QR Code Generator & Reader Library

A comprehensive C library for generating and reading QR codes, supporting all QR Code Model 2 specifications from version 1 to 40.

English | 中文 | 日本語

English

Overview

This library provides functionality for both generating and reading QR codes. It includes:

• QR Code Generation: Create QR codes from text or binary data
• QR Code Reading: Decode QR codes from image data using ZXing integration

Features

• ✅ All QR Code versions (1-40) supported
• ✅ All 4 error correction levels (Low, Medium, Quartile, High)
• ✅ Multiple encoding modes (Numeric, Alphanumeric, Byte, Kanji, ECI)
• ✅ Automatic mask pattern selection
• ✅ Image reading capabilities for QR code decoding
• ✅ Thread-safe operations
• ✅ No heap allocation required

Quick Start

Generating QR Codes

#include "qrcodegen.h"

// Text encoding
uint8_t qrcode[qrcodegen_BUFFER_LEN_MAX];
uint8_t tempBuffer[qrcodegen_BUFFER_LEN_MAX];

bool ok = qrcodegen_encodeText("Hello, World!", tempBuffer, qrcode,
    qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX,
    qrcodegen_Mask_AUTO, true);

if (ok) {
    int size = qrcodegen_getSize(qrcode);
    // Use qrcodegen_getModule(qrcode, x, y) to access individual modules
}

Reading QR Codes

#include "ImageReaderSource.h"

// Create image source from raw image data
ImageReaderSource source(imageData, width, height, components);

// Process with ZXing decoder
// (Additional ZXing integration code required)

API Reference

Main Functions

• qrcodegen_encodeText() - Encode text string to QR code
• qrcodegen_encodeBinary() - Encode binary data to QR code
• qrcodegen_encodeSegments() - Encode custom segments
• qrcodegen_getSize() - Get QR code size
• qrcodegen_getModule() - Get module state at coordinates

Error Correction Levels

• qrcodegen_Ecc_LOW - ~7% error correction
• qrcodegen_Ecc_MEDIUM - ~15% error correction
• qrcodegen_Ecc_QUARTILE - ~25% error correction
• qrcodegen_Ecc_HIGH - ~30% error correction

License

This project uses code from:

• QR Code generator library by Project Nayuki (MIT License)
• ZXing library components (Apache License 2.0)

Building

# Compile the library
gcc -c qrcodegen.c -o qrcodegen.o
gcc -c ImageReaderSource.cpp -o ImageReaderSource.o

# Link with your application
gcc your_app.c qrcodegen.o ImageReaderSource.o -o your_app

Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

Support

For questions and issues, please refer to the original libraries' documentation:

• QR Code generator by Project Nayuki
• ZXing Project