Install
That writes one file:compositions/components/caption-camera-follow.html.
Paste it into your composition
Opencompositions/components/caption-camera-follow.html and copy what is inside into your own composition.
A component has no size or duration of its own. It takes both from the composition
you paste it into.
Variables
Every one of these has a default, so the piece works untouched. Set the ones you want to change on the element:| Variable | Default | Accepts | What it does |
|---|---|---|---|
accent | gold | gold, green, blue, violet | Colour of the highlighted words. gold is the original. |
framing | standard | tight, standard, wide | Air the camera leaves around the written block, so the words land larger or smaller in frame. |
smear | standard | off, subtle, standard, heavy | Scales the radial motion blur each camera move carries, from none to a heavy streak. |
data-variable-values on the element that mounts it. These are the
defaults, so this behaves exactly like the preview above until you change one:
<div
data-composition-id="caption-camera-follow"
data-composition-src="compositions/components/caption-camera-follow.html"
data-variable-values='{"accent":"gold","framing":"standard","smear":"standard"}'
></div>
Source
caption-camera-follow.html
caption-camera-follow.html
<!doctype html>
<!--
caption-camera-follow: the words do not move, the camera does.
One sentence. Layout is self similar: every new word is sized as a fraction of the
bounding box of everything written so far, and is dropped either to the right of that
box or onto a new line below it, alternating. Because each word is measured against a
box that keeps growing, the box grows geometrically, so the camera pulls back at a
steady exponential rate and every word arrives at roughly the same size on screen. Old
words stay lit and simply become small, piling up toward the top left the way
handwriting fills a page. The last beat carries the same pull back all the way out
until the whole sentence is readable at once.
Variables. The script reads each one, falls back to the declared default on
anything missing or unrecognised, and applies it before the timeline is built.
Duration, word order and cadence are untouched by them.
- accent (gold | green | blue | violet, default gold): the colour of the
highlighted words.
- framing (tight | standard | wide, default standard): the air the camera
leaves around the written block. tight lands each word larger in frame,
wide sits further back. Every move and the closing pull back scale
together, so the shot stays one continuous camera.
- smear (off | subtle | standard | heavy, default standard): scales the
radial motion blur each move carries. off renders every frame sharp.
On every default the result is identical to the original: gold highlights, a
1.36 margin around the block and a peak smear of 2.6 percent of frame width.
Every ease is a cubic bezier written out by hand and solved in this file. No preset is
used anywhere. Motion blur is radial, the way it reads in real camera footage: each word
carries its own blur share, scaled by how far that word sits from the centre of the move,
so the frame smears outward from the point the camera is pushing toward. One shared
amount variable is tweened per move and every word multiplies it by its own distance
share, so the whole radial pulse costs one tween instead of fourteen.
Mount contract: everything lives inside <template>, styles and scripts included, and the
scripts sit INSIDE the composition root. A host clones template content into its own
mount and only runs scripts found inside the root; markup left outside is copied without
its behaviour, which renders a black card with no timeline at all.
