frames/skills/frames-animation/rules/ambient-glow-bloom.md

name, description, metadata

name	description	metadata
ambient-glow-bloom	Un-triggered soft radial glow that blooms in behind a hero element and holds with a bounded idle breathe, or a single-pass traveling sweep across a surface. No click, no word-sync — it just blooms. Finite, deterministic, seek-safe.	tags glow, bloom, ambient, radial, sweep, hero, presence, finite, un-triggered

Ambient Glow Bloom

A soft radial glow that blooms in behind a hero element (card, logo, metric) and holds, giving it presence. Unlike press-release-spring's click-triggered burst or asr-keyword-glow's word-timed envelope, this glow is un-triggered — it blooms on the hero's settle and stays lit. Two forms: a hero bloom that swells behind a settling element then breathes, and a traveling sweep that translates a soft highlight across a surface exactly once.

How It Works

A radial-gradient layer sits behind the hero (glow z-index: 1, hero z-index: 2 — a glow in front occludes it), starting at opacity: 0. Over the bloom-in window it ramps opacity: 0 → peak with a gentle scale swell, timed so BLOOM_START + BLOOM_DUR lands on the hero's settle — glow and hero resolve as ONE beat ("powering on"), never glow-then-card. After bloom-in:

1. Hero bloom — a bounded idle breathe during the hold: a finite ease: "none" tween advances a phase proxy and onUpdate nudges opacity + scale a hair around peak (never a yoyo loop). sin(0) = 0 → the breathe starts exactly at the bloom's resting state.
2. Traveling sweep — a narrow highlight band at one edge translates once across to the other (x off-surface to off-surface), clipped to the surface (overflow: hidden). One pass, no return — a repeating sweep reads as a loading shimmer, not a reveal accent (the shimmer-sweep variation below is the sanctioned exception).

Peak opacity stays restrained (≤ 0.45 hard ceiling) so the glow gives presence without washing the frame; the glow color is darker + more saturated than the element it backs (a same-hue, same-lightness glow disappears into the surface).

Recipe

<!-- inside a standard scene clip -->
<div class="bloom-stage">
  <div class="bloom-glow" id="bloom-glow"></div>
  <!-- z-index: 1; inset: GLOW_INSET (negative); background: {glowGradient} -->
  <div class="hero-card" id="hero-card">{HeroLabel}</div>
  <!-- z-index: 2 -->
</div>
<!-- sweep form: <div class="sweep" id="sweep"> inside the overflow:hidden surface -->

// ── Form A: HERO BLOOM ── bloom in soft, landing on the hero's settle.
tl.fromTo(
  "#bloom-glow",
  { opacity: 0, scale: GLOW_START_SCALE },
  { opacity: GLOW_PEAK_OPACITY, scale: 1, duration: BLOOM_DUR, ease: "power2.out" },
  BLOOM_START,
);
// Bounded breathe during the hold — finite phase tween, NOT a yoyo loop.
const glow = document.getElementById("bloom-glow");
const phase = { p: 0 };
tl.to(
  phase,
  {
    p: Math.PI * 2 * BREATHE_CYCLES,
    duration: BREATHE_DUR,
    ease: "none",
    onUpdate: () => {
      const s = Math.sin(phase.p);
      glow.style.opacity = String(GLOW_PEAK_OPACITY + s * OPACITY_AMP);
      glow.style.transform = `scale(${1 + s * SCALE_AMP})`;
    },
  },
  BLOOM_START + BLOOM_DUR,
);

// ── Form B: TRAVELING SWEEP ── one finite pass, constant glide.
tl.fromTo(
  "#sweep",
  { x: SWEEP_START_X, opacity: 0 },
  { x: SWEEP_END_X, opacity: SWEEP_PEAK_OPACITY, duration: SWEEP_DUR, ease: "none" },
  SWEEP_START,
);
tl.to("#sweep", { opacity: 0, duration: SWEEP_FADE_DUR, ease: "power1.in" }, SWEEP_FADE_START);

Variations

• Bloom-and-hold — for scenes <3s or a hero with its own idle, skip the breathe: the single fromTo is the whole recipe.
• Pulse-on-arrival — bloom slightly PAST peak (GLOW_OVERSHOOT_OPACITY, scale: 1.06), then a second adjacent tween eases down to a steady hold — one breath punctuating the landing, no ongoing loop.
• Multi-hero relay — stagger per-glow BLOOM_START by ~0.15–0.3s across a row; shrink OPACITY_AMP / SCALE_AMP per the /√N rule below.
• Diagonal raked sweep — angle {sweepGradient} (~105°) across a wordmark: the classic one-pass logo sheen. Narrower SWEEP_WIDTH, higher SWEEP_PEAK_OPACITY.

