Install
That writescompositions/hw-write-title.html, plus 2 supporting files under assets/baked/ and assets/fonts/.
Add it to your video
It runs for 6 seconds at 1920×1080. Paste this into your composition:index.html
<div
data-composition-id="hw-write-title"
data-composition-src="compositions/hw-write-title.html"
data-start="0"
data-duration="6"
data-track-index="1"
data-width="1920"
data-height="1080"
></div>
data-start. Put it on a different timeline row with
data-track-index. See data attributes for the rest.
Source
hw-write-title.html
hw-write-title.html
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
<script src="assets/baked/caveat-pen.js"></script>
<style>
/* Caveat is NOT auto-resolved by the renderer — bundle it. Asset paths
are ROOT-relative. The glyph write-on itself renders BAKED outlines
(no live font dependency); the bundled face serves the fallback path
for characters outside the baked table. */
@font-face {
font-family: "Caveat";
src: url("assets/fonts/Caveat-700-latin.woff2") format("woff2");
font-weight: 700;
font-display: block;
}
*,
*::before,
*::after {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body {
background: transparent;
overflow: hidden;
}
/* ---- hw-write-title -------------------------------------------------
TRUE glyph write-on: filled Caveat letterforms revealed by animated
per-glyph centerline strokes (the AE mask-reveal classic — "a mask
barely covering the line"), traced in real stroke order with a
curvature-adaptive pen-velocity ease (fast on straights, slow into
curves; inter-stroke pen lifts). Centerlines + outlines + stem widths
ship baked (assets/baked/caveat-pen.js, generated deterministically
from Caveat-700 — regeneration script in the PR).
RULES: hwBoil owns x/y/rotation of the boil target; entrances/exits
ride the outer wrapper. One timeline has ONE onUpdate (hwOnUpdate). */
#hw-wt-root {
--hw-font-print: "Caveat", cursive;
--hw-ink: #f4f2ec;
--hw-ink-dark: #26241f;
--hw-accent-warm: #ffb020;
position: relative;
width: 1920px;
height: 1080px;
overflow: hidden;
background: transparent; /* overlays footage or a board */
font-family: var(--hw-font-print, "Caveat", cursive);
}
#hw-wt-wrap {
position: absolute;
pointer-events: none;
}
#hw-wt-svg {
overflow: visible;
display: block;
}
#hw-wt-under {
overflow: visible;
display: block;
margin-top: -8px;
}
#hw-wt-under path {
fill: none;
stroke: var(--hw-accent-warm);
stroke-width: 7;
stroke-linecap: round;
}
.hw-wt-fallback {
font-weight: 700;
white-space: pre;
}
</style>
</head>
<body>
<div
id="hw-wt-root"
data-composition-id="hw-write-title"
data-start="0"
data-duration="6"
data-width="1920"
data-height="1080"
>
<div id="hw-wt-move">
<div id="hw-wt-boil">
<div id="hw-wt-wrap">
<svg id="hw-wt-svg"></svg>
<svg id="hw-wt-under" width="10" height="40"><path id="hw-wt-under-path"></path></svg>
</div>
</div>
</div>
<div
id="hw-wt-drv"
class="clip"
data-start="0"
data-duration="6"
data-track-index="0"
style="position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none"
></div>
</div>
<script>
(function () {
window.__timelines = window.__timelines || {};
var CONFIG = {
// ── Content (freely editable — not counted) ─────────────────────
text: "write it on",
fontSize: 170, // px; the word block auto-centers when x/y are null
