08An Edge Lens Where Cards Near Both Ends of the Track Bend and Shrink Like a Fisheye and Flatten Out in the Middle
For every screen pixel, its distance from the center is passed through a lens curve to decide which point of the source strip to read. Toward the edges a wider range is squeezed into less space.
Best forApp icon docks and category chip rows
LENS_KLENS_PBENDPITCH
<main class="stage">
<div class="hs is-demo" id="hs">
<canvas class="hs__canvas" data-role="canvas" width="480" height="300" tabindex="0" aria-label="A row of icons that shrinks and curves toward the screen edges like a fisheye lens"></canvas>
<p class="hs__status" data-role="status" aria-live="off">Lens on</p>
<div class="hs__tools">
<button class="hs__btn" data-role="btn" type="button" aria-pressed="false">Turn lens off</button>
</div>
</div>
</main>@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);
.hs {
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;
}
.hs__canvas {
display: block;
width: 100%;
height: 100%;
cursor: grab;
}
.hs__canvas:active {
cursor: grabbing;
}
.hs__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, .85);
outline-offset: -6px;
}
.hs__status {
position: absolute;
left: $sp-3;
bottom: $sp-3;
max-width: 46%;
margin: 0;
padding: $sp-1 $sp-3;
border-radius: $r-control;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.hs__tools {
position: absolute;
right: $sp-3;
bottom: $sp-3;
display: flex;
gap: $sp-2;
}
.hs__btn {
margin: 0;
padding: $sp-1 $sp-3;
border: 0;
border-radius: $r-pill;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
transition: background-color $dur-quick ease-out;
}
.hs__btn:hover {
background: $subject-cream;
}
.hs__btn[aria-pressed="true"] {
background: $subject-mint;
}
.hs__btn:focus-visible {
outline: 2px solid rgba(255, 255, 255, .95);
outline-offset: 2px;
}
// 손가락 가로 끌기는 이 캔버스가 받고, 세로 쓸기는 브라우저에 남겨 페이지 스크롤이 막히지 않게 한다
.hs__canvas { touch-action: pan-y; }
@media (max-width: 340px) {
.hs__btn { font-size: 10px; padding: $sp-1 $sp-2; }
.hs__status { font-size: 10px; padding: $sp-1 $sp-2; }
}
@media (prefers-reduced-motion: reduce) {
.hs__btn { transition: 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);
}
.hs {
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;
}
.hs__canvas {
display: block;
width: 100%;
height: 100%;
cursor: grab;
}
.hs__canvas:active {
cursor: grabbing;
}
.hs__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.85);
outline-offset: -6px;
}
.hs__status {
position: absolute;
left: 12px;
bottom: 12px;
max-width: 46%;
margin: 0;
padding: 4px 12px;
border-radius: 12px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.hs__tools {
position: absolute;
right: 12px;
bottom: 12px;
display: flex;
gap: 8px;
}
.hs__btn {
margin: 0;
padding: 4px 12px;
border: 0;
border-radius: 999px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
transition: background-color 220ms ease-out;
}
.hs__btn:hover {
background: #fff7e6;
}
.hs__btn[aria-pressed=true] {
background: #4cd4a6;
}
.hs__btn:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.95);
outline-offset: 2px;
}
.hs__canvas {
touch-action: pan-y;
}
@media (max-width: 340px) {
.hs__btn {
font-size: 10px;
padding: 4px 8px;
}
.hs__status {
font-size: 10px;
padding: 4px 8px;
}
}
@media (prefers-reduced-motion: reduce) {
.hs__btn {
transition: none;
}
}(function () {
const root = document.getElementById("hs");
if (!root) return;
const W = 480;
const H = 300;
const FIXED_DT = 16;
// 파스텔 팔레트 — 어두운 무대 위에 밝은 카드를 얹어 명도 차로 읽힌다
const BG = [29, 26, 44];
const PAPER = [255, 248, 234];
const INK = [58, 48, 76];
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 TINTS = [SKY, PINK, MINT, LILAC, PEACH];
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 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)]; }
const canvasEl = root.querySelector('[data-role="canvas"]');
const statusEl = root.querySelector('[data-role="status"]');
const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
if (!canvasEl || !ctxRaw || !statusEl) {
return;
}
const cv = canvasEl;
const ctx = ctxRaw;
const status = statusEl;
const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
const still = reduceQuery.matches;
// 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
let demo = root.classList.contains('is-demo');
function wake() {
if (!demo) {
return;
}
demo = false;
root.classList.remove('is-demo');
status.setAttribute('aria-live', 'polite');
}
function say(text) {
if (status.textContent !== text) {
status.textContent = text;
}
}
// 휠 한 번의 이동량을 px 로 — 줄 단위(deltaMode 1)·쪽 단위(deltaMode 2) 장치도 같은 눈금으로 맞춘다.
