gifsicle

README

gifsicle-go

A Go wrapper around gifsicle with bundled binaries for quick and easy GIF compression with just a single go get!

gifsicle is one of the most popular GIF compression tools used by many online GIF compression websites like ezgif.com.

Table of Contents

• Install
• Usage
  • Compress
  • Gifsicle
• Contributing

Install

We bundle the binaries through embeds, so all you need is a go get:

go get github.com/munchpass/gifsicle-go

No need to have gifsicle pre-installed!

Usage

Compress

If you just want to quickly compress a GIF and write the result into a buffer:

	var buf bytes.Buffer
	err = gifsicle.Compress(&buf, decodedGif, &gifsicle.Options{
		Lossy:         80,
		OptimizeLevel: gifsicle.OPTIMIZE_LEVEL_THREE,
	})
	if err != nil {
		return err
	}

Gifsicle

This library also provides the Gifsicle struct which is a thin wrapper around the gifsicle CLI tool.

Here are some examples:

Compress an input GIF file and write the result to an output GIF file:

	sourceGif := path.Join("testfiles", "portrait_3mb.gif")
	outputGif := path.Join("testoutput", "portrait_3mb_output.gif")
	err = g.InputFile(sourceGif).
		OutputFile(outputGif).
		Lossy(80).
		OptimizeLevel(gifsicle.OPTIMIZE_LEVEL_THREE).
		Run()

Compress an input GIF object and write the result to an output GIF file:

	err = g.InputGif(sourceGif).
		OutputFile(outputGif).
		Lossy(80).
		OptimizeLevel(gifsicle.OPTIMIZE_LEVEL_THREE).
		Run()

Compress an input GIF object and write the result to an output buffer:

    var buf bytes.Buffer
	err = g.InputGif(sourceGif).
		Output(&buf).
		Lossy(80).
		OptimizeLevel(gifsicle.OPTIMIZE_LEVEL_THREE).
		Run()

Contributing

This library is still in its early stage, but is actively used in production. We welcome any PRs/suggestions!

Documentation

Index

• func Compress(w io.Writer, g *gif.GIF, o *Options) error
• func CompressFromReader(w io.Writer, r io.Reader, o *Options) error
• type Gifsicle
  • func NewGifsicle() (*Gifsicle, error)
  • func (g *Gifsicle) Debug() *Gifsicle
  • func (g *Gifsicle) Input(reader io.Reader) *Gifsicle
  • func (g *Gifsicle) InputFile(file string) *Gifsicle
  • func (g *Gifsicle) InputGif(inputGif *gif.GIF) *Gifsicle
  • func (g *Gifsicle) Lossy(lossy uint) *Gifsicle
  • func (g *Gifsicle) NumColors(numColors uint) *Gifsicle
  • func (g *Gifsicle) OptimizeLevel(l OptimizeLevel) *Gifsicle
  • func (g *Gifsicle) Output(writer io.Writer) *Gifsicle
  • func (g *Gifsicle) OutputFile(file string) *Gifsicle
  • func (g *Gifsicle) Reset() *Gifsicle
  • func (g *Gifsicle) Run() error
  • func (g *Gifsicle) Version() (string, error)
• type OptimizeLevel
• type Options

Functions

func Compress

func Compress(w io.Writer, g *gif.GIF, o *Options) error

Shortcut function to compress GIFs quickly and easily with gifsicle.

func CompressFromReader

func CompressFromReader(w io.Writer, r io.Reader, o *Options) error

Shortcut function to compress GIFs quickly and easily with gifsicle using an io.Reader like a file or buffer.

Example:

testFilePath := path.Join("testfiles", "portrait_3mb.gif")
testFile, err := os.Open(testFilePath)
if err != nil {
	return err
}

var buf bytes.Buffer
err = gifsicle.CompressFromReader(&buf, testFile, &gifsicle.Options{
	Lossy:         200,
	OptimizeLevel: gifsicle.OPTIMIZE_LEVEL_THREE,
	NumColors:     256,
})
if err != nil {
	return err
}

Types

type Gifsicle

type Gifsicle struct {
	// contains filtered or unexported fields
}

Gifsicle wraps the gifsicle CLI tool.

func NewGifsicle

func NewGifsicle() (*Gifsicle, error)

func (*Gifsicle) Debug

func (g *Gifsicle) Debug() *Gifsicle

Turns on debug mode.

func (*Gifsicle) Input

func (g *Gifsicle) Input(reader io.Reader) *Gifsicle

Input sets reader to convert. InputFile or InputImage called before will be ignored.

func (*Gifsicle) InputFile

func (g *Gifsicle) InputFile(file string) *Gifsicle

InputFile sets image file to convert. Input or InputGif called before will be ignored.

func (*Gifsicle) InputGif

func (g *Gifsicle) InputGif(inputGif *gif.GIF) *Gifsicle

InputGif sets gif to convert. InputFile or Input called before will be ignored.

func (*Gifsicle) Lossy

func (g *Gifsicle) Lossy(lossy uint) *Gifsicle

Sets the --lossy parameter.

This parameter ranges from 0-200 (higher value -> more compression).

This is the main compression parameter used in websites like ezgif!

func (*Gifsicle) NumColors

func (g *Gifsicle) NumColors(numColors uint) *Gifsicle

Sets the --colors parameter.

This parameter ranges from 2-256 (lower value -> more compression).

func (*Gifsicle) OptimizeLevel

func (g *Gifsicle) OptimizeLevel(l OptimizeLevel) *Gifsicle

For the -O[level] or --optimize[=level] arguments.

See https://www.lcdf.org/gifsicle/man.html for more information.

func (*Gifsicle) Output

func (g *Gifsicle) Output(writer io.Writer) *Gifsicle

Output specify writer to write jpeg file content. OutputFile called before will be ignored.

func (*Gifsicle) OutputFile

func (g *Gifsicle) OutputFile(file string) *Gifsicle

OutputFile specify the name of the output jpeg file. Output called before will be ignored.

func (*Gifsicle) Reset

func (g *Gifsicle) Reset() *Gifsicle

Reset resets all parameters to default values

func (*Gifsicle) Run

func (g *Gifsicle) Run() error

func (*Gifsicle) Version

func (g *Gifsicle) Version() (string, error)

Version returns gifsicle --version

type OptimizeLevel

type OptimizeLevel string

For the -O[level] or --optimize[=level] arguments.

See https://www.lcdf.org/gifsicle/man.html for more information.

var (
	// Store only the changed portion of each image. This is the default.
	OPTIMIZE_LEVEL_ONE OptimizeLevel = "1"

	// Store only the changed portion of each image, and use transparency.
	OPTIMIZE_LEVEL_TWO OptimizeLevel = "2"

	// Tries several optimization methods (usually slower, sometimes better results).
	OPTIMIZE_LEVEL_THREE OptimizeLevel = "3"

	// Preserve empty transparent frames (they are dropped by default).
	OPTIMIZE_LEVEL_KEEP_EMPTY OptimizeLevel = "keep-empty"
)

type Options

type Options struct {
	// This parameter ranges from 0-200 (higher value -> more compression).
	//
	// This is the main compression parameter used in websites like ezgif!
	Lossy uint

	// Additional compression optimization.
	OptimizeLevel OptimizeLevel

	// Optional parameter to specify the number of colors (2-256) for the GIF
	//
	// Specifying less colors compresses the GIF more.
	// If this is 0, gifsicle will default to using the image's color map.
	NumColors uint
}