Module canvas_fallback 

Eligibility only for independent, horizontal Canvas fallback of a complete extended grapheme. Callers must still check whether bundled shaping supplies the requested glyph and presentation; eligibility alone does not override it.

This is intentionally not a Unicode sequence validator or an RGI emoji database. Han variation selectors are checked structurally, not against the IVD registry. Emoji selectors are checked against the Emoji property, not the registered variation-sequence list. Eligibility does not guarantee browser coverage. Flags accept two regional indicators, not only assigned country codes. ZWJ support is limited to person/profession pairs and a small explicit allowlist; tags are limited to the three subdivision flags. Other sequences stay on Cosmic.

Structs

CanvasFallback

A supported grapheme assumed to be independently renderable.

Enums

CanvasFontFallback

Controls browser-font fallback when loaded fonts lack a glyph or its emoji presentation.

Functions

classify_canvas_fallback

Returns a presentation only when grapheme is exactly one supported extended grapheme cluster. No normalization, splitting, or font-coverage decision occurs.