nycbcra

Documentation

Overview

Package nycbcra provides non-alpha-premultiplied Y'CbCr-with-alpha image and color types.

Index

• Variables
• type Color
  • func (c Color) RGBA() (r, g, b, a uint32)
• type Image
  • func New(r image.Rectangle, subsampleRatio image.YCbCrSubsampleRatio) *Image
  • func (p *Image) AOffset(x, y int) int
  • func (p *Image) At(x, y int) color.Color
  • func (p *Image) ColorModel() color.Model
  • func (p *Image) NYCbCrAAt(x, y int) Color
  • func (p *Image) Opaque() bool
  • func (p *Image) SubImage(r image.Rectangle) image.Image

Variables

var ColorModel color.Model = color.ModelFunc(nYCbCrAModel)

ColorModel is the Model for non-alpha-premultiplied Y'CbCr-with-alpha colors.

Types

type Color

type Color struct {
	color.YCbCr
	A uint8
}

Color represents a non-alpha-premultiplied Y'CbCr-with-alpha color, having 8 bits each for one luma, two chroma and one alpha component.

func (Color) RGBA

func (c Color) RGBA() (r, g, b, a uint32)

type Image

type Image struct {
	image.YCbCr
	A       []uint8
	AStride int
}

Image is an in-memory image of non-alpha-premultiplied Y'CbCr-with-alpha colors. A and AStride are analogous to the Y and YStride fields of the embedded YCbCr.

func New

func New(r image.Rectangle, subsampleRatio image.YCbCrSubsampleRatio) *Image

New returns a new Image with the given bounds and subsample ratio.

func (*Image) AOffset

func (p *Image) AOffset(x, y int) int

AOffset returns the index of the first element of A that corresponds to the pixel at (x, y).

func (*Image) At

func (p *Image) At(x, y int) color.Color

func (*Image) ColorModel

func (p *Image) ColorModel() color.Model

func (*Image) NYCbCrAAt

func (p *Image) NYCbCrAAt(x, y int) Color

func (*Image) Opaque

func (p *Image) Opaque() bool

Opaque scans the entire image and reports whether it is fully opaque.

func (*Image) SubImage

func (p *Image) SubImage(r image.Rectangle) image.Image

SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.