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# vImageCVImageFormat_SetAlphaHint(_:_:)

Sets the alpha hint of a Core Video image format.

```
func vImageCVImageFormat_SetAlphaHint(_ format: vImageCVImageFormat, _ alphaIsOne: Int32) -> vImage_Error
```

## Parameters

`format`

The Core Video image format to update.

`alphaIsOne`

The new value of the alpha hint.

## Return Value

[`kvImageNoError`](/documentation/Accelerate/kvImageNoError); otherwise, one of the error codes in <doc://com.apple.documentation/documentation/Accelerate/data-types-and-constants>.

## Discussion

When an image format contains an alpha channel, but the image is fully opaque, set this property to a nonzero value.

## See Also

[`alphaIsOpaqueHint`](/documentation/Accelerate/vImageCVImageFormat/alphaIsOpaqueHint)

The alpha hint of the Core Video image format.


---

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