> ## Documentation Index
> Fetch the complete documentation index at: https://hyperframes.heygen.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Weight Wave

> A crest of thickness travels along a headline: each character swells from light to black and leans forward as the wave passes, driven by the wght and slnt variable-font axes rather than by transforms.

export const InstallCommand = ({command}) => {
  const [copied, setCopied] = React.useState(false);
  const copy = async () => {
    try {
      if (navigator.clipboard && window.isSecureContext) {
        await navigator.clipboard.writeText(command);
      } else {
        const previous = document.activeElement;
        const scratch = document.createElement("textarea");
        scratch.value = command;
        scratch.setAttribute("readonly", "");
        scratch.style.position = "fixed";
        scratch.style.opacity = "0";
        document.body.appendChild(scratch);
        scratch.select();
        document.execCommand("copy");
        document.body.removeChild(scratch);
        previous?.focus?.();
      }
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
    } catch {}
  };
  return <div className="hf-install-command not-prose my-4 flex items-stretch overflow-hidden rounded-xl border border-zinc-200 bg-zinc-50 dark:border-zinc-800 dark:bg-zinc-900">
      <code className="flex-1 overflow-x-auto whitespace-nowrap border-r border-zinc-200 px-4 py-3 font-mono text-sm text-zinc-800 dark:border-zinc-800 dark:text-zinc-100">
        {command}
      </code>
      <button type="button" onClick={copy} data-copied={copied ? "true" : "false"} aria-label={`Copy ${command} to the clipboard`} className="hf-install-copy">
        <svg className="hf-install-copy-clipboard" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M14.25 5.25H7.25C6.14543 5.25 5.25 6.14543 5.25 7.25V14.25C5.25 15.3546 6.14543 16.25 7.25 16.25H14.25C15.3546 16.25 16.25 15.3546 16.25 14.25V7.25C16.25 6.14543 15.3546 5.25 14.25 5.25Z" />
          <path d="M2.80103 11.998L1.77203 5.07397C1.61003 3.98097 2.36403 2.96397 3.45603 2.80197L10.38 1.77297C11.313 1.63397 12.19 2.16297 12.528 3.00097" />
        </svg>
        <svg className="hf-install-copy-check" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M2.75 9.5L6.5 13.25L15.25 4.5" />
        </svg>
      </button>
      <span className="hf-install-copy-status" role="status" aria-live="polite">
        {copied ? "Copied" : ""}
      </span>
    </div>;
};

<iframe className="w-full aspect-video rounded-xl border-0 bg-zinc-100 dark:bg-zinc-800" title="weight-wave preview" loading="lazy" srcDoc={`<!doctype html><html><head><meta charset="utf-8"><style>html,body{margin:0;height:100%;overflow:hidden;background:transparent}hyperframes-player{display:block;width:100%;height:100%}</style><script src="https://cdn.jsdelivr.net/npm/@hyperframes/player@0.7/dist/hyperframes-player.global.js"><\/script></head><body><script>fetch("/public/catalog/blocks/weight-wave.json").then(function(r){return r.json()}).then(function(d){var p=document.createElement("hyperframes-player");p.setAttribute("srcdoc",d.html);p.setAttribute("controls","");p.setAttribute("autoplay","");p.setAttribute("loop","");p.setAttribute("muted","");p.setAttribute("poster","https://static.heygen.ai/hyperframes-oss/docs/images/catalog/blocks/weight-wave.png");document.body.appendChild(p)});<\/script></body></html>`} />

## Install

<InstallCommand command="npx hyperframes add weight-wave" />

That writes `compositions/weight-wave.html`, plus 2 supporting files under `compositions/assets/fonts/`.

## Add it to your video

It runs for 6 seconds at 1920×1080. Paste this into your composition:

```html index.html theme={null}
<div
  data-composition-id="weight-wave"
  data-composition-src="compositions/weight-wave.html"
  data-start="0"
  data-duration="6"
  data-track-index="1"
  data-width="1920"
  data-height="1080"
></div>
```

Move it in time with `data-start`. Put it on a different timeline row with
`data-track-index`. See [data attributes](/concepts/data-attributes) for the rest.

