A switch you fasten. A waxed canvas tab is sewn to a length of navy webbing and held down by a nickel press stud, with a small woven label that reads ON. Press it and the cloth bulges for a moment against the stud, lets go, and springs up into a curl that rocks before it settles. Now you can see the yellow lining, the socket on the underside, the stud standing on the webbing and the word OFF printed where the tab used to lie. Press again and it comes down, lands and gives a small bounce. The tab is one strip that keeps its length while it bends, drawn from an angled camera with its own shadow. On phones the whole drawing scales down with its box and the tap area stays large.
import { useEffect, useRef, useState } from "react";
// The setting this switch controls, and the two words woven and printed on the strap.
const SETTING = "Notifications";
const WORD_ON = "ON"; // on the label sewn to the tab, seen when it is fastened
const WORD_OFF = "OFF"; // printed on the webbing underneath, seen when the tab is up
const TAB: [number, number, number] = [214, 98, 36]; // waxed canvas of the tab
const LINING: [number, number, number] = [232, 190, 74]; // its inside face
const WEB: [number, number, number] = [30, 40, 62]; // the webbing it is sewn to
const THREAD = "#f1e6cf";
// World units. The strap lies along x, y runs across it, z is up off the table.
const BASE_L = 380, BASE_W = 104, TAB_L = 280, TAB_W = 66, SEWN = 70, FREE = TAB_L - SEWN, STUD_S = 256, TH = 3.4;
const VW = 450, VH = 336; // the drawing is made for this box and scaled to fit
const YAW = -0.42, EL = 0.9; // camera: turned a little to the right, looking down at about 52 degrees
const TS = 4; // texture pixels per world unit
const LIGHT = (() => { const v = [0.4, -0.3, 0.86], n = Math.hypot(v[0], v[1], v[2]); return [v[0] / n, v[1] / n, v[2] / n]; })();
const CAM = [-Math.cos(EL) * Math.sin(YAW), -Math.cos(EL) * Math.cos(YAW), Math.sin(EL)];
const clamp = (v: number, lo: number, hi: number) => Math.min(hi, Math.max(lo, v));
export default function PressStudSnapToggle() {
const canvas = useRef<HTMLCanvasElement>(null);
const box = useRef<HTMLDivElement>(null);
const api = useRef<{ set: (on: boolean) => void } | null>(null);
const [on, setOn] = useState(true);
const onRef = useRef(true);
useEffect(() => {
const cv = canvas.current, wrap = box.current;
if (!cv || !wrap) return;
const ctx = cv.getContext("2d");
if (!ctx) return;
const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
const dpr = Math.min(2, window.devicePixelRatio || 1);
let k = 1;
// ---- Cloth and hardware are painted once into flat textures, then bent in the frame loop. ----
let seed = 5;
const rand = () => { seed = (seed * 16807) % 2147483647; return seed / 2147483647; };
const sheet = (wu: number, hu: number) => { const c = document.createElement("canvas"); c.width = Math.round(wu * TS); c.height = Math.round(hu * TS); return c; };
const woven = (c: HTMLCanvasElement, col: [number, number, number], p: number, ribbed: boolean) => {
const x = c.getContext("2d");
if (!x) return;
const im = x.createImageData(c.width, c.height);
for (let j = 0; j < c.height; j++) for (let i = 0; i < c.width; i++) {
const fx = (i % p) / p, fy = (j % p) / p, over = (Math.floor(i / p) + Math.floor(j / p)) & 1;
const bump = ribbed
? Math.pow(Math.sin(Math.PI * (((j + (Math.floor(i / (p * 2)) & 1) * p * 0.5) % p) / p)), 0.6) * (0.8 + 0.2 * Math.sin(Math.PI * (((i % (p * 2)) / (p * 2)))))
: Math.pow(Math.sin(Math.PI * (over ? fx : fy)), 0.55) * (0.72 + 0.28 * Math.sin(Math.PI * (over ? fy : fx)));
const cloud = Math.sin(i / 47 + 1) * Math.sin(j / 31 + 2) * 0.04;
const v = (ribbed ? 0.62 : 0.72) + (ribbed ? 0.5 : 0.32) * bump + (rand() - 0.5) * 0.09 + cloud, o = (j * c.width + i) * 4;
im.data[o] = clamp(col[0] * v, 0, 255); im.data[o + 1] = clamp(col[1] * v, 0, 255); im.data[o + 2] = clamp(col[2] * v, 0, 255); im.data[o + 3] = 255;
}
x.putImageData(im, 0, 0);
};
const pen = (c: HTMLCanvasElement) => { const x = c.getContext("2d"); if (x) x.setTransform(TS, 0, 0, TS, 0, 0); return x; };
// Trim a finished texture to its outline, so nothing painted on it spills past the rounded ends.
