Application-Defined Routines
This section describes the I/O methods you can implement to handle a custom object type. Your custom methods are reported to QuickDraw 3D by your object metahandler. This section also describes how to write a file idler callback routine.
These I/O methods define how QuickDraw 3D handles your custom objects when reading them from or writing them to a metafile. Each distinct object in a metafile consists of a root object that determines the object's type and default data. Some types of objects can have child objects attached to them, which add information to the parent object or override the parent's default data. A parent object and its child (or children) are encapsulated in a container, the first object in which is always the parent object.
- Note
- For information about defining an object metahandler and about the basic methods for handling custom objects, see the chapter "QuickDraw 3D Objects."
To read a custom object from a file, you need to define a read data method for the custom object. To write a custom object to a file, you need to define two I/O methods for the custom object: a traversal method and a write method.