Struct TextShapeCache 

pub struct TextShapeCache { /* private fields */ }

Tier 2: bounded global LRU shaping cache.

Stores shaped text results keyed by (FontId, font_size_bits, text_hash). Evicts least-recently-used entries when the total memory budget is exceeded.

The cache tracks access order via an internal age counter. Each access updates the entry’s age. When the budget is exceeded, the oldest entries are evicted first.

Examples

use martensite_text::TextShapeCache;

let cache = TextShapeCache::with_default_budget();
assert!(cache.is_empty());
assert_eq!(cache.budget(), 16 * 1024 * 1024);

Implementations

impl TextShapeCache

pub fn new(budget: usize) -> Self

Creates a new cache with the given memory budget in bytes.

pub fn with_default_budget() -> Self

Creates a cache with the default 16 MB budget.

pub fn len(&self) -> usize

Returns the number of entries in the cache.

pub fn is_empty(&self) -> bool

Returns true if the cache is empty.

pub fn total_memory(&self) -> usize

Returns the total estimated memory usage in bytes.

pub fn budget(&self) -> usize

Returns the memory budget in bytes.

pub fn hits(&self) -> u64

Returns the number of cache hits.

pub fn misses(&self) -> u64

Returns the number of cache misses.

pub fn hit_rate(&self) -> f64

Returns the cache hit rate as a fraction in [0.0, 1.0].

pub fn get(&mut self, key: &ShapeCacheKey) -> Option<&CachedShape>

Looks up a cached shape by key.

Returns Some(&CachedShape) on hit, None on miss. Updates the entry’s access age on hit.

pub fn insert(&mut self, key: ShapeCacheKey, shape: CachedShape)

Inserts a shaped result into the cache.

If the entry’s memory pushes the total over budget, LRU entries are evicted until the budget is satisfied.

pub fn clear(&mut self)

Clears all entries from the cache.

pub fn trim(&mut self, keep_age: u64)

Trims entries that haven’t been accessed in keep_age ticks.

This is a softer eviction than the memory-based eviction in Self::insert.

pub fn invalidate_font(&mut self, font_id: FontId)

Invalidates all entries for a specific font (e.g., when a font is unloaded or changed).

pub fn invalidate_font_size(&mut self, font_size: f32)

Invalidates all entries for a specific font size.

pub fn resize(&mut self, new_budget: usize)

Resizes the memory budget, evicting entries if the new budget is smaller than current usage.

Trait Implementations

impl Debug for TextShapeCache

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

Formats the value using the given formatter.

impl Default for TextShapeCache

fn default() -> Self

Returns the “default value” for a type.