const cut = (x: CanvasRenderingContext2D, shape: (x: CanvasRenderingContext2D) => void) => {
x.shadowColor = "transparent"; x.globalCompositeOperation = "destination-in"; x.fillStyle = "#000"; shape(x); x.fill(); x.globalCompositeOperation = "source-over";
};
const stitch = (x: CanvasRenderingContext2D, path: () => void) => {
x.setLineDash([4.4, 2.6]); x.lineCap = "butt"; x.lineWidth = 1.5;
x.save(); x.translate(0.5, 0.7); x.strokeStyle = "rgba(0,0,0,0.45)"; path(); x.stroke(); x.restore();
x.strokeStyle = THREAD; path(); x.stroke();
x.lineWidth = 0.5; x.strokeStyle = "rgba(255,255,255,0.55)"; x.save(); x.translate(-0.2, -0.4); path(); x.stroke(); x.restore();
x.setLineDash([]);
};
const nickel = (x: CanvasRenderingContext2D, cx: number, cy: number, r: number, hx: number, hy: number) => {
const g = x.createRadialGradient(cx + hx, cy + hy, r * 0.05, cx, cy, r);
g.addColorStop(0, "#ffffff"); g.addColorStop(0.22, "#e9edf0"); g.addColorStop(0.55, "#a9b1b8"); g.addColorStop(0.8, "#6c747c"); g.addColorStop(0.93, "#c3cad0"); g.addColorStop(1, "#4d545b");
return g;
};
const tabShape = (x: CanvasRenderingContext2D) => { x.beginPath(); x.roundRect(0, 0, TAB_L, TAB_W, [5, 30, 30, 5]); };
const baseShape = (x: CanvasRenderingContext2D) => { x.beginPath(); x.roundRect(0, 0, BASE_L, BASE_W, 15); };
const front = sheet(TAB_L, TAB_W), back = sheet(TAB_L, TAB_W), base = sheet(BASE_L, BASE_W);
const baseDark = sheet(BASE_L, BASE_W);
woven(front, TAB, 8, false); woven(back, LINING, 6, false); woven(base, WEB, 12, true);
const dx = baseDark.getContext("2d");
if (dx) { dx.setTransform(TS, 0, 0, TS, 0, 0); dx.fillStyle = "#0b101b"; baseShape(dx); dx.fill(); }
const fx = pen(front);
if (fx) {
const mid = TAB_W / 2;
// Wax wears pale along the edges and where the cloth is handled.
const wear = fx.createLinearGradient(0, 0, 0, TAB_W);
wear.addColorStop(0, "rgba(255,226,190,0.28)"); wear.addColorStop(0.12, "rgba(255,226,190,0)"); wear.addColorStop(0.88, "rgba(60,20,0,0)"); wear.addColorStop(1, "rgba(60,20,0,0.3)");
fx.fillStyle = wear; fx.fillRect(0, 0, TAB_L, TAB_W);
stitch(fx, () => { fx.beginPath(); fx.roundRect(6, 6, TAB_L - 12, TAB_W - 12, [3, 24, 24, 3]); });
stitch(fx, () => { fx.beginPath(); fx.rect(12, 12, SEWN - 22, TAB_W - 24); fx.moveTo(12, 12); fx.lineTo(SEWN - 10, TAB_W - 12); fx.moveTo(SEWN - 10, 12); fx.lineTo(12, TAB_W - 12); });
// The woven label.
