JVips, a libvips Java wrapper

JVips is a Java wrapper for libvips using JNI.

Status

This project is deployed and used in production at Criteo to serve billions of images a day.

Not all libvips capabilities are implemented. JVips currently exposes:

• Resize
• Pad
• Crop
• Find trim (get bounding box)
• Get pixel point
• Get image width / height / bands / Nb frame
• Has alpha channel
• Is sRGB colorspace
• Compose image with another one

Feel free to contribute.

Example

Look at the hello world program in SimpleExample.java. It opens an image file, resize it, and prints its size.

Installation

From prebuilt packages

You can download the latest JVips build from GitHub Releases. We currently don't release to Maven Central.

Then, ensure your libvips and its dependencies are available on your system.

🐧 Linux

Install libvips with your favorite package manager.

For Ubuntu and Debian:

sudo apt-get install libvips42

For Fedora and CentOS:

sudo yum install vips

However, note that JVips.jar embeds libvips.so and its dependencies. The jar file is self-sufficient for Linux. Look the --minimal flag documented below if you don't want this behavior and prefer to rely on system-wide libraries.

🏁 Windows

Install libvips from GitHub Releases:

1. Download the prebuilt Windows libvips archive matching the JVips version and unzip it
2. Add a VIPS_HOME environment variable pointing to the extracted directory
3. Append $VIPS_HOME/bin and $VIPS_HOME to your $PATH environment variable

🍎 macOS

Install libvips with Homebrew:

1. brew install vips

From source

The build system relies on numerous dependencies including CMake 3 and Maven, as well as other native code compilers. Instead of listing them here, please refer to Dockerfile for an up-to-date list.

The build.sh script will download and build a subset of JVips dependencies from source in order to maximize optimizations. However, it is recommended to install all dependencies on the system first, as documented in the sections below.

Additionally, build.sh accepts the following options:

• --with-w64, --without-w64: enable/disable Windows 64 build (default: disable)
• --with-linux, --without-linux: enable/disable Linux build (default: enable)
• --with-macos, --without-macos: enable/disable Linux build (default: disable)
• --skip-test: disable unit tests (default: enable)
• --run-benchmark: launch benchmark suite (default: disable)
• --dist: build a .tar.gz archive containing all the build artifacts (default: disable)
• --minimal: build 'minimal' Maven profile so JVips dependencies aren't embedded in the .jar file (default: all)
• --debug: enable debugging in JVips and its dependencies (default: release mode)
• --jobs N: use N jobs to build (default: 8)

Run the build with:

$ ./build.sh [options]

Clean the project with:

$ ./clean.sh

🐧 Linux

Install libvips development packages with your favorite package manager.

For Ubuntu and Debian:

$ sudo apt-get install libvips-dev
$ ./build.sh --without-w64 --with-linux --without-macos

For Fedora and CentOS:

$ sudo yum install vips-devel
$ ./build.sh --without-w64 --with-linux --without-macos

To build with Docker:

$ docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) -f .github/docker/linux/Dockerfile -t jvips-builder-linux .
$ docker run --rm -v $(pwd):/app -w /app jvips-builder-linux

🏁 Windows

Windows builds are cross-compiled from Linux using MingW64. Docker and WSL are both supported.

To build with Docker:

$ docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) -f .github/docker/windows/Dockerfile -t builder .
$ docker run --rm -v $(pwd):/app -w /app builder bash -ex build.sh --with-w64 --without-linux --without-macos

To build with WSL:

$ ./setup-for-ubuntu-wsl-w64-target.sh
$ ./build.sh --with-w64 --without-linux --without-macos

🍎 macOS

As macOS is mostly a development environment, JVips doesn't provide tools to build dependencies from sources and will always use system-wide libraries. Homebrew installs all the required dependencies and headers to build JVips as is:

$ brew install vips
$ ./build.sh --without-w64 --without-linux --with-macos

Maintenance

Dependency upgrades

Libraries are downloaded from hard-coded URL in lib/build.sh. Libraries can be upgraded by changing the version number in lib/variable.sh.

Benchmark

To run a benchmark:

1. ./build.sh --run-benchmark

On an Ubuntu 18.04 VM running with a quad-core Xeon E3-1271 v3 @ 3.6GHz, we apply the following operations:

• open an 1920x1080 jpg image
• resize to 512x512 dimension
• crop a 128x128 rectangle on the top left corner
• pad to a 256x256 image
• write the output image into a buffer
• release resources

Implementation	Run time (ms)	Times slower
Vips C 8.7	12	1.0
JVips 1.0	22	1.83

According to these results, JVips is as slower as py-vips.

Tests

JVips tests are a good starting point to see how methods can be used.

vips function bindings

The following steps explain how to bind a function from libvips.

Let's add hasAlpha() method:

1. Declare method in VipsImage interface
2. Declare native method in VipsImageImpl

public native boolean hasAlpha();

3. Run build.sh to generate JNI header file:

/*
 * Class:     com_criteo_vips_VipsImageImpl
 * Method:    hasAlpha
 * Signature: ()Z
 */
JNIEXPORT jboolean JNICALL Java_com_criteo_vips_VipsImageImpl_hasAlpha
  (JNIEnv *, jobject);

4. Define and implement function in src/main/c/VipsImage.c

JNIEXPORT jboolean JNICALL
Java_com_criteo_vips_VipsImageImpl_hasAlpha(JNIEnv *env, jobject obj)
{
    VipsImage *im = (VipsImage *) (*env)->GetLongField(env, obj, handle_fid);
    return vips_image_hasalpha(im);
}

Docker debugging

To debug the Docker image, you should build, run, and enter it as root:

$ docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) -f .github/docker/linux/Dockerfile -t builder .
$ docker run --rm -v $(pwd):/app -w /app -u root -it builder bash

TODO

• Add the missing operations
• Adapt the binding design for calling function by operation name (see also: https://libvips.github.io/libvips/API/current/binding.md.html)
• Publish artifacts to Maven Central

Contact

JVips is developed and maintained by Criteo. All inquiries should go to github@criteo.com.