x: null,
y: null,
// ── Controls (family base + 2 item-specific; comment grammar is the published-parameter list) ──
scheme: "chalk", // variant: "chalk" | "ink" — selects the authored token set (family default "chalk")
animationIn: true, // toggle: entrance on/off — write-on IS the entrance; false = hard-on at t=0 (pairs with animationOut; the pair counts as one control)
animationOut: true, // (exit fade; duration derived from DUR, never exposed)
boil: "calm", // variant: "off" | "calm" | "lively" — authored amp/rot pairs over the family-locked frameDrop 3; seed locked
writeOn: "trace", // variant: "trace" | "reveal" | "off" — trace = pen-traced glyph write-on (curvature-adaptive velocity, pen lifts); reveal = per-glyph staggered fade; off = hard-on; durations derived from stroke count, never exposed
underline: true, // toggle: seeded squiggle underline drawn after the write completes
// ── Locked (edit the item source to change) ─────────────────────
// seed, pen-velocity constants (kCurve 10, floor 0.22, lift 60ms),
// trace-duration derivation, boil pose tables, all eases/durations
};
var SEED = 8; // locked — determinism
var DUR = 6;
function clamp(v, lo, hi) {
return Math.min(hi, Math.max(lo, v));
}
var OUT = clamp(DUR * 0.06, 0.25, 0.6);
/* ---- hw family runtime (copy identical across hw items) ---- */
window.hwOnUpdate = function (tl, fn) {
if (!tl.__hwRenders) {
tl.__hwRenders = [];
tl.eventCallback("onUpdate", function () {
for (var i = 0; i < tl.__hwRenders.length; i++) tl.__hwRenders[i]();
});
}
tl.__hwRenders.push(fn);
fn();
};
window.hwHash = function (n, seed) {
var x = Math.sin(n * 127.1 + (seed || 1) * 311.7) * 43758.5453;
return (x - Math.floor(x)) * 2 - 1;
};
window.hwBoil = function (tl, target, opts) {
opts = opts || {};
var amp = opts.amp !== undefined ? opts.amp : 1.6;
var rot = opts.rot !== undefined ? opts.rot : 0.5;
var fps = opts.fps || 30;
var drop = opts.frameDrop || 3;
var seed = opts.seed || 1;
var els = gsap.utils.toArray(target);
window.hwOnUpdate(tl, function () {
var step = Math.floor((tl.time() * fps) / drop);
for (var i = 0; i < els.length; i++) {
gsap.set(els[i], {
x: window.hwHash(step * 3 + i * 97, seed) * amp,
y: window.hwHash(step * 3 + 1 + i * 97, seed) * amp,
rotation: (opts.baseRot || 0) + window.hwHash(step * 3 + 2 + i * 97, seed) * rot,
});
}
});
};
// boil control: authored poses over the family-locked frameDrop.
// Unknown pose → default + console error (bounded-controls law).
window.hwBoilPose = function (tl, target, pose, opts) {
opts = opts || {};
var poses = { calm: { amp: 1.6, rot: 0.5 }, lively: { amp: 2.6, rot: 0.9 } };
if (pose === "off") return;
var p = poses[pose];
if (!p) {
console.error('hw: unknown boil pose "' + pose + '" — falling back to "calm"');
p = poses.calm;
}
window.hwBoil(tl, target, { amp: p.amp, rot: p.rot, frameDrop: 3, seed: opts.seed || 1 });
};
/* ---- pen-velocity ease: pure function of the path geometry ----
Sample 25–75 curvature-adaptive points, speed ∝ 1/(1+k·curvature)
floored at 0.22 (a pen slows into curves, never stalls), integrate
ds/speed, invert to a normalized time→distance ease. Seek-safe:
no per-frame state. */
window.hwPenEase = function (pathEl, opts) {
opts = opts || {};
