Trait ElementExt 

pub trait ElementExt: Any {
    // Provided methods
    fn into_element(self) -> Element
       where Self: Sized + Into<Element> { ... }
    fn changed(&self, _other: &Rc<dyn ElementExt>) -> bool { ... }
    fn diff(&self, _other: &Rc<dyn ElementExt>) -> DiffModifies { ... }
    fn layout(&self) -> Cow<'_, LayoutData> { ... }
    fn accessibility(&self) -> Cow<'_, AccessibilityData> { ... }
    fn effect(&self) -> Option<Cow<'_, EffectData>> { ... }
    fn style(&self) -> Cow<'_, StyleState> { ... }
    fn is_transparent(&self) -> bool { ... }
    fn text_style(&self) -> Cow<'_, TextStyleData> { ... }
    fn layer(&self) -> Layer { ... }
    fn events_handlers(&self) -> Option<Cow<'_, EventHandlers>> { ... }
    fn measure(
        &self,
        _context: LayoutContext<'_>,
    ) -> Option<(Size2D, Rc<dyn Any>)> { ... }
    fn should_hook_measurement(&self) -> bool { ... }
    fn should_measure_inner_children(&self) -> bool { ... }
    fn needs_post_measure(&self) -> bool { ... }
    fn post_measure(
        &self,
        _context: PostMeasureContext<'_>,
    ) -> PostMeasure<NodeId> { ... }
    fn is_point_inside(&self, context: EventMeasurementContext<'_>) -> bool { ... }
    fn clip(&self, _context: ClipContext<'_>) { ... }
    fn render(&self, _context: RenderContext<'_>) { ... }
    fn render_rect(&self, area: &Area, scale_factor: f32) -> SkRRect { ... }
    fn finish_accessibility(&self, _builder: &mut Node) { ... }
}

Tells Freya how to lay out, handle events for, describe accessibility and draw an element.

To make your own element, implement this trait and override what you need. For example, render draws it, layout supplies its layout, measure gives it a custom size, and is_point_inside changes how pointer hits are detected. Everything has a default, so you can start with just the methods your element needs. Override changed and diff when changes to its data need to update the UI.

To put it in the UI tree, implement From<YourElement> for Element (or otherwise make it convertible into Element). You can also implement builder traits like LayoutExt to let callers set its properties. Freya stores elements as Rc<dyn ElementExt>, so they must be 'static through the Any.

See feature_element.rs for a full example.

Provided Methods

fn into_element(self) -> Element

where Self: Sized + Into<Element>,

Converts this value into an Element if it implements Into<Element>.

fn changed(&self, _other: &Rc<dyn ElementExt>) -> bool

Returns whether this element has changed compared to another one.

fn diff(&self, _other: &Rc<dyn ElementExt>) -> DiffModifies

Tells Freya what needs updating when this element changes.

fn layout(&self) -> Cow<'_, LayoutData>

Returns layout properties used to position and size this element.

fn accessibility(&self) -> Cow<'_, AccessibilityData>

Returns accessibility properties for this element.

fn effect(&self) -> Option<Cow<'_, EffectData>>

Returns optional effect properties for this element.

fn style(&self) -> Cow<'_, StyleState>

Returns visual style properties for this element.

fn is_transparent(&self) -> bool

Whether the element paints nothing, letting events fall through to non-ancestor elements behind it.

fn text_style(&self) -> Cow<'_, TextStyleData>

Returns text styling inherited by text content in this element.

fn layer(&self) -> Layer

Returns the drawing layer assigned to this element.

fn events_handlers(&self) -> Option<Cow<'_, EventHandlers>>

Returns event handlers registered on this element.

fn measure(&self, _context: LayoutContext<'_>) -> Option<(Size2D, Rc<dyn Any>)>

Measures the element and optionally returns measurement data for later layout stages.

fn should_hook_measurement(&self) -> bool

Returns whether this element hooks into layout measurement.

fn should_measure_inner_children(&self) -> bool

Returns whether to measure this element’s children.

fn needs_post_measure(&self) -> bool

Whether this element needs a ElementExt::post_measure step after the layout pass.

fn post_measure(&self, _context: PostMeasureContext<'_>) -> PostMeasure<NodeId>

Runs after this element and its children are measured.

fn is_point_inside(&self, context: EventMeasurementContext<'_>) -> bool

Tests whether the pointer position is inside this element’s hit area.

fn clip(&self, _context: ClipContext<'_>)

Applies clipping for this element before it and its children are rendered.

fn render(&self, _context: RenderContext<'_>)

Renders this element using the supplied canvas and layout context.

fn render_rect(&self, area: &Area, scale_factor: f32) -> SkRRect

Creates a rounded rectangle from an area using this element’s corner radius.

fn finish_accessibility(&self, _builder: &mut Node)

Mutates the accessibility node immediately before it enters the accessibility tree.

Dyn Compatibility

This trait is dyn compatible.

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

Implementors

impl ElementExt for ImageElement

impl ElementExt for LabelElement

impl ElementExt for ParagraphElement

impl ElementExt for RectElement