go-imagequant

This package wraps some (not all) functionality of libimagequant if you want to use the current version 4.2.0 rust based library. Older version of libimagequant should also work, but will show different results.

Please follow the instructions to get a working c lib.

See cmd/go-imagequant.go how to use this package.

Using docker to use the command line binary.

The example cli binary supports reading and writing png, jpeg and gif (non-animated) and serves as an example how to use this package.

See docker/alpine/Dockerfile for details.

Requirements:

• docker
• make

call

make docker-cmd

to create a local image. Check if image was created:

docker image ls
REPOSITORY      TAG       IMAGE ID       CREATED        SIZE
go-imagequant   latest    6b9f9364ab77   10 hours ago   51.8MB
<none>          <none>    f5648e483897   10 hours ago   64.3MB
<none>          <none>    139c553f6e4a   10 hours ago   51.8MB

You should see image go-imagequant.

---

Docker run:

docker run go-imagequant
  -dst string
        dst image path
  -gamma float
        gamma
  -max.quality uint
        min allowed quality (default 100)
  -min.quality uint
        min allowed quality (default 0)
  -showLibImageQuantVersion
        show lib image quant version and exit
  -speed uint
        speed to to use (default 4)
  -src string
        src image path
no src image

Examples:

Converting a png assuming you got image benchmark_image_1.png in your current path:

docker run -v $PWD:/tmp go-imagequant -max.quality 75 -src /tmp/imagequant/test/benchmark_image_1.png -dst /tmp/benchmark_image_1.docker.max40.png

using c libs

Under ./lib/ you find the c lib of imagequant ubuntu.

Copy all files into /usr/lib to enable for example daffy to run.

recreate c libs artifacts for ubuntu

make docker-lib-ubuntu-amd64

copy ubuntu libs to /usr/local

sudo cp -a lib/ubuntu/22.04/. /usr/local

Ensure go-imagequant is using version 4.2.0 of the c lib:

cd cmd
go run . -showLibImageQuantVersion

should show 40000. If you get another lower number you probably are using an ubuntu installed version. Check

apt search libimagequant
p   libimagequant-dev                                                               - palette quantization library (development files)
p   libimagequant0                                                                  - palette quantization library

shows not i (installed). Consider to remove libimagequant0 and libimagequant-dev by calling

apt purge libimagequant0 libimagequant-dev

Also check your linker search paths:

ld --verbose | grep SEARCH_DIR | tr -s ' ;' \\012

You could also try to refresh your linker cache:

sudo ldconfig