Inside Macintosh: Advanced Color Imaging on the Mac OS /

Chapter 5 - Developing Color Management Modules

This chapter describes how to create a component called a color management module (CMM) to use with the ColorSync Manager instead of or in conjunction with the Apple-supplied default CMM. At a minimum, a CMM created for use with the ColorSync Manager must be able to match colors across color spaces belonging to different base families and check colors expressed in the color gamut of one device against the color gamut of another device.

In addition to the minimum set of requests a CMM must service, a CMM can also implement support for other requests a ColorSync-supportive application or device driver might make. Among the optional services a CMM might provide are verifying if a particular profile contains the base set of required elements for a profile of its type and directing the process of converting profile data embedded in a graphics file to data in an external profile file accessed through a profile reference and vice versa. A CMM can also provide services for PostScript\x89 printers by obtaining or deriving from a profile specific data required by PostScript printers for color-matching processes and returning the data in a format that can be sent to the PostScript printer.

You should read this chapter if you are a third-party developer who creates CMMs for use with version 2.x of the ColorSync Manager.

This chapter gives a brief overview of what a CMM is and the role a CMM plays in the ColorSync Manager color management system (CMS). Before reading this chapter, you should read "Introduction to the ColorSync Manager" (page 3-3) for a more complete conceptual explanation of how a CMM fits within the ColorSync Manager CMS.

This chapter provides a basic structure you can follow in creating a CMM. It provides a high-level discussion of the required and optional ColorSync Manager request codes your CMM might be called to handle, and also describes the Component Manager required request codes to which every component must respond.

For complete details on components and their structure, see the chapter "Component Manager" in Inside Macintosh: More Macintosh Toolbox.

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Chapter Contents

About Color Management Modules

Creating a Color Management Module

Creating a Component Resource for a CMM

How Your CMM Is Called by the Component Manager

Required Component Manager Request Codes

Required ColorSync Manager Request Codes

Optional ColorSync Manager Request Codes

Handling Request Codes

Responding to Required Component Manager Request Codes

Establishing the Environment for a New Component Instance

Releasing Private Storage and Closing the Component Instance

Determining Whether Your CMM Supports a Request

Providing Your CMM Version Number

Responding to ColorSync Manager Required Request Codes

Initializing the Current Component Instance for a Session Involving Two Profiles

Matching a List of Colors to the Destination Profile's Color Space

Checking a List of Colors

Responding to ColorSync Manager Optional Request Codes

Validating That a Profile Meets the Base Content Requirements

Matching the Colors of a Bitmap

Checking the Colors of a Bitmap

Matching the Colors of a Pixel Map Image

Checking the Colors of a Pixel Map Image

Initializing the Component Instance for a Session Using Concatenated Profiles

Creating a Device-Linked Profile and Opening a Reference to It

Obtaining PostScript-Related Data From a Profile

Obtaining the Size of the Color Rendering Dictionary for PostScript Printers

Flattening a Profile for Embedding in a Graphics File

Unflattening a Profile

Supplying Named Color Space Information

Summary of the Color Management Modules

Constants

Functions

Required Functions

Optional Functions