ShapePath.fillItem doesn't work with all items; doesn't scale correctly with QT_SCALE_FACTOR

It's documented that the item must be a texture provider, such as a layered item. But setting layer.enabled: true is not enough to make Text show up, for example.

An Image works. (If it has a Text child, that is not rendered.) But then if I set QT_SCALE_FACTOR it's not stretched correctly.

There can also be a warning:

QQuickShaderEffectSource::textureProvider: can only be queried on the rendering thread of an exposed window