---
title: "Rich text — React"
description: "Text boxes can mix styles, like a bold word or a red sentence. How they're stored, how your toolbar formats them, and how to show your own fonts."
framework: "React"
source: "https://www.embedpdf.com/docs/headless/react/concepts/rich-text"
---

# Rich text

A text box (a free text annotation) can mix styles: a bold word, a red sentence, a bigger heading.
Double-click the box below, select a word, and use the buttons, or press `Ctrl`/`Cmd` with `B`, `I`
or `U` while you type:

**`rich-text.tsx`**

```tsx
import { useEffect, useRef } from 'react';
import { Viewer, DocumentGate } from '@embedpdf/react/runtime';
import type { OpenInput } from '@embedpdf/react/runtime';
import { Stage, stagePlugin, useStage } from '@embedpdf/react/stage';
import { RenderLayer, renderPlugin } from '@embedpdf/react/render';
import { SelectionLayer, selectionPlugin } from '@embedpdf/react/selection';
import { interactionPlugin } from '@embedpdf/react/interaction';
import {
  AnnotationLayer,
  annotationPlugin,
  useAnnotation,
  useAnnotationProperties,
  useAnnotationState,
} from '@embedpdf/react/annotation';
import { localEngine } from '@embedpdf/engine';

import './rich-text.css';

const engine = localEngine();
const plugins = [
  stagePlugin(),
  renderPlugin(),
  interactionPlugin(),
  selectionPlugin(),
  annotationPlugin(),
];

const notice = async (): Promise<OpenInput> => {
  const response = await fetch('/pdfs/notice.pdf');
  return { kind: 'bytes', id: 'notice', bytes: new Uint8Array(await response.arrayBuffer()) };
};

// On load: the document's rich text box, selected.
function SelectRichText() {
  const annotation = useAnnotation();
  const stage = useStage();
  const ready = useAnnotationState((state) => state.status === 'ready');
  const done = useRef(false);

  useEffect(() => {
    if (!ready || done.current) return;
    done.current = true;
    const richText = annotation.list().find((each) => each.nm === 'rich-text');
    if (!richText) return;
    annotation.selection.set([richText.ref]);
    stage.reveal(richText.page, { rect: richText.rect });
  }, [annotation, stage, ready]);

  return null;
}

type Format = 'bold' | 'italic' | 'underline';

// The same calls style the selected words while typing, and the whole box otherwise.
function RichTextToolbar() {
  const annotation = useAnnotation();
  const { properties, values, mixed } = useAnnotationProperties();
  const hasText = properties.some((property) => property.control === 'textFormat');
  // On when every selected word has it; `mixed` lists what the words disagree on.
  const isOn = (format: Format) => values[format] === true && !mixed.includes(format);

  return (
    <div className="toolbar">
      {(['bold', 'italic', 'underline'] as const).map((format) => (
        <button
          key={format}
          type="button"
          className={`button ${format}`}
          aria-pressed={isOn(format)}
          disabled={!hasText}
          onClick={() => annotation.text.toggleFormat(format)}
        >
          {format[0]!.toUpperCase()}
        </button>
      ))}
      <button
        type="button"
        className="button"
        disabled={!hasText}
        onClick={() => annotation.selection.update({ fontColor: '#c00000' })}
      >
        Red
      </button>
      <button
        type="button"
        className="button"
        disabled={!hasText}
        onClick={() => annotation.selection.update({ fontSize: values.fontSize === 24 ? 16 : 24 })}
      >
        {values.fontSize === 24 ? '16 pt' : '24 pt'}
      </button>
      <p className="hint">Ctrl or Cmd with B, I or U works while you type</p>
    </div>
  );
}

export default function App() {
  return (
    <Viewer engine={engine} plugins={plugins} initialDocuments={[{ source: notice }]}>
      <DocumentGate fallback={<p className="loading">Loading…</p>}>
        <SelectRichText />
        <RichTextToolbar />
        <Stage className="stage">
          {() => (
            <>
              <RenderLayer />
              <SelectionLayer />
              <AnnotationLayer />
            </>
          )}
        </Stage>
      </DocumentGate>
    </Viewer>
  );
}
```

