This helps with portability and defines some top-level structure around
the event loop, so in the future, backends can get an idea of what API
to use.
This also changes the API to be object safe by using `dyn` throughout.
For EventLoop, EventLoopBuilder, EventLoopProxy and by requiring it as
a supertrait of Window and ActiveEventLoop.
It is especially useful for user to be able to know that Window is Debug.
* Add cursor position drag and drop events.
* Reword drag events to match pointer ones.
* appkit: Use `convertPoint_fromView` for coordinate conversion.
* appkit: use ProtocolObject<dyn NSDraggingInfo>.
* x11: store dnd.position as pair of i16
It's what translate_coords takes anyway, so the extra precision is
misleading if we're going to cast it to i16 everywhere it's used.
We can also simplify the "unpacking" from the XdndPosition message--we
can and should use the value of 16 as the shift instead of
size_of::<c_short> * 2 or something like that, because the specification
gives us the constant 16.
* x11: store translated DnD coords.
* x11: don't emit DragLeave without DragEnter.
* windows: only emit DragEnter if valid.
* windows: in DnD, always set pdwEffect.
It appears other apps (like Chromium) set pdwEffect on Drop too:
61a391b86b/ui/base/dragdrop/drop_target_win.cc
* docs: make it clearer that drag events are for dragged *files*.
* examples/dnd: handle RedrawRequested event.
Co-authored-by: amrbashir <amr.bashir2015@gmail.com>