-->
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>Camera Follow Captions</title>
</head>
<body>
<template>
<div
id="root"
class="clip cf-root"
data-composition-id="caption-camera-follow"
data-duration="9"
data-fps="30"
data-composition-variables='[
{ "id": "accent", "type": "enum", "role": "style", "label": "Accent", "description": "Colour of the highlighted words. gold is the original.", "default": "gold", "options": [{ "value": "gold", "label": "Gold" }, { "value": "green", "label": "Green" }, { "value": "blue", "label": "Blue" }, { "value": "violet", "label": "Violet" }] },
{ "id": "framing", "type": "enum", "role": "style", "label": "Framing", "description": "Air the camera leaves around the written block, so the words land larger or smaller in frame.", "default": "standard", "options": [{ "value": "tight", "label": "Tight" }, { "value": "standard", "label": "Standard" }, { "value": "wide", "label": "Wide" }] },
{ "id": "smear", "type": "enum", "role": "style", "label": "Smear", "description": "Scales the radial motion blur each camera move carries, from none to a heavy streak.", "default": "standard", "options": [{ "value": "off", "label": "Off" }, { "value": "subtle", "label": "Subtle" }, { "value": "standard", "label": "Standard" }, { "value": "heavy", "label": "Heavy" }] }
]'
>
<style>
[data-composition-id="caption-camera-follow"] {
--cf-accent: #ffd84d;
--ink: #ffffff;
position: absolute;
inset: 0;
overflow: hidden;
background: transparent;
pointer-events: none;
}
#cf-stage {
position: absolute;
inset: 0;
overflow: hidden;
}
#cf-world {
position: absolute;
left: 0;
top: 0;
width: 0;
height: 0;
--amt: 0px;
}
.cf-word {
position: absolute;
white-space: nowrap;
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
font-weight: 700;
text-transform: uppercase;
letter-spacing: 0.005em;
line-height: 0.78;
color: var(--ink);
opacity: 0;
--k: 0;
filter: blur(calc(var(--k) * var(--amt)));
}
.cf-word.is-accent {
color: var(--cf-accent);
}
#cf-vignette {
position: absolute;
inset: 0;
background: radial-gradient(
ellipse at 50% 50%,
rgba(0, 0, 0, 0) 42%,
rgba(0, 0, 0, 0.55) 100%
);
}
</style>
<div id="cf-stage">
<div id="cf-world"></div>
</div>
<div id="cf-vignette"></div>
<script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
<script>
(function () {
gsap.defaults({ immediateRender: false });
/* Cubic bezier solver. Newton first, bisection as the fallback, so it is
exact and deterministic for every input. */
function bezier(x1, y1, x2, y2) {
function curve(t, a1, a2) {
var A = 1 - 3 * a2 + 3 * a1;
var B = 3 * a2 - 6 * a1;
var C = 3 * a1;
return ((A * t + B) * t + C) * t;
}
function slope(t, a1, a2) {
var A = 1 - 3 * a2 + 3 * a1;
var B = 3 * a2 - 6 * a1;
var C = 3 * a1;
return (3 * A * t + 2 * B) * t + C;
}
return function (p) {
if (p <= 0) return 0;
if (p >= 1) return 1;
var t = p;
for (var i = 0; i < 8; i++) {
var d = slope(t, x1, x2);
if (Math.abs(d) < 1e-6) break;
var e = curve(t, x1, x2) - p;
if (Math.abs(e) < 1e-7) return curve(t, y1, y2);
t -= e / d;
}
var lo = 0;
var hi = 1;
t = p;
for (var j = 0; j < 24; j++) {
var x = curve(t, x1, x2);
if (Math.abs(x - p) < 1e-7) break;
if (x > p) hi = t;
else lo = t;
t = (lo + hi) / 2;
}
return curve(t, y1, y2);
};
}
/* Leaves the mark fast, spends most of its time arriving. */
var EASE_STEP = bezier(0.31, 0, 0.11, 1);
/* The closing pull back: slower to leave, glides a long way out. */
var EASE_WIDE = bezier(0.42, 0, 0.14, 1);
/* Word ink coming up. */
var EASE_INK = bezier(0.2, 0.7, 0.3, 1);
/* Blur rising into the move and wiped off out of it. */