**`rich-text.css`**

```css
/* Colors */
:root {
  --ink: #1a2748;
  --text: #3b4b7a;
  --muted: #5a6b92;
  --line: #e6eaf2;
  --line-strong: #dce8fc;
  --surface: #ffffff;
  --tint: #f3f7fe;
  --canvas: #f7f9fc;
  --accent: #054fb3;
  --focus: #7db6ff;
  --shadow: rgb(7 32 76 / 0.04);
}

/* The controls, above the pages */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font: inherit;
  font-size: 13px;
  font-weight: 550;
  line-height: 1.1;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 8px 12px;
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 1px 2px var(--shadow);
  transition:
    background-color 0.15s ease,
    border-color 0.15s ease;
}

.button:hover {
  background: var(--tint);
  border-color: var(--line-strong);
}

.button:active {
  transform: translateY(1px);
}

.button:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.button[aria-pressed='true'] {
  color: var(--accent);
  background: var(--tint);
  border-color: var(--line-strong);
}

.button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.hint {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

/* Each format button shows its own format */
.bold {
  font-weight: 800;
}

.italic {
  font-style: italic;
}

.underline {
  text-decoration: underline;
}

/* The pages */
.stage {
  height: 420px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--canvas);
  box-shadow:
    0 1px 2px var(--shadow),
    0 18px 40px -28px rgb(7 32 76 / 0.28);
}

.loading {
  margin: 0;
  padding: 24px 0;
  text-align: center;
  font-size: 13px;
  color: var(--muted);
}
```

## How it's stored

A text box has a **body style**, which is how its text looks by default, and **paragraphs** of
**runs**. A run is a piece of text with the styles it changes, and nothing else: a bold word in a
regular box is one run with `{ weight: 700 }`.

```ts
annotation.richText;
// {
//   body: { family: 'Helvetica', size: 12, color: '#000000' },
//   paragraphs: [{ runs: [{ text: 'Paid ' }, { text: 'in full', style: { weight: 700 } }] }],
// }
```

The engine writes it the way Acrobat does, so the formatting is the same there. The engine docs
have the full model: [Free text](https://www.embedpdf.com/docs/engine/annotations/free-text#rich-text).

## Format from your toolbar

The same calls work while someone types in a box and when boxes are only selected:

```ts
await annotation.selection.update({ bold: true });
await annotation.selection.update({ fontSize: 24, fontColor: '#c00000' });
await annotation.text.toggleFormat('italic'); // italic on, or off if all of it already is
```

Where a change lands depends on what's selected:

- **Words selected while typing**: the change styles those words.
- **A caret while typing**: the change is for the text typed next, as in a word processor. Nothing
  changes until someone types, and moving the caret drops it.
- **Otherwise**: it styles all the text of every selected box. A word with its own style follows
  the change: turn the box red, and a blue word turns red too.

A property that isn't about text, such as opacity or the border, always applies to the whole box.

To show the state in your toolbar, [`useAnnotationProperties()`](../annotations/selecting#a-style-panel)
reports what the next change would style:

- **Words selected**: `values.bold` is true when every selected word is bold, and `mixed` lists what
  the words disagree on.
- **A caret**: the style of the text before it (at the start of a line, the text after it), with the
  changes made at the caret since.
- **A selected box**: all of its text, the way selected words read.

Text boxes also give you `textFormat` properties, so a style panel shows the bold, italic and
underline buttons without extra code.

> The engine's own update keeps the PDF's rule: `fontColor`, `fontSize` and `fontFamily` change the
> box's body style, and a word with its own style keeps it. See
> [Free text](https://www.embedpdf.com/docs/engine/annotations/free-text#rich-text).

