event()->device() was the most common use case anyway.
The idea that the "parent" of a QEventPoint is the QPointerEvent
interferes with the ability to copy and move event objects: the parent
pointers are dangling unless we use the QPointerEvent subclass
destructors to set the points' parents to null. Since there is no move
constructor, even returning a QEventPoint from a function by value
results in destroying the temporary instance and copying it to the
caller's space. So the parent pointer is often useless, unless we do
even more work to maintain it when the event moves.
If we optimize to avoid copying QEventPoints too much (and perhaps
enable exposing _mutable_ points to QML) by storing reusable instances in
QPointingDevice (which is the current plan), then the actual parent will
no longer be the event. Events are usually stack-allocated, thus
temporary and intended to be movable.
Change-Id: I24b648dcc046fc79d2401c781f1fda6cb00f47b0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
38806273e5