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# CVImageTransferFunction

The transfer function describes the tonality of an image for use in color matching operations.
This value is used along with a color primaries gamut [`CVImageColorPrimaries`](/documentation/CoreVideo/CVImageColorPrimaries). Most apps should use the
[`CVImageTransferFunction.itu_R_709_2`](/documentation/CoreVideo/CVImageTransferFunction/itu_R_709_2) transfer function.

```
enum CVImageTransferFunction
```

## Topics

### Enumeration Cases

[`case itu_R_2020`](/documentation/CoreVideo/CVImageTransferFunction/itu_R_2020)

The transfer function for HDR video specified in ITU-R BT2020 standard.

[`case itu_R_2100_HLG`](/documentation/CoreVideo/CVImageTransferFunction/itu_R_2100_HLG)

The transfer function for HDR video specified in ITU-R BT2020 HLG standard.

[`case itu_R_709_2`](/documentation/CoreVideo/CVImageTransferFunction/itu_R_709_2)

The default transfer function for high-definition and standard-definition video.

[`case linear`](/documentation/CoreVideo/CVImageTransferFunction/linear)

[`case sRGB`](/documentation/CoreVideo/CVImageTransferFunction/sRGB)

The standard transfer function for web and desktop publishing.

[`case smpte_240M_1995`](/documentation/CoreVideo/CVImageTransferFunction/smpte_240M_1995)

The transfer function for HDTV interim video.

[`case smpte_ST_2084_PQ`](/documentation/CoreVideo/CVImageTransferFunction/smpte_ST_2084_PQ)

The transfer function for mapping HDR gamma to absolute light levels.

[`case smpte_ST_428_1`](/documentation/CoreVideo/CVImageTransferFunction/smpte_ST_428_1)

The transfer function for digital cinema distribution master.

[`case useGamma`](/documentation/CoreVideo/CVImageTransferFunction/useGamma)

The transfer function that’s defined by the gamma level value of the image buffer.

## Relationships

### Conforms To

[`CVAttachmentValueRepresentable`](/documentation/CoreVideo/CVAttachmentValueRepresentable)

[`Copyable`](/documentation/Swift/Copyable)

[`Equatable`](/documentation/Swift/Equatable)

[`Sendable`](/documentation/Swift/Sendable)

[`Escapable`](/documentation/Swift/Escapable)

[`Hashable`](/documentation/Swift/Hashable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

---

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