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Inside Macintosh: Advanced Color Imaging Reference /

Chapter 3 - ColorSync Manager Reference for Applications and Device Drivers / Constants and Data Types

Color Values

Fixed XYZ Color Value

ColorSync uses the CMFixedXYZColor data type to specify the profile illuminant in the profile header's white field and to specify other profile element values. Color component values defined by the Fixed type definition can be used to specify a color value in the XYZ color space with greater precision than a color whose components are expressed as CMXYZComponent data types. The Fixed data type is a signed 32-bit value. A color value expressed in the XYZ color space whose color components are of type Fixed is defined by the CMFixedXYZColor type definition.

Your application can convert colors defined in the XYZ color space between CMXYZColor data types (in which the color components are expressed as 16-bit unsigned values) and CMFixedXYZColor data types (in which the colors are expressed as 32-bit signed values). To convert color values, you use the CMConvertFixedXYZToXYZ function (page 3-152) and the CMXYZToFixedXYZ function (page 3-151).

struct CMFixedXYZColor {
   Fixed X; /* Fixed X component of color in XYZ color space */
   Fixed Y; /* Fixed Y component of color in XYZ color space */
   Fixed Z; /* Fixed Z component of color in XYZ color space */
};