// 가로·세로 중 큰 쪽을 쓴다: 트랙패드의 가로 쓸기와 마우스 휠의 세로 굴림이 같은 방향으로 들어온다
function wheelPx(ev) {
const unit = ev.deltaMode === 1 ? 16 : (ev.deltaMode === 2 ? W : 1);
const d = Math.abs(ev.deltaX) > Math.abs(ev.deltaY) ? ev.deltaX : ev.deltaY;
return d * unit;
}
// 시연 시계가 loop 주기 안의 at 시각을 이번 스텝에 막 지났는가
function crossed(t, at, loop) {
const p = t % loop;
return p >= at && p - FIXED_DT < at;
}
function fitCanvas() {
const dpr = window.devicePixelRatio || 1;
cv.width = Math.round(W * dpr);
cv.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
}
function onResize() {
fitCanvas();
draw();
}
fitCanvas();
window.addEventListener('resize', onResize);
// 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
function toScene(ev) {
const r = cv.getBoundingClientRect();
return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
}
function roundRectPath(c, x, y, w, h, r) {
const rr = Math.min(r, w / 2, h / 2);
c.beginPath();
c.moveTo(x + rr, y);
c.lineTo(x + w - rr, y);
c.quadraticCurveTo(x + w, y, x + w, y + rr);
c.lineTo(x + w, y + h - rr);
c.quadraticCurveTo(x + w, y + h, x + w - rr, y + h);
c.lineTo(x + rr, y + h);
c.quadraticCurveTo(x, y + h, x, y + h - rr);
c.lineTo(x, y + rr);
c.quadraticCurveTo(x, y, x + rr, y);
c.closePath();
}
// 카드 한 장 — 사진 대신 계산한 그림 칸(그라디언트 하늘·해·언덕) + 글줄 막대 두 개 + 번호
function drawCard(c, x, y, w, h, i, light) {
const t1 = TINTS[i % TINTS.length];
const t2 = TINTS[(i + 2) % TINTS.length];
const k = clamp(light, 0, 1);
roundRectPath(c, x, y, w, h, 10);
c.fillStyle = rgba(mix(BG, PAPER, k), 1);
c.fill();
const ih = h * 0.58;
const g = c.createLinearGradient(x, y, x + w, y + ih);
g.addColorStop(0, rgba(mix(BG, t1, k), 1));
g.addColorStop(1, rgba(mix(BG, t2, k * 0.92), 1));
c.save();
roundRectPath(c, x + 6, y + 6, w - 12, ih - 6, 7);
c.fillStyle = g;
c.fill();
c.clip();
c.fillStyle = rgba(mix(BG, PAPER, k * 0.9), 0.9);
c.beginPath();
c.arc(x + w * 0.7, y + ih * 0.36, Math.min(w, ih) * 0.13, 0, Math.PI * 2);
c.fill();
c.fillStyle = rgba(mix(BG, INK, k), 0.55);
c.beginPath();
c.moveTo(x, y + ih);
c.lineTo(x + w * 0.32, y + ih * 0.55);
c.lineTo(x + w * 0.55, y + ih * 0.8);
c.lineTo(x + w * 0.78, y + ih * 0.62);
c.lineTo(x + w, y + ih);
c.closePath();
c.fill();
c.restore();
c.fillStyle = rgba(mix(BG, INK, k), 0.75);
c.fillRect(x + 10, y + ih + 12, w * 0.62, 6);
c.fillStyle = rgba(mix(BG, INK, k), 0.4);
c.fillRect(x + 10, y + ih + 24, w * 0.44, 5);
c.fillStyle = rgba(mix(BG, INK, k), 0.9);
c.font = '700 13px sans-serif';
c.textAlign = 'right';
c.textBaseline = 'alphabetic';
c.fillText(String(i + 1).padStart(2, '0'), x + w - 9, y + h - 10);
}
const TILE_N = 16;
const TILE_W = 92;
const TILE_H = 116;
const TILE_GAP = 14;
const PITCH = TILE_W + TILE_GAP;
const PAD = 24;
const SRC_W = PAD * 2 + TILE_N * PITCH - TILE_GAP;
const CY = 136;
const LENS_K = 0.35;
const LENS_P = 2;
const BEND = 26;
const K_LERP = 0.12;
const S_LERP = 0.1;
const DEMO_LOOP = 4400;
const TXT_FLOW = 'Flowing under the lens';
const TXT_ON = 'Lens on';
const TXT_OFF = 'Lens off';
const lensBtn = root.querySelector('[data-role="btn"]');
// 화면 가로 위치 u(−1~1) → 원본 표본 위치 s. s = u·(1 + K·|u|^P) — 가장자리일수록 원본을 더 많이 눌러 담는다
function lensSample(u, k) { return u * (1 + k * Math.pow(Math.abs(u), LENS_P)); }
// 그 자리의 확대율 du/ds — 가운데 1, 가장자리 1/(1 + K·(P+1))
function lensScale(u, k) { return 1 / (1 + k * (LENS_P + 1) * Math.pow(Math.abs(u), LENS_P)); }
// 렌즈 세기 k 일 때 화면 반쪽(240px)이 담는 원본 폭의 반
function halfSpan(k) { return (W / 2) * (1 + k); }
function maxScroll(k) { return SRC_W - 2 * halfSpan(k); }
// 원본 — 평평한 아이콘 줄을 한 번만 그려 픽셀을 읽어 둔다(getImageData 는 시작 때 1회)
const srcCanvas = document.createElement('canvas');
srcCanvas.width = SRC_W;
srcCanvas.height = H;
const sctxRaw = srcCanvas.getContext('2d');
const bufCanvas = document.createElement('canvas');
bufCanvas.width = W;
bufCanvas.height = H;
const bctxRaw = bufCanvas.getContext('2d');
if (!sctxRaw || !bctxRaw) {
return;
}
const sctx = sctxRaw;
const bctx = bctxRaw;
sctx.fillStyle = rgba(BG, 1);
sctx.fillRect(0, 0, SRC_W, H);
// 바탕 격자 — 렌즈가 휘는 모양이 선으로 드러난다
sctx.fillStyle = rgba(mix(BG, LILAC, 0.16), 1);
for (let gx = 0; gx < SRC_W; gx += 24) {
sctx.fillRect(gx, 0, 1, H);
}
for (let gy = 16; gy < H; gy += 24) {
sctx.fillRect(0, gy, SRC_W, 1);
}
for (let i = 0; i < TILE_N; i += 1) {
drawCard(sctx, PAD + i * PITCH, CY - TILE_H / 2, TILE_W, TILE_H, i, 1);
}
const src = sctx.getImageData(0, 0, SRC_W, H).data;
const out = bctx.createImageData(W, H);
const dst = out.data;
const bgR = BG[0];
const bgG = BG[1];
const bgB = BG[2];
let kNow = LENS_K;
let kTarget = LENS_K;
let target = 0;
let scroll = 0;
let dirty = true;
let flowing = false;
// 한 장 다시 그리기 — 화면 픽셀마다 렌즈 곡선으로 원본 위치를 거꾸로 찾아 그 색을 가져온다
function remap() {
const center = scroll + halfSpan(kNow);
for (let x = 0; x < W; x += 1) {
const u = (x + 0.5 - W / 2) / (W / 2);
const sx = Math.round(center + lensSample(u, kNow) * (W / 2));
const sc = lensScale(u, kNow);
const sag = BEND * u * u * (kNow / LENS_K);
for (let y = 0; y < H; y += 1) {
const sy = Math.round(CY + (y - CY - sag) / sc);
const o = (y * W + x) * 4;
if (sx < 0 || sx >= SRC_W || sy < 0 || sy >= H) {
dst[o] = bgR;
dst[o + 1] = bgG;
dst[o + 2] = bgB;
dst[o + 3] = 255;
continue;
}
const i = (sy * SRC_W + sx) * 4;
dst[o] = src[i];
dst[o + 1] = src[i + 1];
dst[o + 2] = src[i + 2];
dst[o + 3] = 255;
}
}
bctx.putImageData(out, 0, 0);
dirty = false;
}
function step() {
const ps = scroll;
const pk = kNow;
kNow += (kTarget - kNow) * K_LERP;
if (Math.abs(kTarget - kNow) < 0.001) {
kNow = kTarget;
}
target = clamp(target, 0, maxScroll(kNow));
scroll += (target - scroll) * S_LERP;
if (Math.abs(target - scroll) < 0.05) {
scroll = target;
}
if (scroll !== ps || kNow !== pk) {
dirty = true;
}
const now = Math.abs(scroll - ps) > 0.05;
if (now && !flowing) {
say(TXT_FLOW);
}
flowing = now;
}
function settle() {
kNow = kTarget;
scroll = clamp(target, 0, maxScroll(kNow));
dirty = true;
}
function demoTick(t) {
if (crossed(t, 200, DEMO_LOOP)) {
target = 520;
}
if (crossed(t, 1350, DEMO_LOOP)) {
target = 120;
}
}
function draw() {
if (dirty) {
remap();
}
ctx.drawImage(bufCanvas, 0, 0, W, H);
// 가장자리 그늘 — 렌즈 바깥이 둥글게 꺼지는 느낌
const g = ctx.createLinearGradient(0, 0, W, 0);
g.addColorStop(0, rgba(BG, 0.55 * kNow / LENS_K));
g.addColorStop(0.12, rgba(BG, 0));
g.addColorStop(0.88, rgba(BG, 0));
g.addColorStop(1, rgba(BG, 0.55 * kNow / LENS_K));
ctx.fillStyle = g;
ctx.fillRect(0, 0, W, H);
}
function canMove(d) { return d > 0 ? target < maxScroll(kNow) - 0.5 : target > 0.5; }
function moveTo(p) {
target = clamp(p, 0, maxScroll(kNow));
if (still) {
settle();
draw();
}
}
function onWheel(ev) {
const d = wheelPx(ev);
if (d === 0 || !canMove(d)) {
return;
}
ev.preventDefault();
wake();
moveTo(target + d);
}
cv.addEventListener('wheel', onWheel, { passive: false });
let dragId = -1;
let dragX = 0;
cv.addEventListener('pointerdown', function (ev) {
wake();
dragId = ev.pointerId;
cv.setPointerCapture(ev.pointerId);
dragX = toScene(ev)[0];
});
cv.addEventListener('pointermove', function (ev) {
if (ev.pointerId !== dragId) {
return;
}
const sx = toScene(ev)[0];
moveTo(target - (sx - dragX));
dragX = sx;
});
function endDrag(ev) { if (ev.pointerId === dragId) {
dragId = -1;
} }
cv.addEventListener('pointerup', endDrag);
cv.addEventListener('pointercancel', endDrag);
cv.addEventListener('keydown', function (ev) {
let goal = NaN;
if (ev.key === 'ArrowRight') {
goal = target + PITCH;
}
else if (ev.key === 'ArrowLeft') {
goal = target - PITCH;
}
else if (ev.key === 'Home') {
goal = 0;
}
else if (ev.key === 'End') {
goal = maxScroll(kNow);
}
if (Number.isNaN(goal) || !canMove(goal - target)) {
return;
}
ev.preventDefault();
wake();
moveTo(goal);
});
if (lensBtn) {
lensBtn.addEventListener('click', function () {
wake();
const off = kTarget > 0;
kTarget = off ? 0 : LENS_K;
lensBtn.setAttribute('aria-pressed', off ? 'true' : 'false');
say(off ? TXT_OFF : TXT_ON);
if (still) {
settle();
draw();
}
});
}
say(TXT_ON);
let rafId = 0;
let lastTs = -1;
let acc = 0;
let clock = 0;
function frame(ts) {
if (lastTs < 0) {
lastTs = ts;
}
// 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
acc += Math.min(ts - lastTs, 100);
lastTs = ts;
let n = 0;
while (acc >= FIXED_DT && n < 6) {
clock += FIXED_DT;
if (demo) {
demoTick(clock);
}
step();
acc -= FIXED_DT;
n += 1;
}
draw();
rafId = window.requestAnimationFrame(frame);
}
if (still) {
settle();
draw();
}
else {
rafId = window.requestAnimationFrame(frame);
}
return function () {
window.cancelAnimationFrame(rafId);
window.removeEventListener('resize', onResize);
};
})();// HscEdgeFisheyePixelRemap - vanilla 판(08-hsc-edge-fisheye-pixel-remap) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./HscEdgeFisheyePixelRemap.module.scss";
const cx = (s: string): string => s.split(" ").map((n) => styles[n] ?? n).join(" ");
