Struct iced::widget::canvas::Canvas

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

This is supported on crate features canvas or glow_canvas only.

A widget capable of drawing 2D graphics.

Examples

The repository has a couple of examples showcasing how to use a Canvas:

• clock, an application that uses the Canvas widget to draw a clock and its hands to display the current time.
• game_of_life, an interactive version of the Game of Life, invented by John Conway.
• solar_system, an animated solar system drawn using the Canvas widget and showcasing how to compose different transforms.

Drawing a simple circle

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

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

// 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 {
    fn draw(&self, 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, P> Canvas<Message, P> where
    P: Program<Message>, 

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

Creates a new Canvas.

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

Sets the width of the Canvas.

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

Sets the height of the Canvas.

Trait Implementations

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

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

Formats the value using the given formatter.

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

pub fn width(&self) -> Length

Returns the width of the [Widget].

pub fn height(&self) -> Length

Returns the height of the [Widget].

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

Returns the Node of the [Widget].

pub fn on_event(
    &mut self,
    event: Event,
    layout: Layout<'_>,
    cursor_position: Point,
    _renderer: &Renderer<B>,
    _clipboard: &mut dyn Clipboard,
    messages: &mut Vec<Message, Global>
) -> Status

Processes a runtime [Event].

pub fn draw(
    &self,
    _renderer: &mut Renderer<B>,
    _defaults: &Defaults,
    layout: Layout<'_>,
    cursor_position: Point,
    _viewport: &Rectangle<f32>
) -> (Primitive, Interaction)

Draws the [Widget] using the associated Renderer.

pub fn hash_layout(&self, state: &mut Hasher)

Computes the layout hash of the [Widget].

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

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