NAME

Clay::UI::_FrameRegistry - what one Clay::UI frame laid out

DESCRIPTION

Clay::UI builds one registry per frame while it walks the widget tree and replaces the previous one only when the frame completes, so a failed frame leaves the last good registry in place. It answers the questions the next frame's pointer and scroll handling asks about the last layout: which widget a render command's userData or a Clay element id belongs to, where widgets came in the walk, which scroll containers were declared under which element id, and how far they have scrolled since.

It also defines what a scroll container is: a widget composing Clay::UI::Role::Layout::HasScroll. The walker injects Clay's scroll offset only into scroll containers, and only they receive OnScroll.

Widget references are weak.

This module is internal. The API is not part of the public contract.

METHODS

add_back_reference($widget)

Records $widget; returns the userData value for its render commands.

is_scroll_container($widget)

1 if $widget is a scroll container, else 0.

add_element($widget, $element_id, $padding)

Records a widget Clay declared an element for (an element or a text widget) in walk order under the element id hash Clay named it by, with the padding of its declaration (a Clay_Padding hash, or undef for none; missing sides are 0); a scroll container is also listed by scroll_containers.

element_count

How many widgets add_back_reference recorded: the Clay layout elements the walk declared, element and text widgets alike.

widget_for($user_data), widget_for_element($id)

The widget, or undef.

element_id_of($widget), padding_of($widget)

The element id hash, or a copy of the padding ({ left, top, right, bottom }), the walk declared $widget with; undef for a widget the walk did not reach.

in_tree_order(@widgets)

@widgets sorted by walk position. Widgets the walk did not reach come last, in the depth-first pre-order of the tree they are in now; ties keep their original order.

scroll_containers

List of [ $widget, $element_id ] for the scroll containers that still exist, in walk order.

scroll_positions($ui)

Hashref refaddr => [ $widget, $element_id, $position ] for the scroll containers that still belong to $ui and that Clay knows, with their current scroll position. Needs $ui's Clay context to be current.

scroll_changes($positions)

List of [ $widget, $delta_x, $delta_y ] for the containers of an earlier scroll_positions result that have moved since.