Trait Element

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pub trait Element: 'static + IntoElement {
    type RequestLayoutState: 'static;
    type PrepaintState: 'static;

    // Required methods
    fn id(&self) -> Option<ElementId>;
    fn source_location(&self) -> Option<&'static Location<'static>>;
    fn request_layout(
        &mut self,
        id: Option<&GlobalElementId>,
        inspector_id: Option<&InspectorElementId>,
        window: &mut Window,
        cx: &mut App,
    ) -> (LayoutId, Self::RequestLayoutState);
    fn prepaint(
        &mut self,
        id: Option<&GlobalElementId>,
        inspector_id: Option<&InspectorElementId>,
        bounds: Bounds<Pixels>,
        request_layout: &mut Self::RequestLayoutState,
        window: &mut Window,
        cx: &mut App,
    ) -> Self::PrepaintState;
    fn paint(
        &mut self,
        id: Option<&GlobalElementId>,
        inspector_id: Option<&InspectorElementId>,
        bounds: Bounds<Pixels>,
        request_layout: &mut Self::RequestLayoutState,
        prepaint: &mut Self::PrepaintState,
        window: &mut Window,
        cx: &mut App,
    );

    // Provided methods
    fn a11y_role(&self) -> Option<Role> { ... }
    fn write_a11y_info(&self, _node: &mut Node) { ... }
    fn a11y_synthetic_children(
        &mut self,
        _prepaint: &mut Self::PrepaintState,
        _builder: &mut A11ySubtreeBuilder<'_>,
    ) { ... }
    fn into_any(self) -> AnyElement { ... }
}

Expand description

Implemented by types that participate in laying out and painting the contents of a window. Elements form a tree and are laid out according to web-based layout rules, as implemented by Taffy. You can create custom elements by implementing this trait, see the module-level documentation for more details.

Required Associated Types§

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type RequestLayoutState: 'static

The type of state returned from Element::request_layout. A mutable reference to this state is subsequently provided to Element::prepaint and Element::paint.

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type PrepaintState: 'static

The type of state returned from Element::prepaint. A mutable reference to this state is subsequently provided to Element::paint.

Required Methods§

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fn id(&self) -> Option<ElementId>

If this element has a unique identifier, return it here. This is used to track elements across frames, and will cause a GlobalElementId to be passed to the request_layout, prepaint, and paint methods.

The global id can in turn be used to access state that’s connected to an element with the same id across frames. This id must be unique among children of the first containing element with an id.

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fn source_location(&self) -> Option<&'static Location<'static>>

Source location where this element was constructed, used to disambiguate elements in the inspector and navigate to their source code.

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fn request_layout( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, Self::RequestLayoutState)

Before an element can be painted, we need to know where it’s going to be and how big it is. Use this method to request a layout from Taffy and initialize the element’s state.

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fn prepaint( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, request_layout: &mut Self::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> Self::PrepaintState

After laying out an element, we need to commit its bounds to the current frame for hitbox purposes. The state argument is the same state that was returned from Element::request_layout().

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fn paint( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, request_layout: &mut Self::RequestLayoutState, prepaint: &mut Self::PrepaintState, window: &mut Window, cx: &mut App, )

Once layout has been completed, this method will be called to paint the element to the screen. The state argument is the same state that was returned from Element::request_layout().

Provided Methods§

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fn a11y_role(&self) -> Option<Role>

Returns the accessible role for this element, if any. Elements that return None are not included in the accessibility tree.

Note: inclusion in accessibility tree requires non-None id.

See the accessibility guide for an overview.

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fn write_a11y_info(&self, _node: &mut Node)

Write accessibility properties to the given node. Called only when a11y_role() returns Some.

See the accessibility guide for an overview.

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fn a11y_synthetic_children( &mut self, _prepaint: &mut Self::PrepaintState, _builder: &mut A11ySubtreeBuilder<'_>, )

Add synthetic child nodes to an Element that has an .id() and a .role().

Some elements may want to inject accessibility nodes that do not correspond to any GPUI element. For example, a custom text field element may want to inject synthetic child nodes for the text content.

See Synthetic children in the accessibility guide for more detail.

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fn into_any(self) -> AnyElement

Convert this element into a dynamically-typed AnyElement.

Dyn Compatibility§

This trait is not dyn compatible.

