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webengineview will cause performance degradation?

  • I use QT 5.12.3 in windows 10
    I put some widgets in mdiArea by using mdi->addsubwindow(widges)
    if one of the widgets contains webengineview widget, all the widgets in mdiArea will have a delay to move when I drag their title bars.
    if I delete the webengineview in a widget, there will be no delay for all widgets when I try to move them.

  • I just promote the widget to webengineview and nothing is done

  • Lifetime Qt Champion

    So you dont even load a page to the webengineview ?

  • @mrjj yeah, I just new a QWebEngineView like this:
    m_webView = new QWebEngineView;
    it will cause the delay for movement.

  • Lifetime Qt Champion

    ok. thats a bit odd.
    Should not be that heavy.
    If you just use it in a MainWindow, its also lags ?
    Could be something with MDI windows.

  • @mrjj I just tried, it doesn't lag if use in MainWindow, so there is something with MDI windows. thats odd, if I comment the line // ui->verticalLayout_webFrame->addWidget(m_webView);
    it doesn't lag, but it lags (the mouse will go outof the title bar some distance and then the widget starts to move) if this line is added.
    how can I make further checks? thanks a lot

  • Lifetime Qt Champion

    I tried with
    auto m_webView = new QWebEngineView;
    auto it = ui->mdiArea->addSubWindow(m_webView );

    and did get any lag even i made several of them.

    Could you try same code ?
    Only difference is there is no layout.

  • I tried your code, and it lags.
    the attachment is my project (testmdi.rar) and I take a short video (mdi_with_webengine.mp4) to show how it lags.
    As a comparison, the video named 'mdi_demo_by_qt.mp4' is generated using the QT demo 'MDI Example' in Qt 5.12.3 MSVC2017 32 bit.
    In mdi_demo_by_qt.mp4, I think it doesn't lag, but in mdi_with_webengine.mp4, it lags
    As I cannot upload file, I put them in my github ''
    thanks a lot

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