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 rasterizer. That is this module: it parses each face exactly once, at registration, and produces an immutable SoftwareTextFontSet that measurement and rasterization then share. 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, consumed into a font set, and the font set is cloned (it is Arc-backed) into every measurer and rasterizer that needs it.

Fonts that are not files on disk come in through SoftwareTextFontRegistry::register_face_reader or SoftwareTextFontRegistry::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

SoftwareTextFontRegistry

Parsed app-supplied faces, on their way to a SoftwareTextFontSet.

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 SoftwareTextFontRegistry::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.