AnnotationDragContext class

Context provided to annotations during drag and node lifecycle operations.

This context allows annotations to interact with nodes during drag, enabling behaviors like moving contained nodes when a group is dragged, or refitting bounds when member nodes are deleted.

Example Usage in a Custom Annotation

class MyGroupAnnotation extends Annotation {
  Set<String>? _containedNodeIds;

  @override
  void onDragStart(AnnotationDragContext context) {
    // Capture nodes inside this annotation at drag start
    _containedNodeIds = context.findNodesInBounds(bounds);
  }

  @override
  void onDragMove(Offset delta, AnnotationDragContext context) {
    // Move the contained nodes along with this annotation
    if (_containedNodeIds != null && _containedNodeIds!.isNotEmpty) {
      context.moveNodes(_containedNodeIds!, delta);
    }
  }

  @override
  void onDragEnd() {
    _containedNodeIds = null;
  }
}

Constructors

AnnotationDragContext({required void moveNodes(Set<String> nodeIds, Offset delta), required Set<String> findNodesInBounds(Rect bounds), required Node? getNode(String nodeId)})
const

Properties

findNodesInBounds → Set<String> Function(Rect bounds)
Finds all node IDs whose bounds are completely contained within the given rect.
final
getNode → Node? Function(String nodeId)
Looks up a node by ID.
final
hashCode → int
The hash code for this object.
no setterinherited
moveNodes → void Function(Set<String> nodeIds, Offset delta)
Moves a set of nodes by the given delta.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited