gpui-context

---

name: gpui-context description: Context management in GPUI including App, Window, and AsyncApp. Use when working with contexts, entity updates, or window operations. Different context types provide different capabilities for UI rendering, entity management, and async operations.

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

Copyimpl 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

Copyfn 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

Copyimpl 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

Copycx.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

Copy// 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

Copy// 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

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

// Close window
window.remove_window();

Async Operations

Copy// 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

CopyApp (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