Struct Label 

pub struct Label {
    pub buffered: bool,
    /* private fields */
}

A non-interactive text widget.

Used directly as a standalone label, and as a child of composite widgets such as [Button] and (in the future) Checkbox, RadioGroup, etc.

When no explicit color is set via with_color, the label reads its text color from the active Visuals at paint time (ctx.visuals().text_color), so it automatically adapts to dark / light mode switches.

Fields

buffered: bool

When true (the default), this Label owns a CPU backbuffer that’s re-rasterised on dirty and blitted every frame. Set to false only for text that changes every frame (e.g. live counters) where caching adds overhead with no benefit — those go through ctx.fill_text direct every paint.

Implementations

impl Label

pub fn new(text: impl Into<String>, font: Arc<Font>) -> Self

pub fn with_font_size(self, size: f64) -> Self

pub fn with_color(self, color: Color) -> Self

Override the label colour. Pass an explicit Color to always use that colour regardless of the active theme. Omit this call to follow the theme’s text_color automatically.

pub fn with_align(self, align: LabelAlign) -> Self

pub fn with_has_backbuffer(self, v: bool) -> Self

pub fn with_wrap(self, wrap: bool) -> Self

Enable or disable word-wrapping. When true, long lines are broken at word boundaries to fit the available width; the label height expands to accommodate all lines. Newlines in the text are always honoured.

pub fn with_lcd(self, pref: Option<bool>) -> Self

Opt OUT of the system-wide font override for this Label. The Label will render with self.font (passed to Label::new) regardless of what font_settings::set_system_font is pointing at. Useful for font-preview UI — each entry in a font picker dropdown needs its OWN face, not the currently selected one. Pin this label’s LCD setting: Some(true) always LCD, Some(false) always grayscale, None (default) defers to the global toggle.

pub fn with_ignore_system_font(self, ignore: bool) -> Self

pub fn with_margin(self, m: Insets) -> Self

pub fn with_h_anchor(self, h: HAnchor) -> Self

pub fn with_v_anchor(self, v: VAnchor) -> Self

pub fn with_min_size(self, s: Size) -> Self

pub fn with_max_size(self, s: Size) -> Self

pub fn text_str(&self) -> &str

Return the current label text as a &str.

pub fn set_font_size(&mut self, size: f64)

pub fn set_text(&mut self, text: impl Into<String>)

pub fn set_color(&mut self, color: Color)

pub fn clear_color(&mut self)

pub fn set_align(&mut self, align: LabelAlign)

Trait Implementations

impl Widget for Label

fn hit_test(&self, _: Point) -> bool

Labels are never independently hittable. This lets their interactive parent (e.g., Button) retain full hit-test and focus ownership even when the label fills the parent’s entire bounds.

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

A static name for this widget type, used by the inspector. Default: “Widget”.

fn bounds(&self) -> Rect

Bounding rectangle in parent-local Y-up coordinates.

fn set_bounds(&mut self, b: Rect)

Set the bounding rectangle. Called by the parent during layout.

fn children(&self) -> &[Box<dyn Widget>]

Immutable access to child widgets.

fn children_mut(&mut self) -> &mut Vec<Box<dyn Widget>>

Mutable access to child widgets (required for event dispatch + layout).

fn lcd_preference(&self) -> Option<bool>

Per-widget LCD subpixel preference for backbuffered text rendering.

fn set_label_color(&mut self, color: Color)

If this widget is text-bearing (e.g. Label), update its foreground colour. Default is a no-op. Composite widgets call this on their children to retint labels without rebuilding them — used by Button when toggling between active (white text on accent) and inactive (theme text on subtle bg) appearances.

fn set_label_text(&mut self, text: &str)

If this widget is text-bearing (e.g. Label), update its displayed text. Default is a no-op. Composite widgets that own a Label child use this to push live values (e.g. an FPS counter) into the child without bypassing the standard backbuffered glyph cache — calling this on a Label only invalidates the cache when the text actually changed.

fn backbuffer_cache_mut(&mut self) -> Option<&mut BackbufferCache>

Opt into per-widget CPU bitmap caching with a dirty flag.

fn backbuffer_mode(&self) -> BackbufferMode

Storage format for this widget’s backbuffer. Ignored unless [backbuffer_cache_mut] returns Some. Default BackbufferMode::Rgba — correct for any widget. Opt into BackbufferMode::LcdCoverage only when the widget paints opaque content covering its full bounds.

fn layout(&mut self, available: Size) -> Size

Compute desired size given available space, and update internal layout.

fn paint(&mut self, ctx: &mut dyn DrawCtx)

Paint this widget’s own content into ctx.

fn margin(&self) -> Insets

Outer margin around this widget in logical units.

fn widget_base(&self) -> Option<&WidgetBase>

Direct read access to the widget’s embedded WidgetBase.

fn widget_base_mut(&mut self) -> Option<&mut WidgetBase>

Mutable counterpart of widget_base.

fn h_anchor(&self) -> HAnchor

Horizontal anchor: how this widget sizes/positions itself horizontally within the slot the parent assigns. Default: HAnchor::FIT (take natural content width).

