---
title: "vImageHistogramSpecification_ARGB8888(_:_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/vimagehistogramspecification_argb8888(_:_:_:_:)"
---

# vImageHistogramSpecification_ARGB8888(_:_:_:_:)

Specifies the histogram of an 8-bit-per-channel, 4-channel interleaved buffer.

## Declaration

```swift
func vImageHistogramSpecification_ARGB8888(_ src: UnsafePointer<vImage_Buffer>, _ dest: UnsafePointer<vImage_Buffer>, _ desired_histogram: UnsafeMutablePointer<UnsafePointer<vImagePixelCount>?>, _ 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.
- `desired_histogram`: The histograms that the operation applies to the source buffer.
- `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. To specify that the function doesn’t apply the operation to the alpha channel, set the doc://com.apple.accelerate/documentation/Accelerate/kvImageLeaveAlphaUnchanged flag.

## Return Value

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

## Discussion

Discussion Use this function to apply a histogram — that you’ve generated using vImageHistogramSpecification_ARGBFFFF(_:_:_:_:_:_:_:_:) — to each channel of another image. The following code applies a histogram to a 4-channel interleaved vImage buffer: // `histogramAlpha`, `histogramRed`, `histogramGreen`, and `histogramBlue` are `entryCount` element arrays. histogramAlpha.withUnsafeBufferPointer { zeroPtr in     histogramRed.withUnsafeBufferPointer { onePtr in         histogramGreen.withUnsafeBufferPointer { twoPtr in             histogramBlue.withUnsafeBufferPointer { threePtr in                                  var histogramBins = [zeroPtr.baseAddress, onePtr.baseAddress,                                      twoPtr.baseAddress, threePtr.baseAddress]                                  histogramBins.withUnsafeMutableBufferPointer { histogramBinsPtr in                     // `buffer` is a `vImage_Buffer` structure                     _ = vImageHistogramSpecification_ARGB8888(&buffer, &buffer,                                                               histogramBinsPtr.baseAddress!,                                                               vImage_Flags(kvImageNoFlags))                 }             }         }     } }

## See Also

### Related Documentation

- [Enhancing image contrast with histogram manipulation](accelerate/enhancing-image-contrast-with-histogram-manipulation.md)
- [Specifying histograms with vImage](accelerate/specifying-histograms-with-vimage.md)

### Specifying a histogram

- [vImageHistogramSpecification_Planar8(_:_:_:_:)](accelerate/vimagehistogramspecification_planar8(_:_:_:_:).md)
- [vImageHistogramSpecification_PlanarF(_:_:_:_:_:_:_:_:)](accelerate/vimagehistogramspecification_planarf(_:_:_:_:_:_:_:_:).md)
- [vImageHistogramSpecification_ARGBFFFF(_:_:_:_:_:_:_:_:)](accelerate/vimagehistogramspecification_argbffff(_:_:_:_:_:_:_:_:).md)