Module font_source 

Turning app-declared font families into parsed faces.

FontFamily::FileBacked and FontFamily::LoadedTypeface name faces by file rather than by a name inside the font, so something has to read those files and hand the bytes to the text engine. That is this module: it parses each face exactly once, at registration, into the typefaces text lays out and draws with. The process keeps one copy of each font file’s contents, shared by every face instanced from it and by later reads that find the file unchanged.

Nothing here runs per frame or per string. A registry is built at startup and consumed into typefaces, which are Arc-backed.

Fonts that are not files on disk come in through FontRegistry::register_face_reader or FontRegistry::register_face_bytes: an APK asset opened with AndroidApp::asset_manager(), or anything cranpose-assets resolved out of a desktop bundle. cranpose-assets is a filesystem path resolver, so it covers bundles but not APK entries, which are not filesystem paths.

Structs

FontRegistry

Parsed app-supplied faces, on their way to the typefaces text lays out with.

Enums

FontLoadError

Why an app-supplied face could not be registered.

Constants

ANDROID_SYSTEM_FONT_DIR

Directory Android keeps its system font files in.

DEFAULT_SYSTEM_FAMILY_WEIGHTS

The weights FontRegistry::register_system_family registers when an app does not name its own: Compose’s Regular/Medium/Bold set.

Functions

system_declared_weight

The weight a platform’s own matcher resolves weight to for a generic family alias — never a value that family’s font config does not declare.

system_font_file

The file a platform backs family with at weight, if one is present.