# Signature Pad · Pro

A signature pad with pen-like ink: stroke width follows speed, points are smoothed with curves, and undo and clear are built in. Emits a PNG data URL.

This is a Charcoal UI Pro component. Its source and examples are available with a Pro seat: https://charcoalui.com/pricing

## With a Pro seat

1. Add the registry to components.json:

```json
{
  "registries": {
    "@charcoal": {
      "url": "https://charcoalui.com/r/{name}.json",
      "headers": {
        "Authorization": "Bearer ${CHARCOAL_LICENSE_KEY}"
      }
    }
  }
}
```

2. Copy your licence key from https://charcoalui.com/dashboard and put it in .env.local as CHARCOAL_LICENSE_KEY, then:

```bash
npx shadcn@latest add @charcoal/signature-pad
```

To read Pro source through this MCP server, reconnect it with the header "Authorization: Bearer <licence key>".

## API — Signature Pad
| Prop | Type | Default | Notes |
| --- | --- | --- | --- |
| `onChange` | `(dataUrl: string) => void` | — |  |
| `width` | `number` | `360` |  |
| `height` | `number` | `160` |  |
| `strokeWidth` | `number` | `2.5` |  |
| `color` | `string` | `"var(--foreground)"` |  |
| `className` | `string` | — |  |

See it live: https://charcoalui.com/docs/components/signature-pad