Structure

vImageTransferFunction

A structure that represents a transfer function to convert from linear to nonlinear RGB.

Declaration

typedef struct vImageTransferFunction {
    ...
} vImageTransferFunction;

Overview

The transfer function here is defined in the style of ITU-R BT.709 and is the inverse operation of what appears in an ICC color profile.

The conversion is:

if (R >= cutoff) {
    R' = c0 * pow( c1 * R + c2, gamma ) + c3
} 
else {
    R' = c4 * R + c5                             
}

Topics

Transfer Function Properties

c0

The c0 in the transfer function.

c1

The c1 in the transfer function.

c2

The c2 in the transfer function.

c3

The c3 in the transfer function.

cutoff

The cutoff in the transfer function.

gamma

The gamma in the transfer function.

c4

The c4 in the transfer function.

c5

The c5 in the transfer function.

See Also

Creating Core Graphics Image Formats

vImage_CGImageFormat

The description of a Core Graphics image.

vImageCreateRGBColorSpaceWithPrimariesAndTransferFunction

Creates an RGB color space based on primitives typically found in Y'CbCr specifications.

vImageRGBPrimaries

A structure that represents the chromaticity of primaries defining a color space.

vImageCreateMonochromeColorSpaceWithWhitePointAndTransferFunction

Creates a monochrome color space based on primitives typically found in Y'CbCr specifications.

vImageWhitePoint

A structure that represents a white point according to the CIE 1931 color space.