## 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 |
| ------------ | ----------------------------- | -------------------------------------------- | ------------ |
| `text`       | `PRESSURE MOVES THROUGH TYPE` | string                                       |              |
| `color`      | `#f5f5f7`                     | color                                        |              |
| `background` | `#0b0b0d`                     | color                                        |              |
| `weightFrom` | `400`                         | 300 to 1000, step 10                         |              |
| `weightTo`   | `1000`                        | 300 to 1000, step 10                         |              |
| `crestWidth` | `4`                           | 1chars to 24chars, step 0.5chars             |              |
| `sweepSpeed` | `0.5`                         | 0.05passes/s to 3passes/s, step 0.05passes/s |              |
| `slant`      | `-12`                         | -15deg to 0deg, step 0.5deg                  |              |
| `direction`  | `ltr`                         | `ltr`, `rtl`                                 |              |

Set them with `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:

```html wrap theme={null}
<div
  data-composition-id="weight-wave"
  data-composition-src="compositions/weight-wave.html"
  data-variable-values='{"text":"PRESSURE MOVES THROUGH TYPE","color":"#f5f5f7","background":"#0b0b0d","weightFrom":400,"weightTo":1000,"crestWidth":4,"sweepSpeed":0.5,"slant":-12,"direction":"ltr"}'
></div>
```

