# vImageHistogramCalculation_ARGB8888(_:_:_:) Calculates the histogram of an 8-bit-per-channel, 4-channel interleaved buffer. ``` func vImageHistogramCalculation_ARGB8888(_ src: UnsafePointer, _ histogram: UnsafeMutablePointer?>, _ flags: vImage_Flags) -> vImage_Error ``` ## Parameters `src` The source vImage buffer. `histogram` An array of four collections that contain 256 elements that receive the histogram data. `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 calculate the alpha channel histogram, set the [`kvImageLeaveAlphaUnchanged`](/documentation/Accelerate/kvImageLeaveAlphaUnchanged) flag. ## Return Value [`kvImageNoError`](/documentation/Accelerate/kvImageNoError); otherwise, one of the error codes in . ## Discussion The following code populates the `histogramAlpha` , `histogramRed`, `histogramGreen`, and `histogramBlue` arrays with the histograms for each channel of the specified [`vImage_Buffer`](/documentation/Accelerate/vImage_Buffer) structure. ```swift var histogramAlpha = [vImagePixelCount](repeating: 0, count: 256) var histogramRed = [vImagePixelCount](repeating: 0, count: 256) var histogramGreen = [vImagePixelCount](repeating: 0, count: 256) var histogramBlue = [vImagePixelCount](repeating: 0, count: 256) histogramAlpha.withUnsafeMutableBufferPointer { zeroPtr in histogramRed.withUnsafeMutableBufferPointer { onePtr in histogramGreen.withUnsafeMutableBufferPointer { twoPtr in histogramBlue.withUnsafeMutableBufferPointer { threePtr in var histogramBins = [zeroPtr.baseAddress, onePtr.baseAddress, twoPtr.baseAddress, threePtr.baseAddress] histogramBins.withUnsafeMutableBufferPointer { histogramBinsPtr in // `buffer` is a `vImage_Buffer` structure. _ = vImageHistogramCalculation_ARGB8888(&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)