Module cache 

Layout cache for memoizing layout computation results.

This module provides LayoutCache which caches the Vec<Rect> results from layout computations to avoid redundant constraint solving during rendering.

Overview

Layout computation (constraint solving, flex distribution) can be expensive for complex nested layouts. During a single frame, the same layout may be queried multiple times with identical parameters. The cache eliminates this redundancy.

Usage

use ftui_layout::{Flex, Constraint, LayoutCache, LayoutCacheKey, Direction};
use ftui_core::geometry::Rect;

let mut cache = LayoutCache::new(64);

let flex = Flex::horizontal()
    .constraints([Constraint::Percentage(50.0), Constraint::Fill]);

let area = Rect::new(0, 0, 80, 24);

// First call computes and caches
let rects = flex.split_cached(area, &mut cache);

// Second call returns cached result
let cached = flex.split_cached(area, &mut cache);

Invalidation

Generation-Based (Primary)

Call LayoutCache::invalidate_all() after any state change affecting layouts:

match msg {
    Msg::DataChanged(_) => {
        self.layout_cache.invalidate_all();
    }
    Msg::Resize(_) => {
        // Area is part of cache key, no invalidation needed!
    }
}

Cache Eviction

The cache uses LRU (Least Recently Used) eviction when at capacity.

Structs

CoherenceCache

Stores previous layout allocations for temporal coherence.

CoherenceId

Identity for a layout computation, used as key in the coherence cache.

LayoutCache

Cache for layout computation results.

LayoutCacheKey

Key for layout cache lookups.

LayoutCacheStats

Statistics about layout cache performance.

S3FifoLayoutCache

Layout cache backed by S3-FIFO eviction.