# Remotion Rule: Measuring Text

> Remotion skill rule: Measuring text dimensions, fitting text to containers, and checking overflow. Part of the official Remotion Agent Skill for programmatic video in React.

## Install

Save the content below to `.claude/skills/` or append to your `CLAUDE.md`:

## Quick Use

```bash
npx skills add remotion-dev/skills
```

This rule activates automatically when working with measuring text in a Remotion project.

---

## Intro

Measuring text dimensions, fitting text to containers, and checking overflow. Part of the [Remotion AI Skill](https://tokrepo.com/en/workflows/57997ead-c8fa-409c-916f-28bbc0adc8d9) — the official Agent Skill for programmatic video creation in React.

**Best for**: Developers using Remotion for measuring text
**Works with**: Claude Code, OpenAI Codex, Cursor

---

## Rule Content

# Measuring text in Remotion

## Prerequisites

Install @remotion/layout-utils if it is not already installed:

```bash
npx remotion add @remotion/layout-utils
```

## Measuring text dimensions

Use `measureText()` to calculate the width and height of text:

```tsx
import { measureText } from "@remotion/layout-utils";

const { width, height } = measureText({
  text: "Hello World",
  fontFamily: "Arial",
  fontSize: 32,
  fontWeight: "bold",
});
```

Results are cached - duplicate calls return the cached result.

## Fitting text to a width

Use `fitText()` to find the optimal font size for a container:

```tsx
import { fitText } from "@remotion/layout-utils";

const { fontSize } = fitText({
  text: "Hello World",
  withinWidth: 600,
  fontFamily: "Inter",
  fontWeight: "bold",
});

return (
  <div
    style={{
      fontSize: Math.min(fontSize, 80), // Cap at 80px
      fontFamily: "Inter",
      fontWeight: "bold",
    }}
  >
    Hello World
  </div>
);
```

## Checking text overflow

Use `fillTextBox()` to check if text exceeds a box:

```tsx
import { fillTextBox } from "@remotion/layout-utils";

const box = fillTextBox({ maxBoxWidth: 400, maxLines: 3 });

const words = ["Hello", "World", "This", "is", "a", "test"];
for (const word of words) {
  const { exceedsBox } = box.add({
    text: word + " ",
    fontFamily: "Arial",
    fontSize: 24,
  });
  if (exceedsBox) {
    // Text would overflow, handle accordingly
    break;
  }
}
```

## Best practices

**Load fonts first:** Only call measurement functions after fonts are loaded.

```tsx
import { loadFont } from "@remotion/google-fonts/Inter";

const { fontFamily, waitUntilDone } = loadFont("normal", {
  weights: ["400"],
  subsets: ["latin"],
});

waitUntilDone().then(() => {
  // Now safe to measure
  const { width } = measureText({
    text: "Hello",
    fontFamily,
    fontSize: 32,
  });
});
```

**Use validateFontIsLoaded:** Catch font loading issues early:

```tsx
measureText({
  text: "Hello",
  fontFamily: "MyCustomFont",
  fontSize: 32,
  validateFontIsLoaded: true, // Throws if font not loaded
});
```

**Match font properties:** Use the same properties for measurement and rendering:

```tsx
const fontStyle = {
  fontFamily: "Inter",
  fontSize: 32,
  fontWeight: "bold" as const,
  letterSpacing: "0.5px",
};

const { width } = measureText({
  text: "Hello",
  ...fontStyle,
});

return <div style={fontStyle}>Hello</div>;
```

**Avoid padding and border:** Use `outline` instead of `border` to prevent layout differences:

```tsx
<div style={{ outline: "2px solid red" }}>Text</div>
```

---

## Source & Thanks

> Created by [Remotion](https://github.com/remotion-dev). Licensed under MIT.
> [remotion-dev/skills](https://github.com/remotion-dev/skills) — Rule: `measuring-text`

Part of the [Remotion AI Skill](https://tokrepo.com/en/workflows/57997ead-c8fa-409c-916f-28bbc0adc8d9) collection on TokRepo.

---
Source: https://tokrepo.com/en/workflows/7c51fb5b-4260-455e-9f73-3d0b11015d99
Author: Skill Factory