Struct Core 

pub struct Core {
    pub tree: Tree,
    pub caches: SharedState,
    pub active_subscriptions: HashMap<String, Vec<SubscriptionEntry>>,
    pub default_event_rate: Option<u32>,
    pub default_text_size: Option<f32>,
    pub default_font: Option<Font>,
    pub cached_theme: Option<Theme>,
    pub cached_theme_chrome: ThemeChrome,
    pub effect_stubs: HashMap<String, Value>,
    pub validate_props: Option<bool>,
    /* private fields */
}

Pure state core, decoupled from the iced runtime.

Owns the retained UI tree, widget caches, active subscriptions, and global rendering defaults. The host calls apply with each incoming message and executes the returned CoreEffects.

Fields

tree: Tree

The retained UI tree (snapshots replace it, patches update it).

caches: SharedState

Caches for stateful widgets (text_editor content, markdown items, etc.).

active_subscriptions: HashMap<String, Vec<SubscriptionEntry>>

Active event subscriptions: kind -> list of entries. Each kind can have multiple entries with different tags and optional window scoping.

default_event_rate: Option<u32>

Global default event rate from Settings (events per second). None = no limit (full speed).

default_text_size: Option<f32>

Global default text size from Settings.

default_font: Option<Font>

Global default font from Settings.

cached_theme: Option<Theme>

Cached resolved theme from the root node’s theme prop. Only re-resolved when the raw JSON value changes.

cached_theme_chrome: ThemeChrome

effect_stubs: HashMap<String, Value>

Registered effect stubs: kind -> response value. When an effect request matches a stub, the renderer returns the stubbed response immediately without executing the real effect. Used for testing and scripting.

validate_props: Option<bool>

Per-session prop-validation override.

Some(true) enables validation for this session. None falls back to the process-wide is_validate_props_enabled check (which itself defaults to cfg(debug_assertions) when no global value has been set). validate_props: false in Settings does not disable validation; it leaves the fallback in control so hosts cannot turn off debug/default validation for a session.

Implementations

impl Core

pub fn new() -> Self

pub fn is_validate_props_enabled(&self) -> bool

Resolve whether prop validation should run for this session.

A per-session true forces validation on. Otherwise the process-wide flag decides.

pub fn has_subscription(&self, kind: &str) -> bool

Check whether at least one entry is registered for the given kind.

pub fn matching_entries( &self, kind: &str, window_id: Option<&str>, ) -> Vec<&SubscriptionEntry>

Return all entries matching a kind, filtered by window_id. An entry matches if its window_id is None (global) or equals the event’s window_id.

pub fn matching_entries_with_catchall( &self, kind: &str, catchall_kind: &str, window_id: Option<&str>, ) -> Vec<&SubscriptionEntry>

Return all entries matching a specific kind plus the catch-all SUB_EVENT kind, filtered by window_id. Useful for event emission where both specific and catch-all subscriptions should fire.

pub fn subscription_rates(&self) -> impl Iterator<Item = (&str, u32)>

Collect all max_rate values from subscription entries, keyed by tag. Returns (tag, max_rate) pairs for entries that have a max_rate set. The tag includes window scope when present, so rate limiting is isolated per subscription entry.

pub fn subscription_rate_tags(&self) -> impl Iterator<Item = &str>

Collect all tags that have a max_rate set.

pub fn tree_hash(&self) -> String

Compute the canonical SHA-256 hash of the current tree. Returns the hex-encoded hash string, or an empty string if no tree.

pub fn apply(&mut self, message: IncomingMessage) -> Vec<CoreEffect>

Process an incoming message, mutate state, return effects.

Trait Implementations

impl Default for Core

fn default() -> Self

Returns the “default value” for a type.