Have a function first called before the children, and then the main function
called after the children if they did not accept the event. This will allow
processing the Flickable gesture properly
Remove the pos parameter to the render functions and instead let
the item renderer apply the transformation on the rendere (femtovg
canvas or QPainter).
So `draw_*` functions in the backend now always operate in item local
coordinates.
For all other items the default is the empty size.
This also required three fixes for the HTML image loading:
* The upload_pending property value was inverted, it needs to start
out as true (pending yes) and be set to false when it finished
loading (not pending anymore)
* Mark the upload_pending property as dirty before scheduling the
redraw, in case it's sync
* Pass the item rendering cache to the image_size function to ensure
that the Rc<CachedImage> is not only weak inside the image_cache
of the GLRendererData but also strong on the item.
This means going back to an immutable renderer reference and interior
mutability for the canvas and the gpu cache. This is because while
traversing the item tree for rendering we may end up destroying
other items due to the lazyness of the models.
This is the start of a different rendering abstraction, the result of a
separate discussion.
The objective is to provide a better backend encapsulation, that will
make it easier to implement other backends and let the backend decide
what to cache and what not. This is done by passing the struct with the
Property<> fields directly to the backend, so that it can decide what
the cache and what to use every time.
Ideally we would put the bindings dirrectly in the builtins.60
But this is unfortunately not possible because the "StyleMetrics" is not
yet available there and that would be a circular dependencies.
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 also removes the funny binding on the button in the gallery.
UI wise it's confusing that a button changes its size when pressed, and we can
show off bindings somewhere else :-)
* Set the Enabled state throughout the "widgets". This corrects the visual appearance of Button and CheckBox in particular.
* Render a button that's not down as raised, in order to show its outline.
