Struct GlyphMap 

pub struct GlyphMap { /* private fields */ }

Cached character-to-glyph mapping for one font at one size.

Font::glyph_id re-reads the font’s tables on every call; per-frame text needs the answer for thousands of characters, so this caches it: ASCII is resolved up front into a table, any other character on first use (that first use allocates, later ones don’t). Characters the font lacks map to its ? glyph.

Memory is bounded: after MAX_CACHED_CHARS distinct non-ASCII characters (streaming text, CJK), the non-ASCII memory is cleared, keeping its capacity, and refilled on use.

Implementations

impl GlyphMap

pub fn new(font: Font, px: f32) -> Self

A map for font at px pixels per em.

pub fn font(&self) -> &Font

The font this map resolves against.

pub fn px(&self) -> f32

The size in pixels per em.

pub fn cached_chars(&self) -> usize

Non-ASCII characters currently remembered (at most MAX_CACHED_CHARS).

pub fn line_metrics(&self) -> LineMetrics

The font’s line metrics at this size.

pub fn get(&mut self, ch: char) -> Option<MappedGlyph>

The glyph for ch, or the ? glyph if the font has none; None only if the font lacks ? too.

pub fn measure(&mut self, text: &str) -> f32

Total advance of text in pixels.

Trait Implementations

impl Clone for GlyphMap

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GlyphMap

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

Formats the value using the given formatter.