This is just a starting point, to be turned into a real Transform
element later, along with syntactic sugar to turn rotation, etc. into a
transform matrix in the generated output.
In the nightly it appears that `no_mangle` is now considered "unsafe",
so we need to allow that in the ffi modules. For the layout code this
patch also creates that ffi module with prefixed function names, like in
the other modules and only allows unsafe in there.
This intends to provide a configurable rectangular "drop shadow". The
API is modeled after CSS/HTML5 Canvas where the element can be "bound"
to an existing rectangular shape (geometry and radius), the offset can
be used to place the shadow and color and blur configure the shadow.
The shadow's color fades into transparent.
TODO (in subsequent changes):
* Documentation
* Qt implementation
This allows creating multiple windows for example, and it will allow for
showing windows in those tests that require a mapped window.
As a bonus, the run() function on generated components is not consuming
anymore.
Instead of determining the focus item through item tree traversal and
pointer comparison and storing the intermediate indices in the
components in the tree, remember the focus item by a pair of
VWeak<ComponentVTable, Dyn> and item_index: usize.
This speeds up determining the focus item as well as delivering events,
which can now be done directly after retrieving an ItemRef with
get_item_ref.
This also fixes the duplicate line edit focus in the 7gui cells
test case.
This is in preparation for allowing the run-time / items to clone VRc's
of the component.
ComponentVTable functions like visit_children_item contine to take a
ComponentRefPin as "self" parameter type, as a VRc would not be
supported by rust right now. That means the implementation then uses
self_weak to obtain a strong self-reference.
Centralize the self_weak setup to be emitted only once, in the create()
function. create() is now always emitted and equipped with a parent
parameter, for non-root components. This allows slightly simplifying the
generic repeater code.
Move the layout constraint tracker into the window where we can apply
the constraints right before drawing, instead of doing that from within
the event loop. This allows to remove the component parameter from the
run function.
