goepeg

README

goepeg

Go wrapper for epeg.

Epeg is a C library for insanely fast JPEG/JPG thumbnail scaling with the minimum fuss and CPU overhead. It makes use of libjpeg features of being able to load an image by only decoding the DCT coefficients needed to reconstruct an image of the size desired.

The library has bundled archive which are automatically linked. This means that installing libepeg and libjpeg is not necessary.

Current archive files are built from epeg v0.1.0 and libjpeg-turbo 2.1.91.

Install

go get github.com/koofr/goepeg

Testing

go test

Test in Docker

docker run --rm -v $(pwd):/app -w /app golang:1.20.2-bullseye sh -c 'go test'

Update libepeg

git clone https://github.com/koofr/epeg.git

macOS

brew install cmake nasm

cd epeg
mkdir build
cd build
cmake -DCMAKE_OSX_DEPLOYMENT_TARGET=10.14.6 ..
make install

cp epeg/dist/lib/libepeg.a libepeg_darwin_amd64.a
cp epeg/dist/lib/libjpeg.a libjpeg_darwin_amd64.a
cp epeg/dist/include/Epeg.h Epeg.h

Linux

Docker is needed to build for Ubuntu 16.04 compatibility:

cd epeg
docker build -t epeg .
docker create --name epeg-copy epeg
mkdir out
cd out
docker cp epeg-copy:/epeg/dist/lib/libepeg.a libepeg_linux_amd64.a
docker cp epeg-copy:/epeg/dist/lib/libjpeg.a libjpeg_linux_amd64.a
docker cp epeg-copy:/epeg/dist/include/Epeg.h Epeg.h
docker rm epeg-copy

cp epeg/out/{libepeg_linux_amd64.a,libjpeg_linux_amd64.a,Epeg.h} .

Documentation

Index

• Constants
• func Thumbnail(input string, output string, size int, quality int, scaleType ScaleType) error
• func Transform(input string, output string, transform TransformType) error
• type ScaleType
• type TransformType

Constants

const (
	TransformNone       TransformType = iota
	TransformFlipH                    = iota
	TransformFlipV                    = iota
	TransformTranspose                = iota
	TransformTransverse               = iota
	TransformRot90                    = iota
	TransformRot180                   = iota
	TransformRot270                   = iota
)

Functions

func Thumbnail

func Thumbnail(input string, output string, size int, quality int, scaleType ScaleType) error

func Transform

func Transform(input string, output string, transform TransformType) error

Types

type ScaleType

type ScaleType int

const (
	ScaleTypeFitMax ScaleType = iota
	ScaleTypeFitMin           = iota
)

type TransformType

type TransformType int