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Package jpeg

import "image/jpeg"
Overview
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Overview ▾

Package jpeg implements a JPEG image decoder and encoder.

JPEG is defined in ITU-T T.81: http://www.w3.org/Graphics/JPEG/itu-t81.pdf.

Constants

const DefaultQuality = 75

DefaultQuality is the default quality encoding parameter.

func Decode

func Decode(r io.Reader) (image.Image, error)

Decode reads a JPEG image from r and returns it as an image.Image.

func DecodeConfig

func DecodeConfig(r io.Reader) (image.Config, error)

DecodeConfig returns the color model and dimensions of a JPEG image without decoding the entire image.

func Encode

func Encode(w io.Writer, m image.Image, o *Options) error

Encode writes the Image m to w in JPEG 4:2:0 baseline format with the given options. Default parameters are used if a nil *Options is passed.

type FormatError

type FormatError string

A FormatError reports that the input is not a valid JPEG.

func (FormatError) Error

func (e FormatError) Error() string

type Options

type Options struct {
        Quality int
}

Options are the encoding parameters. Quality ranges from 1 to 100 inclusive, higher is better.

type Reader

type Reader interface {
        io.Reader
        ReadByte() (c byte, err error)
}

If the passed in io.Reader does not also have ReadByte, then Decode will introduce its own buffering.

type UnsupportedError

type UnsupportedError string

An UnsupportedError reports that the input uses a valid but unimplemented JPEG feature.

func (UnsupportedError) Error

func (e UnsupportedError) Error() string