## When it's saved

Typing is written after a short pause, at every format change, and when editing ends, so the engine
never gets half a word. `documents.download()` waits for the last write, so the file you download has
everything the user typed.

## Show your own fonts

The engine puts a font into the PDF, and the browser draws the text while people type, in the same
font: the fonts plugin (`fontsPlugin()`, from the `fonts` entry) hands the browser the file the
engine writes with. Register the font with the engine:

**`web-font.ts`**

```typescript
import { localEngine } from '@embedpdf/engine';

export const engine = localEngine(); // the engine you give the viewer

const data = await fetch('/fonts/brand-sans.ttf').then((response) => response.arrayBuffer());

await engine.fonts.register({ key: 'brand-sans', data });
```

The key is the font's name: `fontFamily: 'brand-sans'` on a text box. The standard PDF fonts need
nothing: they show in the engine's own faces. Without the fonts plugin, a box shows in its standard
font, or in Helvetica. More in [Fonts](https://www.embedpdf.com/docs/engine/documents/fonts).

## Draw your own text box

The annotation layer's text box already edits rich text. If you [draw text boxes
yourself](../annotations/custom-rendering), `useRichTextEditor()` makes your element the editor:
it draws the runs, turns typing back into runs, keeps the caret when the style changes, and handles
pasting, input methods and the format shortcuts:

**`branded-text-box.tsx`**

```tsx
import { useRichTextEditor, type AnnotationRendererProps } from '@embedpdf/react/annotation';

// The box fills its frame (`width` and `height` 100% in your CSS) and draws
// it; the editor inside fills the box.
export function BrandedTextBox({ annotation }: AnnotationRendererProps) {
  const editor = useRichTextEditor(annotation);

  return (
    <div className={editor.editing ? 'text-box editing' : 'text-box'}>
      <div ref={editor.ref} style={editor.style} />
    </div>
  );
}
```

**`branded-text-box.tsx`**

```tsx
import { useEffect, useRef } from 'react';
import { Viewer, DocumentGate } from '@embedpdf/react/runtime';
import type { OpenInput } from '@embedpdf/react/runtime';
import { Stage, stagePlugin, useStage } from '@embedpdf/react/stage';
import { RenderLayer, renderPlugin } from '@embedpdf/react/render';
import { SelectionLayer, selectionPlugin } from '@embedpdf/react/selection';
import { interactionPlugin } from '@embedpdf/react/interaction';
import {
  AnnotationLayer,
  annotationPlugin,
  useAnnotation,
  useAnnotationState,
  useRichTextEditor,
  type AnnotationRenderer,
  type AnnotationRendererProps,
} from '@embedpdf/react/annotation';
import { localEngine } from '@embedpdf/engine';

import './branded-text-box.css';

const engine = localEngine();
const plugins = [
  stagePlugin(),
  renderPlugin(),
  interactionPlugin(),
  selectionPlugin(),
  annotationPlugin(),
];

const notice = async (): Promise<OpenInput> => {
  const response = await fetch('/pdfs/notice.pdf');
  return { kind: 'bytes', id: 'notice', bytes: new Uint8Array(await response.arrayBuffer()) };
};

// Your own text box, in your app's look: it fills its frame, which the layer
// places and turns like the text box. The element inside is the editor and
// fills the box, so the box draws the fill, border and padding.
function BrandedTextBox({ annotation }: AnnotationRendererProps) {
  const editor = useRichTextEditor(annotation);

  return (
    <div className={editor.editing ? 'text-box editing' : 'text-box'}>
      <div ref={editor.ref} style={editor.style} />
    </div>
  );
}

const RENDERERS: AnnotationRenderer[] = [
  { for: (annotation) => annotation.subtype === 'free-text', component: BrandedTextBox },
];

// On load: the document's text box, selected, drawn by your component.
function SelectTextBox() {
  const annotation = useAnnotation();
  const stage = useStage();
  const ready = useAnnotationState((state) => state.status === 'ready');
  const done = useRef(false);

  useEffect(() => {
    if (!ready || done.current) return;
    done.current = true;
    const textBox = annotation.list().find((each) => each.nm === 'text-box');
    if (!textBox) return;
    annotation.selection.set([textBox.ref]);
    stage.reveal(textBox.page, { rect: textBox.rect });
  }, [annotation, stage, ready]);

  return null;
}

// The formatting calls work on your element as they do on the built-in one.
function FormatButtons() {
  const annotation = useAnnotation();
  const hasText = useAnnotationState((state) =>
    state.selected.some((selected) => selected.subtype === 'free-text'),
  );

  return (
    <div className="toolbar">
      {(['bold', 'italic', 'underline'] as const).map((format) => (
        <button
          key={format}
          type="button"
          className={`button ${format}`}
          disabled={!hasText}
          onClick={() => annotation.text.toggleFormat(format)}
        >
          {format[0]!.toUpperCase()}
        </button>
      ))}
    </div>
  );
}

export default function App() {
  return (
    <Viewer engine={engine} plugins={plugins} initialDocuments={[{ source: notice }]}>
      <DocumentGate fallback={<p className="loading">Loading…</p>}>
        <SelectTextBox />
        <FormatButtons />
        <Stage className="stage">
          {() => (
            <>
              <RenderLayer />
              <SelectionLayer />
              <AnnotationLayer renderers={RENDERERS} />
            </>
          )}
        </Stage>
      </DocumentGate>
    </Viewer>
  );
}
```

