QWebEnginePage::setBackgroundColor(Qt::transparent) prevents rendering it with QPainter. Visual artefacts on transparent areas.

The attached simple test project (test.zip, only 13 lines of code) puts a QWebEnginePage on top of a QLabel. QWebEnginePage is set to a transparent page background (mainwindow.cpp line 14), so that the QLabel text is still visible behind it. After 1 second, MainWindow is rendered with a QPainter, and the resulting QImage is saved to /tmp/screenshot.png.

When the application is run, its MainWindow displays correctly. However, the screenshot /tmp/screenshot.png only shows the QLabel, but not the QWebEnginePage.

If the transparent background is not set, QWebEnginePage is present in the screenshot.

Attachment Selection_135.jpg shows both the MainWindow as well as its screenshot side-by-side for comparison, when transparency is set, illustrating the problem.

Attachment Selection_136.jpg shows both the MainWindow as well as its screenshot, without the transparency.

In addition, both variants exhibit visual artefacts on top of the transparent areas.