Trait coffee::ui::core::Widget

pub trait Widget<Message, Renderer>: Debug {
    fn node(&self, renderer: &Renderer) -> Node;
    fn draw(
        &self, 
        renderer: &mut Renderer, 
        layout: Layout, 
        cursor_position: Point
    ) -> MouseCursor;
    fn hash(&self, state: &mut Hasher);

    fn on_event(
        &mut self, 
        _event: Event, 
        _layout: Layout, 
        _cursor_position: Point, 
        _messages: &mut Vec<Message>
    ) { ... }
}

A component that displays information or allows interaction.

If you want to build a custom widget, you will need to implement this trait. Additionally, remember to also provide Into<Element> so your users can easily turn your Widget into a generic Element

Required methods

fn node(&self, renderer: &Renderer) -> Node

Returns the Node of the Widget.

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

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

Draws the Widget using the associated Renderer.

It must return the MouseCursor state for the Widget.

fn hash(&self, state: &mut Hasher)

Computes the layout hash of the Widget.

The produced hash is used by the runtime to decide if the Layout needs to be recomputed between frames. Therefore, to ensure maximum efficiency, the hash should only be affected by the properties of the Widget that can affect layouting.

For example, the Text widget does not hash its color property, as its value cannot affect the overall Layout of the user interface.

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Provided methods

fn on_event(
    &mut self,
    _event: Event,
    _layout: Layout,
    _cursor_position: Point,
    _messages: &mut Vec<Message>
)

Processes a runtime Event.

It receives:

• an Event describing user interaction
• the computed Layout of the Widget
• the current cursor position
• a mutable Message vector, allowing the Widget to produce new messages based on user interaction.

By default, it does nothing.

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Implementors

impl<'a, Message, Renderer> Widget<Message, Renderer> for Button<'a, Message> where
    Renderer: Renderer,
    Message: Copy + Debug, 

fn node(&self, _renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<'a, Message, Renderer> Widget<Message, Renderer> for Panel<'a, Message, Renderer> where
    Renderer: Renderer, 

fn node(&self, renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<'a, Message, Renderer> Widget<Message, Renderer> for Slider<'a, Message> where
    Renderer: Renderer, 

fn node(&self, _renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<'a, Message, Renderer> Widget<Message, Renderer> for Column<'a, Message, Renderer>

fn node(&self, renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<'a, Message, Renderer> Widget<Message, Renderer> for Row<'a, Message, Renderer>

fn node(&self, renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<Message, Renderer> Widget<Message, Renderer> for Checkbox<Message> where
    Renderer: Renderer + Renderer, 

fn node(&self, renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<Message, Renderer> Widget<Message, Renderer> for Image where
    Renderer: Renderer, 

fn node(&self, _renderer: &Renderer) -> Node

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    _cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<Message, Renderer> Widget<Message, Renderer> for ProgressBar where
    Renderer: Renderer, 

fn node(&self, _renderer: &Renderer) -> Node

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    _cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<Message, Renderer> Widget<Message, Renderer> for Radio<Message> where
    Renderer: Renderer + Renderer,
    Message: Copy + Debug, 

fn node(&self, renderer: &Renderer) -> Node

fn on_event(
    &mut self,
    event: Event,
    layout: Layout,
    cursor_position: Point,
    messages: &mut Vec<Message>
)

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

impl<Message, Renderer> Widget<Message, Renderer> for Text where
    Renderer: Renderer, 

fn node(&self, renderer: &Renderer) -> Node

fn draw(
    &self,
    renderer: &mut Renderer,
    layout: Layout,
    _cursor_position: Point
) -> MouseCursor

fn hash(&self, state: &mut Hasher)

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