fx.save(); fx.translate(128, mid - 13); fx.shadowColor = "rgba(40,12,0,0.6)"; fx.shadowBlur = 3 * TS; fx.shadowOffsetY = 1 * TS;
fx.fillStyle = "#efe6d0"; fx.fillRect(0, 0, 56, 26); fx.shadowColor = "transparent";
fx.strokeStyle = "rgba(90,70,40,0.16)"; fx.lineWidth = 0.4; for (let y = 1; y < 26; y += 1.3) { fx.beginPath(); fx.moveTo(0, y); fx.lineTo(56, y); fx.stroke(); }
fx.fillStyle = `rgb(${WEB[0]},${WEB[1]},${WEB[2]})`; fx.font = "800 15px ui-sans-serif, system-ui, -apple-system, Helvetica, Arial, sans-serif"; fx.textAlign = "center"; fx.textBaseline = "middle";
fx.fillText(WORD_ON.split("").join("\u200a"), 28, 13.8);
fx.setLineDash([2, 1.6]); fx.lineWidth = 1; fx.strokeStyle = "#b5482b"; for (const px of [3, 53]) { fx.beginPath(); fx.moveTo(px, 1.5); fx.lineTo(px, 24.5); fx.stroke(); }
fx.setLineDash([]); fx.restore();
// The cap of the press stud: a domed nickel button seen from the camera's side.
fx.save(); fx.shadowColor = "rgba(40,12,0,0.75)"; fx.shadowBlur = 5 * TS; fx.shadowOffsetX = -2.2 * TS; fx.shadowOffsetY = 3 * TS;
fx.fillStyle = "#3d444b"; fx.beginPath(); fx.arc(STUD_S, mid + 1.4, 13.2, 0, Math.PI * 2); fx.fill(); fx.restore();
fx.fillStyle = nickel(fx, STUD_S, mid, 13, 4.5, -4.5); fx.beginPath(); fx.arc(STUD_S, mid, 13, 0, Math.PI * 2); fx.fill();
fx.lineWidth = 0.8; fx.strokeStyle = "rgba(255,255,255,0.75)"; fx.beginPath(); fx.arc(STUD_S, mid, 10.4, -1.9, 0.3); fx.stroke();
fx.strokeStyle = "rgba(30,36,42,0.5)"; fx.beginPath(); fx.arc(STUD_S, mid, 10.4, 1.1, 3.4); fx.stroke();
fx.fillStyle = "rgba(255,255,255,0.9)"; fx.beginPath(); fx.ellipse(STUD_S + 4.6, mid - 4.8, 3.4, 2, -0.7, 0, Math.PI * 2); fx.fill();
cut(fx, tabShape);
}
const bx = pen(back);
if (bx) {
const mid = TAB_W / 2;
bx.strokeStyle = "rgba(120,80,10,0.35)"; bx.lineWidth = 1.2; for (let y = 9; y < TAB_W; y += 12) { bx.beginPath(); bx.moveTo(0, y); bx.lineTo(TAB_L, y); bx.stroke(); }
stitch(bx, () => { bx.beginPath(); bx.roundRect(6, 6, TAB_L - 12, TAB_W - 12, [3, 24, 24, 3]); });
// The socket: a pressed ring with a sprung hole that grips the stud.
