Struct re_viewer_context::drag_and_drop::DragAndDropManager

pub struct DragAndDropManager {
    undraggable_items: ItemCollection,
    feedback: AtomicCell<DragAndDropFeedback>,
}

Helper to handle drag-and-drop operations.

This helper must be constructed at the beginning of the frame and disposed of at the end. Its Self::payload_cursor_ui method should be called late during the frame (after the rest of the UI has a chance to update the feedback).

Fields

undraggable_items: ItemCollection

Items that may not be dragged, e.g., because they are not movable nor copiable.

feedback: AtomicCell<DragAndDropFeedback>

Implementations

impl DragAndDropManager

pub fn new(undraggable_items: impl Into<ItemCollection>) -> Self

Create a DragAndDropManager by providing a list of undraggable items.

pub fn set_feedback(&self, feedback: DragAndDropFeedback)

Set the feedback to display to the user based on drop acceptability for the UI currently hovered.

By default, the feedback is unset and the pill/cursor are displayed in a “neutral” way, indicating that the current drag-and-drop payload is valid but not hovered over a related UI.

If the payload type is compatible with the hovered UI element, that element should set the feedback to either DragAndDropFeedback::Accept or DragAndDropFeedback::Reject, based on whether the actual payload content may meaningfully be dropped.

For example, a view generally accepts a dragged entity but may occasionally reject it if it already contains it.

pub fn are_items_draggable(&self, items: &ItemCollection) -> bool

Checks if items are draggable based on the list of undraggable items.

pub fn payload_cursor_ui(&self, ctx: &Context)

Display the currently dragged payload as a pill in the UI.

This should be called once per frame.