Chapter 17. Draggers and Manipulators

Chapter Objectives. After reading this chapter, you'll be able to do the following:

  • Connect draggers to fields or engines in the scene graph

  • Explain the difference between a dragger and a manipulator

  • Write callback functions that are performed when interaction starts or finishes, when the mouse moves, or when the value in a dragger's field changes

  • Use manipulators in your application to allow the user to edit nodes in the scene graph directly

  • Customize the appearance of a dragger

This chapter describes how to use draggers and manipulators, which are special objects in the scene graph that have a user interface and respond to events. Manipulators, such as the handle box, trackball, and directional light manipulator, are nodes that employ draggers to enable the user to interact with them and edit them. For information on how draggers receive and respond to events, see Chapter 10, Handling Events and Selection.