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# dictionaryRepresentation(forAuxiliaryDataType:)

Returns a dictionary of primitive map information to use when writing an image file with a semantic segmentation matte.

```
func dictionaryRepresentation(forAuxiliaryDataType outAuxDataType: AutoreleasingUnsafeMutablePointer<NSString?>?) -> [AnyHashable : Any]?
```

## Parameters

`outAuxDataType`

On output, the auxiliary data type to be used when calling the ImageIO framework’s <doc://com.apple.documentation/documentation/ImageIO/CGImageDestinationAddAuxiliaryDataInfo(_:_:_:)> function. Currently supported auxiliary data types are enumerated in `CGImageProperties`.

## Return Value

A dictionary of `CGImageDestination`-compatible semantic segmentation matte information, or `nil` if the auxiliary data type is unsupported.

## Discussion

---

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