export default function HscEdgeFisheyePixelRemap() {
const rootRef = useRef<HTMLDivElement | null>(null);
useEffect(() => {
const rootEl = rootRef.current;
if (!rootEl) return;
const root: HTMLElement = rootEl;
type RGB = [number, number, number];
const W = 480;
const H = 300;
const FIXED_DT = 16;
// 파스텔 팔레트 — 어두운 무대 위에 밝은 카드를 얹어 명도 차로 읽힌다
const BG: RGB = [29, 26, 44];
const PAPER: RGB = [255, 248, 234];
const INK: RGB = [58, 48, 76];
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 TINTS: RGB[] = [SKY, PINK, MINT, LILAC, PEACH];
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 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)]; }
const canvasEl = root.querySelector('[data-role="canvas"]') as HTMLCanvasElement | null;
const statusEl = root.querySelector('[data-role="status"]') as HTMLElement | null;
const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
if (!canvasEl || !ctxRaw || !statusEl) { return; }
const cv: HTMLCanvasElement = canvasEl;
const ctx: CanvasRenderingContext2D = ctxRaw;
const status: HTMLElement = statusEl;
const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
const still = reduceQuery.matches;
// 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
let demo = root.classList.contains('is-demo');
function wake(): void {
if (!demo) { return; }
demo = false;
root.classList.remove('is-demo');
status.setAttribute('aria-live', 'polite');
}
function say(text: string): void {
if (status.textContent !== text) { status.textContent = text; }
}
// 휠 한 번의 이동량을 px 로 — 줄 단위(deltaMode 1)·쪽 단위(deltaMode 2) 장치도 같은 눈금으로 맞춘다.
// 가로·세로 중 큰 쪽을 쓴다: 트랙패드의 가로 쓸기와 마우스 휠의 세로 굴림이 같은 방향으로 들어온다
function wheelPx(ev: WheelEvent): number {
const unit = ev.deltaMode === 1 ? 16 : (ev.deltaMode === 2 ? W : 1);
const d = Math.abs(ev.deltaX) > Math.abs(ev.deltaY) ? ev.deltaX : ev.deltaY;
return d * unit;
}
// 시연 시계가 loop 주기 안의 at 시각을 이번 스텝에 막 지났는가
function crossed(t: number, at: number, loop: number): boolean {
const p = t % loop;
return p >= at && p - FIXED_DT < at;
}
function fitCanvas(): void {
const dpr = window.devicePixelRatio || 1;
cv.width = Math.round(W * dpr);
cv.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
}
function onResize(): void {
fitCanvas();
draw();
}
fitCanvas();
window.addEventListener('resize', onResize);
// 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
function toScene(ev: PointerEvent): [number, number] {
const r = cv.getBoundingClientRect();
return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
}
function roundRectPath(c: CanvasRenderingContext2D, x: number, y: number, w: number, h: number, r: number): void {
const rr = Math.min(r, w / 2, h / 2);
c.beginPath();
c.moveTo(x + rr, y);
c.lineTo(x + w - rr, y);
c.quadraticCurveTo(x + w, y, x + w, y + rr);
c.lineTo(x + w, y + h - rr);
c.quadraticCurveTo(x + w, y + h, x + w - rr, y + h);
c.lineTo(x + rr, y + h);
c.quadraticCurveTo(x, y + h, x, y + h - rr);
c.lineTo(x, y + rr);