bx.save(); bx.shadowColor = "rgba(70,40,0,0.6)"; bx.shadowBlur = 4 * TS; bx.shadowOffsetY = 1.6 * TS;
bx.fillStyle = nickel(bx, STUD_S, mid, 13, -4, -5); bx.beginPath(); bx.arc(STUD_S, mid, 13, 0, Math.PI * 2); bx.fill(); bx.restore();
bx.fillStyle = "#59616a"; bx.beginPath(); bx.arc(STUD_S, mid, 8.6, 0, Math.PI * 2); bx.fill();
bx.fillStyle = nickel(bx, STUD_S, mid, 8, 3, 3.5); bx.beginPath(); bx.arc(STUD_S, mid, 7.6, 0, Math.PI * 2); bx.fill();
const hole = bx.createRadialGradient(STUD_S - 1, mid - 1.4, 0.5, STUD_S, mid, 5.4);
hole.addColorStop(0, "#05070a"); hole.addColorStop(0.75, "#1b2026"); hole.addColorStop(1, "#6d757d");
bx.fillStyle = hole; bx.beginPath(); bx.arc(STUD_S, mid, 5.2, 0, Math.PI * 2); bx.fill();
bx.lineWidth = 0.7; bx.strokeStyle = "rgba(255,255,255,0.8)"; bx.beginPath(); bx.arc(STUD_S, mid, 12, 3.6, 5.6); bx.stroke();
cut(bx, tabShape);
}
const gx = pen(base);
if (gx) {
const edge = gx.createLinearGradient(0, 0, 0, BASE_W);
edge.addColorStop(0, "rgba(200,220,255,0.2)"); edge.addColorStop(0.1, "rgba(200,220,255,0)"); edge.addColorStop(0.9, "rgba(0,0,0,0)"); edge.addColorStop(1, "rgba(0,0,0,0.4)");
gx.fillStyle = edge; gx.fillRect(0, 0, BASE_L, BASE_W);
stitch(gx, () => { gx.beginPath(); gx.roundRect(7, 7, BASE_L - 14, BASE_W - 14, 9); });
// The word under the tab, screen printed and a little worn.
gx.font = "800 34px ui-sans-serif, system-ui, -apple-system, Helvetica, Arial, sans-serif"; gx.textAlign = "center"; gx.textBaseline = "middle";
gx.fillStyle = "rgba(241,230,207,0.9)"; gx.fillText(WORD_OFF.split("").join("\u2009"), 202, BASE_W / 2 + 1.5);
cut(gx, baseShape);
}
// Two working copies of the tab get relit every frame, so the shading runs smoothly along the bend with no seams.
const litFront = sheet(TAB_L, TAB_W), litBack = sheet(TAB_L, TAB_W);
const relight = (dst: HTMLCanvasElement, src: HTMLCanvasElement, tones: [number, number][]) => {
const x = dst.getContext("2d");
if (!x) return;
x.globalCompositeOperation = "copy"; x.drawImage(src, 0, 0); x.globalCompositeOperation = "source-atop";
const dark = x.createLinearGradient(0, 0, dst.width, 0), bright = x.createLinearGradient(0, 0, dst.width, 0);
for (const [u, lam] of tones) {
const tone = 0.46 + 0.66 * lam, at = clamp(u / TAB_L, 0, 1);
dark.addColorStop(at, `rgba(8,6,10,${clamp((1 - tone) * 0.9, 0, 1).toFixed(3)})`);
bright.addColorStop(at, `rgba(255,250,240,${clamp((tone - 1) * 0.55 + Math.pow(lam, 14) * 0.2, 0, 1).toFixed(3)})`);
}
x.fillStyle = dark; x.fillRect(0, 0, dst.width, dst.height); x.fillStyle = bright; x.fillRect(0, 0, dst.width, dst.height);
};
// ---- Camera ----
const P = (x: number, y: number, z: number): [number, number] => {
const xr = x * Math.cos(YAW) - y * Math.sin(YAW), yr = x * Math.sin(YAW) + y * Math.cos(YAW);
return [(VW / 2 + 8 + xr) * k, (VH / 2 + 22 - yr * Math.sin(EL) - z * Math.cos(EL)) * k];
};
// Lay a slice of a flat texture onto the parallelogram a, b, c (far start, far end, near start).
