How to render WebEngineView correctly after scrolling?

Matty

Saving an image of a webpage with a WebEngineView works fine, but when I want to scroll and save another image, the resulting image does not show the website has been scrolled (it shows the top of the webpage).

My question is: how do I scroll down in the QWebEngineView then save a screen shot that shows the correctly scrolled webpage?

I take a screenshot at the top of the webpage, scroll down ~700 pixels, wait for a javascript callback to trigger which then takes another screenshot. The javascript and callback works fine (I observe the QWebEngineView scrolling).

this->setScrollPageHandlerFunc([&] (const QVariant &result) {
    saveSnapshotScroll();
});
saveSnapshotScroll();
view->page()->runJavaScript("scrollPage();",this->scrollPageHandlerFunc);

Screenshot code:

void MainWindow::saveSnapshotScroll()
{

QPixmap pixmap(this->size());
view->page()->view()->render(&pixmap);
pixmap.save(QString::number(QDateTime::currentMSecsSinceEpoch()) + ".png");

}

Javascript:

function scrollPage()
{
    var y = qt_jq.jQuery(window).scrollTop();
    qt_jq.jQuery(window).scrollTop(y+708);
}