Inside Macintosh: QuickTime Components /

Chapter 4 - Image Compressor Components

This chapter discusses the attributes of image compressor components and the functional interfaces these components must support. An image compressor component is a code resource that provides compression or decompression services for image data. Throughout this chapter, the term image compressor component is used to describe both compressor and decompressor components.

Note

The information in this chapter is intended for developers of image compressor components. Application developers normally do not need to be familiar with this material to use the Image Compression Manager.

This chapter has been divided into the following sections:

• "About Image Compressor Components" presents general information about image compressor components.
• "Using Image Compressor Components" discusses how the Image Compression Manager uses image compressor components to compress and decompress images.
• "Image Compressor Components Reference" describes the data structures used by the Image Compression Manager to communicate with image compressor components. It also provides a comprehensive reference to the functions that your image compressor component must support.
• "Summary of Image Compressor Components" presents a summary of image compressor components in C and in Pascal.

If you are developing an image compressor component, you should read all the material in this chapter. In addition, you should read the appropriate sections of the chapter "Component Manager" in Inside Macintosh: More Macintosh Toolbox.

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Chapter Contents

About Image Compressor Components

Banding and Extending Images

Spooling of Compressed Data

Data Loading

Data Unloading

Compressing or Decompressing Images Asynchronously

Progress Functions

Using Image Compressor Components

Performing Image Compression

Choosing a Compressor

Compressing a Horizontal Band of an Image

Decompressing an Image

Choosing a Decompressor

Decompressing a Horizontal Band of an Image

Image Compressor Components Reference

Constants

Image Compressor Component Capabilities

Format of Compressed Data and Files

Data Types

The Compressor Capability Structure

The Compression Parameters Structure

The Decompression Parameters Structure

Functions

Direct Functions

Indirect Functions

Image Compression Manager Utility Functions

Summary of Image Compressor Components

C Summary

Constants

Data Types

Functions

Direct Functions

Indirect Functions

Image Compression Manager Utility Functions

Pascal Summary

Constants

Data Types

Routines

Direct Functions

Indirect Functions

Image Compression Manager Utility Functions

Result Codes