05A Check Where the Pointer Trail Drawn Along a Winding Guide Becomes a Score From Its Mean Distance to That Guide
The guide line is sampled at a fixed spacing, and for every pointer point the distance to the nearest sample is collected and averaged. The mean distance becomes a score, and a pass mark appears when the score reaches the threshold.
Best forTrace-the-path checks and a step before a signature box
GUIDE_AMPTOL_PXSCORE_PASSSAMPLE_STEP
<main class="stage">
<div class="cp is-demo" id="cp">
<canvas class="cp__canvas" data-role="canvas" width="480" height="300" tabindex="0" aria-label="A Check Where the Pointer Trail Drawn Along a Winding Guide Becomes a Score From Its Mean Distance to That Guide"></canvas>
<p class="cp__status" data-role="status" aria-live="polite">Starting the demo</p>
<button class="cp__btn" data-role="btn" type="button">Pause</button>
</div>
</main>@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);
.cp {
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: $subject-ink;
}
.cp__canvas {
display: block;
width: 100%;
height: 100%;
touch-action: none;
}
.cp__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, .85);
outline-offset: -6px;
}
.cp__status {
position: absolute;
left: $sp-3;
top: $sp-3;
max-width: 62%;
margin: 0;
padding: $sp-1 $sp-3;
border-radius: $r-pill;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.cp__btn {
position: absolute;
right: $sp-3;
bottom: $sp-3;
margin: 0;
padding: $sp-1 $sp-3;
border: 0;
border-radius: $r-pill;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font-family: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
}
.cp__btn:focus-visible {
outline: 2px solid #ffffff;
outline-offset: 2px;
}
@media (max-width: 340px) {
.cp__btn { font-size: 10px; padding: $sp-1 $sp-2; }
.cp__status { font-size: 10px; }
}
@media (prefers-reduced-motion: reduce) {
.cp { 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);
}
.cp {
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;
}
.cp__canvas {
display: block;
width: 100%;
height: 100%;
touch-action: none;
}
.cp__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.85);
outline-offset: -6px;
}
.cp__status {
position: absolute;
left: 12px;
top: 12px;
max-width: 62%;
margin: 0;
padding: 4px 12px;
border-radius: 999px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.cp__btn {
position: absolute;
right: 12px;
bottom: 12px;
margin: 0;
padding: 4px 12px;
border: 0;
border-radius: 999px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font-family: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
}
.cp__btn:focus-visible {
outline: 2px solid #ffffff;
outline-offset: 2px;
}
@media (max-width: 340px) {
.cp__btn {
font-size: 10px;
padding: 4px 8px;
}
.cp__status {
font-size: 10px;
}
}
@media (prefers-reduced-motion: reduce) {
.cp {
cursor: default;
}
}(function () {
const root = document.getElementById("cp");
if (!root)
return;
const W = 480;
const H = 300;
const PI2 = Math.PI * 2;
const FIXED_DT = 16;
const IDLE_TICKS = 150;
const BTN_PAUSE = 'Pause';
const BTN_PLAY = 'Play';
const BTN_NEXT = 'Next scene';
// 파스텔 팔레트 - 어두운 판 위에 밝은 색을 얹어 명도 차로 읽힌다
const BG = [29, 26, 44];
const PANEL = [44, 40, 68];
const MINT = [126, 226, 192];
const SKY = [124, 196, 255];
const LILAC = [190, 164, 255];
const PINK = [255, 160, 190];
const PEACH = [255, 208, 168];
const CREAM = [255, 244, 224];
const CHARSET = 'ABCDEFGHJKLMNPQRSTUVWXYZabdefghmnqrt23456789';
function clamp(v, lo, hi) { return v < lo ? lo : (v > hi ? hi : v); }
function lerp(a, b, k) { return a + (b - a) * k; }
