Struct MenuBar 

pub struct MenuBar { /* private fields */ }

A horizontal application menu bar with labelled trigger buttons and dropdown menus.

Each top-level entry becomes a focusable trigger; activating it opens a floating MenuList overlay. See the module documentation for the full keyboard, mnemonic, and collapsible-mode details.

Implementations

impl MenuBar

pub fn new() -> Self

Create an empty menu bar with no menus, slots, or collapse policy.

pub fn from_model(model: MenuModel) -> Self

Build a menu bar from a declarative MenuModel — the single source of truth shared with the native OS menu bar. Each top-level menu in the model becomes an in-window dropdown; combine with native_on_macos to also mirror it into the macOS system menu bar.

pub fn native_on_macos(self, mode: NativeMenuMode) -> Self

Choose how this bar behaves on macOS, where the convention is a global menu bar at the top of the screen. Requires the bar to have been built with from_model and the app to have called install_native_menu(). No effect on other platforms (the in-window bar renders there regardless).

pub fn collapsible(self) -> Self

Enable the optional hamburger representation. When there isn’t room for the full inline bar, it collapses to a single hamburger (☰) IconButton; activating it (click, Alt+ mnemonic, F10, or bare-Alt-tap) reveals the full bar as a floating overlay over content. Clicking outside the bar or pressing Escape hides it again.

Uses CollapsePolicy::Responsive. Observe the collapsed state via is_collapsed, or bind your own signal with collapsed_signal.

pub fn collapsed_signal(self, collapsed: Signal<bool>) -> Self

Like collapsible, but uses the supplied signal as the collapsed-state source so the application can observe (and react to) collapse transitions. The responsive decision writes this signal (it is not a plain read-only input) — kept as a Signal<bool> rather than Prop<bool> since a static value would have nowhere to receive those writes.

pub fn collapse_policy(self, policy: CollapsePolicy) -> Self

Set the collapse policy (and enable collapsible mode). CollapsePolicy::Always forces the hamburger regardless of available width — i.e. collapsed by default.

pub fn hamburger_size(self, size: IconButtonSize) -> Self

Set the size variant of the collapsed-mode hamburger IconButton. Mirrors IconButton::size — pick IconButtonSize::Toolbar, IconButtonSize::Large, IconButtonSize::Hero, etc. so the hamburger matches the surrounding chrome. Defaults to IconButtonSize::Default.

pub fn is_collapsed(&self) -> Signal<bool>

A clone of the collapsed-state signal (true while the hamburger is shown). Call after collapsible.

pub fn no_dispatcher_install(self) -> Self

Skip the window-state dispatcher install. The MenuBar still renders, intercepts mouse clicks, and supports keyboard navigation when its triggers have focus — only F10 / Alt+letter / Alt-tap routing through the window-level slot is disabled. Use this for demo / showcase MenuBars that share a window with a primary functional MenuBar — the slot is single-occupancy and a second install would debug_assert!.

pub fn menu( self, label: impl Into<LocalizedString>, factory: impl Fn() -> Box<dyn Widget> + 'static, ) -> Self

Add a top-level menu entry. label is the trigger text (supports & mnemonic markers, e.g. "&File"); factory is called each build to produce the dropdown content — typically a MenuList.

pub fn leading_slot(self, widget: impl Widget + 'static) -> Self

Add content before the menu buttons (e.g. an app icon). Call more than once to stack several.

Takes the widget by value, like every other widget’s slot. MenuBar builds it once and reuses it across rebuilds (it preserves_children_on_rebuild), so the slot — and any state it holds — survives a theme / locale / model-version rebuild.

pub fn trailing_slot(self, widget: impl Widget + 'static) -> Self

Add content after the menu buttons (e.g. a search box or avatar). Like leading_slot, taken by value and preserved across rebuilds.

Trait Implementations

impl Debug for MenuBar

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MenuBar

fn default() -> Self

Returns the “default value” for a type.

impl Widget for MenuBar

fn preserves_children_on_rebuild(&self) -> bool

Reconcile on rebuild. The menu triggers are re-derived fresh each build (the model may have changed) and the reconcile reaps the superseded ones; the memoized leading/trailing slot widgets (see add_slot) are re-attached by id and kept alive, so a stateful slot control — a search field, a focused button, an avatar with hover state — survives a model-version / theme / locale rebuild instead of being rebuilt from scratch.

fn build(&mut self, ctx: &mut BuildContext<'_>) -> Vec<WidgetId>

Compose child widgets. Called once after the widget is placed in the arena, and again on environment change (theme switch, locale switch). Takes &mut self — store child IDs, signal handles, any state needed later. Returns the list of root child IDs (empty for leaf widgets).

fn layout_response( &self, proposal: SizeProposal, ctx: &LayoutContext<'_>, ) -> LayoutResponse

Respond to the parent’s size proposal with this widget’s wanted size, grow/shrink weights, and compression floor (see [LayoutResponse]).

