lossypng

README

Warning: This library should probably not be used just yet

lossypng

Library version of the lossypng command line tool.

Shrink PNG files by applying a lossy filter

Installation

go get -u github.com/peterhellberg/lossypng

Feel free to copy all or parts of this package into your own codebase.

Examples

Original image 320 KB

The optimized images were encoded to PNG using a png.Encoder{png.BestCompression}

Optimize(m, RGBAConversion, 10) 156 KB

Optimize(m, GrayscaleConversion, 10) 40 KB

Credit

This compression technique was invented by Michael Vinther for his excellent Windows program, Image Analyzer. It does much more than just compression. It was ported and improved by William MacKay.

I have just converted it into a library.

License

All code in lossypng is public domain. You may use it however you wish.

Documentation

Overview

Package lossypng is a library version of the lossypng command line tool.

Installation

go get -u github.com/peterhellberg/lossypng

Index

• Constants
• func Optimize(original image.Image, colorConversion int, quantization int) image.Image

Constants

const (
	// NoConversion does not convert the image
	NoConversion = iota

	// GrayscaleConversion convert image to grayscale
	GrayscaleConversion

	// RGBAConversion convert image to 32-bit color
	RGBAConversion
)

Functions

func Optimize

func Optimize(original image.Image, colorConversion int, quantization int) image.Image

Optimize optimizes an image using the selected color conversion and quantization