fn v_anchor(&self) -> VAnchor

Vertical anchor: how this widget sizes/positions itself vertically within the slot the parent assigns. Default: VAnchor::FIT (take natural content height).

fn min_size(&self) -> Size

Minimum size constraint (logical units).

fn max_size(&self) -> Size

Maximum size constraint (logical units).

fn measure_min_height(&self, available_w: f64) -> f64

Report the minimum height this widget needs to fully render its content when given the supplied available_w for width.

fn on_event(&mut self, _: &Event) -> EventResult

Handle an event. The event’s positions are already in local Y-up coordinates. Return EventResult::Consumed to stop bubbling.

fn properties(&self) -> Vec<(&'static str, String)>

Return type-specific properties for the inspector properties pane.

fn claims_pointer_exclusively(&self, _local_pos: Point) -> bool

When true, hit_test_subtree stops recursing into this widget’s children and returns this widget as the hit target. Used for floating overlays (e.g. a scrollbar painted above its content) that must claim the pointer before children that happen to share the same pixels. Default: false.

fn hit_test_global_overlay(&self, _local_pos: Point) -> bool

Return true when local_pos hits an app-level overlay owned by this widget. Unlike normal hit testing, ancestors may be missed because the overlay is painted outside their bounds.

fn has_active_modal(&self) -> bool

Whether this widget currently owns an app-modal interaction layer.

fn on_unconsumed_key( &mut self, _key: &Key, _modifiers: Modifiers, ) -> EventResult

Handle a key that was not consumed by the focused widget path.

fn is_focusable(&self) -> bool

Whether this widget can receive keyboard focus. Default: false.

fn id(&self) -> Option<&str>

Optional human-readable identifier for this widget instance.

fn is_visible(&self) -> bool

Return false to suppress painting this widget and all its children. The widget’s own paint() will not be called. Default: true.

fn as_reflect(&self) -> Option<&dyn Reflect>

Opt-in reflection accessor for the inspector’s typed property editors.

fn as_reflect_mut(&mut self) -> Option<&mut dyn Reflect>

Mutable counterpart of as_reflect. Used by the inspector to write edits back into the live widget.

fn has_backbuffer(&self) -> bool

Whether this widget renders into its own offscreen buffer before compositing into the parent.

fn compositing_layer(&mut self) -> Option<CompositingLayer>

Request that this widget subtree be painted into a transient transparent compositing layer before being blended into its parent.

fn backbuffer_spec(&mut self) -> BackbufferSpec

Unified widget-owned backbuffer request.

fn backbuffer_state_mut(&mut self) -> Option<&mut BackbufferState>

Mutable retained backbuffer state for widgets that request a BackbufferSpec other than BackbufferKind::None.

fn mark_dirty(&mut self)

Mark this widget’s own retained surface dirty, if it owns one.

fn contributes_children_to_inspector(&self) -> bool

Whether the inspector should recurse into this widget’s children.

fn show_in_inspector(&self) -> bool

Return false to hide this widget (and its subtree) from the inspector node snapshot entirely. Intended for zero-size utility widgets such as layout-time watchers / tickers / invisible composers — they bloat the inspector tree without providing user-relevant information and, at scale, can make the inspector’s per-frame tree rebuild expensive.

fn paint_overlay(&mut self, _ctx: &mut dyn DrawCtx)

Paint decorations that must appear on top of all children.

fn finish_paint(&mut self, _ctx: &mut dyn DrawCtx)

Called after paint, child painting, and optional overlay painting.

fn paint_global_overlay(&mut self, _ctx: &mut dyn DrawCtx)

Paint app-level overlays after the entire widget tree has been painted.

fn clip_children_rect(&self) -> Option<(f64, f64, f64, f64)>

Return a clip rectangle (in local coordinates) that constrains all child painting. paint_subtree applies this clip before recursing into children, then restores the previous clip state afterward. The clip does not affect paint_overlay, which runs after the clip is removed.

fn padding(&self) -> Insets

Inner padding — space the widget reserves between its own bounds and its child layout area. Only container widgets carry padding; leaf widgets default to Insets::ZERO.

fn enforce_integer_bounds(&self) -> bool

Whether paint_subtree should snap this widget’s incoming translation to the physical pixel grid.

fn take_raise_request(&mut self) -> bool

Container widgets (notably crate::widgets::Stack) call this on each child at the start of layout(). A widget that returns true is moved to the END of its parent’s child list — painted last, i.e. raised to the top of the z-order. take_ semantics: the call is also expected to clear the request so the child doesn’t keep getting raised every frame.

fn needs_draw(&self) -> bool

Return true if this widget, or any visible descendant, has an ongoing draw need that should keep the host drawing.

fn next_draw_deadline(&self) -> Option<Instant>

Return the earliest wall-clock instant at which this widget (or any visible descendant) wants the next draw. None = no scheduled wake. The host loop turns a Some(t) into ControlFlow::WaitUntil(t) so e.g. a cursor blink fires without continuous polling.