c.quadraticCurveTo(x, y, x + rr, y);
c.closePath();
}
// 카드 한 장 — 사진 대신 계산한 그림 칸(그라디언트 하늘·해·언덕) + 글줄 막대 두 개 + 번호
function drawCard(c: CanvasRenderingContext2D, x: number, y: number, w: number, h: number, i: number, light: number): void {
const t1 = TINTS[i % TINTS.length];
const t2 = TINTS[(i + 2) % TINTS.length];
const k = clamp(light, 0, 1);
roundRectPath(c, x, y, w, h, 10);
c.fillStyle = rgba(mix(BG, PAPER, k), 1);
c.fill();
const ih = h * 0.58;
const g = c.createLinearGradient(x, y, x + w, y + ih);
g.addColorStop(0, rgba(mix(BG, t1, k), 1));
g.addColorStop(1, rgba(mix(BG, t2, k * 0.92), 1));
c.save();
roundRectPath(c, x + 6, y + 6, w - 12, ih - 6, 7);
c.fillStyle = g;
c.fill();
c.clip();
c.fillStyle = rgba(mix(BG, PAPER, k * 0.9), 0.9);
c.beginPath();
c.arc(x + w * 0.7, y + ih * 0.36, Math.min(w, ih) * 0.13, 0, Math.PI * 2);
c.fill();
c.fillStyle = rgba(mix(BG, INK, k), 0.55);
c.beginPath();
c.moveTo(x, y + ih);
c.lineTo(x + w * 0.32, y + ih * 0.55);
c.lineTo(x + w * 0.55, y + ih * 0.8);
c.lineTo(x + w * 0.78, y + ih * 0.62);
c.lineTo(x + w, y + ih);
c.closePath();
c.fill();
c.restore();
c.fillStyle = rgba(mix(BG, INK, k), 0.75);
c.fillRect(x + 10, y + ih + 12, w * 0.62, 6);
c.fillStyle = rgba(mix(BG, INK, k), 0.4);
c.fillRect(x + 10, y + ih + 24, w * 0.44, 5);
c.fillStyle = rgba(mix(BG, INK, k), 0.9);
c.font = '700 13px sans-serif';
c.textAlign = 'right';
c.textBaseline = 'alphabetic';
c.fillText(String(i + 1).padStart(2, '0'), x + w - 9, y + h - 10);
}
const TILE_N = 16;
const TILE_W = 92;
const TILE_H = 116;
const TILE_GAP = 14;
const PITCH = TILE_W + TILE_GAP;
const PAD = 24;
const SRC_W = PAD * 2 + TILE_N * PITCH - TILE_GAP;
const CY = 136;
const LENS_K = 0.35;
const LENS_P = 2;
const BEND = 26;
const K_LERP = 0.12;
const S_LERP = 0.1;
const DEMO_LOOP = 4400;
const TXT_FLOW = '렌즈 아래로 흐르는 중';
const TXT_ON = '렌즈 켬';
const TXT_OFF = '렌즈 끔';
const lensBtn = root.querySelector('[data-role="btn"]') as HTMLButtonElement | null;
// 화면 가로 위치 u(−1~1) → 원본 표본 위치 s. s = u·(1 + K·|u|^P) — 가장자리일수록 원본을 더 많이 눌러 담는다
function lensSample(u: number, k: number): number { return u * (1 + k * Math.pow(Math.abs(u), LENS_P)); }
// 그 자리의 확대율 du/ds — 가운데 1, 가장자리 1/(1 + K·(P+1))
function lensScale(u: number, k: number): number { return 1 / (1 + k * (LENS_P + 1) * Math.pow(Math.abs(u), LENS_P)); }
// 렌즈 세기 k 일 때 화면 반쪽(240px)이 담는 원본 폭의 반
function halfSpan(k: number): number { return (W / 2) * (1 + k); }
function maxScroll(k: number): number { return SRC_W - 2 * halfSpan(k); }
// 원본 — 평평한 아이콘 줄을 한 번만 그려 픽셀을 읽어 둔다(getImageData 는 시작 때 1회)
const srcCanvas = document.createElement('canvas');
srcCanvas.width = SRC_W;
srcCanvas.height = H;
const sctxRaw = srcCanvas.getContext('2d');
const bufCanvas = document.createElement('canvas');
bufCanvas.width = W;
bufCanvas.height = H;
const bctxRaw = bufCanvas.getContext('2d');
if (!sctxRaw || !bctxRaw) { return; }
const sctx: CanvasRenderingContext2D = sctxRaw;
