4ba4525b5a
When a non-raster widget is inserted into the widget hierarchy, widgets switches into using RHI for flushing its backingstore, matching the window's surface type with the non-raster widget that was inserted. This happens for example when inserting an QOpenGLWidget, which switches the surface type to QWindow::OpenGLSurface, or a QQuickWidget, which switches the surface type to that used for Qt Quick. In these cases, there might still be child widgets with their own window handle, and as long as these child windows have the same surface type as the window owning the backing store these child windows are flushed through the same rhiFlush() code path as the top level window. For child windows with a different surface type, QWidgetRepaintManager chooses the pain QPlatformBackingStore::flush(). Unfortunately, the implementation of QRhiBackingStore::flush() bails out when flushing child windows, so when we were using QRhiBackingStore on macOS for non-raster surfaces we would end up not flushing these child windows. The way to fix this is to use QCALayerBackingStore for the case where we know the client of the backing store (QWidgetWindow) is going to call rhiFlush() explicitly for non-raster surfaces. That will lead us into QCALayerBackingStore::flush() for the child windows with a non-matching surface type, typically QWindow::RasterSurface, and we'll flush those child windows by setting the layer's contents property. Fixes: QTBUG-119309 Pick-to: 6.5 Change-Id: Ia7052b9e651d575d8e34942a25e17ab5a1f5ce05 Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io> (cherry picked from commit f16f31ba3093f35134ceff6a784ad99c1867bfee) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> (cherry picked from commit d26be2a2062e4b24a5177a7ee92403c58ffa718e)