const lay = (tex: HTMLCanvasElement, u0: number, u1: number, a: number[], b: number[], c: number[], alpha = 1) => {
const du = (u1 - u0) * TS, hh = tex.height;
ctx.setTransform((b[0] - a[0]) / du, (b[1] - a[1]) / du, (c[0] - a[0]) / hh, (c[1] - a[1]) / hh, a[0], a[1]);
ctx.globalAlpha = alpha; ctx.drawImage(tex, u0 * TS, 0, Math.min(du + 2, tex.width - u0 * TS), hh, 0, 0, Math.min(du + 2, tex.width - u0 * TS), hh); ctx.globalAlpha = 1;
};
const s = { a: 0, av: 0, target: 0, held: 0, m: 0, mv: 0, b: 0, bv: 0, press: 0 };
const NS = 44;
const draw = () => {
ctx.setTransform(1, 0, 0, 1, 0, 0); ctx.clearRect(0, 0, cv.width, cv.height);
const hw = BASE_W / 2, tw = TAB_W / 2, x0 = -BASE_L / 2, tabX = -152;
// Webbing: its shadow on the table, six stacked silhouettes for its thickness, then the face.
const baseAt = (z: number, tex: HTMLCanvasElement, alpha = 1) => lay(tex, 0, BASE_L, P(x0, hw, z), P(x0 + BASE_L, hw, z), P(x0, -hw, z), alpha);
const ground = (blur: number, alpha: number, ox: number, oy: number) => {
ctx.setTransform(1, 0, 0, 1, 0, 0); ctx.save(); ctx.shadowColor = `rgba(20,28,44,${alpha})`; ctx.shadowBlur = blur * k; ctx.shadowOffsetX = 9000 + ox * k; ctx.shadowOffsetY = oy * k; ctx.translate(-9000, 0);
ctx.beginPath();
for (const [cx, cy, a0] of [[x0 + BASE_L - 15, hw - 15, 0], [x0 + 15, hw - 15, 1], [x0 + 15, -hw + 15, 2], [x0 + BASE_L - 15, -hw + 15, 3]])
for (let j = 0; j <= 6; j++) { const an = (a0 + j / 6) * Math.PI * 0.5, q = P(cx + Math.cos(an) * 15, cy + Math.sin(an) * 15, -7); ctx.lineTo(q[0], q[1]); }
ctx.closePath(); ctx.fillStyle = "#000"; ctx.fill(); ctx.restore();
};
ground(30, 0.36, -14, 20); ground(6, 0.55, -3, 4);
for (let z = -6; z < 0; z += 1) baseAt(z, baseDark);
baseAt(0, base);
// The bent tab: walk along it adding up the bend, so it keeps its length whatever shape it takes.
const pts: { x: number; z: number; f: number }[] = [{ x: tabX, z: TH, f: 0 }, { x: tabX + SEWN, z: TH, f: 0 }];
let px = tabX + SEWN, pz = TH;
for (let i = 1; i <= NS; i++) {
const t = i / NS, sl = t * FREE, ds = FREE / NS;
const f = Math.max(0, s.a) * (1 - Math.exp(-sl / 50)) + s.b * t * t + s.m * 0.045 * Math.sin(Math.PI * Math.min(1, sl / (STUD_S - SEWN))) * (sl < STUD_S - SEWN ? Math.cos(Math.PI * Math.min(1, sl / (STUD_S - SEWN))) : 0);
px += Math.cos(f) * ds; pz += Math.sin(f) * ds;
pts.push({ x: px, z: Math.max(TH - s.press, pz), f });
}
const sAt = (i: number) => (i === 0 ? 0 : SEWN + ((i - 1) / NS) * FREE);
// Half the width of the tab at a point along it: full until the last stretch, then the rounded tip.
