09Candlestick Chart Drawing Open-High-Low-Close With Body and Wick

<main class="stage">
<div class="cdl is-demo" id="cdlRoot">
  <canvas class="cdl__canvas" id="cdlCanvas" width="480" height="300"></canvas>
  <div class="cdl__kbd" id="cdlKbd" tabindex="0" aria-label="Browse candles"></div>
  <p class="cdl__caption">The range between the open and close is drawn as a rectangular body, and the reach to the high and low as a thin wick line, so one bar holds four values of the day layered together</p>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);

.cdl {
  position: relative;
  width: min(92vw, calc(160vh - 12.8vw));
  aspect-ratio: 480 / 300;
  margin: 0 auto;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
  background: $stage-ink;
}

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

.cdl__kbd {
  position: absolute;
  inset: 0;
  background: transparent;
  outline-offset: -2px;
  pointer-events: none;
}

.cdl__kbd:focus-visible {
  outline: 2px solid $subject-blue-light;
}

.cdl__caption {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  max-width: 78%;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 247, 230, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

@media (max-width: 340px) {
  .cdl__caption { font-size: 10px; padding: $sp-1 $sp-2; }
}

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

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);
}

.cdl {
  position: relative;
  width: min(92vw, 160vh - 12.8vw);
  aspect-ratio: 480/300;
  margin: 0 auto;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: #17141a;
}

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

.cdl__kbd {
  position: absolute;
  inset: 0;
  background: transparent;
  outline-offset: -2px;
  pointer-events: none;
}

.cdl__kbd:focus-visible {
  outline: 2px solid #5b8cf8;
}

.cdl__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  max-width: 78%;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

@media (max-width: 340px) {
  .cdl__caption {
    font-size: 10px;
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cdl {
    cursor: default;
  }
}

(function () {
  // 기법: 시가·종가 사이를 몸통 사각형, 고가·저가 사이를 얇은 꼬리선으로 실제 값 좌표에 맞춰
  // 계산해 그린다. 등장할 때는 값 위치는 고정한 채 중심에서부터 높이만 커지도록(진행도 스케일)
  // 그려 부드럽게 나타나게 하고, 포인터·화살표 키로 특정 막대를 가리키면 크로스헤어와 함께
  // 시가·고가·저가·종가 네 숫자를 칩에 표시한다.
  var root = document.getElementById('cdlRoot');
  var canvas = document.getElementById('cdlCanvas');
  var kbdEl = document.getElementById('cdlKbd');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;

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

  var rand = seedRand(425091);
  var CANDLE_COUNT = 10;
  var candles = [];
  var price = 100;
  for (var i = 0; i < CANDLE_COUNT; i += 1) {
    var open = price;
    var vol = 4 + rand() * 10;
    var close = open + (rand() - 0.5) * 2 * vol;
    var high = Math.max(open, close) + rand() * vol * 0.6;
    var low = Math.min(open, close) - rand() * vol * 0.6;
    candles.push({ open: open, close: close, high: high, low: low });
    price = close;
  }
  var scaleMin = Math.min.apply(null, candles.map(function (c) { return c.low; }));
  var scaleMax = Math.max.apply(null, candles.map(function (c) { return c.high; }));

  var CANDLE_REVEAL_STAGGER_MS = 110, CANDLE_REVEAL_DUR_MS = 160;
  var hoverIndex = -1;
  var lastUserInputAt = -9999;

  var LOOP_MS = 2000;
  var T0 = 200;
  var ALL_DONE_MS = T0 + (CANDLE_COUNT - 1) * CANDLE_REVEAL_STAGGER_MS + CANDLE_REVEAL_DUR_MS;
  var cw = 480, ch = 300;

  function clamp(v, lo, hi) { return Math.max(lo, Math.min(hi, v)); }
  function easeOutCubic(x) { return 1 - Math.pow(1 - x, 3); }

  function candleX(idx) {
    var padX = cw * 0.06;
    var slot = (cw - padX * 2) / CANDLE_COUNT;
    return padX + slot * (idx + 0.5);
  }
  function priceY(v) {
    var padY = ch * 0.12;
    return ch - padY - (ch - padY * 2) * (v - scaleMin) / (scaleMax - scaleMin);
  }
  function growP(idx, t) {
    return clamp((t - T0 - idx * CANDLE_REVEAL_STAGGER_MS) / CANDLE_REVEAL_DUR_MS, 0, 1);
  }
  function nearestCandle(x) {
    var best = 0, bestD = Infinity;
    for (var k = 0; k < CANDLE_COUNT; k += 1) {
      var d = Math.abs(candleX(k) - x);
      if (d < bestD) { bestD = d; best = k; }
    }
    return best;
  }