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

Trait Element Copy item path

Required Associated Types§

type RequestLayoutState: 'static

type PrepaintState: 'static

Required Methods§

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, Self::RequestLayoutState)

fn prepaint( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, request_layout: &mut Self::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> Self::PrepaintState

fn paint( &mut self, id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, request_layout: &mut Self::RequestLayoutState, prepaint: &mut Self::PrepaintState, window: &mut Window, cx: &mut App, )

Provided Methods§

fn a11y_role(&self) -> Option<Role>

fn write_a11y_info(&self, _node: &mut Node)

fn a11y_synthetic_children( &mut self, _prepaint: &mut Self::PrepaintState, _builder: &mut A11ySubtreeBuilder<'_>, )

fn into_any(self) -> AnyElement

Dyn Compatibility§

Implementations on Foreign Types§

impl Element for &'static str

type RequestLayoutState = TextLayout

type PrepaintState = ()

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, _id: Option<&GlobalElementId>, _inspector_id: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <&'static str as Element>::RequestLayoutState)

fn prepaint( &mut self, _id: Option<&GlobalElementId>, _inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, text_layout: &mut <&'static str as Element>::RequestLayoutState, _window: &mut Window, _cx: &mut App, )

fn paint( &mut self, _id: Option<&GlobalElementId>, _inspector_id: Option<&InspectorElementId>, _bounds: Bounds<Pixels>, text_layout: &mut TextLayout, _: &mut (), window: &mut Window, cx: &mut App, )

impl Element for MotionReveal

type RequestLayoutState = ()

type PrepaintState = ()

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, global_id: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <MotionReveal as Element>::RequestLayoutState)

fn prepaint( &mut self, global_id: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut <MotionReveal as Element>::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> <MotionReveal as Element>::PrepaintState

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut <MotionReveal as Element>::RequestLayoutState, _: &mut <MotionReveal as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for PlotAppearScope

type RequestLayoutState = (Option<AnyElement>, Rc<RefCell<HashMap<GlobalElementId, u64>>>)

type PrepaintState = ()

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, global_id: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <PlotAppearScope as Element>::RequestLayoutState)

fn prepaint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut <PlotAppearScope as Element>::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> <PlotAppearScope as Element>::PrepaintState

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut <PlotAppearScope as Element>::RequestLayoutState, _: &mut <PlotAppearScope as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for Positioner

type RequestLayoutState = PositionerState

type PrepaintState = ()

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <Positioner as Element>::RequestLayoutState)

fn prepaint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, request_layout: &mut <Positioner as Element>::RequestLayoutState, window: &mut Window, cx: &mut App, )

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut <Positioner as Element>::RequestLayoutState, _: &mut <Positioner as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for RoundedFrameCover

type RequestLayoutState = ()

type PrepaintState = Bounds<Pixels>

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <RoundedFrameCover as Element>::RequestLayoutState)

fn prepaint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut <RoundedFrameCover as Element>::RequestLayoutState, _: &mut Window, _: &mut App, ) -> <RoundedFrameCover as Element>::PrepaintState

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut <RoundedFrameCover as Element>::RequestLayoutState, cover_bounds: &mut <RoundedFrameCover as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for ScrollBounce

type RequestLayoutState = ()

type PrepaintState = ScrollBouncePrepaintState

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, ())

fn prepaint( &mut self, id: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut (), window: &mut Window, cx: &mut App, ) -> <ScrollBounce as Element>::PrepaintState

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut (), prepaint: &mut <ScrollBounce as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for Scrollbar

type RequestLayoutState = ()

type PrepaintState = PrepaintState

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <Scrollbar as Element>::RequestLayoutState)

fn prepaint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut <Scrollbar as Element>::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> <Scrollbar as Element>::PrepaintState

fn paint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut <Scrollbar as Element>::RequestLayoutState, prepaint: &mut <Scrollbar as Element>::PrepaintState, window: &mut Window, cx: &mut App, )

impl Element for SelectableText

type RequestLayoutState = TextSelectionHandle

type PrepaintState = Hitbox

fn id(&self) -> Option<ElementId>

fn source_location(&self) -> Option<&'static Location<'static>>

fn request_layout( &mut self, global_id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, <SelectableText as Element>::RequestLayoutState)

fn prepaint( &mut self, global_id: Option<&GlobalElementId>, inspector_id: Option<&InspectorElementId>, bounds: Bounds<Pixels>, handle: &mut <SelectableText as Element>::RequestLayoutState, window: &mut Window, cx: &mut App, ) -> <SelectableText as Element>::PrepaintState

Trait Element

impl<E> Element for ContextMenu<E>
where E: ParentElement + Styled + IntoElement + 'static,

impl<H> Element for ScrollableMask<H>
where H: ScrollbarHandle + Clone,

impl<P> Element for PlotElement<P>
where P: Plot + 'static,

impl<T, E> Element for ResizeHandle<T, E>
where T: 'static, E: 'static + Render,