Struct LayoutChild

pub struct LayoutChild {
    pub element_id: ElementId,
}

Handle used by widgets to lay out one retained direct child.

Examples

use ailloli_ui_core::ElementId;
use ailloli_ui_runtime::layout::LayoutChild;

let child = LayoutChild { element_id: ElementId(3) };
assert_eq!(child.element_id, ElementId(3));

Fields

element_id: ElementId

Retained-tree identity delegated to LayoutEngine.

Implementations

impl LayoutChild

Provides the operations defined for LayoutChild.

pub fn layout<A: 'static>( &mut self, engine: &mut LayoutEngine<'_, A>, ctx: &mut LayoutCtx<'_>, constraints: Constraints, ) -> LayoutResult

Lays out this child with the supplied logical-pixel constraints.

A stale or unknown element_id produces LayoutResult::zero and no diagnostic cache event. Other behavior, including widget panics, is delegated to LayoutEngine::layout_element.

Examples

use ailloli_ui_core::{Constraints, ElementId, Scale, Size};
use ailloli_ui_runtime::element::ElementTree;
use ailloli_ui_runtime::layout::{LayoutChild, LayoutCtx, LayoutEngine};

let mut tree = ElementTree::<()>::new();
let mut engine = LayoutEngine::new(&mut tree);
let mut ctx = LayoutCtx::new(Scale::new(1.0));
let mut child = LayoutChild { element_id: ElementId(99) };
assert_eq!(
    child.layout(&mut engine, &mut ctx, Constraints::tight(10.0, 20.0)).size,
    Size::default(),
);