qt5.15.2 QWebEngineView is slow, QWebEnginePage's print function is very slow.

haibianren

Environment:
QT 5.15.2 MSVC2019 32bit
OS: window 10

Reproduce steps:

Open the printme exmaple，replace local html file with remote url (https://github.com/marketplace)

main.cpp

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QApplication app(argc, argv);

    QWebEngineView view;

////////////////////////////////// modification: 
//    view.setUrl(QUrl(QStringLiteral("qrc:/index.html"))); 
    view.setUrl(QUrl("https://github.com/marketplace"));
////////////////////////////////

    view.resize(1024, 750);
    view.show();

    PrintHandler handler;
    handler.setPage(view.page());

    auto printPreviewShortCut = new QShortcut(QKeySequence(Qt::CTRL + Qt::Key_P), &view);
    auto printShortCut = new QShortcut(QKeySequence(Qt::CTRL + Qt::SHIFT + Qt::Key_P), &view);

    QObject::connect(printPreviewShortCut, &QShortcut::activated, &handler, &PrintHandler::printPreview);
    QObject::connect(printShortCut, &QShortcut::activated, &handler, &PrintHandler::print);

    return app.exec();
}

build and run printme，it's slower to open the remote url. Press CTRL + P to preview the page to print，it takes 9-20 seconds, very slow. We tried QT5.9 to build and run printme example, it's very fast to open url, preview page to print.

haibianren

well, QT5.15.0 is fast, finally we choose QT5.15.0

mnbv

Bit old but if anybody finds this post while researching this (and using MSVC), make sure you're building in release mode for performance testing. The debug libs for WebEngine take significantly longer to initialize.

See https://forum.qt.io/topic/52360/qwebengineview-is-very-very-very-slow