Struct MemoizedSubView 

pub struct MemoizedSubView<'a> { /* private fields */ }

A SubView that remembers what each proposal measured.

Containers probe the same child repeatedly — size_that_fits measures at the ideal proposal, place measures again at the resolved bounds, alignment-guide resolution measures once more per guide — and a container that is itself a child re-runs all of that for its own parent’s probes, so the repeats multiply with tree depth. Wrapping each child for the duration of one pass collapses them to one measure per distinct proposal.

The cache is a fixed-capacity inline array, scanned linearly: a pass probes any one child a handful of times, and keeping it inline means wrapping a child costs no allocation — which matters on the embedded backend, whose budget is heap traffic per frame rather than CPU. A child probed at more than MEMOIZED_PROPOSALS distinct proposals simply measures again for the extras. Entries are keyed on the proposal’s bits, so -0.0 and a NaN proposal compare consistently instead of by float equality.

Implementations

impl<'a> MemoizedSubView<'a>

pub fn new(inner: &'a dyn SubView) -> MemoizedSubView<'a>

Wraps inner with a cache that lives as long as this value.

Trait Implementations

impl Debug for MemoizedSubView<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl SubView for MemoizedSubView<'_>

fn measure(&self, proposal: ProposalSize) -> ViewDimensions

Measure the child for a given proposal.

fn stretch_axis(&self) -> StretchAxis

Which axis (or axes) this view stretches to fill available space.

fn priority(&self) -> i32

Layout priority for space distribution.