  function render(elapsedMs) {
    var t = elapsedMs % LOOP_MS;
    ctx.clearRect(0, 0, cw, ch);
    var padX = cw * 0.06;
    var slot = (cw - padX * 2) / CANDLE_COUNT;
    var bw = slot * 0.55;

    for (var idx = 0; idx < CANDLE_COUNT; idx += 1) {
      var c = candles[idx];
      var grow = easeOutCubic(growP(idx, t));
      var x = candleX(idx);

      var wickTopFull = priceY(c.high), wickBotFull = priceY(c.low);
      var wickCenter = (wickTopFull + wickBotFull) / 2;
      var wickHalf = (wickBotFull - wickTopFull) / 2 * grow;
      ctx.strokeStyle = '#9a93a6';
      ctx.lineWidth = 1.5;
      ctx.beginPath();
      ctx.moveTo(x, wickCenter - wickHalf);
      ctx.lineTo(x, wickCenter + wickHalf);
      ctx.stroke();

      var bodyTopFull = priceY(Math.max(c.open, c.close));
      var bodyBotFull = priceY(Math.min(c.open, c.close));
      var bodyCenter = (bodyTopFull + bodyBotFull) / 2;
      var bodyHalf = Math.max(1, (bodyBotFull - bodyTopFull) / 2 * grow);
      var up = c.close >= c.open;
      ctx.fillStyle = up ? '#3ddc97' : '#ff7a5e';
      ctx.fillRect(x - bw / 2, bodyCenter - bodyHalf, bw, bodyHalf * 2);
    }

    if (hoverIndex >= 0) {
      var hc = candles[hoverIndex];
      var hx = candleX(hoverIndex);
      var hy = priceY(hc.close);
      ctx.setLineDash([4, 4]);
      ctx.strokeStyle = 'rgba(255,255,255,.55)';
      ctx.lineWidth = 1;
      ctx.beginPath(); ctx.moveTo(hx, 0); ctx.lineTo(hx, ch); ctx.stroke();
      ctx.beginPath(); ctx.moveTo(0, hy); ctx.lineTo(cw, hy); ctx.stroke();
      ctx.setLineDash([]);

      var label = Math.round(hc.open) + '·' + Math.round(hc.high) + '·' + Math.round(hc.low) + '·' + Math.round(hc.close);
      ctx.font = '11px sans-serif';
      var padChip = 6;
      var textW = ctx.measureText(label).width;
      var chipW = textW + padChip * 2, chipH = 20;
      var chipX = clamp(hx + 8, 4, cw - chipW - 4);
      var chipY = Math.max(4, hy - chipH - 6);
      ctx.fillStyle = '#231f28';
      ctx.fillRect(chipX, chipY, chipW, chipH);
      ctx.fillStyle = '#9a93a6';
      ctx.textBaseline = 'middle';
      ctx.fillText(label, chipX + padChip, chipY + chipH / 2);
    }
  }

  function setHoverIndex(idx) {
    hoverIndex = clamp(idx, -1, CANDLE_COUNT - 1);
    render(elapsed);
  }

  canvas.addEventListener('pointermove', function (e) {
    var rect = canvas.getBoundingClientRect();
    var x = (e.clientX - rect.left) * (cw / rect.width);
    lastUserInputAt = elapsed;
    setHoverIndex(nearestCandle(x));
  });
  canvas.addEventListener('pointerleave', function () {
    setHoverIndex(-1);
  });

  kbdEl.addEventListener('keydown', function (e) {
    e.preventDefault();
    if (e.key === 'ArrowLeft') {
      lastUserInputAt = elapsed;
      setHoverIndex(hoverIndex < 0 ? 0 : hoverIndex - 1);
    } else if (e.key === 'ArrowRight') {
      lastUserInputAt = elapsed;
      setHoverIndex(hoverIndex < 0 ? 0 : hoverIndex + 1);
    }
  });

  function autoDemoStep(elapsedMs) {
    var t = elapsedMs % LOOP_MS;
    if (elapsedMs - lastUserInputAt >= 800 && t >= ALL_DONE_MS) {
      var span = Math.max(1, LOOP_MS - ALL_DONE_MS);
      var frac = (t - ALL_DONE_MS) / span;
      hoverIndex = Math.min(CANDLE_COUNT - 1, Math.floor(frac * CANDLE_COUNT));
    }
    render(elapsedMs);
  }

  function fit() {
    var r = wrap.getBoundingClientRect();
    cw = Math.max(1, Math.round(r.width));
    ch = Math.max(1, Math.round(r.height));
    canvas.width = cw; canvas.height = ch;
    render(elapsed);
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var elapsed = reduce ? ALL_DONE_MS + 50 : 0;
  if (reduce) root.classList.remove('is-demo');

  var lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = Math.min(ts - lastTs, 48);
    lastTs = ts;
    if (!reduce) {
      elapsed += dt;
      autoDemoStep(elapsed);
    }
    requestAnimationFrame(tick);
  }
  fit();
  window.addEventListener('resize', fit);
  render(elapsed);
  requestAnimationFrame(tick);
})();

