Inside Macintosh: QuickDraw GX Objects /

Chapter 4 - Colors and Color-Related Objects

About Color Profile Objects

A color profile is a QuickDraw GX object that describes the color response of a specific device, class of device, or device configuration. As described in the section "Color Profiles" beginning on page 4-28, a color profile provides a quantitative description
of a device's color gamut in terms of standard, usually device-independent colors. QuickDraw GX uses color profiles for color matching when converting colors and when drawing shapes.

QuickDraw GX identifies a color profile object through a color profile reference. To obtain information about a color profile, you must send its reference as a parameter to a QuickDraw GX function (except that you can determine if two references identify the same color profile object simply by comparing them for equality, and you can examine a reference to see if it is nil).

Any QuickDraw GX color (gxColor structure), such as the color in a shape's ink object, can include a reference to a color profile object. Any bitmap structure, including the bitmap in a view device object, can reference a color profile. (View devices are described in the chapter "View-Related Objects" in this book.) A transfer mode structure can
also reference a color profile. If a color, bitmap, or transfer mode contains no specific reference to a color profile, QuickDraw GX uses a default profile when converting colors and when drawing.

Even though color profiles are inherently device-specific, QuickDraw GX uses them consistently and performs color matching when needed. Most applications need not pay attention to color profiles or try to associate them with specific devices except when first creating colors. If you create a color, you should attach to it a color profile that describes the characteristics of the device on which the color was created. If the device's characteristics are equivalent to the Apple 13-inch color monitor--or if you never need to display or print the color on another device--you need not attach a profile.

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Subtopics

Color Profile Properties

Profile Data

The Default Color Profile

Zero-Length Profiles