function smooth(x) { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
function easeOutBack(x) { const c = clamp(x, 0, 1) - 1; return 1 + c * c * (2.7 * c + 1.7); }
function rgba(c, a) {
return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
}
function mix(a, b, k) {
return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
}
// 시드 고정 난수 - 같은 시드면 언제나 같은 수열 (선형 합동 방식)
function lcg(seed) {
let s = seed >>> 0;
return function () {
s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
return s / 4294967296;
};
}
// 정수 두 개와 시드로 0 이상 1 미만의 값을 만드는 해시 (같은 입력은 늘 같은 값)
function hash2(x, y, seed) {
let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
h = Math.imul(h ^ (h >>> 13), 1274126177);
h ^= h >>> 16;
return (h >>> 0) / 4294967296;
}
// 시드로 뜻 없는 글자열을 만든다
function glyphStr(seed, n) {
const r = lcg(seed * 7919 + 13);
let s = '';
for (let i = 0; i < n; i += 1) {
s += CHARSET.charAt(Math.floor(r() * CHARSET.length));
}
return s;
}
function rrect(ctx, x, y, w, h, r) {
const rr = Math.max(0, Math.min(r, w / 2, h / 2));
ctx.beginPath();
ctx.moveTo(x + rr, y);
ctx.lineTo(x + w - rr, y);
ctx.arcTo(x + w, y, x + w, y + rr, rr);
ctx.lineTo(x + w, y + h - rr);
ctx.arcTo(x + w, y + h, x + w - rr, y + h, rr);
ctx.lineTo(x + rr, y + h);
ctx.arcTo(x, y + h, x, y + h - rr, rr);
ctx.lineTo(x, y + rr);
ctx.arcTo(x, y, x + rr, y, rr);
ctx.closePath();
}
function mount(root, make) {
const canvas = root.querySelector('[data-role="canvas"]');
const statusEl = root.querySelector('[data-role="status"]');
const btnEl = root.querySelector('[data-role="btn"]');
if (!canvas || !statusEl || !btnEl) {
return function () { return; };
}
const ctx = canvas.getContext('2d');
if (!ctx) {
return function () { return; };
}
const dpr = Math.min(window.devicePixelRatio || 1, 2);
canvas.width = Math.round(W * dpr);
canvas.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const inp = { idle: 99999, focus: false, key: false };
const scene = make(inp, reduce);
let paused = false;
let rafId = 0;
let lastTs = -1;
let accMs = 0;
let lastLabel = '';
let lastLabelTick = -999;
let lastLive = 'polite';
let tickN = 0;
let clk = 0;
let wasAuto = true;
const cleaners = [];
function listen(target, type, fn) {
target.addEventListener(type, fn);
cleaners.push(function () { target.removeEventListener(type, fn); });
}
function show() {
scene.draw(ctx);
// 시연이 혼자 돌 때는 낭독을 끄고, 사람이 만지는 동안은 값이 바뀌어도 0.7초에 한 번만 갱신한다
const live = (reduce || inp.idle <= IDLE_TICKS) ? 'polite' : 'off';
if (live !== lastLive) {
lastLive = live;
statusEl.setAttribute('aria-live', live);
}
const t = scene.label();
if (t !== lastLabel && (reduce || live === 'off' || tickN - lastLabelTick >= 44)) {
lastLabel = t;
lastLabelTick = tickN;
statusEl.textContent = t;
}
}
// 고정 간격 한 틱 - 입력이 없으면 시연 스크립트가 같은 입구로 입력을 대신 넣는다
function advance() {
inp.idle += 1;
tickN += 1;
const a = inp.idle > IDLE_TICKS;
if (a && !wasAuto) {
scene.reset();
clk = 0;
}
wasAuto = a;
if (a) {
clk += 1;
scene.auto(clk);
if (clk >= scene.CYCLE) {
clk = 0;
scene.reset();
}
}
scene.step();
}
// 움직임 줄이기: 틱을 몰아서 돌린 뒤 한 번만 그린다 (중간 보간 장면은 화면에 나오지 않는다)
function settle(n) {
for (let i = 0; i < n; i += 1) {
inp.idle = 0;
tickN += 1;
scene.step();
}
show();
}
function tick(ts) {
if (lastTs < 0) {
lastTs = ts;
}
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
advance();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
function point(e) {
const r = canvas.getBoundingClientRect();
return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
}
btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
if (reduce) {
root.classList.remove('is-demo');
