Initializerswift-png 4.4.5PNG
init(packing:size:layout:metadata:indexer:)
Creates an image from a scalar pixel array, using a custom indexing function.
PNG.Image.swift:985init<T>(packing pixels: [T], size: (x: Int, y: Int), layout: PNG.Layout, metadata: PNG.Metadata = .init(), indexer: ([(r: UInt8, g: UInt8, b: UInt8, a: UInt8)]) -> (UInt8) -> Int) where T : FixedWidthInteger, T : UnsignedInteger Parameters
- pixels
A scalar pixel array. Its elements are arranged in row-major order. The first pixel in this array corresponds to the top-left corner of the image.
The length of this array must match
size.x * size.y. Passing an array of the wrong length will result in a precondition failure.- size
The size of the image. Both dimensions must be greater than zero. Passing an invalid image size will result in a precondition failure.
- layout
An image layout.
- metadata
A metadata structure. The default value is an empty metadata structure.
- indexer
A function which uses the palette entries in the color
formatto generate a referencing function. This function will only be invoked if the image colorformatis an indexed format.
For an image with a grayscale-alpha color format, this function assigns the gray channel to the given scalars, and sets the alpha channel to T.max.
For an image with an RGB or BGR color format, this function assigns all channels to the given scalars, replicating each scalar three times.
For an image with an RGBA or BGRA color format, this function assigns all opaque channels to the given scalars, replicating each scalar three times, and sets the alpha channel to T.max.
The scalar values are assumed to fill the entire range of T.
See the indexed color tutorial for more about the semantics of this function.
Other members in extension
Type members
init<Color>(packing: [Color], size: (x: Int, y: Int), layout: PNG.Layout, metadata: PNG.Metadata) Creates an image from a pixel array.
init<T>(packing: [T], size: (x: Int, y: Int), layout: PNG.Layout, metadata: PNG.Metadata) Creates an image from a scalar pixel array.
init<Color>(packing: [Color], size: (x: Int, y: Int), layout: PNG.Layout, metadata: PNG.Metadata, indexer: ([(r: UInt8, g: UInt8, b: UInt8, a: UInt8)]) -> (Color.Aggregate) -> Int) Creates an image from a pixel array, using a custom indexing function.
static func decompress(path: String) throws -> `Self`? Decompresses and decodes a PNG from a file at the given file path.
static func decompress<Source>(stream: inout Source) throws -> PNG.Image Decompresses and decodes a PNG from the given bytestream.
Instance members
let layout: PNG.LayoutThe layout of this image.
var metadata: PNG.MetadataThe metadata in this image.
let size: (x: Int, y: Int)The size of this image, measured in pixels.
var storage: [UInt8]The raw backing storage of the image content.
func bindStorage(to: PNG.Layout) -> PNG.Image Rebinds this image to a compatible layout.
func compress(path: String, level: Int, hint: Int) throws -> Void? Encodes and compresses a PNG to a file at the given file path.
func compress<Destination>(stream: inout Destination, level: Int, hint: Int) throws Encodes and compresses a PNG to the given bytestream.
func unpack<Color>(as: Color.Type) -> [Color] Unpacks this image to a pixel array.
func unpack<T>(as: T.Type) -> [T] Unpacks this image to a scalar pixel array.
func unpack<Color>(as: Color.Type, deindexer: ([(r: UInt8, g: UInt8, b: UInt8, a: UInt8)]) -> (Int) -> Color.Aggregate) -> [Color] Unpacks this image to a pixel array, using a custom deindexing function.
func unpack<T>(as: T.Type, deindexer: ([(r: UInt8, g: UInt8, b: UInt8, a: UInt8)]) -> (Int) -> UInt8) -> [T] Unpacks this image to a scalar pixel array, using a custom deindexing function.