Struct ImageStore 

pub struct ImageStore { /* private fields */ }

A cheap-to-clone handle to a shared image cache whose loads run off the UI thread — on the toolkit’s Background for ImageStore::new, or in the host for ImageStore::host_driven.

Implementations

impl ImageStore

pub fn serve_window( window: &WakeHandle, factory: Rc<dyn Fn(u32, &ServedWindow) -> ImageStore>, )

Serve the image stores window builds through factory for as long as its wake scope is open: every store built while that scope is entered comes from the host, whether the window builds it as it is constructed or later (a view part built once the window’s workspace arrived, a part built again). A store the window built on its own would load through the toolkit’s decoders on its background, which a browser page leaves to the host: its pictures would never show.

pub fn serve_successor(window: &WakeHandle, successor: &WakeHandle)

Serve successor, a window opened in window’s place (the window a record opens in once it is had, another record opened here), the way window is served: it shows in the same host, which never built it. Its stores draw for it, not for window: their pictures are read and asked for on its own content, also after window closed. Nothing changes for a window no host serves.

pub fn new( fetch: &Arc<dyn Fn(&str) -> Option<Vec<u8>> + Send + Sync>, ) -> ImageStore

Build a store with the default worker count.

pub fn with_workers( fetch: &Arc<dyn Fn(&str) -> Option<Vec<u8>> + Send + Sync>, workers: usize, ) -> ImageStore

Build a store that runs at most workers fetch/decode jobs at once, clamped to 1..=4 so one store cannot monopolise the background pool. A window its host serves (Self::serve_window) gets the host’s.

pub fn with_max_dimension( fetch: &Arc<dyn Fn(&str) -> Option<Vec<u8>> + Send + Sync>, max_dimension: u32, ) -> ImageStore

Build a store for document images instead of small thumbnails.

Decoded dimensions are bounded to 1..=4096; the worker, queue and total cache memory limits remain the same as for the thumbnail store.

pub fn host_driven() -> (ImageStore, HostImageLoader)

A thumbnail store whose loading the host drives through the returned HostImageLoader; no background work is spawned.

pub fn host_driven_with_max_dimension( max_dimension: u32, ) -> (ImageStore, HostImageLoader)

A host-driven store with a bounded document-image decode dimension (clamped to 1..=4096).

pub fn get(&self, url: &str) -> Option<ImageData>

Decoded image for url, kicking off an async load the first time a URL is seen. Returns None while loading or after a failure — the caller paints a placeholder until a later frame returns Some.

pub fn forget_failed(&self) -> bool

Forget every load that failed, so the next get of its URL asks the fetcher again. A failure is cached (it would otherwise be re-fetched every frame), which is wrong for a source whose bytes were not available yet and now are: a caller that knows they changed calls this. Returns whether any failure was forgotten.

pub fn failed(&self, url: &str) -> bool

Whether the last load of url failed: its bytes are not here, or do not decode.

pub fn is_known(&self, url: &str) -> bool

Whether url has been requested yet (Ready/Loading/Failed all count).

pub fn pending(&self) -> usize

Number of in-flight loads (queued or decoding).

pub fn is_idle(&self) -> bool

Whether every requested load has settled.

pub fn block_until_idle(&self, timeout: Duration)

Block until all in-flight loads settle or timeout elapses on the store’s executor clock. For the synchronous --shots pre-warm and tests only — never call this on a live app’s UI thread. A host-driven store settles only when its host completes requests.

Trait Implementations

impl Clone for ImageStore

fn clone(&self) -> ImageStore

Returns a duplicate of the value.

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

Performs copy-assignment from source.