---
title: sourceAlpha
framework: metalperformanceshaders
role: symbol
role_heading: Instance Property
path: metalperformanceshaders/mpsimageconversion/sourcealpha
---

# sourceAlpha

Premultiplication description for the source texture.

## Declaration

```swift
var sourceAlpha: MPSAlphaType { get }
```

## Discussion

Discussion Most color space conversion operations can not work directly on premultiplied data. Use this property to tag premultiplied data so that the source texture can be un-premultiplied prior to the application of these transforms. The default value is MPSAlphaType.alphaIsOne.

## See Also

### Properties

- [destinationAlpha](metalperformanceshaders/mpsimageconversion/destinationalpha.md)