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Whiteboard sharing

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The Video SDK for macOS lets an app share a whiteboard within a session, allowing users to start, view, and collaborate on a digital canvas. Manage this feature through the dedicated ZMVideoSDKWhiteboardHelper.

Integrate the module

To add whiteboard support to your app, you will primarily use the ZMVideoSDKWhiteboardHelper interface, which is part of the ZMVideoSDKShareHelper interface. You can also manage events using the ZMVideoSDKDelegate protocol.

Share and manage the whiteboard

These helper classes are available for you to manage the whiteboard.

MethodPurpose
getWhiteboardHelper()Retrieves the instance of the whiteboard helper.
canStartShareWhiteboard()Checks if the current user is permitted to start a new whiteboard.
startShareWhiteboard()Starts a new, blank whiteboard session.
canStopShareWhiteboard()Checks if the current user can stop the active whiteboard share.
stopShareWhiteboard()Stops the current whiteboard share.
// 1. Get the Whiteboard Helper
if let whiteboardHelper = ZMVideoSDK.shared().getShareHelper().getWhiteboardHelper() {
    // 2. Start Sharing
    if whiteboardHelper.canStartShareWhiteboard() {
        let result = whiteboardHelper.startShareWhiteboard()
        // Check 'result' for success (.success)
    }

    // 3. Stop Sharing
    if whiteboardHelper.canStopShareWhiteboard() {
        let result = whiteboardHelper.stopShareWhiteboard()
        // Check 'result' for success
    }
}

View or subscribe to the whiteboard

Use the SDK interfaces subscribeWhiteboard, unSubscribeWhiteboard, setWhiteboardViewPos, and setWhiteboardViewSize to control the display of the whiteboard in a dedicated window or view. You manage the position and size using NSPoint and NSSize.

MethodPurpose
subscribeWhiteboardDisplays the whiteboard view when someone is sharing the whiteboard.
unSubscribeWhiteboardCloses the whiteboard view.
setWhiteboardViewPosSets the top-left position (NSPoint) of the whiteboard view.
setWhiteboardViewSizeSets the size (NSSize) of the whiteboard view.
isOtherSharingWhiteboardChecks if any other user is currently sharing a whiteboard.

To view the whiteboard

// Get the helper as shown above
if let whiteboardHelper = ZMVideoSDK.shared().getShareHelper().getWhiteboardHelper() {
    // 1. Subscribe to the whiteboard on your selected NSWindow
    whiteboardHelper.subscribeWhiteboard(selectedNSWindow)

    // 2. Set the position and size of the whiteboard window/view
    let position = NSPoint(x: 100, y: 100) // e.g. x=100, y=100
    let size = NSSize(width: 800, height: 600) // e.g. width=800, height=600

    whiteboardHelper.setWhiteboardViewPos(position)
    whiteboardHelper.setWhiteboardViewSize(size)
}

To stop viewing the whiteboard

// Get the helper as shown above
if let whiteboardHelper = ZMVideoSDK.shared().getShareHelper().getWhiteboardHelper() {
    whiteboardHelper .unSubscribeWhiteboard()
}

Whiteboard events and status changes

You'll handle whiteboard events in your ZMVideoSDKDelegate implementation.

CallbackMethodPurpose
(void)onUserWhiteboardShareStatusChanged:(ZMVideoSDKUser *)user whiteboardHelper:(ZMVideoSDKWhiteboardHelper *)whiteboardHelper {}Called when any user starts or stops sharing a whiteboard. This is your cue to subscribe or unsubscribe.
ZMVideoSDKUser.getWhiteboardStatus()Returns a user's current whiteboard status (.started or .stopped).
// Implement this method in your class that conforms to ZMVideoSDKDelegate
func onUserWhiteboardShareStatusChanged(_ user: ZMVideoSDKUser, whiteboardHelper: ZMVideoSDKWhiteboardHelper) {
    if user.getWhiteboardStatus() == ZMVideoSDKWhiteboardStatus_Started {
        // A user has started sharing a whiteboard. Subscribe to the whiteboard on your selected NSWindow
        whiteboardHelper.subscribeWhiteboard(selectedNSWindow)

        // 2. Set the position and size of the whiteboard window/view
        let position = NSPoint(x: 100, y: 100)
        let size = NSSize(width: 800, height: 600)
        whiteboardHelper.setWhiteboardViewPos(position)
        whiteboardHelper.setWhiteboardViewSize(size)
    } else {
        // The whiteboard sharing has ended. Unsubscribe to close the view.
        whiteboardHelper.unSubscribeWhiteboard()
    }
}

Export whiteboard content

Export the whiteboard as a PDF document.

Method/EnumPurpose
(ZMVideoSDKErrors)exportWhiteboard:(ZMVideoSDKExportFormat)formatTriggers the asynchronous export process. Currently supports .PDF.
ZMVideoSDKExportFormatThe enum value to specify PDF as the export format.
(void)onWhiteboardExported:(ZMVideoSDKExportFormat)format data:(unsigned char *)data dataLength:(long)length {}The delegate callback that provides the exported file data as an unsigned char *(Objective-C) or UnsafeMutablePointer<UInt8> (Swift) object.

To export and retrieve the data

// 1. Trigger the export
if let whiteboardHelper = ZMVideoSDK.shared().getShareHelper().getWhiteboardHelper() {
    whiteboardHelper.exportWhiteboard(ZMVideoSDKExportFormat_PDF)
}

// 2. Receive the data in your delegate
func onWhiteboardExported(_ format: ZMVideoSDKExportFormat, data: UnsafeMutablePointer<UInt8>, dataLength length: Int) {
    if format == ZMVideoSDKExportFormat_PDF {
        // 'data' is the Swift UnsafeMutablePointer<UInt8> object of the PDF file.
        // You can now write these data to a file on the device.
        savePdfFile(data)
    }
}

Manage the data

Because the whiteboard data isn't stored in the cloud, you'll need to handle the data storage. Data can be lost when someone stops sharing the whiteboard, a user leaves a session, or when a user joins a sub-session, or when the app crashes or has network connectivity issues.

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