Struct iced::widget::Canvas

pub struct Canvas<P, Message, Renderer = Renderer<Theme>>where
    Renderer: Renderer,
    P: Program<Message, Renderer>,{ /* private fields */ }

A widget capable of drawing 2D graphics.

Drawing a simple circle

If you want to get a quick overview, here’s how we can draw a simple circle:

// First, we define the data we need for drawing
#[derive(Debug)]
struct Circle {
    radius: f32,
}

// Then, we implement the `Program` trait
impl Program<()> for Circle {
    type State = ();

    fn draw(&self, _state: &(), renderer: &Renderer, _theme: &Theme, bounds: Rectangle, _cursor: mouse::Cursor) -> Vec<Geometry>{
        // We prepare a new `Frame`
        let mut frame = Frame::new(renderer, bounds.size());

        // We create a `Path` representing a simple circle
        let circle = Path::circle(frame.center(), self.radius);

        // And fill it with some color
        frame.fill(&circle, Color::BLACK);

        // Finally, we produce the geometry
        vec![frame.into_geometry()]
    }
}

// Finally, we simply use our `Circle` to create the `Canvas`!
let canvas = Canvas::new(Circle { radius: 50.0 });

Implementations

impl<P, Message, Renderer> Canvas<P, Message, Renderer>where Renderer: Renderer, P: Program<Message, Renderer>,

pub fn new(program: P) -> Canvas<P, Message, Renderer>

Available on crate feature canvas only.

Creates a new Canvas.

pub fn width(self, width: impl Into<Length>) -> Canvas<P, Message, Renderer>

Available on crate feature canvas only.

Sets the width of the Canvas.

pub fn height(self, height: impl Into<Length>) -> Canvas<P, Message, Renderer>

Available on crate feature canvas only.

Sets the height of the Canvas.

Trait Implementations

impl<P, Message, Renderer> Debug for Canvas<P, Message, Renderer>where P: Debug + Program<Message, Renderer>, Message: Debug, Renderer: Debug + Renderer,

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

Formats the value using the given formatter.

impl<P, Message, Renderer> Widget<Message, Renderer> for Canvas<P, Message, Renderer>where Renderer: Renderer, P: Program<Message, Renderer>,

fn tag(&self) -> Tag

Returns the Tag of the Widget.

fn state(&self) -> State

Returns the State of the Widget.

fn width(&self) -> Length

Returns the width of the Widget.

fn height(&self) -> Length

Returns the height of the Widget.

fn layout(&self, _renderer: &Renderer, limits: &Limits) -> Node

Returns the layout::Node of the Widget.

fn on_event( &mut self, tree: &mut Tree, event: Event, layout: Layout<'_>, cursor: Cursor, _renderer: &Renderer, _clipboard: &mut dyn Clipboard, shell: &mut Shell<'_, Message>, _viewport: &Rectangle<f32> ) -> Status

Processes a runtime Event.

fn mouse_interaction( &self, tree: &Tree, layout: Layout<'_>, cursor: Cursor, _viewport: &Rectangle<f32>, _renderer: &Renderer ) -> Interaction

Returns the current mouse::Interaction of the Widget.

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &<Renderer as Renderer>::Theme, _style: &Style, layout: Layout<'_>, cursor: Cursor, _viewport: &Rectangle<f32> )

Draws the Widget using the associated Renderer.

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

Returns the state Tree of the children of the Widget.

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

Reconciliates the Widget with the provided Tree.

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

Applies an Operation to the Widget.

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

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