bevy_input_focus

The "which entity gets keyboard input" subsystem. Defines focus state, focus traversal (Tab / Shift+Tab), and the dispatch path that turns raw key events into per-entity events for the focused widget.

Purpose

Without focus tracking, every keyboard event would have to be matched against every potentially-listening entity. bevy_input_focus introduces:

• InputFocus resource — the currently focused entity (an Option<Entity>).
• InputFocusVisible — whether to draw a focus ring (set on Tab keypress, cleared on mouse use).
• Focus dispatch systems — translate KeyboardInput events into per-entity events delivered through observers.
• Focus traversal — find the next/previous focusable entity in tab order.

Directory layout

crates/bevy_input_focus/src/
├── lib.rs               # InputFocusPlugin, InputDispatchPlugin
├── focus.rs             # InputFocus / InputFocusVisible
├── tab_navigation.rs    # Tab / Shift+Tab traversal
├── directional_navigation.rs  # Arrow-key directional nav
├── autofocus.rs         # AutoFocus marker
└── …

Key abstractions

Type	File	Description
InputFocus	crates/bevy_input_focus/src/focus.rs	Resource: focused entity.
InputFocusVisible	crates/bevy_input_focus/src/focus.rs	Whether to render focus indicators.
TabIndex	crates/bevy_input_focus/src/tab_navigation.rs	Per-entity tab order priority.
AutoFocus	crates/bevy_input_focus/src/autofocus.rs	Marker: focus this entity on spawn.
InputFocusPlugin, InputDispatchPlugin	crates/bevy_input_focus/src/lib.rs	Plugins.

How it works

InputDispatchPlugin runs before user systems each frame. For each KeyboardInput event, it looks at InputFocus. If focus is Some(entity), the event is bubbled as an entity event up the parent chain via observers. Widgets register Observer<KeyboardInput> (or higher-level events) on themselves.

Tab traversal is a separate system that sees Tab / Shift+Tab and updates InputFocus to the next/previous entity in tab order.

Integration points

• Depends on: bevy_app, bevy_ecs, bevy_input, bevy_window.
• Depended on by: bevy_ui, bevy_ui_widgets, bevy_feathers, bevy_a11y.

Entry points for modification

• Custom traversal order: edit tab_navigation.rs.
• Add focus group concept: the existing types support per-window focus; cross-window focus would go here.
• Directional navigation tweaks: directional_navigation.rs.

See also

• bevy_input — events this crate routes.
• bevy_ui, bevy_ui_widgets — consumers.