const halfAt = (i: number) => { const d = sAt(i) - (TAB_L - 30); return d <= 0 ? tw : tw - 30 + Math.sqrt(Math.max(0, 900 - d * d)); };
// Its shadow, thrown along the light onto the webbing and the table.
ctx.setTransform(1, 0, 0, 1, 0, 0);
const cast = (blur: number, alpha: number, below: number) => {
const low = pts.filter((p) => p.z < below);
if (low.length < 2) return;
ctx.save(); ctx.shadowColor = `rgba(10,14,26,${alpha})`; ctx.shadowBlur = blur * k; ctx.shadowOffsetX = 9000; ctx.translate(-9000, 0);
ctx.beginPath();
const down = (p: { x: number; z: number }, y: number) => { const q = (Math.max(0, p.z) + (below < 10 ? 5 : 0)) / LIGHT[2]; return P(p.x - LIGHT[0] * q, y - LIGHT[1] * q, 0); };
low.forEach((p, i) => { const q = down(p, halfAt(pts.indexOf(p))); if (i) ctx.lineTo(q[0], q[1]); else ctx.moveTo(q[0], q[1]); });
for (let i = low.length - 1; i >= 0; i--) { const q = down(low[i], -halfAt(pts.indexOf(low[i]))); ctx.lineTo(q[0], q[1]); }
ctx.closePath(); ctx.fillStyle = "#000"; ctx.fill(); ctx.restore();
};
cast(16, 0.2, 1e9); cast(7, 0.22, 60); cast(6, 0.5, 9); cast(2, 0.5, 9);
// The stud riveted through the webbing.
const studX = tabX + STUD_S, [sx, sy] = P(studX, 0, 0), ry = Math.sin(EL), up = Math.cos(EL) * k;
ctx.setTransform(k, 0, 0, k, sx, sy);
ctx.save(); ctx.shadowColor = "rgba(0,0,0,0.6)"; ctx.shadowBlur = 5 * k; ctx.shadowOffsetX = -3 * k; ctx.shadowOffsetY = 3 * k;
ctx.fillStyle = nickel(ctx, 0, 0, 12.5, 4, -3); ctx.beginPath(); ctx.ellipse(0, -1.2 * up / k, 12.5, 12.5 * ry, 0, 0, Math.PI * 2); ctx.fill(); ctx.restore();
ctx.lineWidth = 0.7; ctx.strokeStyle = "rgba(40,46,54,0.55)"; ctx.beginPath(); ctx.ellipse(0, -1.2 * up / k, 9, 9 * ry, 0, 0, Math.PI * 2); ctx.stroke();
const ph = 6.2 * Math.cos(EL), post = ctx.createLinearGradient(-6, 0, 6, 0);
post.addColorStop(0, "#50575e"); post.addColorStop(0.3, "#9aa2a9"); post.addColorStop(0.62, "#f6f8f9"); post.addColorStop(0.82, "#b4bbc1"); post.addColorStop(1, "#5d646b");
ctx.fillStyle = post; ctx.beginPath(); ctx.ellipse(0, -1.4, 6, 6 * ry, 0, 0, Math.PI); ctx.lineTo(-6.6, -1.4 - ph); ctx.ellipse(0, -1.4 - ph, 6.6, 6.6 * ry, 0, Math.PI, 0, true); ctx.closePath(); ctx.fill();
ctx.fillStyle = nickel(ctx, 0, -1.4 - ph, 6.6, 2, -1.5); ctx.beginPath(); ctx.ellipse(0, -1.4 - ph, 6.6, 6.6 * ry, 0, 0, Math.PI * 2); ctx.fill();
ctx.fillStyle = "rgba(40,46,54,0.5)"; ctx.beginPath(); ctx.ellipse(0, -1.2 - ph, 2.2, 2.2 * ry, 0, 0, Math.PI * 2); ctx.fill();
// Tab segments, farthest from the camera first. Each shows its outside or its lining, whichever faces us.