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

type Candle = { open: number; close: number; high: number; low: number };

export default function ChartAdvancedCandlestickOhlcWick() {
  const rootRef = useRef<HTMLDivElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);
  const kbdRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const root = rootRef.current;
    const canvas = canvasRef.current;
    const kbdEl = kbdRef.current;
    if (!root || !canvas || !kbdEl) return;
    const ctx = canvas.getContext("2d");
    if (!ctx) return;
    const wrap = canvas.parentElement as HTMLElement;

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

    const rand = seedRand(425091);
    const CANDLE_COUNT = 10;
    const candles: Candle[] = [];
    let price = 100;
    for (let i = 0; i < CANDLE_COUNT; i += 1) {
      const open = price;
      const vol = 4 + rand() * 10;
      const close = open + (rand() - 0.5) * 2 * vol;
      const high = Math.max(open, close) + rand() * vol * 0.6;
      const low = Math.min(open, close) - rand() * vol * 0.6;
      candles.push({ open: open, close: close, high: high, low: low });
      price = close;
    }
    const scaleMin = Math.min.apply(null, candles.map((c) => c.low));
    const scaleMax = Math.max.apply(null, candles.map((c) => c.high));

    const CANDLE_REVEAL_STAGGER_MS = 110, CANDLE_REVEAL_DUR_MS = 160;
    let hoverIndex = -1;
    let lastUserInputAt = -9999;

    const LOOP_MS = 2000;
    const T0 = 200;
    const ALL_DONE_MS = T0 + (CANDLE_COUNT - 1) * CANDLE_REVEAL_STAGGER_MS + CANDLE_REVEAL_DUR_MS;
    let cw = 480, ch = 300;

    function clamp(v: number, lo: number, hi: number) { return Math.max(lo, Math.min(hi, v)); }
    function easeOutCubic(x: number) { return 1 - Math.pow(1 - x, 3); }

    function candleX(idx: number) {
      const padX = cw * 0.06;
      const slot = (cw - padX * 2) / CANDLE_COUNT;
      return padX + slot * (idx + 0.5);
    }
    function priceY(v: number) {
      const padY = ch * 0.12;
      return ch - padY - (ch - padY * 2) * (v - scaleMin) / (scaleMax - scaleMin);
    }
    function growP(idx: number, t: number) {
      return clamp((t - T0 - idx * CANDLE_REVEAL_STAGGER_MS) / CANDLE_REVEAL_DUR_MS, 0, 1);
    }
    function nearestCandle(x: number) {
      let best = 0, bestD = Infinity;
      for (let k = 0; k < CANDLE_COUNT; k += 1) {
        const d = Math.abs(candleX(k) - x);
        if (d < bestD) { bestD = d; best = k; }
      }
      return best;
    }

    function render(elapsedMs: number) {
      const t = elapsedMs % LOOP_MS;
      ctx!.clearRect(0, 0, cw, ch);
      const padX = cw * 0.06;
      const slot = (cw - padX * 2) / CANDLE_COUNT;
      const bw = slot * 0.55;

      for (let idx = 0; idx < CANDLE_COUNT; idx += 1) {
        const c = candles[idx];
        const grow = easeOutCubic(growP(idx, t));
        const x = candleX(idx);

        const wickTopFull = priceY(c.high), wickBotFull = priceY(c.low);
        const wickCenter = (wickTopFull + wickBotFull) / 2;
        const wickHalf = (wickBotFull - wickTopFull) / 2 * grow;
        ctx!.strokeStyle = "#9a93a6";
        ctx!.lineWidth = 1.5;
        ctx!.beginPath();
        ctx!.moveTo(x, wickCenter - wickHalf);
        ctx!.lineTo(x, wickCenter + wickHalf);
        ctx!.stroke();

        const bodyTopFull = priceY(Math.max(c.open, c.close));
        const bodyBotFull = priceY(Math.min(c.open, c.close));
        const bodyCenter = (bodyTopFull + bodyBotFull) / 2;
        const bodyHalf = Math.max(1, (bodyBotFull - bodyTopFull) / 2 * grow);
        const up = c.close >= c.open;
        ctx!.fillStyle = up ? "#3ddc97" : "#ff7a5e";
        ctx!.fillRect(x - bw / 2, bodyCenter - bodyHalf, bw, bodyHalf * 2);
      }

