Module key 

Cache key for glyph bitmaps stored in the atlas.

GlyphCacheKey captures every parameter that affects the visual appearance of a rasterized glyph — font identity, size, hinting, subpixel position, COLR context color, and variable-font coordinates. Two keys that compare equal produce identical bitmaps and can safely share a single atlas entry.

Structs

GlyphCacheKey

Unique identifier for a cached glyph bitmap.

Constants

SUBPIXEL_BITMAP 🔒

Sentinel subpixel_x for bitmap glyph cache entries. See SUBPIXEL_COLR.

SUBPIXEL_BUCKETS 🔒

Number of horizontal subpixel quantization buckets (valid range: 1–253).

SUBPIXEL_COLR 🔒

Sentinel subpixel_x for COLR glyph cache entries.

Functions

f32_bits 🔒

join_bits 🔒

pack_color 🔒

Premultiply and pack an RGBA color into a u32 for bitwise hashing/comparison.

quantize_subpixel 🔒

Quantize a fractional pixel offset into one of SUBPIXEL_BUCKETS buckets.

subpixel_offset

Convert a quantized bucket index back to the fractional pixel offset it represents.