# overwriteChannels(_:withPixel:destination:) Overwrites the pixels of one or more channels of the pixel buffer with the provided 32-bit, 4-channel pixel value. ``` func overwriteChannels(_ channels: [UInt8], withPixel pixel: Pixel_FFFF, destination: vImage.PixelBuffer) ``` ## Parameters `channels` An array that contains the indices of the channels that the function overwrites. `pixel` The value that the function writes to the channels. `destination` The destination pixel buffer. ## Discussion Use this function to overwrite one or more channels of an interleaved buffer with a pixel value. The following code overwrites channels `1` and `3` with the corresponding channels in `pixel` : ```swift let pixelValues: [Pixel_F] = [ 1, 2, 3, 4, 5, 6, 7, 8 ] let buffer = vImage.PixelBuffer(pixelValues: pixelValues, size: vImage.Size(width: 1, height: 2), pixelFormat: vImage.InterleavedFx4.self) let destination = vImage.PixelBuffer(size: vImage.Size(width: 1, height: 2), pixelFormat: vImage.InterleavedFx4.self) let pixel = Pixel_FFFF(101, 102, 103, 104) buffer.overwriteChannels([3, 1], withPixel: pixel, destination: destination) ``` On return, `destination.array` contains the following values: ```swift [ 1, 102, 3, 104, 5, 102, 7, 104 ] ``` --- 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)