Node<T> class

Represents a single node in the flow graph.

A node is a visual element that can be connected to other nodes via Ports. Each node has a position, size, and custom data of type T. Nodes can be dragged, selected, and connected to create complex flow diagrams.

The node system uses MobX observables for reactive updates, ensuring that any changes to node properties automatically trigger UI updates.

Capability-Based Design

Node capabilities are added via mixins:

ResizableMixin - Resize functionality (sets isResizable to true)
GroupableMixin - Grouping/container functionality with child node monitoring

Base nodes have port geometry built-in. Specialized nodes like GroupNode and CommentNode add capabilities through mixins.

Example

final node = Node<MyData>(
  id: 'node-1',
  type: 'processor',
  position: Offset(100, 100),
  data: MyData(value: 'example'),
  inputPorts: [
    Port(id: 'in-1', position: PortPosition.left),
  ],
  outputPorts: [
    Port(id: 'out-1', position: PortPosition.right),
  ],
);

Constructors

Node({required String id, required String type, required Offset position, required T data, Size? size, List<Port> inputPorts = const [], List<Port> outputPorts = const [], int initialZIndex = 0, bool visible = true, NodeRenderLayer layer = NodeRenderLayer.middle, bool locked = false, bool selectable = true}): Creates a new node with the specified properties.
Node.fromJson(Map<String, dynamic> json, T fromJsonT(Object? json)): Creates a node from JSON data.
factory

Properties

allPorts → List<Port>: Gets all ports (input and output combined).
no setter
currentZIndex ↔ int: Gets the current z-index value.
getter/setter pair
data → T: Custom data associated with this node.
final
dragging → Observable<bool>: Observable dragging state.
final
hashCode → int: The hash code for this object.
no setterinherited
id → String: Unique identifier for this node.
final
inputPorts → ObservableList<Port>: Observable list of input ports for incoming connections.
final
isDragging ↔ bool: Gets the current dragging state.
getter/setter pair
isEditing ↔ bool: Gets the current editing state.
getter/setter pair
isResizable → bool: Whether this node can be resized.
no setter
isSelected ↔ bool: Gets the current selection state.
getter/setter pair
isVisible ↔ bool: Gets the current visibility state.
getter/setter pair
layer → NodeRenderLayer: Rendering layer for this node.
final
locked → bool: Whether this node is locked from user interactions.
final
outputPorts → ObservableList<Port>: Observable list of output ports for outgoing connections.
final
position → Observable<Offset>: Observable position of the node in graph coordinates.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
selectable → bool: Whether this node participates in marquee selection.
final
selected → Observable<bool>: Observable selection state.
final
size → Observable<Size>: Observable size of the node.
final
type → String: Type classification for this node.
final
visualPosition → Observable<Offset>: Observable visual position for rendering (may include snap-to-grid).
final
zIndex → Observable<int>: Observable z-index for stacking order.
final

Methods

addInputPort(Port port) → void: Adds an input port to the node.
addOutputPort(Port port) → void: Adds an output port to the node.
buildWidget(BuildContext context) → Widget?: Builds the widget for this node.
containsPoint(Offset point) → bool: Checks if a point is within the node's rectangular bounds.
dispose() → void: Disposes of resources used by this node.
findPort(String portId) → Port?: Finds a port by ID in either input or output ports.
getBounds() → Rect: Gets the node's bounding rectangle.
getConnectionPoint(String portId, {required Size portSize, NodeShape? shape}) → Offset: Available on Node<T>, provided by the NodePortGeometry extension
Gets the connection attachment point for a port in graph coordinates.
getPortCapsuleSide(String portId) → CapsuleFlatSide: Available on Node<T>, provided by the NodePortGeometry extension
Gets the capsule flat side orientation for a port.
getPortCenter(String portId, {required Size portSize, NodeShape? shape}) → Offset: Available on Node<T>, provided by the NodePortGeometry extension
Gets the visual center of a port in graph coordinates.
getVisualPortOrigin(String portId, {required Size portSize, NodeShape? shape}) → Offset: Available on Node<T>, provided by the NodePortGeometry extension
Gets the visual position where a port should be rendered within the node container.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
onDragEnd() → void: Called when a drag operation ends.
onDragMove(Offset delta, NodeDragContext context) → void: Called during a drag operation as the node moves.
onDragStart(NodeDragContext context) → void: Called when a drag operation starts on this node.
removeInputPort(String portId) → bool: Removes an input port by ID.
removeOutputPort(String portId) → bool: Removes an output port by ID.
removePort(String portId) → bool: Removes a port by ID from either input or output ports.
setSize(Size newSize) → void: Sets the size of this node.
setVisualPosition(Offset snappedPosition) → void: Updates the visual position based on the actual position and snapping rules.
toJson(Object? toJsonT(T value)) → Map<String, dynamic>: Converts the node to a JSON map.
toString() → String: A string representation of this object.
inherited
updateInputPort(String portId, Port updatedPort) → bool: Updates an existing input port by ID.
updateOutputPort(String portId, Port updatedPort) → bool: Updates an existing output port by ID.
updatePort(String portId, Port updatedPort) → bool: Updates a port by ID in either input or output ports.

Operators

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