image/color
Package color
Overview
Package color implements a basic color library.
Index
Package files
Variables
Standard colors.
var ( Black = Gray16{0} White = Gray16{0xffff} Transparent = Alpha16{0} Opaque = Alpha16{0xffff} )
func CMYKToRGBSource
func CMYKToRGB(c, m, y, k uint8) (uint8, uint8, uint8)
CMYKToRGB converts a CMYK quadruple to an RGB triple.
func RGBToCMYKSource
func RGBToCMYK(r, g, b uint8) (uint8, uint8, uint8, uint8)
RGBToCMYK converts an RGB triple to a CMYK quadruple.
func RGBToYCbCrSource
func RGBToYCbCr(r, g, b uint8) (uint8, uint8, uint8)
RGBToYCbCr converts an RGB triple to a Y'CbCr triple.
func YCbCrToRGBSource
func YCbCrToRGB(y, cb, cr uint8) (uint8, uint8, uint8)
YCbCrToRGB converts a Y'CbCr triple to an RGB triple.
type AlphaSource
Alpha represents an 8-bit alpha color.
type Alpha struct { A uint8 }
func (Alpha) RGBASource
func (c Alpha) RGBA() (r, g, b, a uint32)
type Alpha16Source
Alpha16 represents a 16-bit alpha color.
type Alpha16 struct { A uint16 }
func (Alpha16) RGBASource
func (c Alpha16) RGBA() (r, g, b, a uint32)
type CMYKSource
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.
type CMYK struct { C, M, Y, K uint8 }
func (CMYK) RGBASource
func (c CMYK) RGBA() (uint32, uint32, uint32, uint32)
type ColorSource
Color can convert itself to alpha-premultiplied 16-bits per channel RGBA. The conversion may be lossy.
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, a uint32) }
type GraySource
Gray represents an 8-bit grayscale color.
type Gray struct { Y uint8 }
func (Gray) RGBASource
func (c Gray) RGBA() (r, g, b, a uint32)
type Gray16Source
Gray16 represents a 16-bit grayscale color.
type Gray16 struct { Y uint16 }
func (Gray16) RGBASource
func (c Gray16) RGBA() (r, g, b, a uint32)
type ModelSource
Model can convert any Color to one from its own color model. The conversion may be lossy.
type Model interface { Convert(c Color) Color }
Models for the standard color types.
var ( RGBAModel Model = ModelFunc(rgbaModel) RGBA64Model Model = ModelFunc(rgba64Model) NRGBAModel Model = ModelFunc(nrgbaModel) NRGBA64Model Model = ModelFunc(nrgba64Model) AlphaModel Model = ModelFunc(alphaModel) Alpha16Model Model = ModelFunc(alpha16Model) GrayModel Model = ModelFunc(grayModel) Gray16Model Model = ModelFunc(gray16Model) )
CMYKModel is the Model for CMYK colors.
var CMYKModel Model = ModelFunc(cmykModel)
NYCbCrAModel is the Model for non-alpha-premultiplied Y'CbCr-with-alpha colors.
var NYCbCrAModel Model = ModelFunc(nYCbCrAModel)
YCbCrModel is the Model for Y'CbCr colors.
var YCbCrModel Model = ModelFunc(yCbCrModel)
func ModelFuncSource
func ModelFunc(f func(Color) Color) Model
ModelFunc returns a Model that invokes f to implement the conversion.
type NRGBASource
NRGBA represents a non-alpha-premultiplied 32-bit color.
type NRGBA struct { R, G, B, A uint8 }
func (NRGBA) RGBASource
func (c NRGBA) RGBA() (r, g, b, a uint32)
type NRGBA64Source
NRGBA64 represents a non-alpha-premultiplied 64-bit color, having 16 bits for each of red, green, blue and alpha.
type NRGBA64 struct { R, G, B, A uint16 }
func (NRGBA64) RGBASource
func (c NRGBA64) RGBA() (r, g, b, a uint32)
type NYCbCrASource
NYCbCrA represents a non-alpha-premultiplied Y'CbCr-with-alpha color, having 8 bits each for one luma, two chroma and one alpha component.
type NYCbCrA struct { YCbCr A uint8 }
func (NYCbCrA) RGBASource
func (c NYCbCrA) RGBA() (uint32, uint32, uint32, uint32)
type PaletteSource
Palette is a palette of colors.
type Palette []Color
func (Palette) ConvertSource
func (p Palette) Convert(c Color) Color
Convert returns the palette color closest to c in Euclidean R,G,B space.
func (Palette) IndexSource
func (p Palette) Index(c Color) int
Index returns the index of the palette color closest to c in Euclidean R,G,B,A space.
type RGBASource
RGBA represents a traditional 32-bit alpha-premultiplied color, having 8 bits for each of red, green, blue and alpha.
An alpha-premultiplied color component C has been scaled by alpha (A), so has valid values 0 <= C <= A.
type RGBA struct { R, G, B, A uint8 }
func (RGBA) RGBASource
func (c RGBA) RGBA() (r, g, b, a uint32)
type RGBA64Source
RGBA64 represents a 64-bit alpha-premultiplied color, having 16 bits for each of red, green, blue and alpha.
An alpha-premultiplied color component C has been scaled by alpha (A), so has valid values 0 <= C <= A.
type RGBA64 struct { R, G, B, A uint16 }
func (RGBA64) RGBASource
func (c RGBA64) RGBA() (r, g, b, a uint32)
type YCbCrSource
YCbCr represents a fully opaque 24-bit Y'CbCr color, having 8 bits each for one luma and two chroma components.
JPEG, VP8, the MPEG family and other codecs use this color model. Such codecs often use the terms YUV and Y'CbCr interchangeably, but strictly speaking, 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, slightly different formulae for converting between the two. This package follows the JFIF specification at http://www.w3.org/Graphics/JPEG/jfif3.pdf.
type YCbCr struct { Y, Cb, Cr uint8 }
func (YCbCr) RGBASource
func (c YCbCr) RGBA() (uint32, uint32, uint32, uint32)
Subdirectories
© Google, Inc.
Licensed under the Creative Commons Attribution License 3.0.
https://golang.org/pkg/image/color/