for (let i = 0; i < scene.REDUCE_TICKS; i += 1) {
advance();
}
show();
}
listen(btnEl, 'click', function () {
if (reduce) {
if (scene.next) {
scene.next();
show();
return;
}
const n = Math.round(scene.CYCLE / 3);
inp.idle = 99999;
wasAuto = true;
for (let i = 0; i < n; i += 1) {
advance();
}
show();
return;
}
paused = !paused;
if (paused) {
root.classList.remove('is-demo');
}
else {
root.classList.add('is-demo');
}
btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
});
listen(canvas, 'focus', function () { inp.focus = true; if (reduce) {
show();
} });
listen(canvas, 'blur', function () { inp.focus = false; inp.key = false; if (reduce) {
show();
} });
listen(canvas, 'pointerdown', function (e) {
const p = point(e);
inp.idle = 0;
inp.key = false;
try {
canvas.setPointerCapture(e.pointerId);
}
catch (err) { /* 캡처가 안 되는 환경은 그냥 넘어간다 */ }
scene.down(p[0], p[1]);
if (reduce) {
settle(30);
}
});
listen(canvas, 'pointermove', function (e) {
const p = point(e);
inp.idle = 0;
inp.key = false;
scene.move(p[0], p[1]);
if (reduce) {
settle(30);
}
});
listen(canvas, 'pointerup', function (e) {
const p = point(e);
inp.idle = 0;
scene.up(p[0], p[1]);
if (reduce) {
settle(30);
}
});
listen(canvas, 'keydown', function (e) {
inp.idle = 0;
inp.key = true;
if (scene.key(e.key)) {
e.preventDefault();
}
if (reduce) {
settle(30);
}
});
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
return function () {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
};
}
const GUIDE_AMP = 46; // 안내선이 위아래로 오르내리는 폭 (px)
const TOL_PX = 12; // 안내선에서 이만큼 안이면 허용 띠 안
const SCORE_PASS = 60; // 이 점수 이상이면 통과로 친다 (시연 규칙)
const SAMPLE_STEP = 6; // 궤적을 이만큼 움직일 때마다 한 점씩 표본으로 남긴다 (px)
const X0 = 40;
const X1 = 440;
const TXT_READY = 'Trace along the guide line';
const TXT_TRACE = 'Tracing · {n} samples';
const TXT_PASS = 'Score {s} · mean {m}px, passes the demo rule';
const TXT_FAIL = 'Score {s} · {m}px off the guide on average';
// PURE-BEGIN
// 안내선을 4px 간격 점으로 표본화한다
function guidePoints(seed, amp) {
const r = lcg(seed * 389 + 9);
const p1 = r() * PI2;
const p2 = r() * PI2;
const pts = [];
for (let x = 40; x <= 440; x += 4) {
const u = (x - 40) / 400;
pts.push([x, 172 + amp * (0.6 * Math.sin(u * PI2 + p1) + 0.4 * Math.sin(u * PI2 * 2.3 + p2))]);
}
return pts;
}
// 점 하나에서 안내선 표본까지 가장 가까운 거리
function nearest(px, py, guide) {
let best = 1e9;
for (let i = 0; i < guide.length; i += 1) {
const dx = guide[i][0] - px;
const dy = guide[i][1] - py;
const d = dx * dx + dy * dy;
if (d < best) {
best = d;
}
}
return Math.sqrt(best);
}
// 궤적 표본마다 가장 가까운 안내선 거리를 평균해 점수로 바꾼다 (평균이 허용치의 두 배면 0점)
function scoreTrail(samples, guide, tol) {
if (samples.length === 0) {
return { mean: 0, score: 0 };
}
let sum = 0;
for (let i = 0; i < samples.length; i += 1) {
sum += nearest(samples[i][0], samples[i][1], guide);
}
const mean = sum / samples.length;
const score = Math.round(100 * Math.min(1, Math.max(0, 1 - mean / (tol * 2))));
return { mean: mean, score: score };
}
// PURE-END
const make = (inp, reduce) => {
let seed = 4;
let guide = guidePoints(seed, GUIDE_AMP);
let trail = [];
let dist = [];
let drawing = false;
let res = null;
let cycleN = 1;
let kx = X0;
let ky = 172;
let kdown = false;
let t = 0;
function begin(x, y) {
trail = [];
dist = [];
res = null;
drawing = true;
addPoint(x, y, true);
}
function addPoint(x, y, force) {
if (!drawing) {
return;
}
const last = trail.length ? trail[trail.length - 1] : null;
if (force || !last || Math.hypot(x - last[0], y - last[1]) >= SAMPLE_STEP) {
trail.push([x, y]);
dist.push(nearest(x, y, guide));
}
}
function end() {
