Copyright (c) 2021, Shukant Pal and Contributors
SPDX-License-Identifier: Apache-2.0

Java bindings for libktx, made with love by Shukant Pal originally for the Texture Compression Tool.

The libktx-jni library is built by the CMake project in the repository root. This library glues the libktx API with the interfaces provided in this Java library. You'll need to install libktx and libktx-jni to use the bindings. These, together with the Java archive libktx.jar can be installed from the packages found on the KTX Software Releases page.

Note: Java does not support arrays with more than 2³² elements so you should not use this library for images larger than four gigabytes in size.

The setup is as follows:

import org.khronos.ktx.KtxTexture2;

import java.nio.file.Paths;

public class App {
    static {
        // Load libktx-jni, which provides the JNI stubs for natively
        // implemented Java methods. This should also load libktx
        // automatically! If it doesn't, you may need to load libktx manually.
        System.loadLibrary("ktx-jni");
    }

    public static void main(String[] args) {
        KTXTexture2 texture = KTXTexture2.createFromNamedFile(
                Paths.get("exampleInput.ktx2").toAbsolutePath().toString());
        
        // Do something special with the texture!
        
        texture.writeToNamedFile(
                Paths.get("exampleOutput.ktx2").toAbsolutePath().toString());
    }
}

You must have Maven installed.

Pass -DKTX_FEATURE_JNI=ON when configuring the CMake build for libktx so that libktx-jni and libktx.jar are built as well.

This will place the libraries in a sub-directory of the build directory you configured with CMake corresponding to the configuration you are building, usually Debug or Release and the JAR in the target directory in interfaces/java_binding. When building your application, include this JAR in the build.

The installers install the JAR is the same library directory as libktx and libktx-jni. On GNU/Linux and macOS this is /usr/local/lib.

You must have Maven installed:

mvn package

The JAR is placed in the location described in the previous section.

It's tricky - I know.

 _JAVA_OPTIONS=-Djava.library.path=/usr/local/lib mvn test

The path shown above is for the case when libktx and libktx-jni have been installed. If you have only built them then use

 _JAVA_OPTIONS=-Djava.library.path=/path/to/your/cmake/build/<config> mvn test

where <config> is your build configuration, usually either Debug or Release.