Creates a new legacy layout manager.
Assigns the given width, height, and baseline to a widget, and computes the position and sizes of the children of the widget using the layout management policy of manager.
Retrieves a gtk.layout_child.LayoutChild instance for the gtk.layout_manager.LayoutManager, creating one if necessary.
Retrieves the request mode of manager.
Retrieves the gtk.widget.Widget using the given gtk.layout_manager.LayoutManager.
Queues a resize on the gtk.widget.Widget using manager, if any.
Measures the size of the widget using manager, for the given orientation and size.
gtk.custom_layout.CustomLayout uses closures for size negotiation.
A GtkCustomLayout uses closures matching to the old gtk.widget.Widget virtual functions for size negotiation, as a convenience API to ease the porting towards the corresponding `GtkLayoutManager virtual functions.