if (!drawing) {
return;
}
drawing = false;
res = scoreTrail(trail, guide, TOL_PX);
}
const scene = {
CYCLE: 124,
REDUCE_TICKS: 100,
reset() {
cycleN += 1;
seed += 1;
guide = guidePoints(seed, GUIDE_AMP);
trail = [];
dist = [];
drawing = false;
res = null;
kdown = false;
kx = X0;
ky = guide[0][1];
},
auto(clk) {
// 짝수 바퀴는 손이 떨려 허용 띠를 벗어나고 홀수 바퀴는 안쪽에서 따라간다
const shaky = cycleN % 2 === 0;
if (clk >= 10 && clk <= 84) {
const u = (clk - 10) / 74;
const x = lerp(X0, X1, u);
const gi = Math.min(guide.length - 1, Math.round((x - X0) / 4));
const wob = (shaky ? 26 : 6) * Math.sin(u * 17 + cycleN) * (0.4 + 0.6 * Math.sin(u * 6.3 + 1));
if (clk === 10) {
begin(x, guide[gi][1] + wob);
}
addPoint(x, guide[gi][1] + wob, false);
}
if (clk === 86) {
end();
}
},
step() { t += 1; },
draw(ctx) {
ctx.fillStyle = rgba(BG, 1);
ctx.fillRect(0, 0, W, H);
ctx.fillStyle = rgba(PANEL, 1);
rrect(ctx, 14, 40, W - 28, H - 54, 14);
ctx.fill();
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
// 허용 띠
ctx.strokeStyle = rgba(SKY, 0.2);
ctx.lineWidth = TOL_PX * 2;
ctx.beginPath();
for (let i = 0; i < guide.length; i += 1) {
if (i === 0) {
ctx.moveTo(guide[i][0], guide[i][1]);
}
else {
ctx.lineTo(guide[i][0], guide[i][1]);
}
}
ctx.stroke();
// 안내선
ctx.strokeStyle = rgba(CREAM, 0.75);
ctx.lineWidth = 2;
ctx.setLineDash([6, 6]);
ctx.lineDashOffset = -t * 0.4;
ctx.beginPath();
for (let i = 0; i < guide.length; i += 1) {
if (i === 0) {
ctx.moveTo(guide[i][0], guide[i][1]);
}
else {
ctx.lineTo(guide[i][0], guide[i][1]);
}
}
ctx.stroke();
ctx.setLineDash([]);
// 궤적 - 허용 띠 밖으로 나간 마디는 분홍
ctx.lineWidth = 6;
for (let i = 1; i < trail.length; i += 1) {
ctx.strokeStyle = rgba(dist[i] <= TOL_PX ? MINT : PINK, 1);
ctx.beginPath();
ctx.moveTo(trail[i - 1][0], trail[i - 1][1]);
ctx.lineTo(trail[i][0], trail[i][1]);
ctx.stroke();
}
ctx.fillStyle = rgba(PEACH, 1);
ctx.beginPath();
ctx.arc(guide[0][0], guide[0][1], 7, 0, PI2);
ctx.fill();
ctx.fillStyle = rgba(LILAC, 1);
ctx.beginPath();
ctx.arc(guide[guide.length - 1][0], guide[guide.length - 1][1], 7, 0, PI2);
ctx.fill();
if (drawing && trail.length) {
const p = trail[trail.length - 1];
ctx.fillStyle = rgba(CREAM, 1);
ctx.beginPath();
ctx.arc(p[0], p[1], 8 + Math.sin(t * 0.3) * 1.5, 0, PI2);
ctx.fill();
}
// 점수 막대
const sc = res ? res.score : 0;
ctx.fillStyle = rgba(CREAM, 0.25);
rrect(ctx, 264, 20, 200, 12, 6);
ctx.fill();
ctx.fillStyle = rgba(sc >= SCORE_PASS ? MINT : PINK, 1);
rrect(ctx, 264, 20, Math.max(0, 200 * sc / 100), 12, 6);
ctx.fill();
ctx.fillStyle = rgba(CREAM, 0.9);
ctx.fillRect(264 + 200 * SCORE_PASS / 100 - 1, 16, 2, 20);
if (inp.key && inp.focus) {
ctx.strokeStyle = 'rgba(255,255,255,0.95)';
ctx.lineWidth = 2.5;
ctx.beginPath();
ctx.arc(kx, ky, 12, 0, PI2);
ctx.stroke();
}
},
label() {
if (drawing) {
return TXT_TRACE.replace('{n}', String(trail.length));
}
if (res) {
const m = String(Math.round(res.mean * 10) / 10);
return (res.score >= SCORE_PASS ? TXT_PASS : TXT_FAIL).replace('{s}', String(res.score)).replace('{m}', m);
}
return TXT_READY;
},
down(x, y) { begin(x, y); },
move(x, y) { addPoint(x, y, false); },
up() { end(); },
key(k) {
const dx = k === 'ArrowLeft' ? -SAMPLE_STEP * 1.5 : (k === 'ArrowRight' ? SAMPLE_STEP * 1.5 : 0);
const dy = k === 'ArrowUp' ? -SAMPLE_STEP * 1.5 : (k === 'ArrowDown' ? SAMPLE_STEP * 1.5 : 0);
if (dx !== 0 || dy !== 0) {
kx = clamp(kx + dx, 20, W - 20);
ky = clamp(ky + dy, 50, H - 20);
addPoint(kx, ky, false);
return true;
}
if (k === ' ') {
kdown = !kdown;
if (kdown) {
begin(kx, ky);
}
else {
end();
}
return true;
}
if (k === 'Enter') {
kdown = false;
