bevy_window

Platform-agnostic windowing types. Defines Window, window events, modes (windowed/fullscreen/borderless), cursor settings, and the API the OS-specific backend (bevy_winit) implements against.

Purpose

The crate is data + events. The actual OS window is owned by bevy_winit; bevy_window just exposes the types so other crates (input, picking, rendering) can be backend-agnostic.

Directory layout

crates/bevy_window/src/
├── lib.rs            # WindowPlugin, prelude
├── window.rs         # Window component + WindowResolution
├── event.rs          # WindowResized, CursorEntered, FileDragAndDrop, ...
├── cursor.rs         # CursorIcon, CursorOptions
├── monitor.rs        # Monitor info
├── system.rs         # Per-frame helper systems
└── system_cursor.rs

Key abstractions

Type	File	Description
Window	crates/bevy_window/src/window.rs	Component on a window entity.
WindowPlugin	crates/bevy_window/src/lib.rs	Adds the resources/events.
PrimaryWindow	crates/bevy_window/src/lib.rs	Marker on the main window entity.
WindowResized, WindowCloseRequested, WindowFocused, …	crates/bevy_window/src/event.rs	Lifecycle events.
Monitor, Monitors	crates/bevy_window/src/monitor.rs	Monitor info from the OS.
CursorIcon, CursorOptions	crates/bevy_window/src/cursor.rs	Cursor config.

How it works

Each OS window is an ECS entity with a Window component. bevy_winit owns the OS handle and watches for ECS changes (resize, fullscreen toggle, cursor changes) to push to the OS, and for OS events to translate back into the corresponding event resource.

PrimaryWindow is a marker component the default plugins put on the first window. Many systems use Query<&Window, With<PrimaryWindow>> to grab "the" window.

Integration points

• Depends on: bevy_app, bevy_ecs, bevy_math, bevy_a11y, bevy_image (for cursor images), bevy_reflect.
• Depended on by: bevy_winit, bevy_render, bevy_camera, bevy_input, bevy_picking, bevy_ui.

Entry points for modification

• New window property: add a field to Window and propagate via bevy_winit.
• New event: add to event.rs and emit from bevy_winit.
• Cursor: cursor.rs for the data, bevy_winit for the OS bridge.

See also

• bevy_winit — the OS-specific backend.
• bevy_render — renders into a Window's swapchain.