# init(device:linearGrayColorTransform:) Initializes a Sobel filter on a given device using a specific color transform. ``` init(device: any MTLDevice, linearGrayColorTransform transform: UnsafePointer) ``` ## Parameters `device` The Metal device the filter will run on. `transform` The color transform to use. This matrix is an array of 3 floats that describes the RGB-to-grayscale color transform: `Luminance = transform[0] * pixel.x + transform[1] * pixel.y + transform[2] * pixel.z` ## Return Value An initialized Sobel filter object. --- 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)