QRCoder.Core - QR Code Generator Library

Leia em Portugues (pt-BR)

Documentation

Usage Guide (English) — PNG, SVG, PDF, ASCII, Base64, Postscript, Artistic QR Codes
Guia de Uso (Portugues) — PNG, SVG, PDF, ASCII, Base64, Postscript, QR Codes Artisticos

Project Description

QRCoder.Core is a cross-platform .NET library for QR Code generation using SkiaSharp for image rendering. Compatible with Windows, Linux, macOS, and mobile (Xamarin / MAUI).

Based on QRCoder. Developed and maintained by AFONSOFT.

Supported Output Formats

Format	Class	Description
SKBitmap	`QRCode`	SkiaSharp bitmap image (cross-platform)
PNG	`PngByteQRCode`	PNG byte array (no System.Drawing needed)
SVG	`SvgQRCode`	Scalable vector graphics string
PDF	`PdfByteQRCode`	PDF document as byte array
ASCII	`ASCIIQRCode`	ASCII art for terminal output
Base64	`Base64QRCode`	Base64-encoded image string
Postscript	`PostscriptQRCode`	Postscript/EPS format
Artistic	`ArtQRCode`	Custom QR with rounded dots and backgrounds
BMP Bytes	`BitmapByteQRCode`	Bitmap byte array

Supported Payload Types

The PayloadGenerator class provides formatted strings for common QR code use cases:

Payload	Description
`Url`	Website URL
`WiFi`	Wi-Fi network credentials
`Mail`	Email with subject and body
`SMS`	SMS message
`PhoneNumber`	Phone number
`MMS`	Multimedia message
`Geolocation`	GPS coordinates
`CalendarEvent`	Calendar event (iCal/vEvent)
`ContactData`	vCard / MeCard contact
`BitcoinLikeCryptoCurrencyAddress`	Bitcoin/crypto payment
`Girocode`	European SEPA payment
`BezahlCode`	German payment standard
`SwissQrCode`	Swiss QR-bill payment
`OneTimePassword`	TOTP/HOTP for 2FA
`ShadowSocksConfig`	ShadowSocks proxy config
`Bookmark`	Browser bookmark
`SkypeCall`	Skype call link
`WhatsAppMessage`	WhatsApp message
`RussiaPaymentOrder`	Russian payment order
`SlovenianUpnQr`	Slovenian UPN QR payment

Test Coverage

Metric	Coverage	Status
Line Coverage	78%+	Good
Branch Coverage	83%+	Excellent
Method Coverage	78%+	Good
Total Tests	300+	All Passed

Project Status

Complete - Actively maintained with modern CI/CD pipelines.

Prerequisites

This library is compatible with multiple .NET versions:

.NET Standard 2.1 — Maximum compatibility
.NET 8.0 — LTS recommended
.NET 10.0 — Latest version
.NET Framework 4.8 — Legacy support

Technologies Used:

C# — Primary programming language
SkiaSharp — Cross-platform graphics library for rendering
SkiaSharp.Views — SkiaSharp UI components
System.Text.Encoding.CodePages — Additional code page support

Installation

NuGet Package Manager (recommended)

Install-Package QRCoder.Core

.NET CLI

dotnet add package QRCoder.Core

PackageReference

<PackageReference Include="QRCoder.Core" Version="2.0.0" />

Quick Start

Generate your first QR code with just a few lines of code:

using QRCoder.Core;
using SkiaSharp;

// Create the QR Code generator
using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("https://github.com/afonsoft/QRCoder.Core",
    QRCodeGenerator.ECCLevel.M);

// Render as PNG bytes (cross-platform, no System.Drawing needed)
using var png = new PngByteQRCode(data);
byte[] pngBytes = png.GetGraphic(10);
File.WriteAllBytes("qrcode.png", pngBytes);

// Or render as SKBitmap
using var qrCode = new QRCode(data);
using var bitmap = qrCode.GetGraphic(10);

More Output Formats

// SVG output
using var svg = new SvgQRCode(data);
string svgString = svg.GetGraphic(10);