end();
return true;
}
return false;
},
};
scene.reset();
return scene;
};
return mount(root, make);
})();// CapPointerTrailGuideScore - vanilla 판(05-cap-pointer-trail-guide-score) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./CapPointerTrailGuideScore.module.scss";
const cx = (s: string): string => s.split(" ").map((n) => styles[n] ?? n).join(" ");
export default function CapPointerTrailGuideScore() {
const rootRef = useRef<HTMLDivElement | null>(null);
useEffect(() => {
const root = rootRef.current;
if (!root) return;
type RGB = [number, number, number];
interface Input { idle: number; focus: boolean; key: boolean; }
interface Scene {
CYCLE: number;
REDUCE_TICKS: number;
reset(): void;
auto(clk: number): void;
step(): void;
draw(ctx: CanvasRenderingContext2D): void;
label(): string;
down(x: number, y: number): void;
move(x: number, y: number): void;
up(x: number, y: number): void;
key(k: string): boolean;
next?(): void;
}
type Make = (inp: Input, reduce: boolean) => Scene;
const W = 480;
const H = 300;
const PI2 = Math.PI * 2;
const FIXED_DT = 16;
const IDLE_TICKS = 150;
const BTN_PAUSE = '멈춤';
const BTN_PLAY = '재생';
const BTN_NEXT = '다음 장면';
// 파스텔 팔레트 - 어두운 판 위에 밝은 색을 얹어 명도 차로 읽힌다
const BG: RGB = [29, 26, 44];
const PANEL: RGB = [44, 40, 68];
const MINT: RGB = [126, 226, 192];
const SKY: RGB = [124, 196, 255];
const LILAC: RGB = [190, 164, 255];
const PINK: RGB = [255, 160, 190];
const PEACH: RGB = [255, 208, 168];
const CREAM: RGB = [255, 244, 224];
const CHARSET = 'ABCDEFGHJKLMNPQRSTUVWXYZabdefghmnqrt23456789';
function clamp(v: number, lo: number, hi: number): number { return v < lo ? lo : (v > hi ? hi : v); }
function lerp(a: number, b: number, k: number): number { return a + (b - a) * k; }
function smooth(x: number): number { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
function easeOutBack(x: number): number { const c = clamp(x, 0, 1) - 1; return 1 + c * c * (2.7 * c + 1.7); }
function rgba(c: RGB, a: number): string {
return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
}
function mix(a: RGB, b: RGB, k: number): RGB {
return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
}
// 시드 고정 난수 - 같은 시드면 언제나 같은 수열 (선형 합동 방식)
function lcg(seed: number): () => number {
let s = seed >>> 0;
return function () {
s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
return s / 4294967296;
};
}
// 정수 두 개와 시드로 0 이상 1 미만의 값을 만드는 해시 (같은 입력은 늘 같은 값)
function hash2(x: number, y: number, seed: number): number {
let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
h = Math.imul(h ^ (h >>> 13), 1274126177);
h ^= h >>> 16;
return (h >>> 0) / 4294967296;
}
// 시드로 뜻 없는 글자열을 만든다
function glyphStr(seed: number, n: number): string {
const r = lcg(seed * 7919 + 13);
let s = '';
for (let i = 0; i < n; i += 1) {
s += CHARSET.charAt(Math.floor(r() * CHARSET.length));
}
return s;
}
function rrect(ctx: CanvasRenderingContext2D, x: number, y: number, w: number, h: number, r: number): void {
const rr = Math.max(0, Math.min(r, w / 2, h / 2));
ctx.beginPath();
ctx.moveTo(x + rr, y);
ctx.lineTo(x + w - rr, y);
ctx.arcTo(x + w, y, x + w, y + rr, rr);
ctx.lineTo(x + w, y + h - rr);
ctx.arcTo(x + w, y + h, x + w - rr, y + h, rr);
ctx.lineTo(x + rr, y + h);
ctx.arcTo(x, y + h, x, y + h - rr, rr);
ctx.lineTo(x, y + rr);
ctx.arcTo(x, y, x + rr, y, rr);
ctx.closePath();
}
function mount(root: HTMLElement, make: Make): () => void {
const canvas = root.querySelector('[data-role="canvas"]') as HTMLCanvasElement;
const statusEl = root.querySelector('[data-role="status"]') as HTMLElement;
