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# CGGammaValue

A value used to map a color generated in software to a color supported by the display hardware.

```
typealias CGGammaValue = Float
```

## Discussion

In macOS, the Display panel in System Preferences is used to set the default gamma for a display. Quartz also allows an application to provide its own custom gamma information, using functions such as [`CGSetDisplayTransferByTable(_:_:_:_:_:)`](/documentation/CoreGraphics/CGSetDisplayTransferByTable(_:_:_:_:_:)) and [`CGSetDisplayTransferByFormula(_:_:_:_:_:_:_:_:_:_:)`](/documentation/CoreGraphics/CGSetDisplayTransferByFormula(_:_:_:_:_:_:_:_:_:_:)).

These functions take `CGGammaValue` arguments that specify:

- A set of gamma table entries ranging from 0 to 1
- The positive real coefficients in a gamma equation

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