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): <pre> 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 </pre>

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: <pre> 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 </pre>

In turn, when these widget events are processed, the vtkHandleWidget invokes the following VTK events on itself (which observers can listen for): <pre> vtkCommand::StartInteractionEvent (on vtkWidgetEvent::Select) vtkCommand::EndInteractionEvent (on vtkWidgetEvent::EndSelect) vtkCommand::InteractionEvent (on vtkWidgetEvent::Move) </pre>

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.