# multiply(by:divisor:preBias:postBias:destination:) Multiplies each pixel in an 8-bit planar pixel buffer by the specified factor. ``` func multiply(by factor: Int, divisor: Int, preBias: Int, postBias: Int, destination: vImage.PixelBuffer) ``` ## Parameters `factor` The multiplication factor. `divisor` A value that the function divides the result by. The function treats `0` as `1`. `preBias` A value that the function adds to the source before multiplication. `postBias` A value that the function adds to the result after multiplication. `destination` The destination pixel buffer. ## Discussion This function applies the following operation to each pixel: ```swift destination = (((source + preBias) * factor) + postBias) / divisor ``` For example, the following code multiplies each pixel value in an 8-bit planar buffer by `2` and adds `5`: ```swift let buffer = vImage.PixelBuffer( pixelValues: [10, 20, 30, 40, 50, 60, 70, 80], size: vImage.Size(width: 4, height: 2)) buffer.multiply(by: 2, divisor: 1, preBias: 0, postBias: 5, destination: buffer) // Prints // [ 25, 45, 65, 85, // 105, 125, 145, 165 ] print(buffer.array) ``` --- 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)