Struct PaneHeadless 

pub struct PaneHeadless { /* private fields */ }

A Pane UI instance with no GPU or window — logic, state, and actions only.

Useful for automated testing, server-side UI state machines, or any context where rendering is not needed. All widget state is maintained and actions are emitted normally; draw calls are discarded.

Create with headless, then call update each tick.

Implementations

impl PaneHeadless

pub fn update(&mut self, dt: f32) -> Vec<PaneAction>

Advance the UI by dt seconds and return any actions emitted this tick.

Call at a fixed or variable rate. dt is in seconds; typical values are 1.0 / 60.0 for a 60 Hz simulation tick.

pub fn press(&mut self, id: &str)

Simulate pressing a button by id.

Only works if headless_accessible: true is set in the root definition. Fires the button’s action as if the user clicked it.

pub fn active_root(&self) -> Option<&str>

Returns the name of the currently active root, or None if none has been set.

pub fn read(&self, id: &str) -> Option<(&UiItem, WidgetState)>

Returns the item data and its current visual state for any widget by id.

Same as PaneOverlay::read — pattern-match on UiItem to get widget fields.

pub fn write(&mut self, id: &str, value: &WriteValue)

Set a widget’s value programmatically.

See WriteValue for the supported widget types and their matching variants. Mismatched types and unknown ids are logged and ignored.

pub fn create(&mut self, root: &str, builder: impl WidgetBuilder) -> bool

Add a code-built widget to a named root. Returns false if the id is already in use or the root doesn’t exist.

pub fn destroy(&mut self, id: &str) -> bool

Remove a widget by id from any root. Returns true if a widget was removed.

pub fn create_root(&mut self, name: impl Into<String>)

Create an empty root that can be populated with Self::create.

pub fn style_id(&self, name: &str) -> Option<StyleId>

Resolve a style name to its StyleId for use with builders.

pub fn default_style(&self) -> Option<&str>

Returns the name of the current default style, if one is set.

pub fn set_default_style(&mut self, name: &str) -> bool

Switch the default style by name. Returns false if the name is not registered.

pub const fn set_debug(&mut self, on: bool)

Enable or disable debug message logging (no-op in headless mode, but kept for API symmetry with PaneOverlay::set_debug).

pub fn push_toast( &mut self, message: impl Into<String>, duration: f32, x: f32, y: f32, width: f32, height: f32, )

Spawn a transient toast notification.

In headless mode toasts are tracked but not rendered.

pub fn actor_move_to(&mut self, id: &str, x: f32, y: f32, speed: f32)

Programmatically send an actor to a fixed position, overriding its RON behaviours.

pub fn actor_follow_cursor(&mut self, id: &str, speed: f32, trail: f32)

Programmatically make an actor follow the cursor, overriding its RON behaviours.

pub fn actor_reset(&mut self, id: &str)

Clear any programmatic override on an actor, returning it to its RON behaviours.

pub fn actor_set_pos(&mut self, id: &str, x: f32, y: f32)

Teleport an actor to a position instantly, without lerping.