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.
The Q_WS_MAC pre-processor macro does not exist anymore. The original
reason for the widget was erroneously applied - the cocoa controls
themselves are NSViews and it's just that the backing store view in the
style will be nil -- that seems to make no visual difference though.
Similar to the parent commit, don't calculate the native_padding_* as a side-effect of calling
layout_info(), but calculate it property through a binding.
Setting the value of the native_padding_{left, right, top, bottom}
properties *during* the layout_info() call is too late, as the calling
compute_layout implementation has already queried for those properties.
Instead, this patch moves the padding calculation into a shared property
binding that's queried from bindings to the individual native_padding_*
properties and layout_info() just uses the properties, too.
