libimagequant-java is a JNI wrapper around the C API for libimagequant, enabling you to quantize 32-bit RGBA images.

libimagequant-java is kept intentionally simple, only operating on byte[] arrays and direct ByteBuffer instances.

The required native shared library is automatically loaded for your operating system. No messing around with -Djava.library.path. libimagequant-java supports Windows 32- & 64-bit, Linux 32- & 64-bit as well as macOS out of the box.

本项目修改了JNI代码，并使用pngquant原来的JNI接口，且梳理了编译流程，如需使用自行编译即可.
如果想直接使用libimagequant-java原始库，可通过以下方式添加依赖:

<dependency>
	<groupId>com.badlogicgames</groupId>
	<artifactId>libimagequant-java</artifactId>
	<version>1.2-SNAPSHOT</version>
</dependency>

To include it in your Gradle project, ensure your build.gradle file adds thd repository:

maven { url "https://oss.sonatype.org/content/repositories/snapshots" }

Then add the dependency:

compile "com.badlogicgames:libimagequant-java:1.2-SNAPSHOT"

libimagequant-java is also built on every new commit by Jenkins and published as a SNAPSHOT release to SonaType.

The below code loads a 32-bit RGBA PNG file, quantizes it to 8-bit and then writes it back out to a new file.

new SharedLibraryLoader().load("imagequant-java");

PngQuant pngQuant = new PngQuant();
pngQuant.setQuality(10);
BufferedImage image = ImageIO.read(new File("test/origin.png"));

BufferedImage remapped = pngQuant.getRemapped(image);
ImageIO.write(remapped, "png", new File("test/1.png "));

Refer to the libimagequant documentation for more information.

libimagequant-java includes the upstream libimagequant repository as a submodule in jni/libimagequant. Make sure to clone this repository recursively to also check out the submodule:

git clone --recursive https://github.com/badlogic/libimagequant-java

libimagequant-java is a plain old Maven project and can be imported into any Maven aware IDE. Before importing, run

mvn clean compile

from a terminal. This will download the latest native shared libraries from Jenkins so you do not have to build them yourself. After the above Maven invocation, the native shared libraries will be located in src/main/resources.

To build the native shared libraries yourself, you can use the included jni/build-docker.sh script for Windows 32-bit, Windows 64-bit, Linux 32-bit and Linux 64-bit. Install Docker CE, then in your terminal:

使用Mac OS编译，安装工具：XCode、Command Line Tools、MinGW-w64、Docker；

cd jni/
./build-all.sh

This will build a Docker image with all required toolchains for Windows and Linux, compile the libimagequant-java shared libraries and put them in src/main/resources.

Finally, if you want to build a shared library for your specific host, use the jni/build.sh script:

/build.sh --target=<target-os-arch> --build=<release|debug>

Valid values for the --target parameter to pass to build.sh are macosx, windows-x86, windows-x86_64, linux-64 and linux-x86_64.

Valid values for the --build parameter are release and debug.

To build locally, all required toolchains must be installed; Xcode with command line tools on macOS, Mingw64 on Windows (or Linux for cross-compilation) and GCC on Linux.

libimagequant-java uses gdx-jnigen to generate C++ code embedded in the Java files. When you modify the embedded C++ code, you have to re-generate the C++ files in jni/src/ by running the CodeGenerator class.

AGPL 3, See LICENSE. For alternative licensing options contact the libimagequant author.