Source of getChildren. Only the read side is used.
OptionalalwaysForwarded to the produced RenderLayer.
OptionaldefaultForwarded to the produced RenderLayer.
OptionalidLayer id for the visibility/order map. Default 'children'.
OptionallabelHuman-readable label. Default 'Children'.
OptionalparentParent id (null = root). Function form lets the layer follow a moving
selection or focus. Default null.
Draw one child. Called once per id in z-order (bottom → top). The
per-child outputs are concatenated into the layer's DrawCommand[].
Options for
createChildrenLayer.