lcms2-ffm

Panama FFM (jextract) bindings for the public Little CMS 2.19 API with bundled, from-source native libraries. No JNI and no system lcms2 installation is required.

<dependency>
  <groupId>io.github.ghosthack</groupId>
  <artifactId>lcms2-ffm</artifactId>
  <version>2.19-0.1.0</version>
</dependency>
<dependency>
  <groupId>io.github.ghosthack</groupId>
  <artifactId>lcms2-ffm-natives</artifactId>
  <version>2.19-0.1.0</version>
  <classifier>macos-arm64</classifier> <!-- or windows-x64 / linux-x64 -->
  <scope>runtime</scope>
</dependency>

import io.github.ghosthack.lcms2ffm.lcms2.Lcms2;

MemorySegment inputProfile = Lcms2.cmsOpenProfileFromMem(profileBytes, profileSize);
MemorySegment outputProfile = Lcms2.cmsCreate_sRGBProfile();
MemorySegment transform = Lcms2.cmsCreateTransform(
        inputProfile, Lcms2.TYPE_RGB_8(),
        outputProfile, Lcms2.TYPE_BGRA_8(),
        Lcms2.INTENT_RELATIVE_COLORIMETRIC(), 0);
Lcms2.cmsDoTransform(transform, inputPixels, outputPixels, pixelCount);

Close transforms with cmsDeleteTransform and profiles with cmsCloseProfile. The API is a direct jextract binding: C pointers and opaque handles are MemorySegment values, public C structs have generated layout/accessor classes, and callback typedefs have generated upcall helpers. All portable declarations from lcms2.h are generated; the C-runtime helper cmsfilelength is omitted because its long ABI differs between Unix and Windows.

When using the module path, declare requires lcms2.ffm; and run with --enable-native-access=lcms2.ffm. On the class path use --enable-native-access=ALL-UNNAMED (JDK 22+).

Library resolution

Lcms2Libs.lookup() resolves, in order:

1. -Dlcms2ffm.libdir=<dir> / LCMS2_FFM_LIBDIR;
2. the platform's lcms2-ffm-natives classifier jar, extracted once to ~/.cache/lcms2-ffm/<version>-<platform>/;
3. already loaded and platform-default native symbols.

Classifier jars are built for macos-arm64, windows-x64, and linux-x64.

Building

Fetch the matching source release, build the current platform native, regenerate bindings on macOS, and test:

mkdir -p build
curl -fsSL https://github.com/mm2/Little-CMS/archive/refs/tags/lcms2.19.tar.gz \
  -o build/lcms2.19.tar.gz
tar -xzf build/lcms2.19.tar.gz -C build
build-natives/macos-arm64.sh
jextract/gen-bindings.sh
mvn clean install

The Linux and Windows scripts follow the same layout. jextract defaults to the JDK 22 distribution in sibling ../ffmpeg-ffm; set JEXTRACT to override it.

Licensing

The bindings and bundled Little CMS library are MIT licensed. See THIRD-PARTY.md for native provenance.