Whiteboard sharing

The whiteboard in a meeting is an embedded H5 page (iframe). Stroke sync goes through the whiteboard’s own connection and produces no media streams. On top of that, the meeting layer does one more thing: it manages the “who is sharing the whiteboard right now” status for you, so you don’t have to broadcast it yourself as you would at the SRTC layer.

The whiteboard page’s own capabilities (URL parameters, hiding menus, desktop annotation mode, when it’s destroyed) are exactly the same as at the SRTC layer; see SRTC · Whiteboard. This page only covers how usage differs at the meeting layer.

Get the whiteboard URL

You can read it once you’ve entered the meeting. The SDK has already appended the authorization code, so embed it directly:

await smeeting.enterRoom(/* ... */);

const url = smeeting.getWhiteBoard();
if (url) {
  const iframe = document.createElement("iframe");
  iframe.src = url;
  iframe.style.cssText = "width:100%;height:100%;border:0";
  boardContainer.appendChild(iframe);
}

Whiteboards map one-to-one to meetings—everyone in the same meeting opens the same board. The URL becomes invalid after you exit the meeting.

Whiteboard sharing only broadcasts a status; it doesn’t capture any video:

import { ShareType } from "@seastart/smeeting-web-sdk";

// Start: broadcast "I'm sharing the whiteboard" in the meeting
await smeeting.requestShare(ShareType.WhiteBoard);

// Stop
await smeeting.stopShare();

Only one member in a meeting can share at a time, and screen sharing and the whiteboard are mutually exclusive. When the host has turned on “sharing disabled for the room”, a call from a regular member throws an error.

When someone else opens the whiteboard, you receive a room event; use it to show the whiteboard:

smeeting.onNotifyRoomEvent = (evt: RoomEvent) => {
  switch (evt.type) {
    case CommonRoomEventType.ROOM_SHARE_START:
      if (evt.data.share_type === ShareType.WhiteBoard) {
        showWhiteBoard(smeeting.getWhiteBoard());
      }
      break;
    case CommonRoomEventType.ROOM_SHARE_STOP:
      hideWhiteBoard();
      break;
  }
};

Members who enter mid-meeting don’t receive this event, so check once yourself—the meeting info carries the current sharing status:

const info = smeeting.getRoomInfo();
if (info?.share_state === ShareType.WhiteBoard) {
  // Someone in the meeting is already sharing the whiteboard, so show it on entry
  showWhiteBoard(smeeting.getWhiteBoard());
}

share_state values: 0 no sharing, 1 screen sharing, 2 whiteboard; the sharer is share_uid.

SRTC · Whiteboard—whiteboard page URL parameters, embedding in native apps, lifecycle, and destruction
Events—full definitions of the sharing-related events
SMeeting—method signatures

Overview

Low-code integration

Web SDK

Android SDK

Swift SDK (iOS/macOS)

Server API

Get the whiteboard URL

​Get the whiteboard URL

​Start and stop sharing

​Respond to someone else’s whiteboard sharing

​Related

Get the whiteboard URL

Start and stop sharing

Respond to someone else’s whiteboard sharing

Related