Class LinkingTool

GoJS® Diagramming Components
version 3.0.0a1
by Northwoods Software®

Hierarchy

The LinkingTool lets a user draw a new Link between two ports, using a mouse-drag operation.

By default an instance of this tool is installed as a mouse-move tool in the Diagram.toolManager as the linkingTool. However this tool may be used modally, as described below.

canStart calls findLinkablePort to find a valid "port" element from which (or to which) the user may interactively draw a new link. doActivate sets up a temporary link and two temporary nodes, one at the start port and one following the mouse.

For a general discussion of validation, see Introduction to Validation.

This tool does not utilize any Adornments or tool handles.

This tool conducts a transaction while the tool is active. A successful linking will result in a "LinkDrawn" DiagramEvent and a "Linking" transaction.

If you want to programmatically start a new user mouse-gesture to draw a new link from a given GraphObject that either is a "port" or may be within the visual tree of a "port", set the startObject property to let findLinkablePort find the real "port" element. Then start and activate this tool:

  var tool = myDiagram.toolManager.linkingTool;
tool.startObject = ...;
myDiagram.currentTool = tool;
tool.doActivate();
Index

Constructors

  • You do not normally need to create an instance of this tool because one already exists as the linkingTool, which you can modify.

    The name of this tool is "Linking".

    Returns LinkingTool

Accessors

  • Gets or sets an optional node data object representing a link label, that is copied by insertLink and added to the GraphLinksModel when creating a new Link.

    The default value is null, which causes no such label node data to be added to the model along with the new link data.

    insertLink calls addLabelKeyForLinkData to associate the label node data with the link data.

    Setting this property does not raise any events. This property is ignored if the Diagram.model is not a GraphLinksModel.

  • Gets or sets the direction in which new links may be drawn. Possible values are LinkingDirection values.. This defaults to LinkingDirection.Either. Setting this property does not raise any events.

  • Gets or sets the GraphObject at which findLinkablePort should start its search. The default value is null. Setting this property does not raise any events.

    If you want to explicitly start a new user mouse-gesture to draw a new link from a given GraphObject that may be a "port" object or may be within the visual tree of a "port" object, set this property to that object to let findLinkablePort find the real "port" object. Then start and activate this tool:

      var tool = myDiagram.toolManager.linkingTool;
    tool.startObject = ...;
    myDiagram.currentTool = tool;
    tool.doActivate();

Methods

  • This tool can run when the diagram allows linking, the model is modifiable, the left-button mouse drag has moved far enough away to not be a click, and when findLinkablePort has returned a valid port or when startObject is a valid port.

    This method may be overridden, but we recommend that you call this base method.

    Returns boolean

  • Finishing the linking operation stops the transaction, releases the mouse, and resets the cursor.

    This method may be overridden, but we recommend that you call this base method.

    Returns void

  • A mouse-up ends the linking operation; if there is a valid targetPort nearby, this adds a new Link by calling insertLink.

    If there is a new link, it is selected and the "LinkDrawn" DiagramEvent is raised with the new link as the subject. If there is no new link, this calls doNoLink. In any case this stops the tool.

    This method also raises the "ChangingSelection" and "ChangedSelection" diagram events. Changes are performed in a "Linking" transaction, but the "ChangedSelection" event is raised outside the transaction.

    This method may be overridden, but we recommend that you call this base method. It is usually easier to override insertLink or just set archetypeLinkData. It is also common to implement a "LinkDrawn" DiagramEvent listener on the Diagram.

    Returns void

  • This method is called upon a mouse up when no new link is drawn, either because no valid LinkingBaseTool.targetPort was found or because insertLink returned null.

    This method may be overridden. By default this method does nothing. If you want to successfully perform any side-effects, you will need to set Tool.transactionResult to a string; otherwise this tool's transaction will be rolled-back. Please read the Introduction page on Extensions for how to override methods and how to call this base method.

    Parameters

    • fromnode: Node
    • fromport: GraphObject

      the from-port, or null to use the node itself

    • tonode: Node
    • toport: GraphObject

      the to-port, or null to use the node itself

    Returns void

    since

    1.7

  • Make a copy of the archetypeLinkData, set its node and port properties, and add it to the GraphLinksModel. If the model is a TreeModel, set the parent key of the child's node data object.

    For GraphLinksModels, if archetypeLabelNodeData is non-null, this method also adds that node data as an initial label node for the new link data.

    For TreeModels, if Diagram.isTreePathToChildren is false, the roles of the fromnode and tonode arguments are exchanged.

    This method may be overridden, but we recommend that you call this base method. Usually though it is easiest to just set archetypeLinkData to control what kind of link is created. Please read the Introduction page on Extensions for how to override methods and how to call this base method.

    Parameters

    • fromnode: Node
    • fromport: GraphObject

      the from-port, or null to use the node itself

    • tonode: Node
    • toport: GraphObject

      the to-port, or null to use the node itself

    Returns Link

    the newly created Link, or null if it failed.

Properties

deprecated
deprecated
deprecated