Module symbols 

Symbol/cartography foundations: asset dependencies and placement.

This module provides a small engine-owned symbol system inspired by the higher-level responsibilities in MapLibre’s symbol/placement.ts and image / glyph management. It is intentionally foundational rather than complete: the engine can now derive text/icon dependencies, perform basic collision detection, de-duplicate nearby repeated labels, and preserve per-symbol fade state across frames.

Sub-modules

Module	Purpose
cross_tile_index	Cross-tile symbol deduplication index (MapLibre CrossTileSymbolIndex equivalent).

Modules

cross_tile_index

Cross-tile symbol index for deduplicating labels at tile boundaries.

text_shaper

Text shaping engine for symbol label rendering.

Structs

GlyphAtlas

Requested glyph set for symbol text rendering.

GlyphAtlasEntry

Glyph atlas entry metadata.

GlyphKey

A requested glyph in a font stack.

GlyphQuad

A pre-laid-out glyph quad for GPU rendering.

GlyphRaster

Rasterized glyph bitmap.

ImageManager

Tracks symbol image dependencies.

PlacedSymbol

A placed symbol after collision resolution.

ProceduralGlyphProvider

A tiny built-in procedural glyph source for engine-side symbol plumbing.

SpriteImage

A sprite or standalone image dependency.

SpriteSheet

Registered sprite-sheet metadata.

SymbolAssetDependencies

Asset dependencies for a single placed symbol.

SymbolAssetRegistry

Runtime registry of glyph and image dependencies derived from placed symbols.

SymbolCandidate

Candidate symbol generated from a symbol layer before placement.

SymbolCollisionBox

A simple collision box in world-space meters.

SymbolPlacementConfig

Placement tuning parameters.

SymbolPlacementEngine

Stateful placement engine with collision handling and fade persistence.

Enums

SpriteSheetParseError

Errors while parsing a sprite-sheet index.

SymbolAnchor

Symbol anchor position relative to the anchor point.

SymbolIconTextFit

Icon sizing mode relative to the label text box.

SymbolPlacement

Placement mode for symbol features.

SymbolTextJustify

Horizontal text justification for symbol labels.

SymbolTextTransform

Text transformation applied before shaping and measurement.

SymbolWritingMode

Text writing mode for symbol labels.

Traits

GlyphProvider

Glyph raster source used to populate a glyph atlas.

Functions

layout_symbol_glyphs

Compute per-glyph positions from the glyph atlas and store them in each PlacedSymbol::glyph_quads.

layout_symbol_glyphs_shaped

Lay out symbol glyphs using the text shaping engine.

symbol_mesh_from_placed_symbols

Build a placeholder vector mesh from placed symbols.