Forms

Signature Pad

Canvas signature input with smoothed strokes, undo/clear, and data-URL output.

Import

tsx

import { SignaturePad } from "@cronus-ui/ui";

bash

npx cronus-ui add signature-pad

Examples

Capture a signature

Draw with mouse, touch, or pen — samples become midpoint-smoothed quadratic curves, and the ink follows the surrounding text color token. `onChange` reports a PNG data URL after every committed stroke (or `null` once emptied); the overlaid ghost actions undo the last stroke or clear the pad.

Awaiting signature

tsx

function SignaturePadDemo() {
  const [signature, setSignature] = useState<string | null>(null);

  return (
    <div className="flex w-full max-w-sm flex-col gap-3">
      <SignaturePad onChange={setSignature} aria-label="Contract signature" />
      <div className="flex h-9 items-center justify-between gap-3 text-xs text-fg-tertiary">
        <span>{signature ? "Signature captured" : "Awaiting signature"}</span>
        {signature ? (
          <img
            src={signature}
            alt="Captured signature preview"
            className="h-full rounded-md border border-border bg-surface-base"
          />
        ) : null}
      </div>
    </div>
  );
}

Disabled

Freeze the pad while a document loads or is already countersigned — pointer input is ignored and the overlay actions disable.

tsx

<SignaturePad disabled aria-label="Signature" />

.cronus

The same component declared in Cronus. Emitted at build time from the audit fixtures — the kernel renders it as HTML with no React.

PortedParity: MatchGeometry 1/1Pixel diff 0 pxLogic 1/1Parity scoreboard

default.cronus

app "audit-fixtures" {
  port 5176
}

style {
  preset aurora
  theme dark
}

component SignaturePadDefault layout:inline style:signature-pad {
  aria-label:"Signature pad"
  label "Signature pad"
}

page "/audit/signature-pad/default" type:custom {
  use SignaturePadDefault
}

API Reference

Generated from the component's exported types.

SignaturePadProps

Extends Omit<HTMLAttributes<HTMLDivElement>, "onChange">

Prop	Type	Default	Description
`onChange`	`(dataUrl: string \| null) => void`	—	Fired when a stroke is committed, undone, or the pad is cleared. Receives a PNG data URL of the drawing, or `null` once the pad is empty again.
`disabled`	`boolean`	`false`	Freezes the pad: pointer input is ignored and the overlay actions disable.
`className`	`string`	—	Additional class names merged onto the root.
`children`	`ReactNode`	—	Contents of the component.
`id`	`string`	—	DOM id of the root element.