# layerEffect(_:maxSampleOffset:isEnabled:) Returns a new view that applies `shader` to `self` as a filter on the raster layer created from `self`. ``` nonisolated func layerEffect(_ shader: Shader, maxSampleOffset: CGSize, isEnabled: Bool = true) -> some View ``` ## Parameters `shader` The shader to apply as a layer effect. `maxSampleOffset` If the shader function samples from the layer at locations not equal to the destination position, this value must specify the maximum sampling distance in each axis, for all source pixels. `isEnabled` Whether the effect is enabled or not. ## Return Value A new view that renders `self` with the shader applied as a distortion effect. ## Discussion For a shader function to act as a layer effect it must have a function signature matching: ``` [[ stitchable ]] half4 name(float2 position, SwiftUI::Layer layer, args...) ``` where `position` is the user-space coordinates of the destination pixel applied to the shader, and `layer` is a subregion of the rasterized contents of `self`. `args...` should be compatible with the uniform arguments bound to `shader`. The `SwiftUI::Layer` type is defined in the `` header file. It exports a single `sample()` function that returns a linearly-filtered pixel value from a position in the source content, as a premultiplied RGBA pixel value: ``` namespace SwiftUI { struct Layer { half4 sample(float2 position) const; }; }; ``` The function should return the color mapping to the destination pixel, typically by sampling one or more pixels from `layer` at location(s) derived from `position` and them applying some kind of transformation to produce a new color. > Important: Views backed by AppKit or UIKit views may not > render into the filtered layer. Instead, they log a warning > and display a placeholder image to highlight the error. --- 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)