Struct SegmentedControl 

pub struct SegmentedControl { /* private fields */ }

A segmented control binding a Signal<Option<SegmentId>> to a row of mutually exclusive segments. Build the segment list with segment or segments.

Implementations

impl SegmentedControl

pub fn new(selected: Signal<Option<SegmentId>>) -> Self

Create an empty segmented control bound to selected. Add segments with segment or segments.

pub fn indexed(index: Signal<usize>) -> Self

Bind a positional Signal<usize> instead of a keyed selection, mirrored in both directions.

Use this only when position is the meaning and the segment list is closed and local — an enum discriminant over a fixed ALL array, a Switcher index, a settings choice. For anything else prefer new: an index silently stops meaning the same thing the moment a segment is inserted ahead of it, which is the entire reason selection is keyed. A persisted selection, or segments contributed by another crate, are both firmly in “anything else”.

Positions address the declared list, so a segment hidden with Segment::visible does not renumber the others.

// `bucket_idx` already drives the rollup maths and a Switcher.
SegmentedControl::indexed(bucket_idx.clone())
    .segments([lit!("×2"), lit!("×4"), lit!("×8")])

pub fn segment(self, segment: impl Into<Segment>) -> Self

Append one segment. Accepts a Segment or, via From<LocalizedString>, a bare tr!(...) / lit!(...) label (which gets a freshly allocated SegmentId).

pub fn segments( self, segments: impl IntoIterator<Item = impl Into<Segment>>, ) -> Self

Append several segments. Label-only: .segments([tr!(day()), tr!(week())]); rich: .segments([Segment::new(...).id(DAY).icon(...), ...]).

pub fn segment_ids(&self) -> Vec<SegmentId>

The ids of the segments added so far, in declaration order. Convenient for feeding index_signal without repeating the list.

pub fn enabled(self, enabled: impl Into<Prop<bool>>) -> Self

Set the enabled state, statically or reactively. Forwarded to the arena at build time via ctx.enabled_when(segmented_control_id, self.enabled.clone()).

pub fn label(self, label: impl Into<LocalizedString>) -> Self

Accessible name for the group — e.g. “View mode”. Screen readers announce it before the selected segment. Matches RadioGroup::label and RadioTileGroup::label.

pub fn on_change( self, f: impl Fn(SegmentId, &mut EventContext<'_>) + 'static, ) -> Self

Called whenever the user changes the selection — by click, arrow key, assistive technology, or the overflow menu. Receives the newly selected SegmentId and an EventContext, so it can do things a bare Signal write cannot (ctx.set_locale(...), ctx.send_intent(...), opening a window).

Does not fire for programmatic writes to the bound signal — there is no event in flight to carry. Observe the signal for that.

pub fn style(self, style: impl SegmentedControlStyle) -> Self

Per-call override for the segmented-control chrome.

pub fn text_style(self, style: impl Into<TextStyleProp>) -> Self

Override every segment’s label text style (font, size, weight). Accepts a TextStyleRole, a TextStyle, or a Signal of either. Default (unset) is TextStyleRole::Small. Text color stays state-driven and is intentionally not overridable here.

pub fn display(self, display: SegmentDisplay) -> Self

What each segment paints: its icon, its label, or both. See SegmentDisplay. Icon-only fits far more segments, so it is worth reaching for before the control starts overflowing.

pub fn sizing(self, sizing: SegmentSizing) -> Self

How the visible segments divide the width. See SegmentSizing.

pub fn overflow(self, mode: SegmentOverflow) -> Self

What to do when the segments do not fit. See SegmentOverflow.

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

Reactive “some segments are in the overflow menu right now”.

Republished from place_children behind an equality guard, so it is safe for RepaintOnly / AccessibilityOnly consumers and for Relayout consumers that do not feed back into this control’s own width. Mirrors Toolbar::is_overflowing.

pub fn fill_width(self, fill: bool) -> Self

Whether the control claims all the width offered to it (the default, and the behaviour before this knob existed) or hugs its segments.

false also makes the control shrinkable: in an over-constrained stack it compresses — and overflows — instead of spilling past its bounds.

Trait Implementations

impl Debug for SegmentedControl

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

Formats the value using the given formatter.

impl Widget for SegmentedControl

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 preserves_children_on_rebuild(&self) -> bool

How rebuild_single_widget treats this widget’s existing children when re-running its build().

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).