var EASE_BLUR_UP = bezier(0.2, 0.8, 0.4, 1);
var EASE_BLUR_DOWN = bezier(0.5, 0, 0.2, 1);
var vars =
window.__hyperframes && window.__hyperframes.getVariables
? window.__hyperframes.getVariables()
: {};
/* Unrecognised overrides return to their declared defaults. */
function pick(table, value, fallback) {
return Object.prototype.hasOwnProperty.call(table, value) ? value : fallback;
}
var ACCENTS = {
gold: "#ffd84d",
green: "#34d399",
blue: "#38bdf8",
violet: "#a78bfa",
};
/* Framing scales the margin every camera pose is fitted with, so one
number moves the whole shot in or out without touching cadence. */
var FRAMINGS = { tight: 0.82, standard: 1, wide: 1.25 };
var SMEARS = { off: 0, subtle: 0.5, standard: 1, heavy: 1.9 };
var ACCENT = ACCENTS[pick(ACCENTS, vars.accent, "gold")];
var FRAMING = FRAMINGS[pick(FRAMINGS, vars.framing, "standard")];
var SMEAR = SMEARS[pick(SMEARS, vars.smear, "standard")];
var DUR = 9;
var STEP = 0.52;
var MOVE = 0.4;
var WORDS = [
{ text: "write" },
{ text: "the" },
{ text: "html", accent: true },
{ text: "and" },
{ text: "the" },
{ text: "video", accent: true },
{ text: "renders" },
{ text: "itself" },
{ text: "no" },
{ text: "timeline" },
{ text: "no" },
{ text: "keyframes", accent: true },
{ text: "just" },
{ text: "code", accent: true },
];
var world = document.getElementById("cf-world");
var stage = document.getElementById("cf-stage");
/* The runtime strips the root id on clone, so reach the root through a
descendant instead of getElementById. */
var root = stage.parentElement;
var FRAME_W = root.clientWidth || 1080;
var FRAME_H = root.clientHeight || 1920;
root.style.setProperty("--cf-accent", ACCENT);
/* Base size is picked so the opening shot sits near 1:1. Everything after it
is a pull back, so the world is only ever scaled down and type stays crisp. */
var BASE = Math.max(FRAME_W, FRAME_H) * 0.16;
/* Each new word is this fraction of the current box height. */
var RATIO = 0.72;
var MARGIN = 1.36 * FRAMING;
var ruler = document.createElement("div");
ruler.style.cssText =
"position:absolute;left:-99999px;top:0;white-space:nowrap;visibility:hidden;" +
'font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-weight:700;' +
"text-transform:uppercase;letter-spacing:0.005em;line-height:0.78";
world.appendChild(ruler);
var box = null;
WORDS.forEach(function (wd, i) {
var fs = i === 0 ? BASE : (box.y1 - box.y0) * RATIO;
ruler.style.fontSize = fs + "px";
ruler.textContent = wd.text;
var w = ruler.getBoundingClientRect().width;
var h = fs * 0.78;
var gap = fs * 0.07;
var x, y;
if (i === 0) {
x = 0;
y = 0;
} else if ((box.x1 - box.x0) / (box.y1 - box.y0) < FRAME_W / FRAME_H) {
/* block is narrower than the frame, so grow sideways: to the right of
everything, sitting on the same baseline */
x = box.x1 + gap;
y = box.y1 - h;
} else {
/* block is already wide enough, so grow downward: onto a new line under
everything, left edges aligned */
x = box.x0;
y = box.y1 + gap;
}
wd.fs = fs;
wd.x = x;
wd.y = y;
box = box
? {
x0: Math.min(box.x0, x),
y0: Math.min(box.y0, y),
x1: Math.max(box.x1, x + w),
y1: Math.max(box.y1, y + h),
}
: { x0: x, y0: y, x1: x + w, y1: y + h };
wd.box = { x0: box.x0, y0: box.y0, x1: box.x1, y1: box.y1 };
});
world.removeChild(ruler);
var FULL = box;
function poseFor(b, margin) {
var bw = (b.x1 - b.x0) * margin;
var bh = (b.y1 - b.y0) * margin;
var s = Math.min(FRAME_W / bw, FRAME_H / bh);
return {
x: FRAME_W / 2 - (s * (b.x0 + b.x1)) / 2,
y: FRAME_H / 2 - (s * (b.y0 + b.y1)) / 2,
scale: s,
};
}
var els = WORDS.map(function (wd) {
var el = document.createElement("div");
