qrcodegen QR Code Generator Library

This library is a C implementation of a QR Code generator designed for correctness, flexibility, and safety.

Key Features:

• No Heap Allocation: The library avoids malloc(), relying instead on caller-provided buffers and fixed-size stack allocations. This makes it suitable for embedded systems.
• Standard Compliance: Supports all 40 versions (sizes) and all 4 error correction levels of the QR Code Model 2 standard.
• Output Format: Produces raw modules/pixels of the QR symbol.
• Flexible Encoding: Supports numeric, special-alphanumeric, and general text encoding, as well as binary data.
• Manual Control: Allows users to specify version ranges, mask patterns, error correction levels, and data segments/ECI segments.
• Safety: Coded to prevent memory corruption, integer overflow, and undefined behavior.

The C++ implementation of the QR Code generator library provides:

• Standard Compliance: Supports all 40 versions (sizes) and all 4 error correction levels per the QR Code Model 2 standard.
• Flexible Encoding: Automatically chooses the smallest version within a user-specified range and can automatically select the optimal mask pattern (out of 8 possible masks).
• Optimized Data: Encodes numeric and special-alphanumeric text more efficiently than general text.
• Output: Provides raw modules/pixels of the QR symbol.
• Safety: Designed to prevent memory corruption, integer overflow, and undefined behavior.

The library provides a high-fidelity implementation of the QR Code Model 2 standard with the following capabilities:

• Multi-language support: Available in Java, TypeScript/JavaScript, Python, Rust, C++, and C.
• Standard Compliance: Supports all 40 versions (sizes) and all 4 error correction levels.
• Flexible Encoding: Automatically chooses the smallest version within a user-specified range and selects the optimal mask pattern (out of 8 possible masks).
• Manual Control: Users can manually specify minimum/maximum versions, mask patterns, absolute error correction levels, and custom data segments (including ECI segments).
• Output: Provides raw modules/pixels for custom rendering.
• Advanced Java Features: Includes support for Japanese Unicode text in kanji mode and optimal segment mode switching for mixed text types.

Use qrcodegen.QrCode.encodeText to generate a QR code from a string. You must specify the error correction level using qrcodegen.QrCode.Ecc.

Supported error correction levels:

• QRC.Ecc.LOW
• QRC.Ecc.MEDIUM
• QRC.Ecc.QUARTILE
• QRC.Ecc.HIGH

const QRC = qrcodegen.QrCode;
const qr0 = QRC.encodeText("Hello, world!", QRC.Ecc.MEDIUM);

For more control, you can create data segments using qrcodegen.QrSegment.makeSegments and then encode them using qrcodegen.QrCode.encodeSegments.

encodeSegments parameters:

• segments: The list of data segments.
• errorCorrectionLevel: The desired qrcodegen.QrCode.Ecc level.
• minVersion: Minimum QR version (1-40).
• maxVersion: Maximum QR version (1-40).
• maskPattern: Manual mask pattern (0-7), or -1 to let the library choose.
• useEnhancedErrorCorrection: Boolean to allow the library to boost error correction if it doesn't increase the version number.

const QRC = qrcodegen.QrCode;
const segs = qrcodegen.QrSegment.makeSegments("3141592653589793238462643383");
const qr1 = QRC.encodeSegments(segs, QRC.Ecc.HIGH, 5, 5, 2, false);

For more control, you can manually create data segments using QrSegment.makeSegments and then use QrCode.encodeSegments. This allows you to specify version ranges, mask patterns, and error correction levels.

Note: While the example below is in Java, other language ports (TypeScript, Python, Rust, C++, C) follow essentially the same API naming and behavior.

import java.util.List;
import io.nayuki.qrcodegen.*;

// Manual operation
List<QrSegment> segs = QrSegment.makeSegments("3141592653589793238462643383");
QrCode qr1 = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, 5, 5, 2, false);

// Accessing modules
for (int y = 0; y < qr1.size; y++) {
    for (int x = 0; x < qr1.size; x++) {
        boolean isBlack = qr1.getModule(x, y);
        // (... paint qr1.getModule(x, y) ...)
    }
}

To generate a QR code with default settings using a single text string, use QrCode::encode_text. You must specify the error correction level using QrCodeEcc.

Available error correction levels include QrCodeEcc::Low, QrCodeEcc::Medium, QrCodeEcc::Quartile, and QrCodeEcc::High.

extern crate qrcodegen;
use qrcodegen::QrCode;
use qrcodegen::QrCodeEcc;

// Simple operation
let qr = QrCode::encode_text("Hello, world!",
    QrCodeEcc::Medium).unwrap();

Use QrCode.encodeText(text, ecc) to generate a QR code from a string. You can specify the Error Correction Code (ECC) level using QrCode.Ecc constants (e.g., MEDIUM, HIGH). The output is a QrCode object containing the raw modules.

import io.nayuki.qrcodegen.*;

// Simple operation
QrCode qr0 = QrCode.encodeText("Hello, world!", QrCode.Ecc.MEDIUM);

Use QrCode.encodeText(text, ecc) to generate a QR code from a string. You must provide the text and an error correction level (QrCode.Ecc).

To visualize the output, you can iterate over the modules using qr.getModule(x, y) or use a helper like toImage (as shown in the example) to convert the raw modules into a BufferedImage.

import io.nayuki.fastqrcodegen.*;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

// 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"));

Use QrCode.encode_text to quickly generate a QR code from a string. You can specify the Error Correction Code (ECC) level using QrCode.Ecc. To convert the resulting QR code to an SVG string, use to_svg_str(qr_code, border_size).

from qrcodegen import *

# Simple operation
qr0 = QrCode.encode_text("Hello, world!", QrCode.Ecc.MEDIUM)
svg = to_svg_str(qr0, 4)