Struct FontCache 

pub struct FontCache { /* private fields */ }

Implementations

impl FontCache

pub fn from_bytes(bytes: &[u8]) -> Self

pub fn from_asset(name: impl AssetRef) -> Option<Self>

Load a font from a bundled asset by logical name — resolved per-platform via rosace_core::asset (dev: assets/<name>; mobile: the app bundle). Returns None if the asset is missing or not a valid font, so callers can fall back to default/[embedded].

let brand = FontCache::from_asset("fonts/Brand.ttf")
    .unwrap_or_else(FontCache::default);

pub fn embedded() -> Self

A fallback font compiled into the binary — DejaVu Sans (permissive Bitstream Vera license). Used when no system font is available, most importantly on the web/wasm target where system_ui() finds nothing. Guarantees text always renders on every platform.

pub fn bundled() -> Self

The DEFAULT app font (Phase 32, user-decided): bundled Inter (SIL OFL — this crate’s own assets/fonts/inter/LICENSE-OFL.txt), the same pleasant, screen-tuned face on EVERY platform with clearly differentiable weights — Regular for body, real Bold (700) for emphasis. Replaces “whatever the OS ships” as the default (system_ui() remains available as an opt-in); also replaces the short-lived Medium-by-default experiment, which read slightly bold.

Italic faces (Inter-Italic/Inter-BoldItalic) are bundled alongside but not yet wired — the text pipeline has no italic axis yet (tracked in PHASE_32.md).

pub fn system_ui() -> Option<Self>

Load a system proportional / UI font plus (when available) a real bold face and the Unicode fallback chain. Prefers a same-family bold face found inside the regular candidate’s own file (see Self::weight_score); only falls back to the unrelated BOLD_PATHS standalone files when the chosen family has no bold member of its own (e.g. plain Arial.ttf, which IS the regular face and needs the separate Arial Bold.ttf).

pub fn system_mono() -> Option<Self>

Load a system monospace font (Menlo, Courier, DejaVu Mono, etc.).

pub fn set_icon_face(&self, font: Arc<OwnedFace>)

Install an in-memory icon face — glyphs the primary faces miss route to it before the disk fallback chain, so icon-font codepoints (PUA) flow through the ordinary text path: physical-px rasterization, glyph cache, and the GPU glyph atlas, with zero new draw commands.

Idempotent: the first registration wins; later calls are no-ops. Registration clears the route cache so codepoints resolved earlier (as tofu) re-route to the new face.

pub fn has_icon_face(&self) -> bool

True once an icon face is installed — lets callers skip re-registration on every paint.

pub fn glyph_weighted( &self, c: char, px: f32, weight: FontWeight, ) -> CachedGlyph

Shared handle to the cached glyph for c at px/weight — routed through the bold face and Unicode fallbacks.

pub fn glyph(&self, c: char, px: f32) -> CachedGlyph

Regular-weight glyph (hot path for plain text).

pub fn rasterize(&self, c: char, px: f32) -> (GlyphMetrics, Vec<u8>)

Rasterize a single character (copies the bitmap — prefer FontCache::glyph in hot paths).

pub fn color_glyph_rgba(&self, c: char, px: f32) -> Option<Arc<ColorGlyph>>

Real color glyph for c at px, if c is in an emoji range AND the emoji fallback face actually has a color bitmap for it (sbix only today — see EMOJI_FALLBACK_PATHS’s doc for the Windows/Linux gap). None for anything else, including a plain character that happens to fail this lookup — callers fall through to the normal outline path.

pub fn kern_weighted( &self, left: char, right: char, px: f32, weight: FontWeight, ) -> f32

Kerning between left and right at px/weight. Zero when the pair spans different faces (fallback boundaries have no kern data), or when the face has no kern table. Reads the kern table directly via ttf_parser (already a dependency here for name-table/ collection-index introspection) — swash’s own shaping module targets full GPOS-based complex-script shaping, a bigger API than the simple pairwise advance this UI-text layout model needs.

pub fn kern(&self, left: char, right: char, px: f32) -> f32

pub fn advance_width_weighted( &self, c: char, px: f32, weight: FontWeight, ) -> f32

Pixel advance width at px/weight. Cached, fallback-routed.

pub fn advance_width(&self, c: char, px: f32) -> f32

pub fn measure_text_weighted( &self, text: &str, px: f32, weight: FontWeight, ) -> f32

Total pixel width of a string at px/weight — advances plus kerning, in lockstep with SkiaCanvas::draw_text_weighted so measured and painted widths agree.

pub fn measure_text(&self, text: &str, px: f32) -> f32

pub fn ascender(&self, px: f32) -> i32

Distance from the top of the line box to the baseline, in pixels. Always from the primary face — mixed-face runs share one baseline.

pub fn line_height(&self, px: f32) -> f32

Full line height (ascender + descender + gap) in pixels.