package jpeg

import "image/jpeg"

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.

Index ¶

• Constants
• func Decode(r io.Reader) (image.Image, error)
• func DecodeConfig(r io.Reader) (image.Config, error)
• func Encode(w io.Writer, m image.Image, o *Options) error
• type FormatError
• func (e FormatError) Error() string
• type Options
• type Reader
• type UnsupportedError
• func (e UnsupportedError) Error() string

Package Files ¶

fdct.go huffman.go idct.go reader.go scan.go writer.go

Constants ¶

const DefaultQuality = 75

DefaultQuality is the default quality encoding parameter.

func Decode ¶ Uses

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

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

func DecodeConfig ¶ Uses

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 ¶ Uses

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 ¶ Uses

type FormatError string

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

func (FormatError) Error ¶ Uses

func (e FormatError) Error() string

type Options ¶ Uses

type Options struct {
    Quality int
}

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

type Reader ¶ Uses

type Reader interface {
    io.ByteReader
    io.Reader
}

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

type UnsupportedError ¶ Uses

type UnsupportedError string

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

func (UnsupportedError) Error ¶ Uses

func (e UnsupportedError) Error() string