@weasel-js/font

MSDF font atlases, glyph metrics, and runtime glyph rasterization for @weasel-js/core.

A Tier A leaf: core depends on this package, never the reverse. It owns the font registry — the one piece of module-level state whose duplication renders no glyphs at all.

What's here

| Module | Role | | --- | --- | | FontAtlas | BMFont metrics parsing | | registerFont | The registry, variant resolution, texture upload | | dynamic/ | Runtime canvas-SDF rasterization for glyphs with no baked atlas | | textureSink | The GlyphTextureSink seam — the renderer injects GL texture upload, so this package never imports one | | textSdf | The GLSL that turns an atlas sample into glyph coverage, for the renderer's batch program to paste in |

Fallback

An unregistered family renders in the default family with a one-time warning:

setFontFallbackPolicy('substitute');  // default — render in the default family
setFontFallbackPolicy('canvas');      // rasterize the real typeface at runtime
setFontFallbackPolicy('none');        // hard miss: render nothing (pre-0.7 behavior)

setDefaultFontFamily('Inter');        // defaults to the first registered family

Substitution changes advance widths, so measurement and wrap differ from the requested font. ResolveResult.substituted reports it structurally so a UI can surface the swap rather than leaving it to the console.

Generating an atlas

npm run gen:font (source in scripts/gen-font.ts).