var kCurve = opts.kCurve !== undefined ? opts.kCurve : 10;
var L = pathEl.getTotalLength();
if (L <= 0)
return {
ease: function (t) {
return t;
},
samples: 2,
inkTime: 1,
len: 0,
};
var PRE = 48;
var pts = [];
for (var i = 0; i <= PRE; i++) pts.push(pathEl.getPointAtLength((L * i) / PRE));
var curv = [0];
for (i = 1; i < PRE; i++) {
var ax = pts[i].x - pts[i - 1].x,
ay = pts[i].y - pts[i - 1].y;
var bx = pts[i + 1].x - pts[i].x,
by = pts[i + 1].y - pts[i].y;
var la = Math.hypot(ax, ay) || 1e-6,
lb = Math.hypot(bx, by) || 1e-6;
var dot = Math.max(-1, Math.min(1, (ax * bx + ay * by) / (la * lb)));
curv.push(Math.acos(dot) / ((la + lb) / 2));
}
curv.push(0);
var mass = 0;
for (i = 0; i < curv.length; i++) mass += curv[i];
var N = Math.max(25, Math.min(75, Math.round(25 + mass * 18)));
var seg = L / N;
var times = [0];
var t = 0;
for (i = 1; i <= N; i++) {
var u = ((i - 0.5) / N) * PRE;
var i0 = Math.floor(u),
f = u - i0;
var c = curv[Math.min(i0, PRE)] * (1 - f) + curv[Math.min(i0 + 1, PRE)] * f;
var speed = Math.max(1 / (1 + kCurve * c * 14), 0.22);
t += seg / speed;
times.push(t);
}
var total = times[N];
for (i = 0; i <= N; i++) times[i] /= total;
var easeFn = function (p) {
if (p <= 0) return 0;
if (p >= 1) return 1;
var lo = 0,
hi = N;
while (hi - lo > 1) {
var mid = (lo + hi) >> 1;
if (times[mid] <= p) lo = mid;
else hi = mid;
}
var span = times[hi] - times[lo] || 1e-9;
return (lo + (p - times[lo]) / span) / N;
};
return { ease: easeFn, samples: N, inkTime: total, len: L };
};
/* ---- word assembly from the baked table ----
Each glyph: <mask> of centerline strokes (stroke-width = the glyph's
baked stem × 1.35) over the filled outline. Characters missing from
the table fall back to live Caveat text revealed by fade (+ console
warning) — the bundled face exists for exactly this path. */
function buildWord(svg, text) {
// everything in GLYPH UNITS (upem 1000, y-down, baseline 0) — the
// svg viewBox maps units → px, no scale transform needed
var table = window.__hwPenCaveat;
var ns = "http://www.w3.org/2000/svg";
// scheme control: bounded lookup — unknown → default + console error
var schemes = { chalk: "var(--hw-ink)", ink: "var(--hw-ink-dark)" };
if (!(CONFIG.scheme in schemes)) {
console.error('hw: unknown scheme "' + CONFIG.scheme + '" — falling back to "chalk"');
}
var ink = schemes[CONFIG.scheme] || schemes.chalk;
var g = document.createElementNS(ns, "g");
var x = 0;
var strokes = [];
var fallbacks = [];
var gi = 0;
for (var ci = 0; ci < text.length; ci++) {
var ch = text[ci];
var gl = table.glyphs[ch];
if (ch === " ") {
x += 340;
continue;
}
if (!gl) {
console.warn(
'hw-write-title: "' + ch + '" not in the baked table — Caveat fallback fade',
);
var ft = document.createElementNS(ns, "text");
ft.setAttribute("x", x);
ft.setAttribute("y", 0);
ft.setAttribute("class", "hw-wt-fallback");
ft.setAttribute("font-size", "1000");
ft.setAttribute("fill", ink);
ft.textContent = ch;
g.appendChild(ft);
fallbacks.push(ft);
x += 450;
continue;
}
var gg = document.createElementNS(ns, "g");
gg.setAttribute("transform", "translate(" + x + ",0)");
var maskId = "hw-wt-m" + gi;
var mask = document.createElementNS(ns, "mask");
mask.setAttribute("id", maskId);
mask.setAttribute("maskUnits", "userSpaceOnUse");