## Source

<Accordion title={`weight-wave.html`}>
  ```html theme={null}
  <!doctype html>
  <html lang="en">
    <head>
      <meta charset="UTF-8" />
      <meta name="viewport" content="width=1920, height=1080" />
      <title>Weight Wave</title>
      <style>
        /*
          Real variable font, bundled locally — a CDN fetch would be a render-time
          network dependency, and a STATIC font would silently render every
          character at one weight (the whole effect vanishes while nothing errors).
          Subset of Recursive (SIL OFL 1.1) with every axis pinned except the two
          this block drives. Ranges below are the font's REAL fvar records, read
          out of the binary: wght 300..1000 (not 100..900) and slnt -15..0. The
          pinned three are MONO 0 (proportional sans, not the monospace face),
          CASL 0 (linear/neutral, not casual) and CRSV 0 (roman letterforms —
          Recursive's 0.5 default swaps in cursive singlestorey forms as soon as
          slnt goes negative, which would pop mid-wave instead of interpolating).
        */
        @font-face {
          font-family: "Recursive Wave";
          font-style: normal;
          font-weight: 300 1000;
          font-display: block;
          src: url("assets/fonts/Recursive-wght-slnt-latin.woff2") format("woff2");
        }
      </style>
      <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
      <style>
        *,
        *::before,
        *::after {
          margin: 0;
          padding: 0;
          box-sizing: border-box;
        }
        html,
        body {
          background: transparent;
          overflow: hidden;
        }
        body {
          width: 1920px;
          height: 1080px;
        }

        #ww-root {
          position: relative;
          width: 1920px;
          height: 1080px;
          overflow: hidden;
        }

        /* Full-bleed fill lives on a CHILD: the producer can drop a background
           painted on the composition root itself (frame renders black). */
        #ww-bg {
          position: absolute;
          inset: 0;
          background: var(--background, #0b0b0d);
        }

        #ww-stage {
          position: absolute;
          inset: 0;
          display: flex;
          align-items: center;
          justify-content: center;
        }

        #ww-line {
          display: block;
          width: 1760px;
          text-align: center;
          white-space: pre;
          font-family: "Recursive Wave", sans-serif;
          font-size: 132px;
          line-height: 1.15;
          letter-spacing: 0.005em;
          color: var(--color, #f5f5f7);
          /* Default instance: the resting end of the wave. If the variable font
             fails to load, every glyph stays here and the probe below shouts. */
          font-variation-settings:
            "wght" 400,
            "slnt" 0;
        }

        /* Per-character axis stamping target: no transform, no opacity — the
           letterforms themselves change. */
        .ww-ch {
          display: inline-block;
        }
      </style>
    </head>
    <body>
      <div
        id="ww-root"
        data-composition-id="weight-wave"
        data-start="0"
        data-duration="6"
        data-width="1920"
        data-height="1080"
        data-composition-variables='[
          {"id":"text","type":"string","label":"Headline","default":"PRESSURE MOVES THROUGH TYPE","maxLength":64},
          {"id":"color","type":"color","label":"Text color","default":"#f5f5f7"},
          {"id":"background","type":"color","label":"Background","default":"#0b0b0d"},
          {"id":"weightFrom","type":"number","label":"Weight (rest)","default":400,"min":300,"max":1000,"step":10},
          {"id":"weightTo","type":"number","label":"Weight (crest)","default":1000,"min":300,"max":1000,"step":10},
          {"id":"crestWidth","type":"number","label":"Crest width","default":4,"min":1,"max":24,"step":0.5,"unit":"chars"},
          {"id":"sweepSpeed","type":"number","label":"Sweep speed","default":0.5,"min":0.05,"max":3,"step":0.05,"unit":"passes/s"},
          {"id":"slant","type":"number","label":"Slant at crest","default":-12,"min":-15,"max":0,"step":0.5,"unit":"deg"},
          {"id":"direction","type":"enum","label":"Direction","default":"ltr","options":[{"value":"ltr","label":"Left to right"},{"value":"rtl","label":"Right to left"}]}
        ]'
      >
        <div id="ww-bg"></div>

        <div id="ww-stage" class="clip" data-start="0" data-duration="6" data-track-index="0">
          <div id="ww-line"></div>
        </div>

        <script>
          (function () {
            window.__timelines = window.__timelines || {};

            var FONT_FAMILY = '"Recursive Wave", sans-serif';
            /* The bundled font's real fvar bounds — declared once here, and
               mirrored in the variable min/max above. A slider must not offer a
               weight the font cannot render. */
            var WGHT_MIN = 300;
            var WGHT_MAX = 1000;
            var SLNT_MIN = -15;
            var LINE_MAX_WIDTH = 1760;
            var BASE_FONT_SIZE = 132;
            var MIN_FONT_SIZE = 40;

            var root = document.getElementById("ww-root");
            var line = document.getElementById("ww-line");
            var duration = Number(root.getAttribute("data-duration")) || 6;

            var vars =
              window.__hyperframes && window.__hyperframes.getVariables
                ? window.__hyperframes.getVariables()
                : {};

            function num(value, fallback, min, max) {
              var n = Number(value);
              if (!Number.isFinite(n)) n = fallback;
              return Math.min(max, Math.max(min, n));
            }

            var TEXT =
              typeof vars.text === "string" && vars.text.length
                ? vars.text
                : "PRESSURE MOVES THROUGH TYPE";
            var W_FROM = num(vars.weightFrom, 400, WGHT_MIN, WGHT_MAX);
            var W_TO = num(vars.weightTo, 1000, WGHT_MIN, WGHT_MAX);
            var CREST = num(vars.crestWidth, 4, 1, 24);
            var SPEED = num(vars.sweepSpeed, 0.5, 0.05, 3);
            var SLANT = num(vars.slant, -12, SLNT_MIN, 0);
            var RTL = vars.direction === "rtl";

            /* ── Build one span per character ─────────────────────────────────
               Spaces get a span too, so the crest travels at a constant rate in
               index space and the visual gap between words is honoured. */
            var chars = Array.prototype.slice.call(TEXT);