const bctx: CanvasRenderingContext2D = bctxRaw;
sctx.fillStyle = rgba(BG, 1);
sctx.fillRect(0, 0, SRC_W, H);
// 바탕 격자 — 렌즈가 휘는 모양이 선으로 드러난다
sctx.fillStyle = rgba(mix(BG, LILAC, 0.16), 1);
for (let gx = 0; gx < SRC_W; gx += 24) { sctx.fillRect(gx, 0, 1, H); }
for (let gy = 16; gy < H; gy += 24) { sctx.fillRect(0, gy, SRC_W, 1); }
for (let i = 0; i < TILE_N; i += 1) {
drawCard(sctx, PAD + i * PITCH, CY - TILE_H / 2, TILE_W, TILE_H, i, 1);
}
const src = sctx.getImageData(0, 0, SRC_W, H).data;
const out = bctx.createImageData(W, H);
const dst = out.data;
const bgR = BG[0];
const bgG = BG[1];
const bgB = BG[2];
let kNow = LENS_K;
let kTarget = LENS_K;
let target = 0;
let scroll = 0;
let dirty = true;
let flowing = false;
// 한 장 다시 그리기 — 화면 픽셀마다 렌즈 곡선으로 원본 위치를 거꾸로 찾아 그 색을 가져온다
function remap(): void {
const center = scroll + halfSpan(kNow);
for (let x = 0; x < W; x += 1) {
const u = (x + 0.5 - W / 2) / (W / 2);
const sx = Math.round(center + lensSample(u, kNow) * (W / 2));
const sc = lensScale(u, kNow);
const sag = BEND * u * u * (kNow / LENS_K);
for (let y = 0; y < H; y += 1) {
const sy = Math.round(CY + (y - CY - sag) / sc);
const o = (y * W + x) * 4;
if (sx < 0 || sx >= SRC_W || sy < 0 || sy >= H) {
dst[o] = bgR; dst[o + 1] = bgG; dst[o + 2] = bgB; dst[o + 3] = 255;
continue;
}
const i = (sy * SRC_W + sx) * 4;
dst[o] = src[i]; dst[o + 1] = src[i + 1]; dst[o + 2] = src[i + 2]; dst[o + 3] = 255;
}
}
bctx.putImageData(out, 0, 0);
dirty = false;
}
function step(): void {
const ps = scroll;
const pk = kNow;
kNow += (kTarget - kNow) * K_LERP;
if (Math.abs(kTarget - kNow) < 0.001) { kNow = kTarget; }
target = clamp(target, 0, maxScroll(kNow));
scroll += (target - scroll) * S_LERP;
if (Math.abs(target - scroll) < 0.05) { scroll = target; }
if (scroll !== ps || kNow !== pk) { dirty = true; }
const now = Math.abs(scroll - ps) > 0.05;
if (now && !flowing) { say(TXT_FLOW); }
flowing = now;
}
function settle(): void {
kNow = kTarget;
scroll = clamp(target, 0, maxScroll(kNow));
dirty = true;
}
function demoTick(t: number): void {
if (crossed(t, 200, DEMO_LOOP)) { target = 520; }
if (crossed(t, 1350, DEMO_LOOP)) { target = 120; }
}
function draw(): void {
if (dirty) { remap(); }
ctx.drawImage(bufCanvas, 0, 0, W, H);
// 가장자리 그늘 — 렌즈 바깥이 둥글게 꺼지는 느낌
const g = ctx.createLinearGradient(0, 0, W, 0);
g.addColorStop(0, rgba(BG, 0.55 * kNow / LENS_K));
g.addColorStop(0.12, rgba(BG, 0));
g.addColorStop(0.88, rgba(BG, 0));
g.addColorStop(1, rgba(BG, 0.55 * kNow / LENS_K));
ctx.fillStyle = g;
ctx.fillRect(0, 0, W, H);
}
function canMove(d: number): boolean { return d > 0 ? target < maxScroll(kNow) - 0.5 : target > 0.5; }
function moveTo(p: number): void {
target = clamp(p, 0, maxScroll(kNow));
if (still) { settle(); draw(); }
}
function onWheel(ev: WheelEvent): void {
const d = wheelPx(ev);
if (d === 0 || !canMove(d)) { return; }
ev.preventDefault();
wake();
moveTo(target + d);
}