fn place_children( &self, bounds: Rect, proposal: SizeProposal, children: &mut [WidgetPlacement], ctx: &LayoutContext<'_>, )

Position children within the allocated bounds.

fn accessibility(&self, builder: &mut AccessNodeBuilder)

Declare this widget’s accessibility identity.

fn children(&self) -> Vec<WidgetId>

Return the child widget IDs that this widget manages.

fn type_name(&self) -> &'static str

Concrete type name of this widget (e.g. "teksilo_widgets::button::Button"). The default implementation resolves at the impl site via std::any::type_name::<Self>(), so calls through &dyn Widget correctly dispatch to the monomorphized fn for the concrete type — getting the concrete name through the vtable without per-impl boilerplate.

fn cacheable_layout(&self) -> bool

Whether this widget’s layout_response may be memoized by the per-pass layout cache. Defaults to true.

fn paint(&self, _bounds: Rect, _canvas: &mut Canvas, _ctx: &PaintContext<'_>)

Draw the widget’s visual representation.

fn wants_after_paint(&self) -> bool

Whether this widget wants its after_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t aggregate descendant geometry.

fn after_paint(&self, _view: &WidgetTreeView<'_>, _ctx: &PaintContext<'_>)

Called once per frame after this widget’s subtree has finished painting. Receives a read-only view of the layout-resolved arena so a parent can read its descendants’ final bounds — e.g. TitleBar aggregates its drag region and control-button rects into a single HitRegions payload for the Windows backend’s WM_NCHITTEST.

fn wants_post_paint(&self) -> bool

Whether this widget wants its post_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t draw a foreground over their children.

fn post_paint( &self, _bounds: Rect, _canvas: &mut Canvas, _ctx: &PaintContext<'_>, )

Draw a foreground layer over this widget’s children.

fn wants_descendant_redirects(&self) -> bool

Whether this widget wants the AT walker to consult its a11y_redirect_descendant hook for every descendant during AT tree emission, not just its direct arena children.

fn a11y_redirect_descendant( &self, _self_id: WidgetId, _descendant: WidgetId, ) -> Option<NodeId>

Optional redirection hook for AT-tree placement of a child.

fn accessible_title_hint(&self) -> Option<String>

Suggest an accessible title to an enclosing container that wraps this widget as content — typically a modal / dialog shell that wants to propagate the inner content’s visible title as the shell’s own accessible name.

fn initial_focus_hint(&self) -> Option<WidgetId>

Optional hint that directs initial focus to a specific descendant when this widget is the root of a deferred-built modal surface.

fn accessibility_children(&self) -> Option<Vec<WidgetId>>

Optional override for the child ORDER presented to assistive technology, when it must differ from the paint / z-order child order returned by children.

fn as_any(&self) -> Option<&(dyn Any + 'static)>

Downcast hook. Default implementation returns None; concrete widgets override with Some(self) when they want to expose their concrete type to test-level introspection or reflection. The trait already bounds on std::any::Any so concrete types satisfy the 'static requirement.

fn as_any_mut(&mut self) -> Option<&mut (dyn Any + 'static)>

Mutable counterpart of as_any. Default returns None; widgets that want to expose mutable state to tests (e.g. so a test can mutate a Scene inside a SceneView post-layout) override with Some(self). Should follow the same opt-in pattern as as_any: only widgets that opt into & introspection should opt into &mut.

fn clips_children(&self) -> bool

Whether this widget clips its children to its bounds.

fn focus_reveal_rect(&self, _bounds: Rect) -> Option<Rect>

The rectangle (in absolute tree coordinates) that best represents this widget when the framework reveals it into an ancestor scroll area on focus gain. Returning None (the default) reveals the widget’s whole bounds — correct for most controls.

fn hit_shape(&self, _local_point: Point, _bounds: Rect) -> bool

Whether the point lies inside this widget’s actual shape, not just its rectangular bounds. Consulted by hit-testing right after the bounds check: returning false for a point that is inside the bounding box makes the widget transparent to the click there, so it falls through to whatever sibling is painted underneath (the same machinery as a fully pass-through node, but shape-aware).

fn tooltip_has_content(&self) -> bool

Whether this widget, used as tooltip content, currently has anything worth showing.

fn declare_shortcuts(&self) -> Vec<Shortcut>

Declare the rebindable keyboard shortcuts this widget exposes, without installing handlers. The framework calls this at arena insertion time (before build()) and at certain lazy boundaries (e.g. Switcher walks declarations on its not-yet-mounted Pending slots), so settings UIs and the ShortcutRegistry see the keystrokes the moment the owning container mounts — even if build() hasn’t run.

fn take_handler_set(&mut self) -> Option<HandlerSet>

Extract attached handler set from a WidgetWithHandlers wrapper. Called during arena insertion to transfer handlers to the WidgetNode. Default: returns None (no attached handlers).