Struct ScrollableMask 

pub struct ScrollableMask<H: ScrollbarHandle + Clone = ScrollHandle> { /* private fields */ }

Make a scrollable mask element to cover the parent view with the mouse wheel event listening.

When the mouse wheel is scrolled, will move the scroll_handle scrolling with the axis direction. You can use this scroll_handle to control what you want to scroll. This is only can handle once axis scrolling.

Axis-dominant wheel events are consumed in the capture phase, so the mask wins over ancestor scrollers (e.g. gpui::list) that register their listeners after their children; events dominated by the other axis keep propagating. The mask stays inert while occluded.

Dominance is decided per gesture, not per event: a precise (trackpad) delta locks onto the axis its gesture started on, so mid-swipe wobble cannot flip which mask consumes the events. Line deltas keep the per-event comparison.

At the scroll edge the two axes differ, matching platform scrollers: a vertical mask hands the event over to the ancestor scroller (CSS overscroll-behavior: auto chaining), while a horizontal mask keeps consuming it — a bubbled horizontal delta would get mapped onto a vertical-only ancestor by gpui’s own wheel listener (see #2468).

Implementations

impl<H: ScrollbarHandle + Clone> ScrollableMask<H>

pub fn new(axis: Axis, scroll_handle: &H) -> Self

Create a new scrollable mask element.

pub fn id(self, id: impl Into<ElementId>) -> Self

Set a specific element id, default is the std::panic::Location::caller.

Only needed when one call site creates several masks of the same axis, which would otherwise share their gesture axis lock.

pub fn debug(self) -> Self

Enable the debug border, to show the mask bounds.

Trait Implementations

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

type RequestLayoutState = ()

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

type PrepaintState = Hitbox

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

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.

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.

fn request_layout( &mut self, _: Option<&GlobalElementId>, _: 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.

fn prepaint( &mut self, _: Option<&GlobalElementId>, _: Option<&InspectorElementId>, bounds: Bounds<Pixels>, _: &mut Self::RequestLayoutState, window: &mut Window, _: &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().

fn paint( &mut self, global_id: Option<&GlobalElementId>, _: Option<&InspectorElementId>, _: Bounds<Pixels>, _: &mut Self::RequestLayoutState, hitbox: &mut Self::PrepaintState, window: &mut Window, _: &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().

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.

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

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

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().

fn into_any(self) -> AnyElement

Convert this element into a dynamically-typed AnyElement.

impl<H: ScrollbarHandle + Clone> IntoElement for ScrollableMask<H>

type Element = ScrollableMask<H>

The specific type of element into which the implementing type is converted. Useful for converting other types into elements automatically, like Strings

fn into_element(self) -> Self::Element

Convert self into a type that implements Element.

fn into_any_element(self) -> AnyElement

Convert self into a dynamically-typed AnyElement.