# withUnsafePixelBuffer(at:_:) Calls the given closure with the pixel buffer that references the individual plane at the given index. ``` func withUnsafePixelBuffer(at index: Int, _ body: (vImage.PixelBuffer) throws -> R) rethrows -> R ``` ## Parameters `index` The index of the plane. `body` A closure with a [`vImage.PixelBuffer`](/documentation/Accelerate/vImage/PixelBuffer) parameter that points to the underlying pixel buffer at the given index. ## Return Value The return value, if any, of the body closure parameter. ## Discussion Use this function to access a single planar pixel buffer from a multiple-plane pixel buffer. For example, the following code converts the 8-bit pixels at plane `2` to 32-bit and writes the result to `dest`: ```swift let src = vImage.PixelBuffer(size: vImage.Size(width: 32, height: 64)) let dest = vImage.PixelBuffer(size: src.size) src.withUnsafePixelBuffer(at: 2) { vImageBuffer in vImageBuffer.convert(to: dest) } ``` --- 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)