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Class RescalingTool

This is an extension and not part of the main GoJS library. Note that the API for this class may change at any time. If you intend to use an extension in production, you should copy the code to your own source directory. Extensions can be found in the GoJS kit under the extensions or extensionsTS folders. See the Extensions intro page for more information.


  • Tool
    • RescalingTool

A custom tool for rescaling an object by modifying its GraphObject.scale property.

Install the RescalingTool as a mouse-down tool by calling: myDiagram.toolManager.mouseDownTools.add(new RescalingTool());

Normally it would not make sense for the same object to be both resizable and rescalable.

Note that there is no Part.rescaleObjectName property and there is no Part.rescalable property. So although you cannot customize any Node to affect this tool, you can set RescalingTool.rescaleObjectName and set RescalingTool.isEnabled to control whether objects are rescalable and when.

If you want to experiment with this extension, try the Rescaling sample.





adornedObject : GraphObject

  • Gets the GraphObject that is being rescaled. This may be the same object as the selected Part or it may be contained within that Part.

    This property is also settable, but should only be set when overriding functions in RescalingTool, and not during normal operation.

handle : GraphObject

handleArchetype : GraphObject

  • Gets or sets a small GraphObject that is copied as a rescale handle for the selected part. By default this is a Shape that is a small blue square. Setting this property does not raise any events.

    Here is an example of changing the default handle to be green "X":

      tool.handleArchetype =
        $(go.Shape, "XLine",
          { width: 8, height: 8, stroke: "green", fill: "transparent" });

rescaleObjectName : string

  • This property returns the name of the GraphObject that identifies the object to be rescaled by this tool.

    The default value is the empty string, resulting in the whole Node being rescaled. This property is used by findRescaleObject when calling Panel.findObject.


Override canStart

  • canStart(): boolean
  • This tool can start running if the mouse-down happens on a "Rescaling" handle.

    Returns boolean


  • computeScale(newPoint: Point): number
  • Compute the new scale given a point.

    This method is called by both doMouseMove and doMouseUp. This method may be overridden. Please read the Introduction page on Extensions for how to override methods and how to call this base method.


    • newPoint: Point

      in document coordinates

    Returns number

Override doActivate

  • doActivate(): void
  • Activating this tool remembers the handle that was dragged, the adornedObject that is being rescaled, starts a transaction, and captures the mouse.

    Returns void

Override doCancel

  • doCancel(): void

Override doDeactivate

  • doDeactivate(): void
  • Stop the current transaction, forget the handle and adornedObject, and release the mouse.

    Returns void

Override doMouseMove

  • doMouseMove(): void
  • Call scale with a new scale determined by the current mouse point. This determines the new scale by calling computeScale.

    Returns void

Override doMouseUp

  • doMouseUp(): void
  • Call scale with a new scale determined by the most recent mouse point, and commit the transaction.

    Returns void


  • Return the GraphObject to be rescaled by the user.


    Returns GraphObject



  • scale(newScale: number): void

Override updateAdornments

  • updateAdornments(part: Part): void
  • Parameters

    Returns void