**`branded-text-box.css`**

```css
/* Colors */
:root {
  --ink: #1a2748;
  --text: #3b4b7a;
  --muted: #5a6b92;
  --line: #e6eaf2;
  --line-strong: #dce8fc;
  --surface: #ffffff;
  --tint: #f3f7fe;
  --canvas: #f7f9fc;
  --accent: #054fb3;
  --focus: #7db6ff;
  --shadow: rgb(7 32 76 / 0.04);
  --brand: #7c3aed;
  --brand-tint: #f5f0ff;
}

/* The controls, above the pages */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font: inherit;
  font-size: 13px;
  font-weight: 550;
  line-height: 1.1;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 8px 12px;
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 1px 2px var(--shadow);
  transition:
    background-color 0.15s ease,
    border-color 0.15s ease;
}

.button:hover {
  background: var(--tint);
  border-color: var(--line-strong);
}

.button:active {
  transform: translateY(1px);
}

.button:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.button[aria-pressed='true'] {
  color: var(--accent);
  background: var(--tint);
  border-color: var(--line-strong);
}

.button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

/* Each format button shows its own format */
.bold {
  font-weight: 800;
}

.italic {
  font-style: italic;
}

.underline {
  text-decoration: underline;
}

/* Your own text box */
.text-box {
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  padding: 6px 10px;
  overflow: hidden;
  background: var(--brand-tint);
  border-left: 4px solid var(--brand);
  border-radius: 4px 10px 10px 4px;
  box-shadow: 0 6px 16px -10px rgb(76 29 149 / 0.45);
}

.text-box.editing {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}

/* The pages */
.stage {
  height: 420px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--canvas);
  box-shadow:
    0 1px 2px var(--shadow),
    0 18px 40px -28px rgb(7 32 76 / 0.28);
}

.loading {
  margin: 0;
  padding: 24px 0;
  text-align: center;
  font-size: 13px;
  color: var(--muted);
}
```

> **Try it:** double-click the box and type. The buttons format the selected words, as on the
> built-in box.

`editor.style` is the box's body style as CSS: font, size, color and alignment. It also makes the element fill its parent: the
text is laid out at 16 px or more and drawn back at the box's size, so iOS doesn't zoom the page in
when the box takes focus. Draw the box's fill, border and padding on the parent, as above; anything
on the element itself would scale with the text. The formatting calls above work on your element as
they do on the built-in one.