const order: number[] = [];
for (let i = 0; i < pts.length - 1; i++) order.push(i);
const depth = (i: number) => ((pts[i].x + pts[i + 1].x) / 2) * CAM[0] + ((pts[i].z + pts[i + 1].z) / 2) * CAM[2];
order.sort((p, q) => depth(p) - depth(q));
const outTone: [number, number][] = [], inTone: [number, number][] = [];
pts.forEach((p, i) => { const l = -Math.sin(p.f) * LIGHT[0] + Math.cos(p.f) * LIGHT[2]; outTone.push([sAt(i), Math.max(0, l)]); inTone.push([sAt(i), Math.max(0, -l)]); });
relight(litFront, front, outTone); relight(litBack, back, inTone);
for (const i of order) {
const p = pts[i], q = pts[i + 1], f = q.f, n = [-Math.sin(f), 0, Math.cos(f)];
const facing = n[0] * CAM[0] + n[2] * CAM[2];
const outside = facing >= 0;
const a = P(p.x, tw, p.z), b = P(q.x, tw, q.z), c = P(p.x, -tw, p.z);
const u0 = sAt(i), u1 = sAt(i + 1);
lay(outside ? litFront : litBack, u0, u1, a, b, c);
// Cut edge on the near side, which gives the cloth its thickness.
const h0 = halfAt(i), h1 = halfAt(i + 1), c2 = P(p.x, -h0, p.z), d2 = P(q.x, -h1, q.z);
const e0 = P(p.x + Math.sin(p.f) * TH, -h0, p.z - Math.cos(p.f) * TH), e1 = P(q.x + Math.sin(f) * TH, -h1, q.z - Math.cos(f) * TH);
ctx.setTransform(1, 0, 0, 1, 0, 0); ctx.beginPath(); ctx.moveTo(c2[0], c2[1]); ctx.lineTo(d2[0], d2[1]); ctx.lineTo(e1[0], e1[1]); ctx.lineTo(e0[0], e0[1]); ctx.closePath();
ctx.fillStyle = `rgb(${(TAB[0] * 0.5) | 0},${(TAB[1] * 0.42) | 0},${(TAB[2] * 0.4) | 0})`; ctx.fill();
}
};
let raf = 0, last = 0, seen = true, t0 = 0, touched = -1e9, demoAt = 750;
const size = () => { const w = wrap.clientWidth; k = (w / VW) * dpr; cv.width = Math.round(VW * k); cv.height = Math.round(VH * k); };
const OPEN = 1.98;
const fire = (toOn: boolean) => {
if (toOn) { s.target = 0; s.held = 0; }
else { s.target = OPEN; s.held = 0.085; s.mv += 150; } // the cloth bulges for a moment while the stud still holds
};
const frame = (now: number) => {
raf = 0;
if (!t0) { t0 = now; last = now; }
const dt = Math.min(0.033, (now - last) / 1000); last = now;
const t = now - t0;
if (now - touched > 7000 && t > demoAt) { const next = !onRef.current; onRef.current = next; setOn(next); fire(next); demoAt = t + (next ? 1900 : 3600); }
const before = s.av;
if (s.held > 0) { s.held -= dt; if (s.held <= 0) s.av = 11.5; } // released: it pops
else if (s.target > 0) { s.av += (120 * (s.target - s.a) - 6.2 * s.av) * dt; s.a += s.av * dt; }
else {
s.av += (150 * (s.target - s.a) - 15 * s.av - 14) * dt; s.a += s.av * dt;
if (s.a < 0) { if (s.av < -1.2) { s.press = 1.6; s.mv -= 60; } s.a = 0; s.av = -s.av * 0.18; }
}
s.mv += (-900 * s.m - 34 * s.mv) * dt; s.m += s.mv * dt;
s.bv += (-210 * s.b - 9 * s.bv) * dt - (s.av - before) * 0.055; s.b += s.bv * dt;
s.press *= Math.pow(0.0001, dt);
draw();
if (seen && !document.hidden) raf = requestAnimationFrame(frame);
};
const wake = () => { if (!raf && !reduce) { last = performance.now(); raf = requestAnimationFrame(frame); } };
const settle = () => { s.a = s.target; s.av = 0; s.m = 0; s.mv = 0; s.b = 0; s.bv = 0; s.press = 0; s.held = 0; draw(); };
size();
if (reduce) settle(); else { draw(); wake(); }
api.current = { set: (toOn) => { touched = performance.now(); fire(toOn); if (reduce) settle(); else wake(); } };
const ro = new ResizeObserver(() => { size(); draw(); });
ro.observe(wrap);
