Struct LayoutCache 

pub struct LayoutCache {
    pub tree: Option<LayoutTree>,
    pub calculated_positions: BTreeMap<usize, LogicalPosition>,
    pub viewport: Option<LogicalRect>,
    pub scroll_ids: BTreeMap<usize, u64>,
    pub scroll_id_to_node_id: BTreeMap<u64, NodeId>,
    pub counters: BTreeMap<(usize, String), i32>,
    pub float_cache: BTreeMap<usize, FloatingContext>,
}

The persistent cache that holds the layout state between frames.

Fields

tree: Option<LayoutTree>

The fully laid-out tree from the previous frame. This is our primary cache.

calculated_positions: BTreeMap<usize, LogicalPosition>

The final, absolute positions of all nodes from the previous frame.

viewport: Option<LogicalRect>

The viewport size from the last layout pass, used to detect resizes.

scroll_ids: BTreeMap<usize, u64>

Stable scroll IDs computed from node_data_hash (layout index -> scroll ID)

scroll_id_to_node_id: BTreeMap<u64, NodeId>

Mapping from scroll ID to DOM NodeId for hit testing

counters: BTreeMap<(usize, String), i32>

CSS counter values for each node and counter name. Key: (layout_index, counter_name), Value: counter value This stores the computed counter values after processing counter-reset and counter-increment.

float_cache: BTreeMap<usize, FloatingContext>

Cache of positioned floats for each BFC node (layout_index -> FloatingContext). This persists float positions across multiple layout passes, ensuring IFC children always have access to correct float exclusions even when layout is recalculated.

Trait Implementations

impl Clone for LayoutCache

fn clone(&self) -> LayoutCache

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LayoutCache

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

Formats the value using the given formatter.

impl Default for LayoutCache

fn default() -> LayoutCache

Returns the “default value” for a type.