libquirc‑java‑wrapper

A lightweight JNI wrapper around Daniel Beer’s quirc C library that lets you decode QR codes in pure Java (no external processes) while shipping the native code you need.

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Why use this project?

• Zero runtime dependencies – the native libquirc is bundled and extracted at startup.
• Simple API – pass a BufferedImage (or raw RGB data) and get all decoded strings back.
• Fast – quirc is one of the quickest open‑source QR scanners.
• Permissive licence – MIT for Java/JNI code, original quirc is ISC.

Getting started

1. Add the dependency

<dependency>
    <groupId>org.libquirc</groupId>
    <artifactId>libquirc-wrapper</artifactId>
    <version>1.2-a9c52e79283d6872728e68fec7892dc7c276c827</version>
</dependency>

Note: pre‑built binaries are included for Linux x86_64. For other platforms you’ll need to build from source.

2. Decode your first QR code

import org.libquirc.*;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;

public class Demo {
    public static void main(String[] args) throws Exception {
        // 1. Load the native library once
        QuircLoader.loadLibrary();

        // 2. Read an image and copy pixel data
        BufferedImage img = ImageIO.read(new File("qr.png"));
        int[] pixels = img.getRGB(0, 0, img.getWidth(), img.getHeight(), null, 0, img.getWidth());

        // 3. Wrap and decode
        QuircImage qimg = new QuircImage(img.getWidth(), img.getHeight(), pixels);
        String[] results = qimg.decode();

        for (String s : results) System.out.println("Decoded: " + s);
    }
}

Build from source

Requires JDK 8+ and a recent GCC/Clang toolchain on Linux. The project uses Maven; the steps below are required to compile C++ objects and JNI.

Required manual build step

1. Open shell
2. Execute cd projroot/src/main/resources/jni/linux
3. Compile JNI
   • g++ -c -fPIC -I/path/to/jvm/include/ -I/path/to/jvm/include/linux org_libquirc_QuircImage.cpp -o ../../../c/org_libquirc_QuircImage.o -I../../native/linux
   • g++ -shared -fPIC -o libquirc.so ../../../c/org_libquirc_QuircImage.o ../../native/linux/libquirc.a -lc
4. Execute Maven clean, compile, install (or deploy)

Automated build

From the project root:

mvn clean package

This compiles the Java sources, builds the JNI objects, and assembles the JAR with libquirc.so inside target/.

Project structure

libquirc-java-wrapper/
 ├── src/main/java           # Java wrapper classes
 │   └── org/libquirc/*
 ├── src/main/c              # JNI glue code
 ├── src/main/resources/
 │   └── jni/linux           # Pre‑built shared library (.so)
 ├── pom.xml                 # Maven build file
 ├── LICENSE                 # MIT licence (wrapper code)
 ├── NOTICE                  # Full copyright notice
 └── README.md               # You are here

Contributing

Issues and pull requests are welcome!

Credits

• Daniel Beer – author of the original quirc library.
• Matteo Riva – Java/JNI wrapper.

See NOTICE for full attribution details.

Licence

This wrapper code is licensed under the MIT License; the bundled quirc C library remains under the ISC License. See LICENSE for details.

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