cv.addEventListener('wheel', onWheel, { passive: false });
let dragId = -1;
let dragX = 0;
cv.addEventListener('pointerdown', function (ev: PointerEvent): void {
wake();
dragId = ev.pointerId;
cv.setPointerCapture(ev.pointerId);
dragX = toScene(ev)[0];
});
cv.addEventListener('pointermove', function (ev: PointerEvent): void {
if (ev.pointerId !== dragId) { return; }
const sx = toScene(ev)[0];
moveTo(target - (sx - dragX));
dragX = sx;
});
function endDrag(ev: PointerEvent): void { if (ev.pointerId === dragId) { dragId = -1; } }
cv.addEventListener('pointerup', endDrag);
cv.addEventListener('pointercancel', endDrag);
cv.addEventListener('keydown', function (ev: KeyboardEvent): void {
let goal = NaN;
if (ev.key === 'ArrowRight') { goal = target + PITCH; }
else if (ev.key === 'ArrowLeft') { goal = target - PITCH; }
else if (ev.key === 'Home') { goal = 0; }
else if (ev.key === 'End') { goal = maxScroll(kNow); }
if (Number.isNaN(goal) || !canMove(goal - target)) { return; }
ev.preventDefault();
wake();
moveTo(goal);
});
if (lensBtn) {
lensBtn.addEventListener('click', function (): void {
wake();
const off = kTarget > 0;
kTarget = off ? 0 : LENS_K;
lensBtn.setAttribute('aria-pressed', off ? 'true' : 'false');
say(off ? TXT_OFF : TXT_ON);
if (still) { settle(); draw(); }
});
}
say(TXT_ON);
let rafId = 0;
let lastTs = -1;
let acc = 0;
let clock = 0;
function frame(ts: number): void {
if (lastTs < 0) { lastTs = ts; }
// 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
acc += Math.min(ts - lastTs, 100);
lastTs = ts;
let n = 0;
while (acc >= FIXED_DT && n < 6) {
clock += FIXED_DT;
if (demo) { demoTick(clock); }
step();
acc -= FIXED_DT;
n += 1;
}
draw();
rafId = window.requestAnimationFrame(frame);
}
if (still) {
settle();
draw();
} else {
rafId = window.requestAnimationFrame(frame);
}
return function (): void {
window.cancelAnimationFrame(rafId);
window.removeEventListener('resize', onResize);
};
}, []);
return (
<div className={cx("hs") + " is-demo"} ref={rootRef}>
<canvas className={cx("hs__canvas")} data-role="canvas" width={480} height={300} tabIndex={0} aria-label="아이콘 줄이 화면 가장자리로 갈수록 어안 렌즈처럼 작아지고 휘어 보이는 장면"></canvas>
<p className={cx("hs__status")} data-role="status" aria-live="off">렌즈 켬</p>
<div className={cx("hs__tools")}>
<button className={cx("hs__btn")} data-role="btn" type="button" aria-pressed="false">렌즈 끄기</button>
</div>
</div>
);
}08 An Edge Lens Where Cards Near Both Ends of the Track Bend and Shrink Like a Fisheye and Flatten Out in the Middle — Measured area 42.474% · moving frames 22/23Original by GODRICH · SCSS and React ship in the zip · Horizontal Scroll Animation CSS: 9 Inertia Scenes
The post this demo lives in
Horizontal Scroll Animation CSS: 9 Inertia ScenesHorizontal scroll animation css is more than turning wheel input sideways — scene 01 glides it on inertia, 06 projects c See all demos in this post
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