Embed

Embedding is a simple way to include the app in your website. Add the following code to your website:

<iframe
  id="butterfly"
  src="https://web.butterfly.linwood.dev/embed"
  width="100%"
  height="500px"
  allowtransparency="true"
></iframe>

Options

Option	ประเภท	Default	คำอธิบาย
บันทึก	Boolean (true, false)	true	Enable save. If disabled, only an exit button will be shown
editable	Boolean (true, false)	true	Enable editing. If disabled, the document will be read-only
language	String (…, system, user)	user	Language of the document. If system, the language will be detected from the browser. If user, the language will set to the users preference

Messaging

The embed uses browser postMessage events. Send messages to the iframe with iframe.contentWindow.postMessage({ type, message }, origin). Butterfly sends messages back to the parent window with the same shape: { type: string, message?: unknown }.

See the embedding example for a live page that sends messages to the iframe and listens for messages from it.

<iframe
  id="butterfly"
  src="https://web.butterfly.linwood.dev/embed?save=true&editable=true"
  width="100%"
  height="500"
></iframe>

<script>
  const butterflyOrigin = 'https://web.butterfly.linwood.dev';
  const butterfly = document.querySelector('#butterfly');

  function sendToButterfly(type, message) {
    butterfly.contentWindow.postMessage({ type, message }, butterflyOrigin);
  }

  window.addEventListener('message', (event) => {
    if (
      event.origin !== butterflyOrigin ||
      event.source !== butterfly.contentWindow
    ) {
      return;
    }

    const { type, message } = event.data ?? {};

    if (type === 'save') {
      const documentBytes = Array.from(message);
      console.log('Save requested by the embed', documentBytes);
    }

    if (type === 'change') {
      console.log('Document changed', message);
    }

    if (type === 'getData') {
      console.log('Current document bytes', message);
    }

    if (type === 'render') {
      const image = new Image();
      image.src = `data:image/png;base64,${message}`;
      document.body.append(image);
    }
  });

  butterfly.addEventListener('load', () => {
    sendToButterfly('getData');

    sendToButterfly('render', {
      x: 0,
      y: 0,
      width: 600,
      height: 400,
      scale: 1,
      renderBackground: true,
    });
  });
</script>

To load document bytes into the embed, send an array of byte values:

sendToButterfly('setData', documentBytes);

Events

Listen for events with window.addEventListener('message', ...).

บันทึก

The save event is emitted when the user clicks the save button.

Parameters:

• message (Type List<int>): The data of the document.

exit

The exit event is emitted when the user clicks the exit button.

Parameters:

• message (Type List<int>): The data of the document.

change

The change event is emitted when the user changes the document.

Parameters:

• message (Type List<int>): The data of the document.

Methods

Call methods with iframe.contentWindow.postMessage(...). Methods that return data send another message back with the same type.

getData

The getData method returns the data of the document.

No parameters. Returns: List<int>

setData

The setData method sets the data of the document.

Parameters:

• data (Type List<int>): The data of the document.

render

The render method renders the document to a png image.

Parameters:

• x (Type Number): The x position of the exported area.
• y (Type Number): The y position of the exported area.
• width (Type Number): The width of the image.
• height (Type Number): The height of the image.
• scale (Type Number): The scale of the image.
• renderBackground (Type Boolean): If true, the background will be rendered.

Returns: String (Base64 encoded image)

renderSVG

The renderSVG method renders the document to a svg image.

Parameters:

• x (Type Number): The x position of the exported area.
• y (Type Number): The y position of the exported area.
• width (Type Number): The width of the image.
• height (Type Number): The height of the image.
• renderBackground (Type Boolean): If true, the background will be rendered.

Returns: String (SVG)