Trait Widget 

pub trait Widget<Message, Theme, Renderer>: Meta {
    // Required methods
    fn size(&self) -> Size<Length>;
    fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits);
    fn draw(
        &self,
        tree: &Tree,
        renderer: &mut Renderer,
        theme: &Theme,
        style: &Style,
        layout: Layout,
        cursor: Cursor,
        viewport: &Rectangle,
    );

    // Provided methods
    fn tag(&self) -> Tag { ... }
    fn state(&self) -> State { ... }
    fn diff(&mut self, tree: &mut Tree) { ... }
    fn operate(
        &mut self,
        _tree: &mut Tree,
        _layout: Layout,
        _viewport: &Rectangle,
        _renderer: &Renderer,
        _operation: &mut dyn Operation,
    ) { ... }
    fn update(
        &mut self,
        _tree: &mut Tree,
        _event: &Event,
        _layout: Layout,
        _cursor: Cursor,
        _renderer: &Renderer,
        _shell: &mut Shell<'_, Message>,
        _viewport: &Rectangle,
    ) { ... }
    fn mouse_interaction(
        &self,
        _tree: &Tree,
        _layout: Layout,
        _cursor: Cursor,
        _viewport: &Rectangle,
        _renderer: &Renderer,
    ) -> Interaction { ... }
    fn overlay<'a>(
        &'a mut self,
        _tree: &'a mut Tree,
        _layout: Layout,
        _renderer: &Renderer,
        _viewport: &Rectangle,
        _translation: Vector,
        _window: Size,
    ) -> Vec<Element<'a, Message, Theme, Renderer>> { ... }
    fn _map<F, B>(self, f: F) -> Map<Self, F, Message>
       where Self: Sized,
             F: Fn(Message) -> B { ... }
    fn _boxed<'a>(self) -> Element<'a, Message, Theme, Renderer>
       where Self: Sized + 'a { ... }
}

A component that displays information and allows interaction.

If you want to build your own widgets, you will need to implement this trait.

Examples

The repository has some examples showcasing how to implement a custom widget:

• custom_widget, a demonstration of how to build a custom widget that draws a circle.
• geometry, a custom widget showcasing how to draw geometry with the Mesh2D primitive in iced_wgpu.

Required Methods

fn size(&self) -> Size<Length>

Returns the Size of the Widget in lengths.

fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits)

Lays out the Widget.

This computes the Layout of the Widget and stores the result in the provided Tree.

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &Theme, style: &Style, layout: Layout, cursor: Cursor, viewport: &Rectangle, )

Draws the Widget using the associated Renderer.

Provided Methods

fn tag(&self) -> Tag

Returns the Tag of the Widget.

fn state(&self) -> State

Returns the State of the Widget.

fn diff(&mut self, tree: &mut Tree)

Reconciles the Widget with the provided Tree.

fn operate( &mut self, _tree: &mut Tree, _layout: Layout, _viewport: &Rectangle, _renderer: &Renderer, _operation: &mut dyn Operation, )

Applies an Operation to the Widget.

fn update( &mut self, _tree: &mut Tree, _event: &Event, _layout: Layout, _cursor: Cursor, _renderer: &Renderer, _shell: &mut Shell<'_, Message>, _viewport: &Rectangle, )

Processes a runtime Event.

By default, it does nothing.

fn mouse_interaction( &self, _tree: &Tree, _layout: Layout, _cursor: Cursor, _viewport: &Rectangle, _renderer: &Renderer, ) -> Interaction

Returns the current mouse::Interaction of the Widget.

By default, it returns mouse::Interaction::None.

fn overlay<'a>( &'a mut self, _tree: &'a mut Tree, _layout: Layout, _renderer: &Renderer, _viewport: &Rectangle, _translation: Vector, _window: Size, ) -> Vec<Element<'a, Message, Theme, Renderer>>

Returns the overlays of the Widget.

fn _map<F, B>(self, f: F) -> Map<Self, F, Message>

where Self: Sized, F: Fn(Message) -> B,

Applies a transformation to the produced message of this Widget, returning a Map.

This method is useful when you want to decouple different parts of your UI and make them composable.

fn _boxed<'a>(self) -> Element<'a, Message, Theme, Renderer>

where Self: Sized + 'a,

Boxes this Widget, turning it into a generic Element.

Implementations on Foreign Types

impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer> for &str

where Theme: Catalog, Renderer: Renderer,

fn size(&self) -> Size<Length>

fn tag(&self) -> Tag

fn state(&self) -> State

fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits)

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &Theme, defaults: &Style, layout: Layout, _cursor_position: Cursor, viewport: &Rectangle, )

fn operate( &mut self, tree: &mut Tree, layout: Layout, _viewport: &Rectangle, _renderer: &Renderer, operation: &mut dyn Operation, )

impl<T, Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Option<T>

where T: Widget<Message, Theme, Renderer>, Renderer: Renderer,

fn size(&self) -> Size<Length>

fn tag(&self) -> Tag

fn state(&self) -> State

fn diff(&mut self, tree: &mut Tree)

fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits)

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &Theme, style: &Style, layout: Layout, cursor: Cursor, viewport: &Rectangle, )

fn operate( &mut self, tree: &mut Tree, layout: Layout, viewport: &Rectangle, renderer: &Renderer, operation: &mut dyn Operation, )

fn update( &mut self, tree: &mut Tree, event: &Event, layout: Layout, cursor: Cursor, renderer: &Renderer, shell: &mut Shell<'_, Message>, viewport: &Rectangle, )

fn mouse_interaction( &self, tree: &Tree, layout: Layout, cursor: Cursor, viewport: &Rectangle, renderer: &Renderer, ) -> Interaction

fn overlay<'a>( &'a mut self, tree: &'a mut Tree, layout: Layout, renderer: &Renderer, viewport: &Rectangle, translation: Vector, window: Size, ) -> Vec<Element<'a, Message, Theme, Renderer>>

impl<T, Message, Theme, Renderer> Widget<Message, Theme, Renderer> for &mut T

where Renderer: Renderer, T: Widget<Message, Theme, Renderer>,

fn size(&self) -> Size<Length>

fn tag(&self) -> Tag

fn state(&self) -> State

fn diff(&mut self, tree: &mut Tree)

fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits)

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &Theme, style: &Style, layout: Layout, cursor: Cursor, viewport: &Rectangle, )

fn operate( &mut self, tree: &mut Tree, layout: Layout, viewport: &Rectangle, renderer: &Renderer, operation: &mut dyn Operation, )

fn update( &mut self, tree: &mut Tree, event: &Event, layout: Layout, cursor: Cursor, renderer: &Renderer, shell: &mut Shell<'_, Message>, viewport: &Rectangle, )

fn mouse_interaction( &self, tree: &Tree, layout: Layout, cursor: Cursor, viewport: &Rectangle, renderer: &Renderer, ) -> Interaction

fn overlay<'a>( &'a mut self, tree: &'a mut Tree, layout: Layout, renderer: &Renderer, viewport: &Rectangle, translation: Vector, window: Size, ) -> Vec<Element<'a, Message, Theme, Renderer>>

Implementors

impl<'a, Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Element<'a, Message, Theme, Renderer>

impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Void

impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Text<'_, Theme>

where Theme: Catalog, Renderer: Renderer,

impl<W, A, B, F, Theme, Renderer> Widget<B, Theme, Renderer> for Map<W, F, A>

where W: Widget<A, Theme, Renderer>, B: 'static, F: Fn(A) -> B, Theme: 'static, Renderer: Renderer + 'static,