Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 7 - QuickDraw GX Stream Format

About QuickDraw GX Stream Format

A QuickDraw GX data stream is a highly structured sequence of bytes that contains all of the information required to store, print, or display QuickDraw GX objects.

QuickDraw GX provides a simple method for creating and interpreting a QuickDraw GX data stream for shape objects. The GXFlattenShape function creates the data stream and the GXUnflattenShape function reconstructs objects from the data stream that the GXFlattenShape function previously created.

When the GXFlattenShape function converts shape objects created by your application from their original format to a QuickDraw GX stream format, the shape is said to be flattened. When the GXUnFlattenShape function interprets the data stream of a flattened shape, the shape is said to be unflattened.

If QuickDraw GX is available and you need to flatten and unflatten QuickDraw GX shapes, you just use the GXFlattenShape and GXUnflattenShape functions. If QuickDraw GX is not available and you need to unflatten a flattened shape, then you need to create an interpreter for the QuickDraw GX data stream that was created when the shape was flattened. The interpreter must be compatible with your current working environment.

Your interpreter needs to parse the data of the QuickDraw GX data stream to extract the original meaning. The format of the data stream is public. This section describes the data stream format and its use in print files and portable digital documents.

In addition to the GXFlattenShape and GXUnflattenShape functions that create and interpret the QuickDraw GX stream format for shapes, there are other flatten and unflatten functions that perform flattening and unflattening operations on job objects, job objects in a handle, collection objects, and fonts. These functions are not directly related to the stream format.

The GXFlattenJob and GXUnFlattenJob functions provide your application with a mechanism for flattening and unflattening all information associated with a job object by specifying a pointer to a flattening function. For more information on these functions, see the chapters "QuickDraw GX Printing" and "Core Printing Features" in Inside Macintosh: QuickDraw GX Printing.

The GXFlattenJobToHdl and GXUnflattenCollectionFromHdl functions provides your application with a means of flattening and unflattening all information associated with a job object in a handle. For more information on these functions, see the chapters "Introduction to Printing with QuickDraw GX" and "Core Printing Features" of Inside Macintosh: QuickDraw GX Printing.

The GXFlattenCollection and GXUnflattenCollection functions flatten and unflatten information in a collection object. For more information on this function, see the chapter "Collection Manager" in this book.

The GXFlattenFont function flattens a font so that it can be included in a flattened shape. The GXFlattenFont function is described in the chapter "Font Objects" in Inside Macintosh: QuickDraw GX Typography.

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Subtopics

Characteristics

Stream Design

Operation Opcode Byte

Data Type Opcode Byte

Data