Trait Widget 

pub trait Widget {
    // Provided methods
    fn connected(&mut self) { ... }
    fn disconnected(&mut self) { ... }
    fn attribute_changed(
        &mut self,
        name: &str,
        old_value: Option<&str>,
        new_value: Option<&str>,
    ) { ... }
    fn can_create_surfaces(&mut self, render_ctx: &mut dyn RenderContext) { ... }
    fn destroy_surfaces(&mut self) { ... }
    fn requires_redraw(&self) -> bool { ... }
    fn handle_event(&mut self, event: &UiEvent) { ... }
    fn paint(
        &mut self,
        render_ctx: &mut dyn RenderContext,
        styles: &ComputedValues,
        width: u32,
        height: u32,
        scale: f64,
    ) -> Scene { ... }
}

Provided Methods

fn connected(&mut self)

The widget was attached to the DOM

fn disconnected(&mut self)

The widget was removed from the DOM

fn attribute_changed( &mut self, name: &str, old_value: Option<&str>, new_value: Option<&str>, )

One of the widget’s attributes changed

fn can_create_surfaces(&mut self, render_ctx: &mut dyn RenderContext)

The renderer is active

ctx parameter can be downcast to get access to renderer-specific contexts (e.g. the WGPU Device and Queue)

fn destroy_surfaces(&mut self)

The renderer is no longer active (destroy textures here)

fn requires_redraw(&self) -> bool

Whether the widget currently requires redraws (e.g. because it is animating).

Returning true causes the document to continuously schedule redraws (and hence repaints of the widget). Static widgets should return false.

fn handle_event(&mut self, event: &UiEvent)

Handle input events (mouse, keyboard, etc)

fn paint( &mut self, render_ctx: &mut dyn RenderContext, styles: &ComputedValues, width: u32, height: u32, scale: f64, ) -> Scene

Callback for the widget to paint it’s content.

Output is recorded to an AnyRender Scene. If the widget wants to render to a WGPU texture or similar then it should:

• Get a handle to the Device and Queue in can_create_surfaces
• Create it’s own texture
• Pass the ResourceId of the paint for an Image in the AnyRender Scene

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors