---
title: "vImageUnpremultiplyData_RGBAFFFF(_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/vimageunpremultiplydata_rgbaffff(_:_:_:)"
---

# vImageUnpremultiplyData_RGBAFFFF(_:_:_:)

Transforms a 32-bit-per-channel, 4-channel RGBA buffer from premultiplied alpha format to nonpremultiplied alpha format.

## Declaration

```swift
func vImageUnpremultiplyData_RGBAFFFF(_ src: UnsafePointer<vImage_Buffer>, _ dest: UnsafePointer<vImage_Buffer>, _ flags: vImage_Flags) -> vImage_Error
```

## Parameters

- `src`: The source vImage buffer.
- `dest`: A pointer to the destination vImage buffer structure. You’re responsible for filling out the doc://com.apple.accelerate/documentation/Accelerate/vImage_Buffer/height, doc://com.apple.accelerate/documentation/Accelerate/vImage_Buffer/width, and doc://com.apple.accelerate/documentation/Accelerate/vImage_Buffer/rowBytes fields of this structure, and for allocating a data buffer of the appropriate size. On return, the data buffer this structure points to contains the destination image data. When you no longer need the data buffer, deallocate the memory to prevent memory leaks.
- `flags`: The options to use when performing the operation. If your code implements its own tiling or its own multithreading, pass doc://com.apple.accelerate/documentation/Accelerate/kvImageDoNotTile; otherwise, pass doc://com.apple.accelerate/documentation/Accelerate/kvImageNoFlags.

## Return Value

Return Value kvImageNoError; otherwise, one of the error codes in Data Types and Constants.

## Discussion

Discussion This function divides color channels by the alpha channel using the following code: float destColor = destColor / alpha; float destAlpha = alpha;

## See Also

### Related Documentation

- [Compositing images with alpha blending](accelerate/compositing-images-with-alpha-blending.md)

### Converting from premultiplied to unpremultiplied format

- [vImageUnpremultiplyData_Planar8(_:_:_:_:)](accelerate/vimageunpremultiplydata_planar8(_:_:_:_:).md)
- [vImageUnpremultiplyData_PlanarF(_:_:_:_:)](accelerate/vimageunpremultiplydata_planarf(_:_:_:_:).md)
- [vImageUnpremultiplyData_ARGB8888(_:_:_:)](accelerate/vimageunpremultiplydata_argb8888(_:_:_:).md)
- [vImageUnpremultiplyData_RGBA8888(_:_:_:)](accelerate/vimageunpremultiplydata_rgba8888(_:_:_:).md)
- [vImageUnpremultiplyData_ARGB16U(_:_:_:)](accelerate/vimageunpremultiplydata_argb16u(_:_:_:).md)
- [vImageUnpremultiplyData_RGBA16U(_:_:_:)](accelerate/vimageunpremultiplydata_rgba16u(_:_:_:).md)
- [vImageUnpremultiplyData_RGBA16F(_:_:_:)](accelerate/vimageunpremultiplydata_rgba16f(_:_:_:).md)
- [vImageUnpremultiplyData_ARGB16Q12(_:_:_:)](accelerate/vimageunpremultiplydata_argb16q12(_:_:_:).md)
- [vImageUnpremultiplyData_RGBA16Q12(_:_:_:)](accelerate/vimageunpremultiplydata_rgba16q12(_:_:_:).md)
- [vImageUnpremultiplyData_ARGBFFFF(_:_:_:)](accelerate/vimageunpremultiplydata_argbffff(_:_:_:).md)