History

Project Nayuki 8329a7108f Slightly simplified the calculation of alignment pattern spacing in a non-obvious way, adapted from David Evans's "Lean QR" project.		3 months ago
..
src/main/java	Slightly simplified the calculation of alignment pattern spacing in a non-obvious way, adapted from David Evans's "Lean QR" project.	3 months ago
QrCodeGeneratorDemo.java	Moved QrCodeGeneratorDemo.java out of the package because it's an informal demo and not a core library feature; this also simplifies the Maven build process.	3 years ago
Readme.markdown	- In the project (top-level) readme file, kept one language's code example and moved all others out to language-specific readme files.	3 years ago
pom.xml	Updated package version numbers.	3 years ago

Readme.markdown

QR Code generator library - Java

Introduction

This project aims to be the best, clearest QR Code generator library. The primary goals are flexible options and absolute correctness. Secondary goals are compact implementation size and good documentation comments.

Home page with live JavaScript demo, extensive descriptions, and competitor comparisons: https://www.nayuki.io/page/qr-code-generator-library

Features

Core features:

Significantly shorter code but more documentation comments compared to competing libraries
Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard
Output format: Raw modules/pixels of the QR symbol
Detects finder-like penalty patterns more accurately than other implementations
Encodes numeric and special-alphanumeric text in less space than general text
Open-source code under the permissive MIT License

Manual parameters:

User can specify minimum and maximum version numbers allowed, then library will automatically choose smallest version in the range that fits the data
User can specify mask pattern manually, otherwise library will automatically evaluate all 8 masks and select the optimal one
User can specify absolute error correction level, or allow the library to boost it if it doesn't increase the version number
User can create a list of data segments manually and add ECI segments

Optional advanced features:

Encodes Japanese Unicode text in kanji mode to save a lot of space compared to UTF-8 bytes
Computes optimal segment mode switching for text with mixed numeric/alphanumeric/general/kanji parts

More information about QR Code technology and this library's design can be found on the project home page.

Examples

import java.awt.image.BufferedImage;
import java.io.File;
import java.util.List;
import javax.imageio.ImageIO;
import io.nayuki.qrcodegen.*;

// Simple operation
QrCode qr0 = QrCode.encodeText("Hello, world!", QrCode.Ecc.MEDIUM);
BufferedImage img = toImage(qr0, 4, 10);  // See QrCodeGeneratorDemo
ImageIO.write(img, "png", new File("qr-code.png"));

// Manual operation
List<QrSegment> segs = QrSegment.makeSegments("3141592653589793238462643383");
QrCode qr1 = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, 5, 5, 2, false);
for (int y = 0; y < qr1.size; y++) {
    for (int x = 0; x < qr1.size; x++) {
        (... paint qr1.getModule(x, y) ...)
    }
}

More complete set of examples: https://github.com/nayuki/QR-Code-generator/blob/master/java/QrCodeGeneratorDemo.java .