Struct Checkbox

pub struct Checkbox<Msg: Clone> {
    pub checked: bool,
    pub on_toggle: Option<Msg>,
    pub label: Option<String>,
    pub id: Option<WidgetId>,
}

A two-state opt-in control with a square box and a check glyph.

Use for individual binary choices inside a form (terms acceptance, multi-select lists, “remember me”). The widget is stateless — the application owns checked and rebuilds the checkbox from current state on every frame.

// In view():
checkbox( self.accept_terms )
    .label( "I accept the terms" )
    .on_toggle( Msg::ToggleTerms )

See also Toggle for prominent on / off switches (settings panels, system toggles) and Radio for mutually-exclusive selection in a group.

Fields

checked: bool

Current checked state. Drawn from this field every frame; the runtime never mutates it.

on_toggle: Option<Msg>

Message emitted on activation. None leaves the checkbox inert.

label: Option<String>

Optional label drawn to the right of the box.

id: Option<WidgetId>

Optional stable identifier for focus management.

Implementations

impl<Msg: Clone> Checkbox<Msg>

pub fn new(checked: bool) -> Self

Create a checkbox in the given state, with no label and no callback. Wire activation through Self::on_toggle before adding it to a widget tree.

pub fn on_toggle(self, msg: Msg) -> Self

Set the message emitted when the checkbox is activated. The application’s update is responsible for flipping checked in response.

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

Set a text label rendered to the right of the box. The checkbox’s preferred width grows to fit box_size + gap + label_width, clamped to max_width.

pub fn id(self, id: WidgetId) -> Self

Assign a stable identifier for focus management.

pub fn preferred_size(&self, max_width: f32, canvas: &Canvas) -> (f32, f32)

pub fn paint_bounds(&self, rect: Rect) -> Rect

Focus ring on the box extends FOCUS_W + 2 + FOCUS_W/2 ≈ 6.5 px beyond the box edge (which sits flush with the widget’s left edge).

pub fn draw(&self, canvas: &mut Canvas, rect: Rect, focused: bool)

Trait Implementations

impl<Msg: Clone + 'static> From<Checkbox<Msg>> for Element<Msg>

fn from(c: Checkbox<Msg>) -> Self

Converts to this type from the input type.