Struct GlyphAtlas 

pub struct GlyphAtlas { /* private fields */ }

A static FontChain plus the char -> slot map for its grid-packed atlas.

Every glyph of every font in the chain is uploaded once; a character maps to a flat slot, which is the font’s base offset in the atlas plus that font’s own glyph index. A renderer never sees characters past this point: resolve hands back a u16 that goes straight into an instance buffer.

Implementations

impl GlyphAtlas

pub fn new(fonts: FontChain<'static>, glyph_size: (u8, u8)) -> Self

An atlas over a static font chain, whose slots are assigned back to back in chain order.

glyph_size is the cell size every font in fonts agrees on. Pass what FontChain::glyph_size returned, and reject a chain it returned None for: a grid has one cell size, so a chain whose fonts disagree has no atlas geometry to build.

pub const fn cell_size(&self) -> (u32, u32)

Glyph cell size in unscaled pixels.

pub const fn space_slot(&self) -> u16

The atlas slot of the space glyph, or 0 for a chain with no space glyph at all.

Only ever used for cells that draw no glyph (a backend still needs some slot in the instance it writes), so a chain without a space still renders correctly.

pub fn slot_count(&self) -> u32

The total number of glyph slots the chain occupies in the atlas.

Compare against MAX_SLOTS before building: a chain past that has glyphs resolve cannot name.

pub const fn fonts(&self) -> &FontChain<'static>

The backing font chain.

pub fn data(&self) -> AtlasData

The full coverage buffer to upload, built fresh each call.

Not cached: a backend uploads it once at resource creation and, on some platforms, again after a lost device, which is rare enough that holding a second copy of the atlas for the renderer’s whole life costs more than rebuilding it.

pub fn resolve(&self, ch: char) -> Option<u16>

Resolves ch to its atlas slot, or None when no font in the chain can draw it, not even as the substituted solid block, in which case the caller draws no glyph for that cell.

Panics

Does not panic. The u16 cast cannot truncate for a chain whose slot_count is within MAX_SLOTS, which a backend’s builder is expected to have checked.

Trait Implementations

impl Clone for GlyphAtlas

fn clone(&self) -> GlyphAtlas

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GlyphAtlas

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.