JNI wrapper for pngquant
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README.md

gifski-java

gifski-java is a JNI wrapper around the C API for Gifski enabling you to encode sequences of 32-bit RGBA images to high-quality animated GIFs.

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

gifski-java bundles the required native shared library and automatically loads the library comaptible with your operating system. No messing around with -Djava.library.path. gifski-java supports Windows 32- & 64-bit, Linux 32- & 64-bit as well as macOS out of the box.

Installation

gifski-java is published to Maven Central. You can include it in your pom.xml as a dependency as follows:

<dependency>
	<groupId>com.badlogicgames.gdx</groupId>
	<artifactId>gifski-java</artifactId>
	<version>1.0</version>
</dependency>

To include it in your Gradle project, ensure your build.gradle file adds the mavenCentral() repository. Then add the dependency:

compile "com.badlogicgames.gdx:gifski-java:1.0"

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

Usage

The below code generates a fade-in animation of a pink rectangle, with a 2 second duration at 25 frames per second.

// Animation duration and frame rate (frameCount / seconds)
int seconds = 2;
int frameCount = 50;

// Define Gifski encoding settings
GifskiSettings settings = new GifskiSettings();
settings.width = 256;
settings.height = 256;
settings.quality = 100;
settings.once = false;
settings.fast = false;

// Create the Gifski instance and start writting
// the output GIF file
Gifski gifski = new Gifski(settings);
gifski.start("output.gif");

// Generate frames and tell gifski to add them to the
// animation
short delay = (short)(seconds * 100 / frameCount);
byte[] pixels = new byte[settings.width * settings.height * 4];
for (int i = 0; i < frameCount; i++) {
	for (int p = 0, n = pixels.length; p < n; p += 4) {
		byte color = (byte)(i * 256f / frameCount);
		pixels[p] = color;
		pixels[p + 1] = 0;
		pixels[p + 2] = color;
		pixels[p + 3] = (byte)0xff;
	}
	gifski.addFrameRGBA(i, settings.width, settings.height, pixels, delay);
}

// Tell Gifski to stop encoding and close the GIF file
gifski.end();

Note: gifski-java automatically sets up the additional thread for writing the added frames to the output file. Call Gifski#start() and Gifski#end() which will ensure the proper setup and tear down of the thread. The Java API allows you to manage the threads manually by exposing the write(), drop() and endAddingFrames() methods, which are direct wrappers of the C API.

Refer to the 'gifski.h` file of the C API for more information.

Working from source

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

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

gifski-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.

Building the native libraries

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:

cd jni/
./build-docker.sh

This will build a Docker image with all required toolchains for Windows and Linux, compile the gifski-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. The Dockerfile shows you a toolchain setup to compile for Windows & Linux on Linux. See the jni/README.md file for more information.

License

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