QR Code Generator for .NET

Open-source library for generating QR codes from text strings and byte arrays.

.NET API Documention

• QrCode: Creates and represents QR codes

• QrSegment: Represents a segment of character/binary/control data in a QR code symbol

• QrSegmentAdvanced: Advanced methods for encoding QR codes using Kanji mode or using multiple segments with different encodings.

• All types and classes

Additional information on GitHub project page

Features

Core features:

• Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard
• Output formats: Raw modules/pixels of the QR symbol and SVG XML string
• Encodes numeric and special alphanumeric text in less space than general text
• Open source code under the permissive MIT License
• Significantly shorter code but more documentation compared to competing libraries
• Available as a NuGet package (named Net.Codecrete.QrCodeGenerator)

Manual parameters:

• You can specify the minimum and maximum version number allowed, and the library will automatically choose the smallest version in the range that fits the data.
• You can specify the mask pattern manually, otherwise library will automatically evaluate all 8 masks and select the optimal one.
• You can specify an error correction level, or optionally allow the library to boost it if it doesn't increase the version number.
• You 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

Examples

Simple operation:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class SimpleOperation
    {
        static void Main()
        {
            var qr = QrCode.EncodeText("Hello, world!", QrCode.Ecc.Medium);
            string svg = qr.ToSvgString(4);
            File.WriteAllText("hello-world-qr.svg", svg, Encoding.UTF8);
        }
    }
}

Manual operation:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class ManualOperation
    {
        static void Main()
        {
            var segments = QrCode.MakeSegments("3141592653589793238462643383");
            var qr = QrCode.EncodeSegments(segments, QrCode.Ecc.High, 5, 5, 2, false);
            for (int y = 0; y < qr.Size; y++)
            {
                for (int x = 0; x < qr.Size; x++)
                {
                    ... paint qr.GetModule(x,y) ...
                }
            }
        }
    }
}

Requirements

QR Code Generator for .NET requires a .NET implementation compatible with .NET Standard 2.0 or higher, i.e. any of:

• .NET Core 2.0 or higher
• .NET Framework 4.6.1 or higher
• Mono 5.4 or higher
• Universal Windows Platform 10.0.16299 or higher
• Xamarin

Raster Images / Bitmaps

The previous version of this library depended on System.Drawing, which - starting with .NET 6 - will only be supported on Windows operation system. Therefore, ToBitmap() has been removed and three options are now offered in the form of method extensions.

In order to use it:

• Select one of the libraries
• Add the NuGet dependencies to your project
• Copy the appropriate QrCodeBitmapExtensions.cs file to your project

Library	Recommendation	NuGet dependencies	Extension file
System.Drawing	For Windows only projects	System.Drawing.Common	QrCodeBitmapExtensions.cs
SkiaSharp	For macOS, Linux, iOS, Android and multi-platform projects	SkiaSharp and SkiaSharp.NativeAssets.Linux (for Linux only)	QrCodeBitmapExtensions.cs
ImageSharp	Currently in beta state	SixLabors.ImageSharp.Drawing	QrCodeBitmapExtensions.cs

Using these extension methods, generating PNG images is straight-forward:

using Net.Codecrete.QrCodeGenerator;

namespace Examples
{
    class PngImage
    {
        static void Main()
        {
            var qr = QrCode.EncodeText("Hello, world!", QrCode.Ecc.Medium);
            qr.SaveAsPng("hello-world-qr.png", 10, 3);
        }
    }
}