Shimmer sweep (text-clipped status-phrase working-state)

The sweep re-aimed inside type: a soft highlight gradient clipped into a status phrase ("Thinking…", "Analyzing dataset…") via background-clip: text travels left→right through the letterforms — the grey-on-grey shimmer that says still working. Unlike every other form here it legitimately repeats while the status is live: the repetition is diegetic working-state, not idle wobble (same defense as a blinking caret — the motion performs status). Two things keep it honest: it is bounded (one finite tween whose pass count is computed from the status window, never repeat: -1), and it is killed at resolve — the moment the status completes, the shimmer stops dead; a shimmer surviving into the answer beat turns a working indicator into decoration.

// Status shimmer — N passes as ONE bounded tween. Killed at resolve.
const status = document.getElementById("status-phrase");
// CSS on #status-phrase: background: {shimmerGradient}; background-size: 300% 100%;
// -webkit-background-clip: text; background-clip: text; color: transparent;
const shimmer = { p: 0 };
const PASSES = Math.round(STATUS_DUR / PASS_PERIOD); // whole passes, computed up front
tl.to(
  shimmer,
  {
    p: PASSES,
    duration: STATUS_DUR,
    ease: "none",
    onUpdate: () => {
      const t = shimmer.p % 1; // 0→1 within each pass; percent axis inverted → left→right travel
      status.style.backgroundPosition = `${(1 - t) * 100}% 50%`;
    },
  },
  STATUS_START,
);
tl.set(status, { backgroundPosition: "100% 50%" }, STATUS_START + STATUS_DUR); // resolve: dead.

Keep it a whisper: {shimmerGradient} is the status text's own grey with one slightly-lighter band (highlight stop a step above the base, nothing near white); background-size ~300% keeps the band narrow in the glyphs; PASS_PERIOD 1.2–1.8s — slower reads as a sheen accent, faster as a spinner. Whole-number PASSES lands the band at its start position exactly at the kill frame, so the tl.set is visually a no-op. This is the working-state cousin of gradient-text-sweep: reach here when the sweep means "in progress," there when the gradient is the typographic treatment itself.

Values

token	range / default	notes
GLOW_PEAK_OPACITY	0.15 (subtle) → 0.30 (default) → 0.45 hard ceiling	higher washes the frame; a glow you consciously notice is too strong
GLOW_INSET	−200 to −450px (1920×1080)	negative so the halo extends past the hero; too small reads as a tight rim
GLOW_START_SCALE	0.80–1.0	≤1.0 — grow into place, never shrink
BLOOM_DUR / BLOOM_START	0.6–1.4s	BLOOM_START + BLOOM_DUR ≈ the hero's settle frame
OPACITY_AMP / SCALE_AMP	0.02–0.05 / 0.01–0.03 default	PEAK + OPACITY_AMP ≤ 0.45; push only when the glow is the sole motion
BREATHE_CYCLES	period 2.5–4s per breath	glow breathes slower than element breathing
SWEEP_WIDTH	15–35% of surface (grid) / 8–15% (wordmark)
SWEEP_DUR	0.8–1.6s	one deliberate pass — slow enough to read as light
SWEEP_PEAK_OPACITY	0.10 → 0.25 (default) → 0.40	same ≤ ~0.45 wash limit; tight sweeps tolerate the high end
SWEEP_START_X / END_X	fully off-surface both ends	no visible spawn/despawn mid-surface; fade reaches 0 as the band clears
PASS_PERIOD (shimmer)	1.2–1.8s	with whole-number PASSES

Critical Constraints

• Glow peak opacity ≤ 0.45 — including breathe amplitude; default to the LOW end (0.15–0.30).
• Glow behind, hero in front; glow color darker + more saturated than the hero surface.
• Land glow and hero as one beat — before or after reads as two separate events.
• Breathe is bounded, sweep is one pass — the only sanctioned repetition is the shimmer sweep, bounded and killed at resolve.
• Concurrent halos compound — per-glow amps ≤ default /√N, stagger breathe periods (2.6s / 2.9s / 3.3s) so they don't pulse in lockstep.
• Don't combine a boxShadow glow on the hero with this halo layer — they compete and read muddy; the glow lives on the dedicated layer.

See also

sine-wave-loop (hero breathes on scale/y while the glow breathes on opacity, out of phase) · press-release-spring (the click-triggered sibling — never both behind one element) · counting-dynamic-scale / stat-bars-and-fills (bloom behind a landing stat) · center-outward-expansion (sweep across the assembled grid) · gradient-text-sweep (the design-beat gradient counterpart).