struct · iOS 17.0+ · SDK 27.1
struct ShaderA reference to a function in a Metal shader library, along with its bound uniform argument values. Shader values can be used as filter effects on views, see the ``View/colorEffect(_:isEnabled:)``, ``View/distortionEffect(_:maxSampleOffset:isEnabled:)``, and ``View/layerEffect(_:maxSampleOffset:isEnabled:)`` functions. Shaders also conform to the ``ShapeStyle`` protocol, letting their MSL shader function provide per-pixel color to fill any shape or text view. For a shader function to act as a fill pattern it must have a function signature matching: [[ stitchable ]] half4 name(float2 position, args...) where `position` is the user-space coordinates of the pixel applied to the shader, and `args...` should be compatible with the uniform arguments bound to `shader`. The function should return the premultiplied color value in the color space of the destination (typically extended sRGB).
get dithersColor(): booleanvar dithersColor: Bool { get set }For shader functions that return color values, whether the returned color has dither noise added to it, or is simply rounded to the output bit-depth. For shaders generating smooth gradients, dithering is usually necessary to prevent visible banding in the result.
set dithersColor(value: boolean)var dithersColor: Bool { get set }For shader functions that return color values, whether the returned color has dither noise added to it, or is simply rounded to the output bit-depth. For shaders generating smooth gradients, dithering is usually necessary to prevent visible banding in the result.
compile(type: Shader_UsageType): Promise<void>func compile(as type: Shader.UsageType) async throwsAttempts to asynchronously compile a shader function, to minimize the chance of stalling when it is first used for rendering. Before being available for rendering each shader must be compiled for the current GPU. By default this happens on first use, but that may cause that frame to be delayed waiting for the compiler, i.e. cause a visible "glitch" in animations. Calling this method for each shader before it's first used allows the necessary compilation to happen ahead of time, eliminating the delay on the first actual use (provided `compile()` completes before the first use of the shader). For compilation to be successful the specified usage type must match how the shader is eventually used to render, and its current argument values must match the types of the arguments used when rendering (however array and data sizes may be empty). For example, to compile a fill shader asynchronously when your app launches: Task { let shader = ShaderLibrary.example(.color(.clear), .float(0)) try! await shader.compile(as: .shapeStyle) } Here the MSL shader function `example` takes two uniform arguments: a color and a numeric value. The placeholder values are replaced with actual values when using the shader, in this case to fill a circle: Circle().fill( ShaderLibrary.example(.color(.orange), .float(32))) - Parameter type: how the shader will eventually be used. - Throws: an error describing why compilation failed.
static init(function_: ShaderFunction, arguments_: Array<Shader_Argument>): Shaderinit(function: ShaderFunction, arguments: [Shader.Argument])Creates a new shader from a function and the uniform argument values to bind to the function.
get function(): ShaderFunctionvar function: ShaderFunctionThe shader function called by the shader.
set function(value: ShaderFunction)var function: ShaderFunctionThe shader function called by the shader.
get arguments(): Array<Shader_Argument>var arguments: [Shader.Argument]The uniform argument values passed to the shader function.
set arguments(value: Array<Shader_Argument>)var arguments: [Shader.Argument]The uniform argument values passed to the shader function.
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