Struct GlyphCacheKey 

pub struct GlyphCacheKey {

    pub font_id: u64,
    pub font_index: u32,
    pub glyph_id: u32,
    pub size_bits: u32,
    pub hinted: bool,
    pub subpixel_x: u8,
    pub context_color: AlphaColor<Srgb>,
    pub context_color_packed: u32,
    pub embolden_x_bits: u32,
    pub embolden_y_bits: u32,
    pub embolden_join_bits: u8,
    pub embolden_miter_limit_bits: u32,
    pub embolden_tolerance_bits: u32,
    pub var_coords: SmallVec<[NormalizedCoord; 4]>,
}

Unique identifier for a cached glyph bitmap.

Two glyphs with the same key are visually identical and can share the same cached bitmap. The key includes all parameters that affect the glyph’s appearance.

var_coords is deliberately excluded from Hash/Eq because the GlyphAtlas uses a two-level map structure that already partitions entries by variation coordinates. Callers that use a flat map must ensure equivalent var_coords externally.

Fields

font_id: u64

Unique identifier for the font blob.

font_index: u32

Index within font collection (for TTC files).

glyph_id: u32

Glyph index within the font.

size_bits: u32

Font size as f32 bits (exact match, no quantization).

hinted: bool

Whether hinting was applied.

subpixel_x: u8

Horizontal subpixel position (0 to SUBPIXEL_BUCKETS-1 for outlines), or a sentinel (SUBPIXEL_COLR / SUBPIXEL_BITMAP) for non-outline glyphs.

context_color: AlphaColor<Srgb>

Context color for COLR glyphs. Only used for rendering, not for Hash/Eq.

context_color_packed: u32

Pre-packed context color (premultiplied RGBA8 as u32) used in Hash/Eq.

embolden_x_bits: u32

Synthetic embolden amount. Only non-zero for outline glyphs.

embolden_y_bits: u32

Synthetic embolden amount. Only non-zero for outline glyphs.

embolden_join_bits: u8

Join style for synthetic embolden. Only meaningful for outline glyphs.

embolden_miter_limit_bits: u32

Miter limit for synthetic embolden. Only meaningful for outline glyphs.

embolden_tolerance_bits: u32

Tolerance for synthetic embolden. Only meaningful for outline glyphs.

var_coords: SmallVec<[NormalizedCoord; 4]>

Variation coordinates for variable fonts.

Implementations

impl GlyphCacheKey

pub fn new( font_id: u64, font_index: u32, glyph_id: u32, size: f32, hinted: bool, fractional_x: f32, context_color: AlphaColor<Srgb>, context_color_packed: u32, embolden: FontEmbolden, var_coords: &[NormalizedCoord], ) -> Self

Creates a new cache key.

fractional_x (the fractional pixel offset) is quantized into SUBPIXEL_BUCKETS buckets, so nearby positions share the same entry.

Trait Implementations

impl Clone for GlyphCacheKey

fn clone(&self) -> GlyphCacheKey

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GlyphCacheKey

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

Formats the value using the given formatter.

impl Hash for GlyphCacheKey

Manual Hash and PartialEq use the pre-packed context_color_packed field (a premultiplied RGBA8 u32) instead of AlphaColor<Srgb>, which doesn’t implement Hash/Eq. Packing once at construction avoids repeated work during lookups. glyph_id is compared first for early short-circuit.

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for GlyphCacheKey

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for GlyphCacheKey