Overview

GPUI uses different context types for different scenarios:

Context Types:

• App : Global app state, entity creation

• Window : Window-specific operations, painting, layout

• Context<T> : Entity-specific context for component T

• AsyncApp : Async context for foreground tasks

• AsyncWindowContext : Async context with window access

Quick Start

Context - Component Context

impl MyComponent { fn update_state(&mut self, cx: &mut Context<Self>) { self.value = 42; cx.notify(); // Trigger re-render

    // Spawn async task
    cx.spawn(async move |cx| {
        // Async work
    }).detach();

    // Get current entity
    let entity = cx.entity();
}

}

App - Global Context

fn main() { let app = Application::new(); app.run(|cx: &mut App| { // Create entities let entity = cx.new(|cx| MyState::default());

    // Open windows
    cx.open_window(WindowOptions::default(), |window, cx| {
        cx.new(|cx| Root::new(view, window, cx))
    });
});

}

Window - Window Context

impl Render for MyView { fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement { // Window operations let is_focused = window.is_window_focused(); let bounds = window.bounds();

    div().child("Content")
}

}

AsyncApp - Async Context

cx.spawn(async move |cx: &mut AsyncApp| { let data = fetch_data().await;

entity.update(cx, |state, inner_cx| {
    state.data = data;
    inner_cx.notify();
}).ok();

}).detach();

Common Operations

Entity Operations

// Create entity let entity = cx.new(|cx| MyState::default());

// Update entity entity.update(cx, |state, cx| { state.value = 42; cx.notify(); });

// Read entity let value = entity.read(cx).value;

Notifications and Events

// Trigger re-render cx.notify();

// Emit event cx.emit(MyEvent::Updated);

// Observe entity cx.observe(&entity, |this, observed, cx| { // React to changes }).detach();

// Subscribe to events cx.subscribe(&entity, |this, source, event, cx| { // Handle event }).detach();

Window Operations

// Window state let focused = window.is_window_focused(); let bounds = window.bounds(); let scale = window.scale_factor();

// Close window window.remove_window();

Async Operations

// Spawn foreground task cx.spawn(async move |cx| { // Async work with entity access }).detach();

// Spawn background task cx.background_spawn(async move { // Heavy computation }).detach();

Context Hierarchy

App (Global) └─ Window (Per-window) └─ Context<T> (Per-component) └─ AsyncApp (In async tasks) └─ AsyncWindowContext (Async + Window)

Reference Documentation

• API Reference: See api-reference.md

• Complete context API, methods, conversions

• Entity operations, window operations

• Async contexts, best practices