Struct FontMetricsCache 

pub struct FontMetricsCache { /* private fields */ }

A font metrics cache that stores computed measurements to avoid redundant width calculations during pipeline processing.

Implementations

impl FontMetricsCache

pub fn new(max_entries: usize) -> Self

Create a new cache with a maximum entry limit.

pub fn default_capacity() -> Self

Create a cache with default capacity (10,000 entries).

pub fn get( &mut self, font_name: &str, font_size: f64, text: &str, ) -> Option<&TextMeasurement>

Look up a cached measurement. Returns None on cache miss.

pub fn put( &mut self, font_name: &str, font_size: f64, text: &str, measurement: TextMeasurement, )

Store a measurement in the cache. If the cache is full, it will be cleared (simple eviction strategy).

pub fn get_or_compute<F>( &mut self, font_name: &str, font_size: f64, text: &str, compute: F, ) -> TextMeasurement

where F: FnOnce() -> TextMeasurement,

Get or compute a measurement, using the cache if available.

pub fn estimate_width( &mut self, font_name: &str, font_size: f64, text: &str, char_widths: &HashMap<char, f64>, default_width: f64, ) -> TextMeasurement

Estimate the width of a text string given per-character widths from a font. This is a convenience method using a simple character-width lookup.

pub fn hits(&self) -> u64

Number of cache hits.

pub fn misses(&self) -> u64

Number of cache misses.

pub fn hit_rate(&self) -> f64

Cache hit rate as a fraction (0.0 to 1.0).

pub fn len(&self) -> usize

Number of entries currently in the cache.

pub fn is_empty(&self) -> bool

Whether the cache is empty.

pub fn clear(&mut self)

Clear all cached entries and reset counters.

Trait Implementations

impl Debug for FontMetricsCache

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

Formats the value using the given formatter.