Struct DropTarget 

pub struct DropTarget { /* private fields */ }

A transparent container that turns its child into a drop target. See the module docs.

Implementations

impl DropTarget

pub fn new() -> Self

A drop target with no child yet — call Self::child (required).

pub fn child(self, widget: impl Widget + 'static) -> Self

The wrapped content — fills the bounds and is always visible.

pub fn child_id(self, id: WidgetId) -> Self

The wrapped content by pre-registered WidgetId.

pub fn region( self, region: DropRegion, f: impl FnOnce(DropRegionSpec) -> DropRegionSpec, ) -> Self

Enable and configure a drop DropRegion. Declaring any region switches the target to exactly the declared regions; declaring none leaves the implicit Center-only whole-bounds default. The spec closure configures the region (currently: an optional hint).

DropTarget::new()
    .child(editor)
    .zone_size_factor(0.25)
    .region(DropRegion::Center,   |z| z.hint(TextWidget::new(lit!("Add tab"))))
    .region(DropRegion::Leading,  |z| z.hint(TextWidget::new(lit!("Split left"))))
    .region(DropRegion::Trailing, |z| z.hint(TextWidget::new(lit!("Split right"))))
    .on_region_drop(|region, payload, _pos, ctx| { route(region, payload); true });

pub fn zone_size_factor(self, factor: f32) -> Self

The fraction of the axis each side zone occupies (clamped to 0.1..=1.0). 0.2 is the default fifth; 0.5 bisects. Applies to all four edge zones in common; Center takes the leftover middle.

pub fn hint(self, widget: impl Widget + 'static) -> Self

Widget shown centered inside a popup card while a drag with an accepted payload hovers. Sugar for .region(DropRegion::Center, |z| z.hint(w)) — the classic whole-bounds single-zone case.

pub fn hint_id(self, id: WidgetId) -> Self

Hint content by pre-registered WidgetId (Center region).

pub fn accept_any(self) -> Self

Accept any payload (internal or external). Explicit form of the default.

pub fn accept_external(self) -> Self

Accept any external (OS) drop, regardless of content.

pub fn accept_external_files(self) -> Self

Accept external drops that carry at least one file. Optimistic at hover on Wayland (where the file bytes only arrive at drop) if the source advertises a text/uri-list.

pub fn accept_external_text(self) -> Self

Accept external text drops. Optimistic at hover on Wayland if the source advertises a text format.

pub fn accept_external_extensions<I, S>(self, extensions: I) -> Self

where I: IntoIterator<Item = S>, S: AsRef<str>,

Accept external file drops whose extension is in extensions (case-insensitive). At hover on Wayland the real check is deferred to drop (no file bytes yet); it is optimistic if a text/uri-list is advertised.

pub fn accept_typed<T: 'static>(self) -> Self

Accept internal drags whose payload carries a value of type T. Ergonomic companion to Self::on_drop_typed.

pub fn accept_when(self, f: impl Fn(&DragPayload) -> bool + 'static) -> Self

Custom predicate — full control over payload inspection.

pub fn targeted_signal(self, signal: Signal<bool>) -> Self

The widget writes true while a drag with an accepted payload is over the target, false otherwise — SwiftUI’s isTargeted pattern. Drive custom visuals off this signal.

pub fn drag_state_signal(self, signal: Signal<DropTargetDragState>) -> Self

Full three-state version of Self::targeted_signal.

pub fn active_region_signal(self, signal: Signal<Option<DropRegion>>) -> Self

The widget writes which DropRegion an accepted drag is currently over (None when idle, rejecting, or over a disabled middle). Drive custom per-zone visuals off this.

pub fn on_drop( self, f: impl FnMut(DragPayload, Point, &mut EventContext<'_>) -> bool + 'static, ) -> Self

Handle a drop. Return true to accept, false to reject. Invoked only when the accept filter passes.

pub fn on_drop_typed<T: 'static>( self, f: impl FnMut(T, Point, &mut EventContext<'_>) -> bool + 'static, ) -> Self

Ergonomic typed drop: implicitly sets accept_typed::<T>() and extracts the typed value before invoking f. Last-call-wins with Self::on_drop.

pub fn on_region_drop( self, f: impl FnMut(DropRegion, DragPayload, Point, &mut EventContext<'_>) -> bool + 'static, ) -> Self

Region-aware drop: receives which DropRegion the pointer released over, plus the payload. Last-call-wins with Self::on_drop — when set, it is used instead of the plain on_drop. Invoked only when the accept filter passes; return true to accept.

pub fn on_drag_leave( self, f: impl FnMut(&mut EventContext<'_>) + 'static, ) -> Self

Called when a drag leaves the target (pointer exit, drop completion, or cancel).

pub fn variant(self, variant: DropTargetVariant) -> Self

Visual prominence of the hover indicator.

pub fn style(self, style: impl DropTargetStyle) -> Self

Per-call style override (Tier-3). Wins over the theme slot and the default recipe.

