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.