Struct iced::widget::Canvas

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

Available on crate feature canvas only.

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:

use iced::widget::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program};
use iced::{Color, Rectangle, Theme};

// 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: &(), _theme: &Theme, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{
        // We prepare a new `Frame`
        let mut frame = Frame::new(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<Message, Theme, P> Canvas<Message, Theme, P>where P: Program<Message, Theme>,

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

Creates a new Canvas.

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

Sets the width of the Canvas.

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

Sets the height of the Canvas.

Trait Implementations

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

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

Formats the value using the given formatter.

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

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<B, T>, limits: &Limits) -> Node

Returns the [layout::Node] of the [Widget].

fn on_event( &mut self, tree: &mut Tree, event: Event, layout: Layout<'_>, cursor_position: Point, _renderer: &Renderer<B, T>, _clipboard: &mut dyn Clipboard, shell: &mut Shell<'_, Message> ) -> Status

Processes a runtime Event.

fn mouse_interaction( &self, tree: &Tree, layout: Layout<'_>, cursor_position: Point, _viewport: &Rectangle<f32>, _renderer: &Renderer<B, T> ) -> Interaction

Returns the current mouse::Interaction of the [Widget].

fn draw( &self, tree: &Tree, renderer: &mut Renderer<B, T>, theme: &T, _style: &Style, layout: Layout<'_>, cursor_position: Point, _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.