Trait Widget

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

    // Provided methods
    fn size_hint(&self) -> Size<Length> { ... }
    fn tag(&self) -> Tag { ... }
    fn state(&self) -> State { ... }
    fn children(&self) -> Vec<Tree> { ... }
    fn diff(&self, _tree: &mut Tree) { ... }
    fn operate(
        &self,
        _state: &mut Tree,
        _layout: Layout<'_>,
        _renderer: &Renderer,
        _operation: &mut dyn Operation,
    ) { ... }
    fn update(
        &mut self,
        _state: &mut Tree,
        _event: Event,
        _layout: Layout<'_>,
        _cursor: Cursor,
        _renderer: &Renderer,
        _clipboard: &mut dyn Clipboard,
        _shell: &mut Shell<'_, Message>,
        _viewport: &Rectangle,
    ) { ... }
    fn mouse_interaction(
        &self,
        _state: &Tree,
        _layout: Layout<'_>,
        _cursor: Cursor,
        _viewport: &Rectangle,
        _renderer: &Renderer,
    ) -> Interaction { ... }
    fn overlay<'a>(
        &'a mut self,
        _state: &'a mut Tree,
        _layout: Layout<'_>,
        _renderer: &Renderer,
        _translation: Vector,
    ) -> Option<Element<'a, Message, Theme, Renderer>> { ... }
}

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:

• bezier_tool, a Paint-like tool for drawing Bézier curves using lyon.
• 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(&self, tree: &mut Tree, renderer: &Renderer, limits: &Limits) -> Node

Returns the layout::Node of the Widget.

This layout::Node is used by the runtime to compute the Layout of the user interface.

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 size_hint(&self) -> Size<Length>

Returns a Size hint for laying out the Widget.

This hint may be used by some widget containers to adjust their sizing strategy during construction.

fn tag(&self) -> Tag

Returns the Tag of the Widget.

fn state(&self) -> State

Returns the State of the Widget.

fn children(&self) -> Vec<Tree>

Returns the state Tree of the children of the Widget.

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

Reconciles the Widget with the provided Tree.

fn operate( &self, _state: &mut Tree, _layout: Layout<'_>, _renderer: &Renderer, _operation: &mut dyn Operation, )

Applies an Operation to the Widget.

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

Processes a runtime Event.

By default, it does nothing.

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

Returns the current mouse::Interaction of the Widget.

By default, it returns mouse::Interaction::Idle.

fn overlay<'a>( &'a mut self, _state: &'a mut Tree, _layout: Layout<'_>, _renderer: &Renderer, _translation: Vector, ) -> Option<Element<'a, Message, Theme, Renderer>>

Returns the overlay of the Widget, if there is any.

Trait Implementations

impl<'a, Message, Theme, Renderer> Borrow<dyn Widget<Message, Theme, Renderer> + 'a> for &Element<'a, Message, Theme, Renderer>

fn borrow(&self) -> &(dyn Widget<Message, Theme, Renderer> + 'a)

Immutably borrows from an owned value.

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

fn borrow(&self) -> &(dyn Widget<Message, Theme, Renderer> + 'a)

Immutably borrows from an owned value.

Implementors

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

where Theme: Catalog, Renderer: Renderer,