const btnEl = root.querySelector('[data-role="btn"]') as HTMLButtonElement;
if (!canvas || !statusEl || !btnEl) {
return function () { return; };
}
const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
if (!ctx) {
return function () { return; };
}
const dpr = Math.min(window.devicePixelRatio || 1, 2);
canvas.width = Math.round(W * dpr);
canvas.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const inp: Input = { idle: 99999, focus: false, key: false };
const scene = make(inp, reduce);
let paused = false;
let rafId = 0;
let lastTs = -1;
let accMs = 0;
let lastLabel = '';
let lastLabelTick = -999;
let lastLive = 'polite';
let tickN = 0;
let clk = 0;
let wasAuto = true;
const cleaners: Array<() => void> = [];
function listen<K extends keyof HTMLElementEventMap>(target: HTMLElement, type: K, fn: (e: HTMLElementEventMap[K]) => void): void {
target.addEventListener(type, fn);
cleaners.push(function () { target.removeEventListener(type, fn); });
}
function show(): void {
scene.draw(ctx);
// 시연이 혼자 돌 때는 낭독을 끄고, 사람이 만지는 동안은 값이 바뀌어도 0.7초에 한 번만 갱신한다
const live = (reduce || inp.idle <= IDLE_TICKS) ? 'polite' : 'off';
if (live !== lastLive) {
lastLive = live;
statusEl.setAttribute('aria-live', live);
}
const t = scene.label();
if (t !== lastLabel && (reduce || live === 'off' || tickN - lastLabelTick >= 44)) {
lastLabel = t;
lastLabelTick = tickN;
statusEl.textContent = t;
}
}
// 고정 간격 한 틱 - 입력이 없으면 시연 스크립트가 같은 입구로 입력을 대신 넣는다
function advance(): void {
inp.idle += 1;
tickN += 1;
const a = inp.idle > IDLE_TICKS;
if (a && !wasAuto) {
scene.reset();
clk = 0;
}
wasAuto = a;
if (a) {
clk += 1;
scene.auto(clk);
if (clk >= scene.CYCLE) {
clk = 0;
scene.reset();
}
}
scene.step();
}
// 움직임 줄이기: 틱을 몰아서 돌린 뒤 한 번만 그린다 (중간 보간 장면은 화면에 나오지 않는다)
function settle(n: number): void {
for (let i = 0; i < n; i += 1) {
inp.idle = 0;
tickN += 1;
scene.step();
}
show();
}
function tick(ts: number): void {
if (lastTs < 0) {
lastTs = ts;
}
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
advance();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
function point(e: PointerEvent): number[] {
const r = canvas.getBoundingClientRect();
return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
}
btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
if (reduce) {
root.classList.remove('is-demo');
for (let i = 0; i < scene.REDUCE_TICKS; i += 1) {
advance();
}
show();
}
listen(btnEl, 'click', function () {
if (reduce) {
if (scene.next) {
scene.next();
show();
return;
}
const n = Math.round(scene.CYCLE / 3);
inp.idle = 99999;
wasAuto = true;
for (let i = 0; i < n; i += 1) {
advance();
}
show();
return;
}
paused = !paused;
if (paused) {
root.classList.remove('is-demo');
}
else {
root.classList.add('is-demo');
}
btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
});
listen(canvas, 'focus', function () { inp.focus = true; if (reduce) { show(); } });
listen(canvas, 'blur', function () { inp.focus = false; inp.key = false; if (reduce) { show(); } });
listen(canvas, 'pointerdown', function (e) {
const p = point(e);
inp.idle = 0;
inp.key = false;
try { canvas.setPointerCapture(e.pointerId); } catch (err) { /* 캡처가 안 되는 환경은 그냥 넘어간다 */ }
scene.down(p[0], p[1]);
if (reduce) { settle(30); }
});
listen(canvas, 'pointermove', function (e) {
const p = point(e);
inp.idle = 0;
inp.key = false;
scene.move(p[0], p[1]);
if (reduce) { settle(30); }
});
listen(canvas, 'pointerup', function (e) {
const p = point(e);
inp.idle = 0;
scene.up(p[0], p[1]);
if (reduce) { settle(30); }
});
listen(canvas, 'keydown', function (e) {
inp.idle = 0;
inp.key = true;
if (scene.key(e.key)) {
