Struct LayoutTask 

pub struct LayoutTask {

    pub snapshot: Arc<DomSnapshot>,
    pub root: NodeId,
    pub resolved_styles: Arc<ResolvedStyles>,
    pub media_environment: MediaEnvironment,
    pub measurer: Arc<dyn TextMeasurer>,
    pub audio_sinks: Arc<dyn AudioSinkFactory>,
    pub system_color_scheme: ColorScheme,
    pub scripting_mode: ScriptingMode,
    pub images: HashMap<String, Image>,
    pub audio: HashMap<String, Arc<[u8]>>,
    pub parent: InheritedCss,
    pub chain: ElementChain,
    pub write_back_sender: Option<DomWriteBack>,
    pub styles_version: u64,
    pub dom_version: u64,
    pub version: u64,
    pub interaction: Arc<InteractionState>,
    pub interaction_version: u64,
    pub existing_custom_nodes: HashMap<u32, Arc<dyn CustomNode>>,
    pub animated_overrides: HashMap<NodeId, HashMap<String, CssValue>>,
}

The complete set of inputs the builder needs to run on the background thread.

Fields

snapshot: Arc<DomSnapshot>

root: NodeId

resolved_styles: Arc<ResolvedStyles>

media_environment: MediaEnvironment

measurer: Arc<dyn TextMeasurer>

audio_sinks: Arc<dyn AudioSinkFactory>

system_color_scheme: ColorScheme

scripting_mode: ScriptingMode

images: HashMap<String, Image>

audio: HashMap<String, Arc<[u8]>>

parent: InheritedCss

chain: ElementChain

write_back_sender: Option<DomWriteBack>

styles_version: u64

Monotonic version of resolved_styles at task creation time. Assigned by the UI thread; see LayoutProcessor for how it drives the RuleSet cache.

dom_version: u64

Monotonic version of the DOM snapshot handed to the task. Selector match results are only reused across tasks with the same version.

version: u64

Monotonic sequence number used to coalesce stale tasks. Assigned by LayoutProcessor::send, ignore when constructing a task.

interaction: Arc<InteractionState>

Pointer interaction state (hover/active) for CSS pseudo-class matching.

interaction_version: u64

Monotonic version of interaction; selector match results depend on it.

existing_custom_nodes: HashMap<u32, Arc<dyn CustomNode>>

Existing custom node instances keyed by snapshot DOM node id, reused across relayouts to preserve component-local UI state.

animated_overrides: HashMap<NodeId, HashMap<String, CssValue>>

Per-element animated style overrides applied on top of cascaded/base styles.