vtkBoxWidget

Section: Visualization Toolkit Widget Classes

Usage

This 3D widget defines a region of interest that is represented by an arbitrarily oriented hexahedron with interior face angles of 90 degrees (orthogonal faces). The object creates 7 handles that can be moused on and manipulated. The first six correspond to the six faces, the seventh is in the center of the hexahedron. In addition, a bounding box outline is shown, the "faces" of which can be selected for object rotation or scaling. A nice feature of the object is that the vtkBoxWidget, like any 3D widget, will work with the current interactor style. That is, if vtkBoxWidget does not handle an event, then all other registered observers (including the interactor style) have an opportunity to process the event. Otherwise, the vtkBoxWidget will terminate the processing of the event that it handles.

To use this object, just invoke SetInteractor() with the argument of the method a vtkRenderWindowInteractor. You may also wish to invoke "PlaceWidget()" to initially position the widget. The interactor will act normally until the "i" key (for "interactor") is pressed, at which point the vtkBoxWidget will appear. (See superclass documentation for information about changing this behavior.) By grabbing the six face handles (use the left mouse button), faces can be moved. By grabbing the center handle (with the left mouse button), the entire hexahedron can be translated. (Translation can also be employed by using the "shift-left-mouse-button" combination inside of the widget.) Scaling is achieved by using the right mouse button "up" the render window (makes the widget bigger) or "down" the render window (makes the widget smaller). To rotate vtkBoxWidget, pick a face (but not a face handle) and move the left mouse. (Note: the mouse button must be held down during manipulation.) Events that occur outside of the widget (i.e., no part of the widget is picked) are propagated to any other registered obsevers (such as the interaction style). Turn off the widget by pressing the "i" key again. (See the superclass documentation on key press activiation.)

The vtkBoxWidget is very flexible. It can be used to select, cut, clip, or perform any other operation that depends on an implicit function (use the GetPlanes() method); or it can be used to transform objects using a linear transformation (use the GetTransform() method). Typical usage of the widget is to make use of the StartInteractionEvent, InteractionEvent, and EndInteractionEvent events. The InteractionEvent is called on mouse motion; the other two events are called on button down and button up (either left or right button).

Some additional features of this class include the ability to control the rendered properties of the widget. You can set the properties of the selected and unselected representations of the parts of the widget. For example, you can set the property for the handles, faces, and outline in their normal and selected states.

To create an instance of class vtkBoxWidget, simply invoke its constructor as follows

  obj = vtkBoxWidget

Methods

The class vtkBoxWidget has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtkBoxWidget class.