Trait Renderer

pub trait Renderer {
    // Required methods
    fn start_layer(&mut self, bounds: Rectangle);
    fn end_layer(&mut self);
    fn start_transformation(&mut self, transformation: Transformation);
    fn end_transformation(&mut self);
    fn fill_quad(&mut self, quad: Quad, background: impl Into<Background>);
    fn reset(&mut self, new_bounds: Rectangle);
    fn allocate_image(
        &mut self,
        handle: &Handle,
        callback: impl FnOnce(Result<Allocation, Error>) + Send + 'static,
    );
    fn hint(&mut self, scale_factor: f32);
    fn scale_factor(&self) -> Option<f32>;

    // Provided methods
    fn with_layer(&mut self, bounds: Rectangle, f: impl FnOnce(&mut Self)) { ... }
    fn with_transformation(
        &mut self,
        transformation: Transformation,
        f: impl FnOnce(&mut Self),
    ) { ... }
    fn with_translation(
        &mut self,
        translation: Vector,
        f: impl FnOnce(&mut Self),
    ) { ... }
}

Available on crate feature advanced only.

Expand description

A component that can be used by widgets to draw themselves on a screen.

Required Methods§

fn start_layer(&mut self, bounds: Rectangle)

Starts recording a new layer.

fn end_layer(&mut self)

Ends recording a new layer.

The new layer will clip its contents to the provided bounds.

fn start_transformation(&mut self, transformation: Transformation)

Starts recording with a new Transformation.

fn end_transformation(&mut self)

Ends recording a new layer.

The new layer will clip its contents to the provided bounds.

fn fill_quad(&mut self, quad: Quad, background: impl Into<Background>)

Fills a Quad with the provided Background.

fn reset(&mut self, new_bounds: Rectangle)

Resets the Renderer to start drawing in the new_bounds from scratch.

fn allocate_image( &mut self, handle: &Handle, callback: impl FnOnce(Result<Allocation, Error>) + Send + 'static, )

Creates an image::Allocation for the given image::Handle and calls the given callback with it.

fn hint(&mut self, scale_factor: f32)

Provides hints to the Renderer about the rendering target.

This may be used internally by the Renderer to perform optimizations and/or improve rendering quality.

For instance, providing a scale_factor may be used by some renderers to perform metrics hinting internally in physical coordinates while keeping layout coordinates logical and, therefore, maintain linearity.