There are three potential variants to add a child inside a Box
with a BinLayout:
- clutter_box_pack(), a variadic argument function which
allows passing arbitrary LayoutMeta properties and values;
- clutter_bin_layout_add(), which uses the backpointer to
the container from the LayoutManager and sets the layout
properties directly without GValue (de)marshalling
- clutter_container_add_actor() and
clutter_bin_layout_set_alignment(), similar to the
clutter_bin_layout_add() function above, but split in two
The test-box interactive test should exercise all three variants.
The ClutterBox::add method is a simple wrapper around the Container
add_actor() method and the LayoutManager layout properties API. It
allows adding an actor to a Box and setting the layout properties in
one call.
If the LayoutManager used by the Box does not support layout properties
then the add() method short-circuits out.
Along with the varargs version of the method there's also a vector-based
variant, for language bindings to use.
Each actor managed by a BinLayout policy should reside inside its
own "layer", with horizontal and vertical alignment. The :x-align
and :y-align properties of the BinLayout are the default alignment
policies, which are copied to each new "layer" when it is created.
The set_alignment() and get_alignment() methods of BinLayout can
be changed to operate on a specific "layer".
The whole machinery uses the new ChildMeta support inside the
LayoutManager base abstract class.
