QtQuick Layouts should allow animating items to new position/size

After a lot of searching I can't find any way to animate items to their new positions/sizes when the layout is recomputed. Setting animation behaviors on x/y/width/height does not seem to work at all.

When I make a dynamic layout with many elements that switch e.g. from side-by-side to above-below based on the available space, I really need it to be animated, because otherwise the sudden transition where everything is in a different place is jarring and confusing.

This is one of those things that is trivial in HTML but extremely frustrating in QML (see also the default size for everything in QML being 0x0).

Bonus points for a new animation type that scales the duration by the value delta up to a maximum, so small changes would be quick/instant but big changes would have visible animation.