e.preventDefault();
}
if (reduce) { settle(30); }
});
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
return function () {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
};
}
const GUIDE_AMP = 46; // 안내선이 위아래로 오르내리는 폭 (px)
const TOL_PX = 12; // 안내선에서 이만큼 안이면 허용 띠 안
const SCORE_PASS = 60; // 이 점수 이상이면 통과로 친다 (시연 규칙)
const SAMPLE_STEP = 6; // 궤적을 이만큼 움직일 때마다 한 점씩 표본으로 남긴다 (px)
const X0 = 40;
const X1 = 440;
const TXT_READY = '안내선을 따라 그린다';
const TXT_TRACE = '따라 그리는 중 · 표본 {n}개';
const TXT_PASS = '점수 {s} — 평균 {m}px, 시연 기준 통과';
const TXT_FAIL = '점수 {s} — 안내선에서 평균 {m}px 벗어남';
interface TrailScore { mean: number; score: number; }
// PURE-BEGIN
// 안내선을 4px 간격 점으로 표본화한다
function guidePoints(seed: number, amp: number): number[][] {
const r = lcg(seed * 389 + 9);
const p1 = r() * PI2;
const p2 = r() * PI2;
const pts: number[][] = [];
for (let x = 40; x <= 440; x += 4) {
const u = (x - 40) / 400;
pts.push([x, 172 + amp * (0.6 * Math.sin(u * PI2 + p1) + 0.4 * Math.sin(u * PI2 * 2.3 + p2))]);
}
return pts;
}
// 점 하나에서 안내선 표본까지 가장 가까운 거리
function nearest(px: number, py: number, guide: number[][]): number {
let best = 1e9;
for (let i = 0; i < guide.length; i += 1) {
const dx = guide[i][0] - px;
const dy = guide[i][1] - py;
const d = dx * dx + dy * dy;
if (d < best) { best = d; }
}
return Math.sqrt(best);
}
// 궤적 표본마다 가장 가까운 안내선 거리를 평균해 점수로 바꾼다 (평균이 허용치의 두 배면 0점)
function scoreTrail(samples: number[][], guide: number[][], tol: number): TrailScore {
if (samples.length === 0) { return { mean: 0, score: 0 }; }
let sum = 0;
for (let i = 0; i < samples.length; i += 1) {
sum += nearest(samples[i][0], samples[i][1], guide);
}
const mean = sum / samples.length;
const score = Math.round(100 * Math.min(1, Math.max(0, 1 - mean / (tol * 2))));
return { mean: mean, score: score };
}
// PURE-END
const make: Make = (inp, reduce) => {
let seed = 4;
let guide = guidePoints(seed, GUIDE_AMP);
let trail: number[][] = [];
let dist: number[] = [];
let drawing = false;
let res: TrailScore | null = null;
let cycleN = 1;
let kx = X0;
let ky = 172;
let kdown = false;
let t = 0;
function begin(x: number, y: number): void {
trail = [];
dist = [];
res = null;
drawing = true;
addPoint(x, y, true);
}
function addPoint(x: number, y: number, force: boolean): void {
if (!drawing) { return; }
const last = trail.length ? trail[trail.length - 1] : null;
if (force || !last || Math.hypot(x - last[0], y - last[1]) >= SAMPLE_STEP) {
trail.push([x, y]);
dist.push(nearest(x, y, guide));
}
}
function end(): void {
if (!drawing) { return; }
drawing = false;
res = scoreTrail(trail, guide, TOL_PX);
}
const scene: Scene = {
CYCLE: 124,
REDUCE_TICKS: 100,
reset() {
cycleN += 1;
seed += 1;
guide = guidePoints(seed, GUIDE_AMP);
trail = [];
dist = [];
drawing = false;
res = null;
kdown = false;
kx = X0;
ky = guide[0][1];
},
auto(clk) {
// 짝수 바퀴는 손이 떨려 허용 띠를 벗어나고 홀수 바퀴는 안쪽에서 따라간다
const shaky = cycleN % 2 === 0;
if (clk >= 10 && clk <= 84) {
const u = (clk - 10) / 74;
const x = lerp(X0, X1, u);
const gi = Math.min(guide.length - 1, Math.round((x - X0) / 4));
const wob = (shaky ? 26 : 6) * Math.sin(u * 17 + cycleN) * (0.4 + 0.6 * Math.sin(u * 6.3 + 1));
if (clk === 10) { begin(x, guide[gi][1] + wob); }
addPoint(x, guide[gi][1] + wob, false);
}
if (clk === 86) { end(); }
},
step() { t += 1; },
draw(ctx) {
ctx.fillStyle = rgba(BG, 1);
ctx.fillRect(0, 0, W, H);
ctx.fillStyle = rgba(PANEL, 1);
rrect(ctx, 14, 40, W - 28, H - 54, 14);
ctx.fill();
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
// 허용 띠
ctx.strokeStyle = rgba(SKY, 0.2);
ctx.lineWidth = TOL_PX * 2;
