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SVG editor and embeddable C⁠+⁠+⁠20 engine.
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donner::svg::EmbeddedFontProvider Class Reference

Curated bundled fonts, sharing one generated WOFF2 catalog on native and Wasm. More...

#include "donner/svg/resources/EmbeddedFontProvider.h"

Inheritance diagram for donner::svg::EmbeddedFontProvider:
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Public Member Functions

 EmbeddedFontProvider (std::shared_ptr< CatalogEncodedFontStore > store)
 Explicit deferred delivery, also usable by native applications and deterministic tests.
std::vector< FontFamilyInfo > families () const override
 List the families this provider can supply.
bool hasFamily (std::string_view family) const override
 Returns true if family is available.
FontFaceAvailability availability (std::string_view family, const FontFaceRequest &request) const override
 Metadata only; the default preserves existing synchronous/system/custom providers.
FontFaceAdmission tryAcquireFace (std::string_view family, const FontFaceRequest &request) const override
 Acquire product-wide copy/decode admission without blocking. Does not fetch missing bytes.
std::vector< uint8_t > loadFamilyData (std::string_view family, const FontFaceRequest &request) const override
 Load encoded font-file bytes (sfnt, or WOFF2 in a full-text consumer) for the face of family that best matches request, or an empty vector if the family is unavailable.
std::shared_ptr< CatalogEncodedFontStore > encodedStore () const
 Session-owned delivery/admission state.

Detailed Description

Curated bundled fonts, sharing one generated WOFF2 catalog on native and Wasm.

Native reads verified compressed installation resources. Wasm links only the manifest and obtains verified encoded bytes from the session store. Enumeration never requests bytes. Each family retains its existing single variable/static file and face-selection behavior.

Member Function Documentation

◆ availability()

FontFaceAvailability donner::svg::EmbeddedFontProvider::availability ( std::string_view family,
const FontFaceRequest &  ) const
overridevirtual

Metadata only; the default preserves existing synchronous/system/custom providers.

Reimplemented from donner::svg::FontFamilyProvider.

◆ families()

std::vector< FontFamilyInfo > donner::svg::EmbeddedFontProvider::families ( ) const
overridevirtual

List the families this provider can supply.

Implements donner::svg::FontFamilyProvider.

◆ hasFamily()

bool donner::svg::EmbeddedFontProvider::hasFamily ( std::string_view family) const
overridevirtual

Returns true if family is available.

Matching must be case-insensitive: callers fold family names when they index them, so a provider that compared case-sensitively would disagree with its own caller about which families exist.

It must also answer in constant or logarithmic time. Text layout asks once per unresolved family per span, and the number of families a provider holds is set by the host rather than by the document, so a linear scan of the provider's list turns one layout into work proportional to spans times families times installed fonts. Providers that enumerate a list should build a folded index alongside it rather than scanning it per call, and must not perform I/O or re-enumerate the underlying font source here.

Parameters
familyFont family name to test.
Returns
True when this provider can supply the family.

Implements donner::svg::FontFamilyProvider.

◆ loadFamilyData()

std::vector< uint8_t > donner::svg::EmbeddedFontProvider::loadFamilyData ( std::string_view family,
const FontFaceRequest & request ) const
overridevirtual

Load encoded font-file bytes (sfnt, or WOFF2 in a full-text consumer) for the face of family that best matches request, or an empty vector if the family is unavailable.

Providers that only hold a single file per family return it for every request, which means bold and italic render as regular for those families - see EmbeddedFontProvider.

The returned bytes are suitable for FontManager::loadFontData() when its feature tier supports that format. They are not necessarily raw sfnt and must not be passed directly to an SFNT-only consumer such as an ImGui TTF loader.

A synchronous provider whose load cost grows with the font's size should poll ScopedFontLoadInterruption::Requested and may return an empty vector once it is true.

Parameters
familyFamily name to load (case-insensitive).
requestFace within the family to prefer.

Implements donner::svg::FontFamilyProvider.

◆ tryAcquireFace()

FontFaceAdmission donner::svg::EmbeddedFontProvider::tryAcquireFace ( std::string_view ,
const FontFaceRequest &  ) const
overridevirtual

Acquire product-wide copy/decode admission without blocking. Does not fetch missing bytes.

Reimplemented from donner::svg::FontFamilyProvider.


The documentation for this class was generated from the following file: