Module focus_state

Focus State Management

This module provides focus state management for the Tessera UI framework.

Overview

Focus is a common requirement in UI frameworks. As a functional UI framework, tessera lacks a stable method for locating specific components by reference. Treating focus as an independent, shared state aligns better with tessera’s design philosophy and provides greater flexibility.

Design Philosophy

The focus system is designed around the following principles:

• Decentralized: Each component can create its own Focus instance
• Thread-safe: Focus state is managed using atomic operations and locks
• Automatic cleanup: Focus is automatically cleared when a Focus instance is dropped
• Unique identification: Each focus instance has a unique UUID to prevent conflicts

Usage

use tessera_ui::Focus;

// Create a new focus instance
let focus = Focus::new();

// Check if this focus is currently active
if focus.is_focused() {
    // Handle focused state
}

// Request focus for this component
focus.request_focus();

// Clear focus when no longer needed
focus.unfocus();

Thread Safety

The focus state is managed through a global static variable protected by read-write locks, making it safe to use across multiple threads. This is essential for Tessera’s parallelized design.

Structs

Focus

A focus handle that represents a focusable component.