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vtkHandleWidget

Section: Visualization Toolkit Widget Classes

# Usage

The vtkHandleWidget is used to position a handle. A handle is a widget with a position (in display and world space). Various appearances are available depending on its associated representation. The widget provides methods for translation, including constrained translation along coordinate axes. To use this widget, create and associate a representation with the widget.

.SECTION Event Bindings By default, the widget responds to the following VTK events (i.e., it watches the vtkRenderWindowInteractor for these events):

       LeftButtonPressEvent - select focal point of widget
       LeftButtonReleaseEvent - end selection
       MiddleButtonPressEvent - translate widget
       MiddleButtonReleaseEvent - end translation
       RightButtonPressEvent - scale widget
       RightButtonReleaseEvent - end scaling
       MouseMoveEvent - interactive movement across widget

Note that the event bindings described above can be changed using this class's vtkWidgetEventTranslator. This class translates VTK events into the vtkHandleWidget's widget events:

       vtkWidgetEvent::Select – focal point is being selected
       vtkWidgetEvent::EndSelect – the selection process has completed
       vtkWidgetEvent::Translate – translate the widget
       vtkWidgetEvent::EndTranslate – end widget translation
       vtkWidgetEvent::Scale – scale the widget
       vtkWidgetEvent::EndScale – end scaling the widget
       vtkWidgetEvent::Move – a request for widget motion

In turn, when these widget events are processed, the vtkHandleWidget invokes the following VTK events on itself (which observers can listen for):

       vtkCommand::StartInteractionEvent (on vtkWidgetEvent::Select)
       vtkCommand::EndInteractionEvent (on vtkWidgetEvent::EndSelect)
       vtkCommand::InteractionEvent (on vtkWidgetEvent::Move)

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

      obj = vtkHandleWidget

# Methods

The class vtkHandleWidget 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 vtkHandleWidget class.

- `string = obj.GetClassName ()` - Standard VTK class macros.
- `int = obj.IsA (string name)` - Standard VTK class macros.
- `vtkHandleWidget = obj.NewInstance ()` - Standard VTK class macros.
- `vtkHandleWidget = obj.SafeDownCast (vtkObject o)` - Standard VTK class macros.
- `obj.SetRepresentation (vtkHandleRepresentation r)` - Create the default widget representation if one is not set. By default an instance of vtkPointHandleRepresenation3D is created.
- `obj.CreateDefaultRepresentation ()` - Create the default widget representation if one is not set. By default an instance of vtkPointHandleRepresenation3D is created.
- `obj.SetEnableAxisConstraint (int )` - Enable / disable axis constrained motion of the handles. By default the widget responds to the shift modifier to constrain the handle along the axis closest aligned with the motion vector.
- `int = obj.GetEnableAxisConstraint ()` - Enable / disable axis constrained motion of the handles. By default the widget responds to the shift modifier to constrain the handle along the axis closest aligned with the motion vector.
- `obj.EnableAxisConstraintOn ()` - Enable / disable axis constrained motion of the handles. By default the widget responds to the shift modifier to constrain the handle along the axis closest aligned with the motion vector.
- `obj.EnableAxisConstraintOff ()` - Enable / disable axis constrained motion of the handles. By default the widget responds to the shift modifier to constrain the handle along the axis closest aligned with the motion vector.
- `obj.SetAllowHandleResize (int )` - Allow resizing of handles ? By default the right mouse button scales the handle size.
- `int = obj.GetAllowHandleResize ()` - Allow resizing of handles ? By default the right mouse button scales the handle size.
- `obj.AllowHandleResizeOn ()` - Allow resizing of handles ? By default the right mouse button scales the handle size.
- `obj.AllowHandleResizeOff ()` - Allow resizing of handles ? By default the right mouse button scales the handle size.
- `int = obj.GetWidgetState ()` - Get the widget state.