Box<HTMLParagraphElement | null>;

  useEffect(() => {
    const ta = taRef.current;
    const bar = barRef.current;
    const countEl = countRef.current;
    const sr = srRef.current;
    if (!ta || !bar || !countEl || !sr) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const seg = makeSegmenter();
    const graphemes = (s: string): string[] =>
      seg ? Array.from(seg.segment(s), (x) => x.segment) : Array.from(s);

    let demo = true;
    const cells: HTMLSpanElement[] = [];
    const born: number[] = [];
    let total = 0;
    let shown = 0;
    let prevCount = 0;
    let stage = 0;
    let lastDemoN = -1;
    let t0: number | null = null;
    let lastTs: number | null = null;
    let raf = 0;
    const perfNow = (): number => (t0 === null ? 0 : performance.now() - t0);

    function paintNumber(): void {
      if (!countEl) return;
      countEl.textContent = String(Math.round(shown));
      countEl.style.color = Math.round(shown) > WIDTH_LIMIT ? "rgb(255,158,187)" : "";
    }

    function update(nowMs: number): void {
      if (!ta || !bar || !sr) return;
      const list = graphemes(ta.value);
      let cum = 0;
      for (let i = 0; i < list.length; i += 1) {
        if (!cells[i]) {
          const c = document.createElement("span");
          bar.appendChild(c);
          cells.push(c);
          born.push(-1);
        }
        const w = weightOf(list[i]);
        const el = cells[i];
        el.style.display = "";
        el.style.left = (cum / WIDTH_LIMIT * 100).toFixed(3) + "%";
        el.style.width = "calc(" + (w / WIDTH_LIMIT * 100).toFixed(3) + "% - 1px)";
        const over = cum + w > WIDTH_LIMIT;
        el.className = [styles.cc__cell, over ? styles["is-over"] : (w === FULL_WEIGHT ? styles["is-full"] : styles["is-half"]), list[i] === " " ? styles["is-space"] : ""].join(" ");
        if (i >= prevCount && !reduce) born[i] = nowMs;
        cum += w;
      }
      for (let j = list.length; j < cells.length; j += 1) cells[j].style.display = "none";
      prevCount = list.length;
      total = cum;
      const next = total > WIDTH_LIMIT ? 2 : 0;
      if (next !== stage) {
        sr.textContent = next === 2 ? "폭 한도를 넘었어요" : "";
        stage = next;
      }
      if (reduce) { shown = total; paintNumber(); }
    }

    function stopDemo(): void { demo = false; }
    const onInput = (): void => { stopDemo(); update(perfNow()); };
    ta.addEventListener("focus", stopDemo);
    ta.addEventListener("keydown", stopDemo);
    ta.addEventListener("paste", stopDemo);
    ta.addEventListener("input", onInput);

    function tick(ts: number): void {
      if (!ta) return;
      if (t0 === null) t0 = ts;
      const now = ts - t0;
      const dt = lastTs === null ? 0.016 : Math.min(0.05, (ts - lastTs) / 1000);
      lastTs = ts;
      if (demo) {
        const cyc = (now - START_MS) % (CHUNKS.length * CHUNK_MS + HOLD_MS);
        const n = now < START_MS ? 0 : Math.min(CHUNKS.length, Math.floor(cyc / CHUNK_MS) + 1);
        if (n !== lastDemoN) {
          if (n === 1) prevCount = 0;
          lastDemoN = n;
          ta.value = CHUNKS.slice(0, n).join(" ");
          update(now);
        }
      }
      shown += (total - shown) * (1 - Math.exp(-dt * COUNT_LERP_RATE));
      paintNumber();
      for (let m = 0; m < born.length; m += 1) {
        if (born[m] < 0) continue;
        const s = popScale(now - born[m]);
        cells[m].style.transform = s === 1 ? "" : "scaleY(" + s.toFixed(3) + ")";
        if (s === 1) born[m] = -1;
      }
      raf = requestAnimationFrame(tick);
    }

    if (reduce) {
      stopDemo();
      ta.value = DEMO_TEXT;
      update(0);
    } else {
      raf = requestAnimationFrame(tick);
    }
    return () => {
      cancelAnimationFrame(raf);
      ta.removeEventListener("focus", stopDemo);
      ta.removeEventListener("keydown", stopDemo);
      ta.removeEventListener("paste", stopDemo);
      ta.removeEventListener("input", onInput);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.cc}>
        <label className={styles.cc__label} htmlFor="ccText">메모</label>
        <textarea className={styles.cc__ta} id="ccText" ref={taRef} aria-describedby="ccCount" placeholder="섞어서 입력해 보세요"></textarea>
        <div className={styles.cc__bar} ref={barRef} aria-hidden="true"></div>
        <div className={styles.cc__row}>
          <div className={styles.cc__big}><span className={styles.cc__num} id="ccCount" ref={countRef}>0</span><span className={styles.cc__unit}>/ 80 폭</span></div>
          <div className={styles.cc__legend}><span className={[styles.cc__chip, styles["cc__chip--half"]].join(" ")}>반각 1</span><span className={[styles.cc__chip, styles["cc__chip--full"]].join(" ")}>전각 2</span></div>
        </div>
        <p className={styles.cc__sr} ref={srRef} aria-live="polite"></p>
      </div>
    </main>
  );
}