apng

README

apng

Fast APNG encoding with concurrent frame encoding.

Installation

go get github.com/setanarut/apng

20 frames animation encoding benchmark

Image Size	kettek	setanarut
125x125	173 ms	43 ms
250x250	655 ms	153 ms
500x500	2542 ms	565 ms
1000x1000	10174 ms	2213 ms
2000x2000	40745 ms	8831 ms

Example

package main

import (
	"image"
	"image/color"
	"math/rand/v2"

	"github.com/setanarut/apng"
)

func main() {
	frames := make([]image.Image, 8)
	for i := range 8 {
		frames[i] = generateNoiseImage(600, 200)
	}
	apng.Save("out.png", frames, 7)
}

func generateNoiseImage(width, height int) *image.RGBA {
	img := image.NewRGBA(image.Rect(0, 0, width, height))
	for y := range height {
		for x := range width {
			col := noisePalette[rand.IntN(4)]
			img.SetRGBA(x, y, col)
		}
	}
	return img
}

var noisePalette = []color.RGBA{
	{R: 0, G: 0, B: 0, A: 255},   // Black
	{R: 255, G: 0, B: 0, A: 255}, // Red
	{R: 0, G: 255, B: 0, A: 255}, // Green
	{R: 0, G: 0, B: 255, A: 255}, // Blue
}

Documentation

Overview

apng is Animated PNG (APNG) encoder

Index

• func APNGBytes(images []image.Image, delay uint16) []byte
• func EncodeAll(w io.Writer, a *APNG) error
• func Save(filePath string, images []image.Image, delay uint16)
• type APNG

Functions

func APNGBytes

func APNGBytes(images []image.Image, delay uint16) []byte

APNGBytes encodes a slice of images into an APNG byte stream with a consistent delay per frame.

Images obtained via image.SubImage() are not supported, If an image is a sub-image, copy it into a new image before encoding.

The successive delay times, one per frame, in 100ths of a second (centiseconds).

func EncodeAll

func EncodeAll(w io.Writer, a *APNG) error

EncodeAll encodes the entire APNG struct to the io.Writer, validating input constraints.

Images obtained via SubImage() are not supported, If an image is a sub-image, copy it into a new image before encoding.

func Save

func Save(filePath string, images []image.Image, delay uint16)

Save writes an APNG file with the given images and uniform frame delay.

Images obtained via image.SubImage() are not supported, If an image is a sub-image, copy it into a new image before encoding.

The successive delay times, one per frame, in 100ths of a second (centiseconds).

Types

type APNG

type APNG struct {
	// The successive images.
	//
	// Images obtained via SubImage() are not supported, If an image is a sub-image, copy it into a new image before encoding.
	Images []image.Image
	// The successive delay times, one per frame, in 100ths of a second (centiseconds).
	Delays    []uint16
	Disposals []byte // The successive disposal methods, one per frame.
	LoopCount uint32 // The loop count. 0 indicates infinite looping.
	Config    image.Config
}

APNG encapsulates animated PNG frames, their delays, disposal methods, loop count, and global configuration.