var (Black       =Gray16{0}White       =Gray16{0xffff}Transparent =Alpha16{0}Opaque      =Alpha16{0xffff})

funcCMYKToRGB¶added ingo1.5

func CMYKToRGB(c, m, y, kuint8) (uint8,uint8,uint8)

CMYKToRGB converts aCMYK quadruple to an RGB triple.

funcRGBToCMYK¶added ingo1.5

func RGBToCMYK(r, g, buint8) (uint8,uint8,uint8,uint8)

RGBToCMYK converts an RGB triple to a CMYK quadruple.

funcRGBToYCbCr¶

func RGBToYCbCr(r, g, buint8) (uint8,uint8,uint8)

RGBToYCbCr converts an RGB triple to a Y'CbCr triple.

funcYCbCrToRGB¶

func YCbCrToRGB(y, cb, cruint8) (uint8,uint8,uint8)

YCbCrToRGB converts a Y'CbCr triple to an RGB triple.

typeAlpha¶

type Alpha struct {Auint8}

Alpha represents an 8-bit alpha color.

func (cAlpha) RGBA() (r, g, b, auint32)

typeAlpha16¶

type Alpha16 struct {Auint16}

Alpha16 represents a 16-bit alpha color.

func (cAlpha16) RGBA() (r, g, b, auint32)

typeCMYK¶added ingo1.5

type CMYK struct {C, M, Y, Kuint8}

CMYK represents a fully opaque CMYK color, having 8 bits for each of cyan,magenta, yellow and black.

It is not associated with any particular color profile.

func (cCMYK) RGBA() (uint32,uint32,uint32,uint32)

typeColor¶

type Color interface {// RGBA returns the alpha-premultiplied red, green, blue and alpha values// for the color. Each value ranges within [0, 0xffff], but is represented// by a uint32 so that multiplying by a blend factor up to 0xffff will not// overflow.//// An alpha-premultiplied color component c has been scaled by alpha (a),// so has valid values 0 <= c <= a.RGBA() (r, g, b, auint32)}

Color can convert itself to alpha-premultiplied 16-bits per channel RGBA.The conversion may be lossy.

typeGray¶

type Gray struct {Yuint8}

Gray represents an 8-bit grayscale color.

func (cGray) RGBA() (r, g, b, auint32)

typeGray16¶

type Gray16 struct {Yuint16}

Gray16 represents a 16-bit grayscale color.

func (cGray16) RGBA() (r, g, b, auint32)

typeModel¶

type Model interface {Convert(cColor)Color}

Model can convert anyColor to one from its own color model. The conversionmay be lossy.

var (RGBAModelModel =ModelFunc(rgbaModel)RGBA64ModelModel =ModelFunc(rgba64Model)NRGBAModelModel =ModelFunc(nrgbaModel)NRGBA64ModelModel =ModelFunc(nrgba64Model)AlphaModelModel =ModelFunc(alphaModel)Alpha16ModelModel =ModelFunc(alpha16Model)GrayModelModel =ModelFunc(grayModel)Gray16ModelModel =ModelFunc(gray16Model))

var CMYKModelModel =ModelFunc(cmykModel)

var NYCbCrAModelModel =ModelFunc(nYCbCrAModel)

var YCbCrModelModel =ModelFunc(yCbCrModel)

func ModelFunc(f func(Color)Color)Model

typeNRGBA¶

type NRGBA struct {R, G, B, Auint8}

NRGBA represents a non-alpha-premultiplied 32-bit color.

func (cNRGBA) RGBA() (r, g, b, auint32)

typeNRGBA64¶

type NRGBA64 struct {R, G, B, Auint16}

NRGBA64 represents a non-alpha-premultiplied 64-bit color,having 16 bits for each of red, green, blue and alpha.

func (cNRGBA64) RGBA() (r, g, b, auint32)

typeNYCbCrA¶added ingo1.6

type NYCbCrA struct {YCbCrAuint8}

NYCbCrA represents a non-alpha-premultiplied Y'CbCr-with-alpha color, having8 bits each for one luma, two chroma and one alpha component.

func (cNYCbCrA) RGBA() (uint32,uint32,uint32,uint32)

typePalette¶

type Palette []Color

Palette is a palette of colors.

func (pPalette) Convert(cColor)Color

func (pPalette) Index(cColor)int

typeRGBA¶

type RGBA struct {R, G, B, Auint8}

RGBA represents a traditional 32-bit alpha-premultiplied color, having 8bits for each of red, green, blue and alpha.

An alpha-premultiplied color component C has been scaled by alpha (A), sohas valid values 0 <= C <= A.

func (cRGBA) RGBA() (r, g, b, auint32)

typeRGBA64¶

type RGBA64 struct {R, G, B, Auint16}

RGBA64 represents a 64-bit alpha-premultiplied color, having 16 bits foreach of red, green, blue and alpha.

An alpha-premultiplied color component C has been scaled by alpha (A), sohas valid values 0 <= C <= A.

func (cRGBA64) RGBA() (r, g, b, auint32)

typeYCbCr¶

type YCbCr struct {Y, Cb, Cruint8}

YCbCr represents a fully opaque 24-bit Y'CbCr color, having 8 bits each forone luma and two chroma components.

JPEG, VP8, the MPEG family and other codecs use this color model. Suchcodecs often use the terms YUV and Y'CbCr interchangeably, but strictlyspeaking, the term YUV applies only to analog video signals, and Y' (luma)is Y (luminance) after applying gamma correction.

Conversion between RGB and Y'CbCr is lossy and there are multiple, slightlydifferent formulae for converting between the two. This package followsthe JFIF specification athttps://www.w3.org/Graphics/JPEG/jfif3.pdf.

func (cYCbCr) RGBA() (uint32,uint32,uint32,uint32)