// ASCII output (great for terminal)
using var ascii = new ASCIIQRCode(data);
Console.WriteLine(ascii.GetGraphic(1));

// PDF output
using var pdf = new PdfByteQRCode(data);
byte[] pdfBytes = pdf.GetGraphic(5);

// Base64 PNG (embed in HTML)
using var b64 = new Base64QRCode(data);
string base64Img = b64.GetGraphic(10);
// Use in HTML: <img src="data:image/png;base64,{base64Img}" />

// With custom colors
using var colorQr = new QRCode(data);
using var colorBmp = colorQr.GetGraphic(10, "#1a1a2e", "#e0e0e0");

// Postscript / EPS
using var ps = new PostscriptQRCode(data);
string psString = ps.GetGraphic(5);

Payload Examples

using QRCoder.Core;

// Wi-Fi QR Code
var wifiPayload = new PayloadGenerator.WiFi("MyNetwork", "MyPassword",
    PayloadGenerator.WiFi.Authentication.WPA);
using var gen = new QRCodeGenerator();
using var wifiData = gen.CreateQrCode(wifiPayload.ToString(), QRCodeGenerator.ECCLevel.M);

// URL QR Code
var urlPayload = new PayloadGenerator.Url("https://github.com/afonsoft/QRCoder.Core");
using var urlData = gen.CreateQrCode(urlPayload.ToString(), QRCodeGenerator.ECCLevel.M);

// Email QR Code
var mailPayload = new PayloadGenerator.Mail("test@example.com", "Subject", "Body text");
using var mailData = gen.CreateQrCode(mailPayload.ToString(), QRCodeGenerator.ECCLevel.M);

// Phone Number
var phonePayload = new PayloadGenerator.PhoneNumber("+5511999999999");
using var phoneData = gen.CreateQrCode(phonePayload.ToString(), QRCodeGenerator.ECCLevel.M);

// Contact Card (vCard)
var contactPayload = new PayloadGenerator.ContactData(
    PayloadGenerator.ContactData.ContactOutputType.VCard3,
    "Doe", "John",
    phone: "+5511999999999",
    email: "john.doe@example.com");
using var contactData = gen.CreateQrCode(contactPayload.ToString(), QRCodeGenerator.ECCLevel.M);

See the full Usage Guide for all output formats, payload types, advanced settings, and error correction levels.

Error Correction Levels

Level	Recovery	Use Case
`ECCLevel.L`	~7%	Maximum data capacity
`ECCLevel.M`	~15%	General purpose (recommended)
`ECCLevel.Q`	~25%	Higher reliability
`ECCLevel.H`	~30%	Maximum error recovery (logos, artistic QR)

Repository Structure

.
├── QRCoder.Core/              # Core library source code
│   ├── QRCodeGenerator.cs     # Main QR code data generator
│   ├── QRCodeData.cs          # QR code data structure
│   ├── QRCode.cs              # SKBitmap renderer
│   ├── PngByteQRCode.cs       # PNG byte array renderer
│   ├── SvgQRCode.cs           # SVG string renderer
│   ├── PdfByteQRCode.cs       # PDF byte array renderer
│   ├── ASCIIQRCode.cs         # ASCII art renderer
│   ├── Base64QRCode.cs        # Base64 image renderer
│   ├── PostscriptQRCode.cs    # Postscript/EPS renderer
│   ├── ArtQRCode.cs           # Artistic QR code renderer
│   ├── BitmapByteQRCode.cs    # BMP byte array renderer
│   ├── AbstractQRCode.cs      # Base class for renderers
│   ├── PayloadGenerator.cs    # Payload formatters (WiFi, URL, etc.)
│   └── Assets/                # NuGet assets
├── QRCoder.Core.Tests/        # Unit tests (300+ tests)
├── docs/
│   ├── en-US/usage-guide.md   # English usage guide
│   └── pt-BR/guia-de-uso.md   # Portuguese usage guide
└── Docs/media/                # Documentation media assets

CI/CD and Build

This project uses a complete CI/CD pipeline with GitHub Actions:

Available Workflows

Build & Pack — Main build with tests, coverage, and package creation
Code Quality — Code analysis with Qodana and SonarCloud
Security Scans — Security analysis with CodeQL, Snyk, and SonarCloud
Publish NuGet — Automatic publishing to NuGet.org and GitHub Packages
CI Build & Test — Continuous build and automated testing

Running Tests Locally

# Build the project
dotnet build QRCoder.Core.sln --configuration Release

# Run all tests with coverage
dotnet test QRCoder.Core.Tests/QRCoder.Core.Tests.csproj \
  --configuration Release \
  --logger "trx;LogFileName=test-results.trx" \
  --results-directory TestResults \
  --collect:"XPlat Code Coverage"

# Generate HTML coverage report
dotnet tool install -g dotnet-reportgenerator-globaltool
reportgenerator \
  -reports:"TestResults/**/coverage.cobertura.xml" \
  -targetdir:"TestResults/CoverageReport" \
  -reporttypes:"Html;XmlSummary;TextSummary"

# View report: open TestResults/CoverageReport/index.html

Contributing

Create a branch from main:
```
git checkout -b feature/your-feature
```
Make your changes following code conventions
Automated workflows will run:
- Build & Pack — Validates your code
- Code Quality — Analyzes quality
- Security Scan — Checks security
Pull Request: Create a PR to main
Review and Merge: After approval, your code will be merged

Developers

Afonso Dutra Nogueira Filho (AFONSOFT) — Lead developer

License

This project is licensed under the MIT License. See the LICENSE.txt file for details.

Changelog

[2.0.0] - Latest

Changed

Multi-language documentation (en-US default + pt-BR)
Updated NuGet package README with examples

[1.0.6] - 2025-02-17

Added

Comprehensive test coverage reporting (78% line, 83.1% branch, 78.1% method)
239 unit tests across all target frameworks
Performance optimization packages
Complete CI/CD pipeline with GitHub Actions
Support for .NET 10.0 target framework
Multiple security scans (CodeQL, Snyk, SonarCloud)

Changed

Updated README with detailed test coverage information
Updated target frameworks: .NET Standard 2.1, .NET 8.0, .NET 10.0, .NET Framework 4.8

Fixed

GitHub Actions syntax issues
Environment variable references

[1.0.5] - 2025-02-17

Added

Support for .NET 10.0 target framework
Complete CI/CD pipeline
Automated NuGet publishing workflow

[1.0.4] - 2025-07-13

Changed

General adjustments in the project and documentation
SkiaSharp adjustments

[1.0.3] - 2024-04-01

Fixed

Action corrections

Changed

Dependency updates (codecov/codecov-action, NuGet/setup-nuget)

Name		Name	Last commit message	Last commit date
Latest commit History 208 Commits
.github		.github
.vscode		.vscode
Docs		Docs
QRCoder.Core.Tests		QRCoder.Core.Tests
QRCoder.Core		QRCoder.Core
docs		docs
.gitattributes		.gitattributes
.gitignore		.gitignore
BUILD_TEST_REPORT.md		BUILD_TEST_REPORT.md
CHANGELOG.md		CHANGELOG.md
LICENSE.txt		LICENSE.txt
QRCoder.Core.Docs.shfbproj		QRCoder.Core.Docs.shfbproj
QRCoder.Core.Docs.sln		QRCoder.Core.Docs.sln
QRCoder.Core.sln		QRCoder.Core.sln
README.md		README.md
README.pt-br.md		README.pt-br.md
readme.md		readme.md

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Latest commit

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QRCoder.Core - QR Code Generator Library

Documentation

Project Description

Supported Output Formats

Supported Payload Types

Test Coverage

Project Status

Prerequisites

Installation

NuGet Package Manager (recommended)

.NET CLI

PackageReference

Quick Start

More Output Formats

Payload Examples

Error Correction Levels

Repository Structure

CI/CD and Build

Available Workflows

Running Tests Locally

Contributing

Developers

License

Changelog

[2.0.0] - Latest

Changed

[1.0.6] - 2025-02-17

Added

Changed

Fixed

[1.0.5] - 2025-02-17

Added

[1.0.4] - 2025-07-13

Changed

[1.0.3] - 2024-04-01

Fixed

Changed

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