# vImageHistogramSpecification_ARGB8888(_:_:_:_:) Specifies the histogram of an 8-bit-per-channel, 4-channel interleaved buffer. ``` func vImageHistogramSpecification_ARGB8888(_ src: UnsafePointer, _ dest: UnsafePointer, _ desired_histogram: UnsafeMutablePointer?>, _ 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 [`height`](/documentation/Accelerate/vImage_Buffer/height), [`width`](/documentation/Accelerate/vImage_Buffer/width), and [`rowBytes`](/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 [`kvImageDoNotTile`](/documentation/Accelerate/kvImageDoNotTile); otherwise, pass [`kvImageNoFlags`](/documentation/Accelerate/kvImageNoFlags). To specify that the function doesn’t apply the operation to the alpha channel, set the [`kvImageLeaveAlphaUnchanged`](/documentation/Accelerate/kvImageLeaveAlphaUnchanged) flag. ## Return Value [`kvImageNoError`](/documentation/Accelerate/kvImageNoError); otherwise, one of the error codes in . ## Discussion Use this function to apply a histogram — that you’ve generated using [`vImageHistogramSpecification_ARGBFFFF(_:_:_:_:_:_:_:_:)`](/documentation/Accelerate/vImageHistogramSpecification_ARGBFFFF(_:_:_:_:_:_:_:_:)) — to each channel of another image. The following code applies a histogram to a 4-channel interleaved vImage buffer: ```swift // `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 --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)