Trait Implementations

impl Debug for DropTarget

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DropTarget

fn default() -> Self

Returns the “default value” for a type.

impl Widget for DropTarget

fn build(&mut self, ctx: &mut BuildContext<'_>) -> Vec<WidgetId>

Compose child widgets. Called once after the widget is placed in the arena, and again on environment change (theme switch, locale switch). Takes &mut self — store child IDs, signal handles, any state needed later. Returns the list of root child IDs (empty for leaf widgets).

fn layout_response( &self, proposal: SizeProposal, ctx: &LayoutContext<'_>, ) -> LayoutResponse

Respond to the parent’s size proposal with this widget’s wanted size, grow/shrink weights, and compression floor (see [LayoutResponse]).

fn place_children( &self, bounds: Rect, _proposal: SizeProposal, children: &mut [WidgetPlacement], _ctx: &LayoutContext<'_>, )

Position children within the allocated bounds.

fn accessibility(&self, builder: &mut AccessNodeBuilder)

Declare this widget’s accessibility identity.

fn children(&self) -> Vec<WidgetId>

Return the child widget IDs that this widget manages.

fn type_name(&self) -> &'static str

Concrete type name of this widget (e.g. "teksilo_widgets::button::Button"). The default implementation resolves at the impl site via std::any::type_name::<Self>(), so calls through &dyn Widget correctly dispatch to the monomorphized fn for the concrete type — getting the concrete name through the vtable without per-impl boilerplate.

fn cacheable_layout(&self) -> bool

Whether this widget’s layout_response may be memoized by the per-pass layout cache. Defaults to true.

fn paint(&self, _bounds: Rect, _canvas: &mut Canvas, _ctx: &PaintContext<'_>)

Draw the widget’s visual representation.

fn wants_after_paint(&self) -> bool

Whether this widget wants its after_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t aggregate descendant geometry.

fn after_paint(&self, _view: &WidgetTreeView<'_>, _ctx: &PaintContext<'_>)

Called once per frame after this widget’s subtree has finished painting. Receives a read-only view of the layout-resolved arena so a parent can read its descendants’ final bounds — e.g. TitleBar aggregates its drag region and control-button rects into a single HitRegions payload for the Windows backend’s WM_NCHITTEST.

fn wants_post_paint(&self) -> bool

Whether this widget wants its post_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t draw a foreground over their children.

fn post_paint( &self, _bounds: Rect, _canvas: &mut Canvas, _ctx: &PaintContext<'_>, )

Draw a foreground layer over this widget’s children.

fn wants_descendant_redirects(&self) -> bool

Whether this widget wants the AT walker to consult its a11y_redirect_descendant hook for every descendant during AT tree emission, not just its direct arena children.

fn a11y_redirect_descendant( &self, _self_id: WidgetId, _descendant: WidgetId, ) -> Option<NodeId>

Optional redirection hook for AT-tree placement of a child.

fn accessible_title_hint(&self) -> Option<String>

Suggest an accessible title to an enclosing container that wraps this widget as content — typically a modal / dialog shell that wants to propagate the inner content’s visible title as the shell’s own accessible name.

fn initial_focus_hint(&self) -> Option<WidgetId>

Optional hint that directs initial focus to a specific descendant when this widget is the root of a deferred-built modal surface.

fn accessibility_children(&self) -> Option<Vec<WidgetId>>

Optional override for the child ORDER presented to assistive technology, when it must differ from the paint / z-order child order returned by children.

fn as_any(&self) -> Option<&(dyn Any + 'static)>

Downcast hook. Default implementation returns None; concrete widgets override with Some(self) when they want to expose their concrete type to test-level introspection or reflection. The trait already bounds on std::any::Any so concrete types satisfy the 'static requirement.

fn as_any_mut(&mut self) -> Option<&mut (dyn Any + 'static)>

Mutable counterpart of as_any. Default returns None; widgets that want to expose mutable state to tests (e.g. so a test can mutate a Scene inside a SceneView post-layout) override with Some(self). Should follow the same opt-in pattern as as_any: only widgets that opt into & introspection should opt into &mut.

fn clips_children(&self) -> bool

Whether this widget clips its children to its bounds.

fn focus_reveal_rect(&self, _bounds: Rect) -> Option<Rect>

The rectangle (in absolute tree coordinates) that best represents this widget when the framework reveals it into an ancestor scroll area on focus gain. Returning None (the default) reveals the widget’s whole bounds — correct for most controls.

fn hit_shape(&self, _local_point: Point, _bounds: Rect) -> bool

Whether the point lies inside this widget’s actual shape, not just its rectangular bounds. Consulted by hit-testing right after the bounds check: returning false for a point that is inside the bounding box makes the widget transparent to the click there, so it falls through to whatever sibling is painted underneath (the same machinery as a fully pass-through node, but shape-aware).

fn preserves_children_on_rebuild(&self) -> bool

How rebuild_single_widget treats this widget’s existing children when re-running its build().

fn tooltip_has_content(&self) -> bool

Whether this widget, used as tooltip content, currently has anything worth showing.

fn declare_shortcuts(&self) -> Vec<Shortcut>

Declare the rebindable keyboard shortcuts this widget exposes, without installing handlers. The framework calls this at arena insertion time (before build()) and at certain lazy boundaries (e.g. Switcher walks declarations on its not-yet-mounted Pending slots), so settings UIs and the ShortcutRegistry see the keystrokes the moment the owning container mounts — even if build() hasn’t run.

fn take_handler_set(&mut self) -> Option<HandlerSet>

Extract attached handler set from a WidgetWithHandlers wrapper. Called during arena insertion to transfer handlers to the WidgetNode. Default: returns None (no attached handlers).