package png

import "image/png"

Package png implements a PNG image decoder and encoder.

The PNG specification is at http://www.w3.org/TR/PNG/.

Index ¶

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

Functions ¶

func Decode ¶

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

Decode reads a PNG image from r and returns it as an image.Image. The type of Image returned depends on the PNG contents.

func DecodeConfig ¶

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

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

func Encode ¶

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

Encode writes the Image m to w in PNG format. Any Image may be encoded, but images that are not image.NRGBA might be encoded lossily.

Types ¶

type CompressionLevel ¶

type CompressionLevel int

const (
	DefaultCompression CompressionLevel = 0
	NoCompression      CompressionLevel = -1
	BestSpeed          CompressionLevel = -2
	BestCompression    CompressionLevel = -3
)

type Encoder ¶

type Encoder struct {
	CompressionLevel CompressionLevel
}

Encoder configures encoding PNG images.

func (*Encoder) Encode ¶

func (enc *Encoder) Encode(w io.Writer, m image.Image) error

Encode writes the Image m to w in PNG format.

type FormatError ¶

type FormatError string

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

func (FormatError) Error ¶

func (e FormatError) Error() string

type UnsupportedError ¶

type UnsupportedError string

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

func (UnsupportedError) Error ¶

func (e UnsupportedError) Error() string

Source Files ¶

paeth.go reader.go writer.go