      if (hoverIndex >= 0) {
        const hc = candles[hoverIndex];
        const hx = candleX(hoverIndex);
        const hy = priceY(hc.close);
        ctx!.setLineDash([4, 4]);
        ctx!.strokeStyle = "rgba(255,255,255,.55)";
        ctx!.lineWidth = 1;
        ctx!.beginPath(); ctx!.moveTo(hx, 0); ctx!.lineTo(hx, ch); ctx!.stroke();
        ctx!.beginPath(); ctx!.moveTo(0, hy); ctx!.lineTo(cw, hy); ctx!.stroke();
        ctx!.setLineDash([]);

        const label = Math.round(hc.open) + "·" + Math.round(hc.high) + "·" + Math.round(hc.low) + "·" + Math.round(hc.close);
        ctx!.font = "11px sans-serif";
        const padChip = 6;
        const textW = ctx!.measureText(label).width;
        const chipW = textW + padChip * 2, chipH = 20;
        const chipX = clamp(hx + 8, 4, cw - chipW - 4);
        const chipY = Math.max(4, hy - chipH - 6);
        ctx!.fillStyle = "#231f28";
        ctx!.fillRect(chipX, chipY, chipW, chipH);
        ctx!.fillStyle = "#9a93a6";
        ctx!.textBaseline = "middle";
        ctx!.fillText(label, chipX + padChip, chipY + chipH / 2);
      }
    }

    function setHoverIndex(idx: number) {
      hoverIndex = clamp(idx, -1, CANDLE_COUNT - 1);
      render(elapsed);
    }

    function onPointerMove(e: PointerEvent) {
      const rect = canvas!.getBoundingClientRect();
      const x = (e.clientX - rect.left) * (cw / rect.width);
      lastUserInputAt = elapsed;
      setHoverIndex(nearestCandle(x));
    }
    function onPointerLeave() { setHoverIndex(-1); }
    function onKeyDown(e: KeyboardEvent) {
      e.preventDefault();
      if (e.key === "ArrowLeft") {
        lastUserInputAt = elapsed;
        setHoverIndex(hoverIndex < 0 ? 0 : hoverIndex - 1);
      } else if (e.key === "ArrowRight") {
        lastUserInputAt = elapsed;
        setHoverIndex(hoverIndex < 0 ? 0 : hoverIndex + 1);
      }
    }

    canvas.addEventListener("pointermove", onPointerMove);
    canvas.addEventListener("pointerleave", onPointerLeave);
    kbdEl.addEventListener("keydown", onKeyDown);

    function autoDemoStep(elapsedMs: number) {
      const t = elapsedMs % LOOP_MS;
      if (elapsedMs - lastUserInputAt >= 800 && t >= ALL_DONE_MS) {
        const span = Math.max(1, LOOP_MS - ALL_DONE_MS);
        const frac = (t - ALL_DONE_MS) / span;
        hoverIndex = Math.min(CANDLE_COUNT - 1, Math.floor(frac * CANDLE_COUNT));
      }
      render(elapsedMs);
    }

    function fit() {
      const r = wrap.getBoundingClientRect();
      cw = Math.max(1, Math.round(r.width));
      ch = Math.max(1, Math.round(r.height));
      canvas!.width = cw; canvas!.height = ch;
      render(elapsed);
    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let elapsed = reduce ? ALL_DONE_MS + 50 : 0;
    if (reduce) root.classList.remove("is-demo");

    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) {
        elapsed += dt;
        autoDemoStep(elapsed);
      }
      raf = requestAnimationFrame(tick);
    }
    fit();
    window.addEventListener("resize", fit);
    render(elapsed);
    raf = requestAnimationFrame(tick);

    return () => {
      cancelAnimationFrame(raf);
      window.removeEventListener("resize", fit);
      canvas.removeEventListener("pointermove", onPointerMove);
      canvas.removeEventListener("pointerleave", onPointerLeave);
      kbdEl.removeEventListener("keydown", onKeyDown);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.cdl} is-demo`} ref={rootRef}>
        <canvas className={styles.cdl__canvas} ref={canvasRef} width={480} height={300} />
        <div className={styles.cdl__kbd} ref={kbdRef} tabIndex={0} aria-label="캔들 탐색" />
        <p className={styles.cdl__caption}>시가와 종가 사이를 몸통 사각형으로, 고가·저가까지를 얇은 꼬리선으로 계산해 그려, 막대 하나에 그날의 값 네 개가 겹쳐 담긴다</p>
      </div>
    </main>
  );
}