Struct Assets 

pub struct Assets { /* private fields */ }

Every image one book refers to, probed once and indexed.

DrawItem::Image.asset indexes this: layout places an image by number, and painters resolve the number back to bytes.

Implementations

impl Assets

pub fn none() -> Assets

No images at all: what a host with no loader supplies.

pub fn probe( book: &Book, styles: &StyleTree, loader: &dyn ImageLoader, ) -> Assets

Probes every image the book places and every image its sheet puts behind a box, the manuscript’s own first. A url the loader cannot resolve, or bytes no probe recognises, is a diagnostic and no asset.

A sheet that names no background image offers the loader nothing beyond what the manuscript named.

pub fn add(&mut self, url: &str, bytes: Vec<u8>) -> Added

Registers one image the host handed over, and what that did: the same bytes it already had, new bytes at a fresh or existing index, or bytes no probe recognises.

This is the door for a host that pushes: a worker has no loader to reach back through, so images cross the wall the way font files do. A url pushed again with the bytes it already answers for costs nothing; pushed again with different bytes, it replaces them in place, keeping the index DrawItem::Image.asset already names.

pub fn lookup(&self, url: &str) -> Option<(u32, Intrinsic)>

The asset registered for a url, and its index.

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

Whether a url has been probed: an asset came of it, or a complaint about why none did. A url nobody offered is neither, and is what layout reports.

pub fn assets(&self) -> &[Asset]

Every asset, in the order DrawItem::Image.asset indexes them.

pub fn bytes(&self, index: u32) -> Option<&[u8]>

The file one asset was probed from: the bytes a painter embeds, unchanged from what the host handed over.

pub fn digest(&self, index: u32) -> Option<u64>

What one asset’s file hashes to: what tells a trace of the bytes an index holds now from a trace of the bytes it held before.

pub fn warnings(&self) -> &[Warning]

What probing had to complain about.

Trait Implementations

impl Debug for Assets

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

Formats the value using the given formatter.

impl Default for Assets

fn default() -> Assets

Returns the “default value” for a type.

impl ImageLoader for Assets

The images a host already handed over answer by the url they were registered under, with the bytes as they arrived.

fn load(&self, url: &str) -> Option<Vec<u8>>

The bytes behind one url, or None when the host cannot resolve it.