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Version: 5.5

Screen share in a group call

This page provides a code example for screen share in a group call (conference).

Sender - Prepare screen capture and start screen capture​

  1. After joining a group call, you can get a list of screens (monitors) and windows (applications) that can be captured.

    class YourApplication {
    private:
        PlanetKit::PlanetKitConference m_pConference;
    }

    void YourApplication::RefreshScreenShareList() {
        PlanetKit::PlanetKitManagerPtr pManager = PlanetKit::PlanetKitManager::GetInstance();
        PlanetKit::ScreenShareControllerPtr pController = pManager->GetScreenShareController();
        PlanetKit::ScreenShareInfoArray arrScreenShare;
        pController->GetScreenShareInfos(arrScreenShare);
    }

  2. Start transmitting screen capture by calling StartMyScreenShare(). The target to capture can be selected from the Array obtained in Step 1.

    • The strSubgroupName parameter determines the destination subgroup of the screen share, and if it is NullOptional, the screen share will be sent to the main room.
    • You can check the result with a callback function of the ResultCallback type. If successful, you can register a window for rendering.
    void YourApplication::StartScreenShare(PlanetKit::ScreenShareInfoPtr pTarget, const WStringOptional& strSubgroupName) {
        // This is result callback function.
        auto callback = [](void* pUserData, bool bSuccess) {
            // You can check result of `StartScreenShare` with parameter `bSuccess`.
            if(bSuccess == true) {
                // You can set rendering window.
                YourApplication* pApp = (YourApplication*)pUserData;
                pApp->m_pConference->AddMyScreenShareVideoView(pApp->m_hScreenShareRenderWnd);
            }
        };

        // Start screen share.
        bool bResult = m_pConference->StartMyScreenShare(
            pTarget,
            strSubgroupName,
            this,
            callback
        );
    }

Sender - Stop sending screen share​

Call StopMyScreenShare() to stop screen share and get the result with a callback function of the ResultCallback type as in Step 2 of Prepare screen capture and start screen capture.

void YourApplication::StopScreenShare() {
    ...
    // You can use callback parameter by using lambda function.
    bool bResult = false = m_pConference->StopMyScreenShare(nullptr, [](void* pUserData, bool bSuccess) {
        // You can check result of `StopMyScreenShare()` with the `bSuccess` parameter.
        if(bSuccess == true) {
        ...
        }
    });

    // Remove rendering window.
    m_pConference->RemoveMyScreenShareVideoView(m_hScreenShareRenderWnd);
}

Receiver - Receive screen share update events​

Check whether a peer's screen share has started or stopped through the OnScreenShareUpdated event of IPeerControlEvent.

class PeerControlEventListener : public PlanetKit::IPeerControlEvent {
public:
    void OnScreenShareUpdated(PlanetKit::PeerControlPtr pPeerControl, PlanetKit::SubgroupPtr pSubgroup, PlanetKit::EScreenShareState eState) override {
        std::wstring message = L"OnScreenShareUpdated, User=" + pPeerControl->GetPeer()->GetUserID()->GetID().c_str() + L" ScreenShareState=" + std::to_wstring(eState) + L"\n";
        OutputDebugStringW(message.c_str());

        if(eState == PlanetKit::EScreenShareState::PLNK_SCREEN_SHARE_STATE_ENABLED) {
            m_pYourApp->RequestPeerScreenShare(pPeerControl, pSubgroup);
        }
        else {
            m_pYourApp->StopPeerScreenShare();
        }
    }
private:
    YourApplication* m_pYourApp;  // Prepare instance of YourApplication
};

Receiver - Request a peer's screen share video and render the video​

To request a screen share video from the peer, call StartScreenShare() of PeerControl.

To render the received screen share video, call SetScreenShareView() of PeerControl.

class YourApplication {
public:
    void RequestPeerScreenShare(PlanetKit::PeerControlPtr pPeerControl, PlanetKit::SubgroupPtr pSubgroup) {
        auto callback = [](void* pUserData, bool bSuccess) {
            YourApplication* pApp = (YourApplication*)pUserData;
            if(bSuccess == true) {
                // Render peer's screen share.
                pApp->m_pScreenSharePeerControl->SetScreenShareView(m_hScreenShareRenderWnd);
            }
        }

        // You can keep instance of PeerControl for the peer who is performing screen share.
        m_pScreenSharePeerControl = pPeerControl;

        // Start peer's screen share.
        pPeerControl->StartScreenShare(pSubgroup->GetSubgroupName(), this, callback);
    }
private:
    PlanetKit::PeerControlPtr m_pScreenSharePeerControl;
}

Receiver - Stop receiving a peer's screen share video​

To stop receiving the peer's screen share video, call ClearScreenShareView() of PeerControl to stop rendering, and then call StopScreenShare() of PeerControl.

class YourApplication {
public :
    void StopPeerScreenShare() {
        // Remove render.
        m_pScreenSharePeerControl->ClearScreenShareView();

        // Request to stop screen share.
        m_pScreenSharePeerControl->StopScreenShare();
    }
}