Object Type

Every metafile object has a type. In a text file, an object type is expressed by a character string, such as Polygon . In a binary file, an object type is expressed by a 4-byte code, such as plyg . In both text and binary files, every object specification begins with an object type.

The metafile file format allows you to introduce new types of custom objects. A new type can be introduced anywhere in a file, so long as its format, and the locations of its occurrences, meet the basic conditions described in this document. For Version 1.5 of the Metafile specification, in binary files only, if the binary 4-byte code is <= -1, then the first occurrence of the 4-byte code must be preceded by a Type object. The Type object establishes a correlation between the character string encoding of the type and the 4-byte code. In Version 1.5, the 4-byte code is dynamically allocated on a per-metafile basis, and may vary from metafile to metafile. It is the character string encoding of the type that remains fixed. See "Types" .

The following section contains an example of an object type.

---

© 1997 Apple Computer, Inc.

Previous | QD3D Book | Overview | Chapter Contents | Next |