mask.setAttribute("x", "-200");
mask.setAttribute("y", "-900");
mask.setAttribute("width", gl.adv + 400);
mask.setAttribute("height", "1400");
for (var si = 0; si < gl.strokes.length; si++) {
var mp = document.createElementNS(ns, "path");
mp.setAttribute("d", gl.strokes[si]);
mp.setAttribute("fill", "none");
mp.setAttribute("stroke", "#fff");
mp.setAttribute("stroke-width", Math.max(30, Math.round(gl.stem * 1.35)));
mp.setAttribute("stroke-linecap", "round");
mp.setAttribute("stroke-linejoin", "round");
mask.appendChild(mp);
strokes.push({ path: mp, glyph: gi });
}
gg.appendChild(mask);
var op = document.createElementNS(ns, "path");
op.setAttribute("d", gl.outline);
op.setAttribute("fill", ink);
op.setAttribute("mask", "url(#" + maskId + ")");
gg.appendChild(op);
g.appendChild(gg);
x += gl.adv;
gi++;
}
svg.appendChild(g);
return { el: g, widthUnits: x, strokes: strokes, fallbacks: fallbacks };
}
/* ---- trace choreography: per-stroke reveals, pen-velocity eases,
60ms pen lifts; duration DERIVED from stroke count (writeOn owns
it — never exposed). One dispatcher-registered render applies the
dashoffsets. */
function writeOnTrace(tl, built, at) {
var strokes = built.strokes;
if (!strokes.length) return at;
var lift = 0.06;
var metas = [];
var inkSum = 0;
for (var i = 0; i < strokes.length; i++) {
var pe = window.hwPenEase(strokes[i].path);
var len = strokes[i].path.getTotalLength();
metas.push({ pe: pe, len: len, st: { p: 0 } });
inkSum += pe.inkTime;
strokes[i].path.setAttribute("stroke-dasharray", len + " " + len);
strokes[i].path.setAttribute("stroke-dashoffset", len);
strokes[i].path.style.opacity = "0"; // no round-cap nub pre-draw
}
var dur = clamp(0.55 + 0.22 * strokes.length, 1.2, 4);
var drawTotal = Math.max(0.1, dur - lift * (strokes.length - 1));
var t = at;
for (i = 0; i < metas.length; i++) {
var d = (metas[i].pe.inkTime / inkSum) * drawTotal;
metas[i].d = d;
tl.to(metas[i].st, { p: 1, duration: d, ease: metas[i].pe.ease }, t);
t += d + lift;
}
window.hwOnUpdate(tl, function () {
for (var i = 0; i < metas.length; i++) {
var m = metas[i];
strokes[i].path.style.strokeDashoffset = m.len * (1 - m.st.p);
strokes[i].path.style.opacity = m.st.p > 0 ? "1" : "0";
}
});
for (i = 0; i < built.fallbacks.length; i++) {
gsap.set(built.fallbacks[i], { opacity: 0 });
tl.to(
built.fallbacks[i],
{ opacity: 1, duration: 0.4, ease: "power2.out" },
at + dur * 0.5,
);
}
return t - lift;
}
/* writeOn pose control — unknown → "trace" + console error */
function writeOnPose(tl, built, at, pose) {
if (pose !== "trace" && pose !== "reveal" && pose !== "off") {
console.error('hw: unknown writeOn pose "' + pose + '" — falling back to "trace"');
pose = "trace";
}
var all = built.strokes
.map(function (s) {
return s.path;
})
.concat(built.fallbacks);
if (pose === "off") {
for (var i = 0; i < all.length; i++) {
all[i].style.opacity = "0";
tl.set(all[i], { opacity: 1 }, at);
}
return at;
}
if (pose === "reveal") {
// per-glyph staggered fade (the family sweep grammar); derived timing
var byGlyph = {};
for (var j = 0; j < built.strokes.length; j++) {
(byGlyph[built.strokes[j].glyph] = byGlyph[built.strokes[j].glyph] || []).push(
built.strokes[j].path,
);
}
var keys = Object.keys(byGlyph);
