---
name: stat-bars-and-fills
description: Data-viz primitives that pair a number with a graphic — growth bars (CSS scaleY stagger), a progress fill (bar or ring), and a partial star-rating wipe. Seek-safe, deterministic.
metadata:
  tags: data, stats, chart, bars, progress, ring, stars, rating, infographic, number
---

# Stat Bars & Fills

The graphics that give a stat **visual weight** beside its number: a small bar chart, a progress bar/ring filling to a percentage, or a star row filling to a fractional rating. Pair these with [counting-dynamic-scale.md](counting-dynamic-scale.md) (the number) for a complete stat scene.

**Layout blueprint — pick ONE and hold it across all stats:**

- **Single-focus** — one centered frame, the number is the hero, a ring or bar sits under/around it. Cleanest for a sequential reveal (stat 1 → stat 2 → stat 3 in the same frame).
- **Split-frame** — big number on the left, paired graphic on the right. Better when stats are shown together or each needs a distinct visual.

Don't mix blueprints between stats in one piece — that reads as inconsistent.

## Recipe

### 1 — Growth Bars (CSS `scaleY` stagger)

Bars grow from the baseline with a stagger; the last bar is the accent. Heights are authored in CSS (inline height per bar); GSAP only reveals `scaleY: 0 → 1` — never animate `height`.

```css
.bars {
  display: flex;
  align-items: flex-end;
  gap: 14px;
  height: 280px;
}
.bar {
  width: 48px;
  background: #3a4a64;
  transform: scaleY(0);
  transform-origin: bottom center; /* grow UP from the baseline, not from center */
}
.bar:last-child {
  background: #ffc300; /* accent the final/current bar */
}
```

```js
tl.to(".bar", { scaleY: 1, duration: 0.7, ease: "power3.out", stagger: 0.08 }, 0.3);
```

### 2 — Progress Fill

**Bar form** — `scaleX` from a left origin:

```css
.track {
  width: 520px;
  height: 16px;
  background: #1b263b;
  border-radius: 8px;
  overflow: hidden;
}
/* width:100% is REQUIRED — an absolutely-positioned fill with no width is 0px, and scaleX of 0 is
   still 0 → the bar renders invisible (automated gates may miss a zero-width scaled element). */
.fill {
  width: 100%;
  height: 100%;
  background: #ffc300;
  transform: scaleX(0);
  transform-origin: left center;
}
```

```js
const PCT = 0.92; // 92%
tl.to(".fill", { scaleX: PCT, duration: 1.0, ease: "power2.out" }, 0.3);
```

**Ring form** — measured stroke draw (mechanics in [svg-path-draw.md](svg-path-draw.md)):

```js
const ring = document.querySelector("#ring");
const LEN = ring.getTotalLength(); // measure, don't hard-code the circumference
ring.style.strokeDasharray = LEN;
ring.style.strokeDashoffset = LEN; // empty
// rotate the <circle> -90deg in CSS so the fill starts at 12 o'clock
tl.to(ring, { strokeDashoffset: LEN * (1 - 0.92), duration: 1.1, ease: "power2.out" }, 0.3);
```

### 3 — Star-Rating Fill (fractional)

A gold star row revealed left-to-right to a fractional value (e.g. 4.6 / 5) via a clip wipe over a gold layer sitting on a gray layer.

```html
<div class="stars">
  <div class="stars-gray">★★★★★</div>
  <div class="stars-gold" id="goldStars">★★★★★</div>
</div>
```

```css
.stars {
  position: relative;
  font-size: 64px;
  letter-spacing: 8px;
}
.stars-gray {
  color: #2b3548;
}
.stars-gold {
  position: absolute;
  inset: 0;
  color: #ffc300;
  width: 100%;
  clip-path: inset(0 100% 0 0);
}
```

```js
const RATING = 4.6,
  MAX = 5;
tl.to(
  "#goldStars",
  { clipPath: `inset(0 ${100 - (RATING / MAX) * 100}% 0 0)`, duration: 1.0, ease: "power2.out" },
  0.3,
);
```

## Values

| token         | range       | notes                                                                               |
| ------------- | ----------- | ----------------------------------------------------------------------------------- |
| bar count     | 4–6         | reads as "a trend" without clutter; the last bar is the current/accent value        |
| fill duration | 0.8–1.2s    | matched to the paired count-up so number and graphic land together (share the ease) |
| stagger       | 0.06–0.1s   | larger feels sluggish, 0 loses the build                                            |
| accent hue    | exactly one | bars/fill/stars all use the same accent, the rest is muted                          |

## Critical Constraints

- **`scaleY` / `scaleX` / `clipPath`, never `height`/`width` tweens** — author each bar's final height in CSS and scale from 0.
- **`transform-origin`** must be `bottom` (bars grow up) / `left` (fills grow right) — the default center origin scales from the middle and looks wrong.
- **`.fill` needs `width: 100%`** — a zero-width fill scaled by any factor is still invisible, and automated gates may miss it.
- **Measure, don't hard-code** — ring length via `getTotalLength()`; a hard-coded circumference breaks if the radius changes.
- **Match the number's timing** — the fill and the count-up peak together (same start + ease) so the stat resolves as one beat, not two; a paired counter's `onUpdate` must be O(1) (see [counting-dynamic-scale.md](counting-dynamic-scale.md)).
- **One accent hue, consistent blueprint** — see `hyperframes-creative/references/data-in-motion.md`.

## See also

`counting-dynamic-scale` (the number beside the graphic — same ease/duration) · `svg-path-draw` (progress-ring draw mechanics) · `hyperframes-creative/references/data-in-motion.md` (stat layout + visual weight).