            var spans = chars.map(function (ch) {
              var el = document.createElement("span");
              el.className = "ww-ch";
              el.textContent = ch;
              line.appendChild(el);
              return el;
            });
            var N = spans.length;

            /* Fit at the HEAVIEST instance so the line never overflows mid-sweep;
               the crest widens glyphs as it passes. */
            var fitCanvas = document.createElement("canvas").getContext("2d");
            var heaviest = Math.max(W_FROM, W_TO);
            var fontSize = BASE_FONT_SIZE;
            while (fontSize > MIN_FONT_SIZE) {
              fitCanvas.font = heaviest + " " + fontSize + "px " + FONT_FAMILY;
              if (fitCanvas.measureText(TEXT).width <= LINE_MAX_WIDTH) break;
              fontSize -= 2;
            }
            line.style.fontSize = fontSize + "px";

            /* ── The wave ─────────────────────────────────────────────────────
               Closed form, no accumulators: every frame's state is a pure
               function of the timeline position p, so a direct seek to frame N
               and playing through to frame N produce identical pixels.

                 crest(p) = -CREST + wrap(p * duration * SPEED) * (N - 1 + 2*CREST)
                 f_i      = clamp(0, 1, 1 - |i - crest| / CREST)
                 wght_i   = round(lerp(W_FROM, W_TO, f_i))
                 slnt_i   = lerp(0, SLANT, f_i)

               Per-character stagger is not a separate mechanism — it falls out of
               the crest's distance to each index. */
            var state = { p: 0 };
            var travel = N - 1 + 2 * CREST;

            function paint() {
              var pass = state.p * duration * SPEED;
              var phase = pass - Math.floor(pass); // wraps cleanly: f_i == 0 at both ends
              var crest = -CREST + phase * travel;
              if (RTL) crest = N - 1 - crest;
              for (var i = 0; i < N; i++) {
                var f = 1 - Math.abs(i - crest) / CREST;
                if (f < 0) f = 0;
                else if (f > 1) f = 1;
                var wght = Math.round(W_FROM + (W_TO - W_FROM) * f);
                var slnt = SLANT * f;
                spans[i].style.fontVariationSettings =
                  '"wght" ' + wght + ', "slnt" ' + slnt.toFixed(2);
              }
            }

            var tl = gsap.timeline({ paused: true });
            tl.to(state, { p: 1, duration: duration, ease: "none", onUpdate: paint }, 0);
            paint();
            window.__timelines["weight-wave"] = tl;

            /* ── The trap, made loud ──────────────────────────────────────────
               A static font (or a failed load) renders every character at one
               weight: the effect is invisible and nothing throws.

               Measuring advance width does NOT detect that here. Recursive is
               DUPLEXED — "HAMBURGEFONSTIV" measures exactly 925px at wght 300 and
               at wght 1000, and identically at slnt 0 and -15. (Nice for layout:
               the headline never reflows as the crest passes. Fatal for a
               width-delta probe, which reads every weight as identical and cries
               wolf on a perfectly healthy font.)

               So rasterize and count ink, which cannot be duplexed away, AND ask
               the font-loading API whether the family is actually there. Both are
               needed: ink alone gives a false PASS when the family is missing,
               because the fallback varies its ink with weight too. */
            function probeAxes() {
              var family = "Recursive Wave";
              var loaded = !!(document.fonts && document.fonts.check('100px "' + family + '"'));
              var c = document.createElement("canvas");
              c.width = 1000;
              c.height = 160;
              var ctx = c.getContext("2d", { willReadFrequently: true });
              function ink(weight) {
                ctx.clearRect(0, 0, c.width, c.height);
                ctx.font = weight + ' 100px "' + family + '"';
                ctx.fillStyle = "#fff";
                ctx.fillText("HAMBURGEFONSTIV", 10, 120);
                var data = ctx.getImageData(0, 0, c.width, c.height).data;
                var n = 0;
                for (var i = 3; i < data.length; i += 4) if (data[i] > 8) n++;
                return n;
              }
              var light = ink(WGHT_MIN);
              var black = ink(WGHT_MAX);
              // Only wght is probed: it is the axis whose absence is measurable
              // from JS, and both axes ship in the same file — if wght is live,
              // the variable font loaded. slnt is verified visually.
              return {
                fontLoaded: loaded,
                wghtLive: black > light * 1.2,
                inkAtMinWeight: light,
                inkAtMaxWeight: black,
              };
            }

            function publishProbe() {
              var status = probeAxes();
              status.ok = status.fontLoaded && status.wghtLive;
              window.__WW_FONT_STATUS = status;
              root.setAttribute("data-ww-font", status.ok ? "ok" : "missing-axes");
              if (!status.ok) {
                console.error(
                  "weight-wave: the variable font is not usable (loaded=" +
                    status.fontLoaded +
                    ", ink at wght " +
                    WGHT_MIN +
                    "=" +
                    status.inkAtMinWeight +
                    " vs " +
                    WGHT_MAX +
                    "=" +
                    status.inkAtMaxWeight +
                    "). assets/fonts/Recursive-wght-slnt-latin.woff2 did not load, or was " +
                    "replaced with a static font — every character will render at one weight.",
                );
              }
            }

            if (document.fonts && document.fonts.ready) {
              document.fonts.ready.then(publishProbe);
            } else {
              publishProbe();
            }
          })();
        </script>
      </div>
    </body>
  </html>
  ```
</Accordion>

Tagged `typography` `kinetic-type` `title` `variable-font` `text`.

## Related topics

* [Browse the complete Catalog](/catalog)
* [Add assets and Catalog items in Studio](/studio/assets-and-blocks)
* [Build a richer composition](/go-further)


## Related topics

- [Ripple Waves](/catalog/blocks/ripple-waves.md)
- [Wordmark Tiles](/catalog/components/wordmark-tiles.md)
- [Color grading and film effects](/prompting/color-grading.md)
