Package jpeg

import "image/jpeg"

Overview ▾

Package jpeg implements a JPEG image decoder and encoder.

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


DefaultQuality is the default quality encoding parameter.

const DefaultQuality = 75

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

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

type FormatError string

func (FormatError) Error

func (e FormatError) Error() string

type Options

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

type Options struct {
    Quality int

type Reader

Deprecated: Reader is not used by the image/jpeg package and should not be used by others. It is kept for compatibility.

type Reader interface {

type UnsupportedError

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

type UnsupportedError string

func (UnsupportedError) Error

func (e UnsupportedError) Error() string