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impl reference

Everything hanging off domtoimage.impl is an internal implementation surface, exposed only so the unit tests (and a few advanced integrations) can reach the moving parts. It is not part of the stable public API (toSvg, toPng, toJpeg, toBlob, toCanvas, toPixelData) and may change between releases without notice.

domtoimage.impl;
Member Kind Summary
util object Low-level helpers (type guards, geometry, URL/resource fetching). Documented separately in UTILS.md.
fontFaces object Discovers @font-face web fonts and inlines them as data: URLs.
images object Inlines <img> and SVG <image> sources and CSS background/background-image/mask URLs.
inliner object The URL-rewriting engine shared by fontFaces and images.
urlCache array Per-render cache of fetched resources, keyed by URL.
options object The live, resolved options for the current/last render.
copyOptions function Merges caller options over the defaults into impl.options.
resetUrlCache function Clears urlCache. Called at the start/end of a render; exposed for tests/advanced callers driving the helpers directly.

impl.options

The resolved options object that the render pipeline actually reads. It is not the object you pass to toPng(node, options) — that one is normalized by copyOptions (filling in defaults for anything omitted) and the result is stored here. Inspecting it after a call shows the effective configuration that was used.

See the Rendering options section of the README for the full list of fields and their defaults.

impl.copyOptions(options)

(options: object) => void

Normalizes options against the library defaults and writes the result into impl.options. Every option is copied through an explicit typeof options.x === 'undefined' ? default : options.x check, so passing {} restores the full default configuration. Called automatically at the start of each top-level render; exposed mainly so tests can set up impl.options directly when exercising helpers like util.getAndEncode in isolation.

impl.fontFaces

Produced by newFontFaces().

Member Signature Summary
resolveAll() () => Promise<string> Reads every web-font @font-face rule, inlines its src URLs as data: URLs, and resolves to the concatenated CSS text (newline-joined) ready to drop into a single <style>.
impl.readAll() () => Promise<WebFont[]> Scans document.styleSheets, keeps only @font-face rules whose src needs processing, and returns one web font object per rule. Stylesheets whose cssRules can't be read (e.g. cross-origin) are skipped with a logged error.

Each web font object returned by readAll() exposes:

  • resolve() → Promise<string> — inline this rule's URLs and return its rewritten cssText.
  • src() → string — the raw src property value of the rule.

impl.images

Produced by newImages().

Member Signature Summary
inlineAll(node) (node: Node) => Promise<…> Recursively walks node, inlining the CSS background/background-image/mask URLs on every element, replacing HTML <img> src values with data: URLs, and inlining SVG <image> href/xlink:href. Non-element nodes pass through untouched.
impl.newImage(element) (element: HTMLImageElement) => { inline(get?) } Wraps a single image element. inline(get?) fetches element.src (via get, defaulting to util.getAndEncode) and swaps in the resulting data: URL; already-data: sources are left as-is.

impl.inliner

Produced by newInliner(). The shared engine that finds url(...) references in CSS text and rewrites them to inlined data: URLs. Used by both fontFaces and images.

Member Signature Summary
inlineAll(string, baseUrl?, type?, get?) (string, baseUrl?, type?, get?) => Promise<string> Finds every non-data: url(...) in string, fetches each (passing type to getAndEncode), and returns the CSS with those URLs replaced by data: URLs. Returns the input unchanged when there is nothing to inline.
shouldProcess(string) (string) => boolean true if string contains at least one url(...) reference.
impl.readUrls(string) (string) => string[] Extracts the URL values from every url(...) in string, excluding ones that are already data: URLs.
impl.inline(string, url, baseUrl?, type?, get?) (string, url, baseUrl?, type?, get?) => Promise<string> Inlines a single url: resolves it against baseUrl (if given), fetches it (passing type to getAndEncode), and replaces every url(...) occurrence of it in string.
impl.urlAsRegex(urlValue) (urlValue) => RegExp Builds the (escaped) global regex that matches url("urlValue") with optional quotes.

impl.urlCache

An array used by the resource fetch core (behind util.getAndEncode and util.getResourceText) to dedupe and cache fetches within a render. Each entry is { url: string, promise: Promise | null }; repeat requests for the same URL share the same in-flight/settled promise. It is cleared at the start/end of each render (and via impl.resetUrlCache()), so each capture fetches fresh.

For the util helpers (isHTMLElement, width, getAndEncode, resolveUrl, uid, …), see UTILS.md.