const io = new IntersectionObserver(([entry]) => { seen = entry.isIntersecting; if (seen) wake(); });
io.observe(cv);
const onVis = () => { if (!document.hidden) wake(); };
document.addEventListener("visibilitychange", onVis);
return () => { cancelAnimationFrame(raf); api.current = null; ro.disconnect(); io.disconnect(); document.removeEventListener("visibilitychange", onVis); };
}, []);
const toggle = () => { const next = !onRef.current; onRef.current = next; setOn(next); api.current?.set(next); };
return (
<div className="flex min-h-[560px] w-full flex-col items-center justify-center overflow-hidden bg-[#d3dade] bg-[radial-gradient(80%_70%_at_60%_30%,#e9eef0_0%,#d3dade_55%,#bcc6cc_100%)] px-4 py-6 sm:min-h-[740px]">
<div ref={box} className="relative aspect-[450/336] w-full max-w-[900px]">
<canvas ref={canvas} aria-hidden="true" className="pointer-events-none absolute inset-0 h-full w-full" />
<button
type="button" role="switch" aria-checked={on} aria-label={SETTING} onClick={toggle}
className="absolute inset-x-[6%] inset-y-[8%] cursor-pointer rounded-[40px] outline-none focus-visible:ring-2 focus-visible:ring-[#1e283e]"
/>
</div>
<p aria-live="polite" className="mt-1 text-center font-mono text-[11px] uppercase leading-5 tracking-[0.18em] text-slate-600">
<span className="text-slate-900">{SETTING}</span>
<span className="mx-2 text-slate-400">/</span>
{on ? "On, fastened" : "Off, undone"}
</p>
</div>
);
}
Install with one command: npx shadcn@latest add https://we.inc/r/press-stud-snap-toggle-on-a-waxed-canvas-strap-that-pops-open-and-curls-back.json
The tab is cut into 44 short slices along its length. Each frame the code walks from the stitched end outward, adding up a bend angle, which gives every slice a position and a tilt. Each slice of the flat texture is then drawn with a single canvas transform onto its place on screen. Because the camera has no perspective, that transform is exact.
For each slice the direction its outer face points is compared with the direction of the camera. If it faces the camera the orange texture is used, otherwise the yellow one. The same direction, compared with the light, sets how much the slice is darkened or brightened.
For the first 85 milliseconds the stud still holds, and only a bulge travels through the middle of the tab. Then the tab is released with a burst of speed on a lightly damped spring, and a second, smaller spring lets the free end lag and wag.
The component ships silent. If you want one, play a short sample inside `fire`, and keep it behind a constant that defaults to off so nobody is surprised by audio.
The `on` state is true while the tab is fastened. Lift it to a parent, or call your own handler inside `toggle` next to `setOn`. The self-running demo stops as soon as someone presses the switch and only resumes after seven idle seconds, so remove the demo block in the frame loop for production forms.
Related: Lathe-Turned Metal Dial Switch with Detents and Light That Stays Put, Hanging Garment Bag Scroll Reveal with a Brass Zip That Parts Waxed Canvas over a Photograph, Velvet Stage Curtain Dialog That Draws Apart on a Pull Cord with Pleats That Gather and Sway.
More toggles and switches or all free UI components. Start for free to have a full site built around it.
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