Module sdf_generator 

SDF (Signed Distance Field) generation from rasterized glyph bitmaps.

Uses a dead-reckoning (8SSEDT) algorithm for O(n) per-pixel SDF computation, with optional multi-channel SDF (MSDF) for sharper corners.

The pipeline:

1. Rasterize each glyph at high resolution (256px) via ab_glyph
2. Compute SDF at output resolution (typically 64px) using dead reckoning
3. Pack glyphs into an atlas using a shelf packing algorithm
4. Optionally cache the atlas to disk as a PNG for fast reload

Structs

MsdfGlyphData

Multi-channel SDF result: R, G, B channels each contain distance to a different edge segment class, producing sharper corners when median-filtered.

SdfAtlasData

Complete result of SDF atlas generation.

SdfConfig

Configuration for SDF generation.

SdfGlyphData

SDF data for a single glyph, before atlas packing.

SdfGlyphMetric

UV rectangle for one glyph in the SDF atlas.

Functions

generate_glyph_msdf

Generate MSDF data for a single glyph using Chlumsky’s approach.

generate_glyph_sdf

Generate SDF data for a single glyph.

generate_sdf_atlas

Generate the complete SDF atlas for all ATLAS_CHARS.