convolve(_:dereference:kernel:)

Converts an image data buffer to a pixel array, using the given pixel kernel and dereferencing function.

static func convolve<A, T, C>(_ buffer: [UInt8], dereference: (Int) -> (A, A, A), kernel: ((T, T, T)) -> C) -> [C] where A : FixedWidthInteger, A : UnsignedInteger, T : FixedWidthInteger, T : UnsignedInteger

Mangled symbol

s3PNGAAO8convolve_11dereference6kernelSayq0_GSays5UInt8VG_x_xxtSiXEq0_q__q_q_t_tXEts17FixedWidthIntegerRzSURzsAJR_SUR_r1_lFZWhat are these?

FNV24: [4SWF6]

Parameters

buffer: An image data buffer.
dereference: A dereferencing function.
kernel: A pixel kernel.

Returns

An array of pixels constructed by the given kernel function. This array has the same number of elements as buffer.

This function casts each byte in buffer to an Int index, and passes each index to the given dereference function, receiving triplets of atoms of type A in return. It then scales the atoms to the range of T, and constructs instances of C by mapping the given kernel function over each (T, T, T) triplet.

A worked example of how to use this function to implement a custom color target can be found in the custom color targets tutorial.

Other members in extension

Protocols

protocol BytestreamDestination
A destination bytestream.
protocol BytestreamSource
A source bytestream.
protocol Color<Aggregate>
A color target.
protocol Error
Functionality common to all library error types.

Types

struct Background
A background descriptor.
struct Chromaticity
A chromaticity descriptor.
struct Chunk
A chunk type identifier.
struct ColorProfile
An embedded color profile.
enum ColorRendering
A color rendering mode.
struct Context
A decoding context.
enum DecodingError
A decoding error.
enum Format
A color format.
enum FormattingError
A formatting error.
struct Gamma
A gamma descriptor.
struct Header
An image header.
struct Histogram
A palette frequency histogram.
struct Image
A rectangular image.
struct Layout
An image layout.
enum LexingError
A lexing error.
struct Metadata
The metadata in a PNG image.
struct Palette
An image palette.
enum ParsingError
A parsing error.
struct Percentmille
A rational percentmille value.
struct PhysicalDimensions
A physical dimensions descriptor.
struct RGBA<T>
An RGBA color target.
struct SignificantBits
A color precision descriptor.
enum Standard
A PNG standard.
struct SuggestedPalette
A suggested image palette.
struct Text
A text comment.
struct TimeModified
An image modification time.
struct Transparency
A transparency descriptor.
struct VA<T>
A grayscale-alpha color target.

Show obsolete interfaces (2)

enum Bytestream
A namespace for bytestream utilities.
enum Data
A namespace containing the Image type.

Type members

static func convolve<A, T, C>([UInt8], dereference: (Int) -> A, kernel: (T) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel and dereferencing function.
static func convolve<A, T, C>([UInt8], dereference: (Int) -> (A, A), kernel: ((T, T)) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel and dereferencing function.
static func convolve<A, T, C>([UInt8], dereference: (Int) -> (A, A, A, A), kernel: ((T, T, T, T)) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel and dereferencing function.
static func convolve<A, T, C>([UInt8], of: A.Type, depth: Int, kernel: ((T, T, T, T)) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel.
static func convolve<A, T, C>([UInt8], of: A.Type, depth: Int, kernel: ((T, T, T), (A, A, A)) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel.
static func convolve<A, T, C>([UInt8], of: A.Type, depth: Int, kernel: ((T, T)) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel.
static func convolve<A, T, C>([UInt8], of: A.Type, depth: Int, kernel: (T, A) -> C) -> [C]
Converts an image data buffer to a pixel array, using the given pixel kernel.
static func deconvolve<A, T, C>([C], as: A.Type, depth: Int, kernel: (C) -> (T, T, T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel.
static func deconvolve<A, T, C>([C], as: A.Type, depth: Int, kernel: (C) -> (T, T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel.
static func deconvolve<A, T, C>([C], as: A.Type, depth: Int, kernel: (C) -> (T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel.
static func deconvolve<A, T, C>([C], as: A.Type, depth: Int, kernel: (C) -> T) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel.
static func deconvolve<A, T, C>([C], reference: (A) -> Int, kernel: (C) -> T) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel and referencing function.
static func deconvolve<A, T, C>([C], reference: ((A, A)) -> Int, kernel: (C) -> (T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel and referencing function.
static func deconvolve<A, T, C>([C], reference: ((A, A, A)) -> Int, kernel: (C) -> (T, T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel and referencing function.
static func deconvolve<A, T, C>([C], reference: ((A, A, A, A)) -> Int, kernel: (C) -> (T, T, T, T)) -> [UInt8]
Converts a pixel array to an image data buffer, using the given pixel kernel and referencing function.
static func premultiply<T>(T, alpha: T) -> T
Premultiplies a color component with an alpha value.
static func straighten<T>(T, alpha: T) -> T
Straightens a premultiplied color component given an alpha value.