Struct Canvas 

pub struct Canvas {
    pub render_fn: Box<dyn Fn(Rect, &mut Buffer) + Send + Sync>,
    pub height: Option<u16>,
    pub desired_height_fn: Option<Box<dyn Fn(u16) -> u16 + Send + Sync>>,
}

A leaf component that renders via a user-provided closure.

See the module-level docs for examples.

Fields

render_fn: Box<dyn Fn(Rect, &mut Buffer) + Send + Sync>

height: Option<u16>

desired_height_fn: Option<Box<dyn Fn(u16) -> u16 + Send + Sync>>

Width-aware height function. Takes priority over height. When set, the framework calls this instead of probe rendering.

Implementations

impl Canvas

pub fn builder() -> CanvasBuilder<((), (), ())>

Create a builder for building Canvas. On the builder, call .render_fn(...)(optional), .height(...)(optional), .desired_height_fn(...)(optional) to set the values of the fields. Finally, call .build() to create the instance of Canvas.

impl Canvas

pub fn new(f: impl Fn(Rect, &mut Buffer) + Send + Sync + 'static) -> Self

Create a new Canvas with the given render function.

pub fn with_height(self, h: u16) -> Self

Set an explicit height hint, skipping probe-render measurement.

Use this for components that fill their entire area (e.g., bordered widgets) where probe rendering would keep growing the buffer.

Trait Implementations

impl Component for Canvas

type State = ()

State type for this component. The framework wraps it in Tracked<S> for automatic dirty detection.

fn update( &self, hooks: &mut Hooks<Self, Self::State>, state: &Self::State, children: Elements, ) -> Elements

where Self: Sized,

Combined lifecycle and view in a single call.