# overwriteChannels(_:withPlanarBuffer:destination:) Overwrites the pixels of one or more channels of the pixel buffer with the provided 32-bit planar pixel buffer. ``` func overwriteChannels(_ channels: [UInt8], withPlanarBuffer buffer: vImage.PixelBuffer, destination: vImage.PixelBuffer) ``` ## Parameters `channels` An array that contains the indices of the channels that the function overwrites. `buffer` The planar buffer 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 planar buffer. The following code overwrites channels `1` and `3` with the values in `overwriteValues`: ```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.Interleaved8x4.self) let destination = vImage.PixelBuffer(size: vImage.Size(width: 1, height: 2), pixelFormat: vImage.Interleaved8x4.self) let overwriteValues: [Pixel_F] = [ 101, 102 ] let overwriteBuffer = vImage.PixelBuffer(pixelValues: overwriteValues, size: vImage.Size(width: 1, height: 2)) buffer.overwriteChannels([3, 1], withPlanarBuffer: overwriteBuffer, destination: destination) ``` On return, `destination.array` contains the following values: ```swift [ 1, 101, 3, 101, 5, 102, 7, 102 ] ``` --- 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)