ctx.beginPath();
for (let i = 0; i < guide.length; i += 1) {
if (i === 0) { ctx.moveTo(guide[i][0], guide[i][1]); } else { ctx.lineTo(guide[i][0], guide[i][1]); }
}
ctx.stroke();
// 안내선
ctx.strokeStyle = rgba(CREAM, 0.75);
ctx.lineWidth = 2;
ctx.setLineDash([6, 6]);
ctx.lineDashOffset = -t * 0.4;
ctx.beginPath();
for (let i = 0; i < guide.length; i += 1) {
if (i === 0) { ctx.moveTo(guide[i][0], guide[i][1]); } else { ctx.lineTo(guide[i][0], guide[i][1]); }
}
ctx.stroke();
ctx.setLineDash([]);
// 궤적 - 허용 띠 밖으로 나간 마디는 분홍
ctx.lineWidth = 6;
for (let i = 1; i < trail.length; i += 1) {
ctx.strokeStyle = rgba(dist[i] <= TOL_PX ? MINT : PINK, 1);
ctx.beginPath();
ctx.moveTo(trail[i - 1][0], trail[i - 1][1]);
ctx.lineTo(trail[i][0], trail[i][1]);
ctx.stroke();
}
ctx.fillStyle = rgba(PEACH, 1);
ctx.beginPath();
ctx.arc(guide[0][0], guide[0][1], 7, 0, PI2);
ctx.fill();
ctx.fillStyle = rgba(LILAC, 1);
ctx.beginPath();
ctx.arc(guide[guide.length - 1][0], guide[guide.length - 1][1], 7, 0, PI2);
ctx.fill();
if (drawing && trail.length) {
const p = trail[trail.length - 1];
ctx.fillStyle = rgba(CREAM, 1);
ctx.beginPath();
ctx.arc(p[0], p[1], 8 + Math.sin(t * 0.3) * 1.5, 0, PI2);
ctx.fill();
}
// 점수 막대
const sc = res ? res.score : 0;
ctx.fillStyle = rgba(CREAM, 0.25);
rrect(ctx, 264, 20, 200, 12, 6);
ctx.fill();
ctx.fillStyle = rgba(sc >= SCORE_PASS ? MINT : PINK, 1);
rrect(ctx, 264, 20, Math.max(0, 200 * sc / 100), 12, 6);
ctx.fill();
ctx.fillStyle = rgba(CREAM, 0.9);
ctx.fillRect(264 + 200 * SCORE_PASS / 100 - 1, 16, 2, 20);
if (inp.key && inp.focus) {
ctx.strokeStyle = 'rgba(255,255,255,0.95)';
ctx.lineWidth = 2.5;
ctx.beginPath();
ctx.arc(kx, ky, 12, 0, PI2);
ctx.stroke();
}
},
label() {
if (drawing) { return TXT_TRACE.replace('{n}', String(trail.length)); }
if (res) {
const m = String(Math.round(res.mean * 10) / 10);
return (res.score >= SCORE_PASS ? TXT_PASS : TXT_FAIL).replace('{s}', String(res.score)).replace('{m}', m);
}
return TXT_READY;
},
down(x, y) { begin(x, y); },
move(x, y) { addPoint(x, y, false); },
up() { end(); },
key(k) {
const dx = k === 'ArrowLeft' ? -SAMPLE_STEP * 1.5 : (k === 'ArrowRight' ? SAMPLE_STEP * 1.5 : 0);
const dy = k === 'ArrowUp' ? -SAMPLE_STEP * 1.5 : (k === 'ArrowDown' ? SAMPLE_STEP * 1.5 : 0);
if (dx !== 0 || dy !== 0) {
kx = clamp(kx + dx, 20, W - 20);
ky = clamp(ky + dy, 50, H - 20);
addPoint(kx, ky, false);
return true;
}
if (k === ' ') {
kdown = !kdown;
if (kdown) { begin(kx, ky); } else { end(); }
return true;
}
if (k === 'Enter') { kdown = false; end(); return true; }
return false;
},
};
scene.reset();
return scene;
};
return mount(root, make);
}, []);
return (
<div className={cx("cp") + " is-demo"} id="cp" ref={rootRef}>
<canvas className={cx("cp__canvas")} data-role="canvas" width="480" height="300" tabIndex={0} aria-label="구불구불한 안내선을 따라 그은 포인터 궤적이 안내선과의 평균 거리로 점수가 되는 확인"></canvas>
<p className={cx("cp__status")} data-role="status" aria-live="polite">시연 준비 중</p>
<button className={cx("cp__btn")} data-role="btn" type="button">멈춤</button>
</div>
);
}05 A Check Where the Pointer Trail Drawn Along a Winding Guide Becomes a Score From Its Mean Distance to That Guide — Measured area 12.908% · moving frames 23/23Original by GODRICH · SCSS and React ship in the zip · CSS Captcha: 9 Warped Text and Rotate Checks
The post this demo lives in
CSS Captcha: 9 Warped Text and Rotate ChecksCall it a human check, but a css captcha is arithmetic on screen — scene 01 slides glyph columns along a sine wave and s See all demos in this post
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