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# Gamma function types

Types of full- or half-precision gamma functions.

## Topics

### User-defined gamma values

[`var kvImageGamma_UseGammaValue: Int`](/documentation/Accelerate/kvImageGamma_UseGammaValue)

A user-defined gamma value with full-precision calculation.

[`var kvImageGamma_UseGammaValue_half_precision: Int`](/documentation/Accelerate/kvImageGamma_UseGammaValue_half_precision)

A user-defined gamma value with half-precision calculation.

### Constant gamma values

[`var kvImageGamma_BT709_forward_half_precision: Int`](/documentation/Accelerate/kvImageGamma_BT709_forward_half_precision)

The ITU-R BT.709 standard.

[`var kvImageGamma_BT709_reverse_half_precision: Int`](/documentation/Accelerate/kvImageGamma_BT709_reverse_half_precision)

The ITU-R BT.709 standard reverse.

[`var kvImageGamma_sRGB_forward_half_precision: Int`](/documentation/Accelerate/kvImageGamma_sRGB_forward_half_precision)

A half-precision calculation using the sRGB standard gamma value of 2.2.

[`var kvImageGamma_sRGB_reverse_half_precision: Int`](/documentation/Accelerate/kvImageGamma_sRGB_reverse_half_precision)

A half-precision calculation using the sRGB standard gamma value of 1/2.2.

[`var kvImageGamma_5_over_9_half_precision: Int`](/documentation/Accelerate/kvImageGamma_5_over_9_half_precision)

A half-precision calculation using a gamma value of 5/9 or 1/1.8.

[`var kvImageGamma_5_over_11_half_precision: Int`](/documentation/Accelerate/kvImageGamma_5_over_11_half_precision)

A half-precision calculation using a gamma value of 5/11 or 1/2.2.

[`var kvImageGamma_9_over_5_half_precision: Int`](/documentation/Accelerate/kvImageGamma_9_over_5_half_precision)

A half-precision calculation using a gamma value of 9/5 or 1.8.

[`var kvImageGamma_9_over_11_half_precision: Int`](/documentation/Accelerate/kvImageGamma_9_over_11_half_precision)

A half-precision calculation using a gamma value of 9/11 or (9/5)/(11/5).

[`var kvImageGamma_11_over_5_half_precision: Int`](/documentation/Accelerate/kvImageGamma_11_over_5_half_precision)

A half-precision calculation using a gamma value of 11/5 or 2.2.

[`var kvImageGamma_11_over_9_half_precision: Int`](/documentation/Accelerate/kvImageGamma_11_over_9_half_precision)

A half-precision calculation using a gamma value of 11/9 or (11/5)/(9/5).


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