Struct Toggle 

pub struct Toggle<M> { /* private fields */ }

A switch: a track, a knob, and a boolean.

Reads better than a Checkbox at arm’s length, which is what a wall panel is. Identical semantics otherwise, including the message being a function of the new value:

enum Message { Muted(bool) }
Toggle::new("Mute", Message::Muted);

The knob slides

Flipping the switch requests animation for the 120 ms crossing and then the widget stops asking — the bounded-transition contract described on Widget::animate. Focus is not involved: the knob finishes its crossing whether or not focus moves away mid-slide, which is what retired the FocusLost-snaps-the-knob workaround this widget shipped with.

The animation is still a courtesy, not a mechanism: nothing about the value depends on a frame arriving, and a Toggle on a tree whose application never calls Ui::tick is merely a switch that jumps.

Implementations

impl<M> Toggle<M>

pub fn new(label: impl Into<String>, message: fn(bool) -> M) -> Self

An off switch whose message is built from the value it changes to.

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

A switch that emits nothing, for a value the application reads rather than reacts to.

pub fn with_checked(self, checked: bool) -> Self

Sets the initial value. The knob starts there rather than sliding into it.

pub fn with_role(self, role: Role) -> Self

Sets the colour role of the track when on.

pub fn with_style(self, style: TextStyle) -> Self

Sets the label’s font and size.

pub fn with_size(self, size_px: u16) -> Self

Sets the label’s size, keeping the font.

pub const fn checked(&self) -> bool

Whether the switch is on.

pub fn set_checked(&mut self, checked: bool)

Sets the value without emitting anything, and without animating.

Silent for the same reason Checkbox::set_checked is: the message reports what a person did, and an application that assigned here and got its own message back would either loop or have to guard against itself.

It does not animate because a setter has no way to request frames — the tree grants them through an event or crate::Ui::request_animation, and a widget cannot reach the tree from here. An application that wants the slide can call request_animation itself; the default is the honest jump.

pub fn label(&self) -> &str

The current label.

pub fn set_label(&mut self, label: impl Into<String>)

Replaces the label.

pub fn set_role(&mut self, role: Role)

Replaces the colour role.

pub fn set_style(&mut self, style: TextStyle)

Replaces the label’s font and size.

pub fn preferred_width(&self, theme: &Theme, engine: &mut TextEngine) -> i32

Width this toggle needs for its track, its gap and its label.

Trait Implementations

impl<M: Clone> Clone for Toggle<M>

fn clone(&self) -> Toggle<M>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<M: Debug> Debug for Toggle<M>

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

Formats the value using the given formatter.

impl<M> Describe for Toggle<M>

const KIND: &'static str = "toggle"

The name a form file uses for this widget. Kebab-case.

const DOC: &'static str = "The same on-or-off as a checkbox, shaped like a switch."

One line saying what this widget is, for somebody choosing one.

const GROUP: Group = Group::Input

Which shelf of the catalogue this belongs on.

const ICON: &'static Icon

The widget’s glyph: a small portrait of the thing, for a palette to draw beside — or instead of — its name.

const PROPERTIES: &'static [Property]

Every property, in the order an inspector should show them.

fn get(&self, name: &str) -> Option<Value>

The current value.

fn apply(&mut self, name: &str, value: Value) -> Result<(), Mismatch>

Applies a value, reporting only what went wrong.

fn set(&mut self, name: &str, value: Value) -> Result<(), PropertyError>

Applies a value, reporting what went wrong and where.

impl<M: 'static> Widget<M> for Toggle<M>

fn snap(&mut self, now_ms: u64) -> Animation

The knob arrives at once. A switch is the clearest case for reduced motion: the slide was always a courtesy, and the value never depended on it.

fn describe(&self) -> Option<&dyn DynDescribe>

This widget’s property description, if it has one.

fn describe_mut(&mut self) -> Option<&mut dyn DynDescribe>

The mutable half of describe.

fn measure(&self, ctx: &mut MeasureCtx<'_>, _offered: Offer) -> Measured

How big this widget would like to be, given what the caller can promise.

fn paint(&self, ctx: &mut PaintCtx<'_>, canvas: &mut Pen<'_>)

Draws into canvas, which is already clipped to this widget’s bounds intersected with the damage region being repainted.

fn on_event(&mut self, event: &Event<'_>, ctx: &mut EventCtx<'_, M>) -> Handled

Reacts to an event routed to this widget.

fn animate(&mut self, now_ms: u64) -> Animation

Advances time-based state. Called only while this widget has asked to animate — see EventCtx::request_animation — and stops being called the moment it answers Wake::Never.

fn accepts_pointer(&self) -> bool

Returns true if the pointer can hit this widget.

fn focusable(&self) -> bool

Returns true if this widget can take keyboard focus.

fn preserves_focus(&self) -> bool

Returns true if a press on this widget should leave focus exactly where it is.