for (var k = 0; k < keys.length; k++) {
var paths = byGlyph[keys[k]];
for (var m = 0; m < paths.length; m++) {
gsap.set(paths[m], { opacity: 0 });
tl.to(paths[m], { opacity: 1, duration: 0.3, ease: "power2.out" }, at + k * 0.12);
}
}
for (var f = 0; f < built.fallbacks.length; f++) {
gsap.set(built.fallbacks[f], { opacity: 0 });
tl.to(
built.fallbacks[f],
{ opacity: 1, duration: 0.3, ease: "power2.out" },
at + keys.length * 0.06,
);
}
return at + keys.length * 0.12 + 0.3;
}
return writeOnTrace(tl, built, at);
}
/* ---- build ---- */
var table = window.__hwPenCaveat;
var scalePx = CONFIG.fontSize / 1000;
var svg = document.getElementById("hw-wt-svg");
var built = buildWord(svg, CONFIG.text);
var wUnits = built.widthUnits;
var hUnits = table.meta.ascent - table.meta.descent;
var wPx = wUnits * scalePx;
var hPx = hUnits * scalePx;
svg.setAttribute("width", Math.ceil(wPx));
svg.setAttribute("height", Math.ceil(hPx));
svg.setAttribute("viewBox", "0 " + -table.meta.ascent + " " + wUnits + " " + hUnits);
var wrap = document.getElementById("hw-wt-wrap");
var move = document.getElementById("hw-wt-move");
move.style.position = "absolute";
move.style.left = (CONFIG.x === null ? Math.round((1920 - wPx) / 2) : CONFIG.x) + "px";
move.style.top = (CONFIG.y === null ? Math.round((1080 - hPx) / 2) : CONFIG.y) + "px";
var tl = gsap.timeline({ paused: true });
var startAt = CONFIG.animationIn ? 0.35 : 0;
var writeEnd = startAt;
if (CONFIG.animationIn) {
writeEnd = writeOnPose(tl, built, startAt, CONFIG.writeOn);
} else {
// hard-on pose regardless of writeOn (animationIn=false = instant-on)
writeEnd = writeOnPose(tl, built, 0, "off");
}
/* squiggle underline (accent), drawn as the write lands */
var underPath = document.getElementById("hw-wt-under-path");
if (CONFIG.underline) {
var uw = Math.round(wPx);
var usvg = document.getElementById("hw-wt-under");
usvg.setAttribute("width", uw);
usvg.setAttribute("viewBox", "0 0 " + uw + " 40");
var segs = Math.max(6, Math.round(uw / 90));
var d = "M 2 " + (18 + window.hwHash(0, SEED) * 4).toFixed(1);
for (var i = 1; i <= segs; i++) {
var x2 = (uw / segs) * i;
var y2 = 18 + window.hwHash(i * 5 + 1, SEED) * 6;
var cxp = x2 - uw / segs / 2 + window.hwHash(i * 5 + 2, SEED) * 10;
var cyp = 18 + (i % 2 ? -1 : 1) * (9 + window.hwHash(i * 5 + 3, SEED) * 4);
d +=
" Q " +
cxp.toFixed(1) +
" " +
cyp.toFixed(1) +
" " +
x2.toFixed(1) +
" " +
y2.toFixed(1);
}
underPath.setAttribute("d", d);
var ulen = underPath.getTotalLength();
gsap.set(underPath, {
strokeDasharray: ulen + " " + ulen,
strokeDashoffset: ulen,
opacity: 0,
});
var uAt = Math.min(writeEnd + 0.1, DUR - 1.2);
tl.set(underPath, { opacity: 1 }, uAt);
tl.to(underPath, { strokeDashoffset: 0, duration: 0.7, ease: "power2.inOut" }, uAt);
} else {
document.getElementById("hw-wt-under").style.display = "none";
}
/* the boil rides its own wrapper; entrances/exits ride #hw-wt-move */
window.hwBoilPose(tl, "#hw-wt-boil", CONFIG.boil, { seed: SEED });
if (CONFIG.animationOut) {
tl.to(move, { opacity: 0, duration: OUT, ease: "power2.in" }, DUR - OUT - 0.05);
}
tl.set("#hw-wt-root", { visibility: "hidden" }, DUR - 0.02);
window.__timelines["hw-write-title"] = tl;
})();
</script>
</body>
</html>
handwritten typography title-card write-on overlay.