el.className = "cf-word" + (wd.accent ? " is-accent" : "");
el.textContent = wd.text;
el.style.left = wd.x + "px";
el.style.top = wd.y + "px";
el.style.fontSize = wd.fs + "px";
world.appendChild(el);
return el;
});
/* Re-derive every framing box from what the browser actually laid out, so
the camera is fitted to real ink and never to arithmetic that drifted. */
var run = null;
els.forEach(function (el, i) {
var r = {
x0: el.offsetLeft,
y0: el.offsetTop,
x1: el.offsetLeft + el.offsetWidth,
y1: el.offsetTop + el.offsetHeight,
};
run = run
? {
x0: Math.min(run.x0, r.x0),
y0: Math.min(run.y0, r.y0),
x1: Math.max(run.x1, r.x1),
y1: Math.max(run.y1, r.y1),
}
: r;
WORDS[i].box = { x0: run.x0, y0: run.y0, x1: run.x1, y1: run.y1 };
});
FULL = run;
/* Rest state is pinned outside the timeline. */
var first = poseFor(WORDS[0].box, MARGIN);
gsap.set(world, {
transformOrigin: "0 0",
x: first.x,
y: first.y,
scale: first.scale,
});
gsap.set(els, { opacity: 0, "--k": 0 });
gsap.set(world, { "--amt": "0px" });
/* The first word is already on the page when the shot opens, so frame zero
is never empty. */
gsap.set(els[0], { opacity: 1 });
var tl = gsap.timeline({ paused: true });
/* Peak smear at the rim of the frame, in screen pixels. */
var BLUR = FRAME_W * 0.026 * SMEAR;
var HALF_DIAG = Math.sqrt(FRAME_W * FRAME_W + FRAME_H * FRAME_H) / 2;
/* Radial blur, the way a real zoom smears: a point far from the centre of
the move sweeps across more of the frame than one sitting on it, so it
streaks more. Each word gets its own share, --k, of one shared amount,
--amt, which is the only thing that animates. The share is fixed for the
length of a move and set with the camera, so this stays one tween per
move rather than one per word per move. --amt is authored in world units,
because a filter on a scaled child is applied before the scale, so the
screen blur has to be divided back out by the camera scale. */
function smear(centre, scale, count, at, up, down, peak) {
for (var j = 0; j < count; j++) {
var el = els[j];
var cx = el.offsetLeft + el.offsetWidth / 2;
var cy = el.offsetTop + el.offsetHeight / 2;
var d =
(scale *
Math.sqrt(
(cx - centre.x) * (cx - centre.x) + (cy - centre.y) * (cy - centre.y),
)) /
HALF_DIAG;
tl.set(el, { "--k": (0.2 + 1.15 * Math.min(1, d)).toFixed(3) }, at);
}
var amt = peak / scale;
tl.fromTo(
world,
{ "--amt": "0px" },
{ "--amt": amt + "px", duration: up, ease: EASE_BLUR_UP },
at,
);
tl.to(world, { "--amt": "0px", duration: down, ease: EASE_BLUR_DOWN }, at + up);
}
WORDS.forEach(function (wd, i) {
var t = i * STEP;
if (i === 0) return;
tl.fromTo(els[i], { opacity: 0 }, { opacity: 1, duration: 0.16, ease: EASE_INK }, t);
var p = poseFor(wd.box, MARGIN);
tl.to(world, { x: p.x, y: p.y, scale: p.scale, duration: MOVE, ease: EASE_STEP }, t);
smear(
{ x: (wd.box.x0 + wd.box.x1) / 2, y: (wd.box.y0 + wd.box.y1) / 2 },
p.scale,
i + 1,
t,
MOVE * 0.24,
MOVE * 0.44,
BLUR,
);
});
/* The resolve: the same pull back, carried all the way out. */
var wide = poseFor(FULL, 1.2 * FRAMING);
var wideAt = (WORDS.length - 1) * STEP + 0.62;
tl.to(
world,
{
x: wide.x,
y: wide.y,
scale: wide.scale,
duration: 0.94,
ease: EASE_WIDE,
},
wideAt,
);
smear(
{ x: (FULL.x0 + FULL.x1) / 2, y: (FULL.y0 + FULL.y1) / 2 },
wide.scale,
els.length,
wideAt,
0.3,
0.58,
BLUR * 0.8,
);
tl.set({}, {}, DUR);
tl.seek(0);
window.__timelines = window.__timelines || {};
window.__timelines["caption-camera-follow"] = tl;
})();
</script>
</div>
</template>
</body>
</html>
captions caption-style camera typography motion-primitive portrait.