Struct DragAndDrop

pub struct DragAndDrop { /* private fields */ }

Plugin for tracking drag-and-drop payload.

This plugin stores the current drag-and-drop payload internally and handles automatic cleanup when the drag operation ends (via Escape key or mouse release).

This is a low-level API. For a higher-level API, see:

• crate::Ui::dnd_drag_source
• crate::Ui::dnd_drop_zone
• crate::Response::dnd_set_drag_payload
• crate::Response::dnd_hover_payload
• crate::Response::dnd_release_payload

This is a built-in plugin in egui, automatically registered during Context creation.

See this example.

Implementations

impl DragAndDrop

pub fn set_payload<Payload>(ctx: &Context, payload: Payload)

where Payload: Any + Send + Sync,

Set a drag-and-drop payload.

This can be read by Self::payload until the pointer is released.

pub fn clear_payload(ctx: &Context)

Clears the payload, setting it to None.

pub fn payload<Payload>(ctx: &Context) -> Option<Arc<Payload>>

where Payload: Any + Send + Sync,

Retrieve the payload, if any.

Returns None if there is no payload, or if it is not of the requested type.

Returns Some both during a drag and on the frame the pointer is released (if there is a payload).

pub fn take_payload<Payload>(ctx: &Context) -> Option<Arc<Payload>>

where Payload: Any + Send + Sync,

Retrieve and clear the payload, if any.

Returns None if there is no payload, or if it is not of the requested type.

Returns Some both during a drag and on the frame the pointer is released (if there is a payload).

pub fn has_payload_of_type<Payload>(ctx: &Context) -> bool

where Payload: Any + Send + Sync,

Are we carrying a payload of the given type?

Returns true both during a drag and on the frame the pointer is released (if there is a payload).

pub fn has_any_payload(ctx: &Context) -> bool

Are we carrying a payload?

Returns true both during a drag and on the frame the pointer is released (if there is a payload).

Trait Implementations

impl Clone for DragAndDrop

fn clone(&self) -> DragAndDrop

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for DragAndDrop

fn default() -> DragAndDrop

Returns the “default value” for a type.

impl Plugin for DragAndDrop

fn on_begin_pass(&mut self, ctx: &Context)

Interrupt drag-and-drop if the user presses the escape key.

This needs to happen at frame start so we can properly capture the escape key.

fn on_end_pass(&mut self, ctx: &Context)

Interrupt drag-and-drop if the user releases the mouse button.

This is a catch-all safety net in case user code doesn’t capture the drag payload itself. This must happen at end-of-frame such that we don’t shadow the mouse release event from user code.

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

Plugin name.

fn setup(&mut self, ctx: &Context)

Called once, when the plugin is registered.

fn input_hook(&mut self, input: &mut RawInput)

Called just before the input is processed.

fn output_hook(&mut self, output: &mut FullOutput)

Called just before the output is passed to the backend.