QRCoder.Core — Usage Guide (en-US)

Cross-platform .NET library for QR Code generation using SkiaSharp. Compatible with Windows, Linux, macOS, and mobile (Xamarin / MAUI).

Installation
Quick Start
Output Formats
- QRCode (SKBitmap)
- PNG Bytes
- SVG
- Base64
- PDF
- ASCII Art
- Postscript / EPS
- Artistic QR Code
- BMP Bytes
Payloads (Content Types)
Advanced Settings
Supported Platforms

Installation

dotnet add package QRCoder.Core

Or via NuGet Package Manager:

Install-Package QRCoder.Core

Platform-Specific Dependencies

SkiaSharp requires native libraries for each platform. QRCoder.Core automatically includes the correct dependencies:

Platform	Native Package
Linux	`SkiaSharp.NativeAssets.Linux`
macOS	`SkiaSharp.NativeAssets.macOS`
Windows	`SkiaSharp.NativeAssets.Win32`
Android	`SkiaSharp.NativeAssets.Android`
iOS	`SkiaSharp.NativeAssets.iOS`

Quick Start

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

// 1. Create the generator
using var generator = new QRCodeGenerator();

// 2. Generate QR Code data
using var data = generator.CreateQrCode("https://github.com/afonsoft/QRCoder.Core",
    QRCodeGenerator.ECCLevel.M);

// 3. Render as image
using var qrCode = new QRCode(data);
using var image = qrCode.GetGraphic(10); // 10 pixels per module

// 4. Save as PNG
using var stream = File.OpenWrite("qrcode.png");
image.Encode(stream, SKEncodedImageFormat.Png, 100);

Output Formats

QRCode (SKBitmap)

Generates an SKBitmap with the QR Code rendered via SkiaSharp.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Hello World!", QRCodeGenerator.ECCLevel.H);
using var qr = new QRCode(data);

// Default black and white
using var bmp = qr.GetGraphic(10);

// Custom colors
using var colorBmp = qr.GetGraphic(10, SKColors.DarkBlue, SKColors.LightGray, true);

// Using hex colors
using var hexBmp = qr.GetGraphic(10, "#1a1a2e", "#e0e0e0");

// With centered logo
using var logo = SKBitmap.Decode("logo.png");
using var logoBmp = qr.GetGraphic(10, SKColors.Black, SKColors.White,
    icon: logo, iconSizePercent: 15, iconBorderWidth: 2);

PNG Bytes

Generates the QR Code directly as a PNG byte array — ideal for APIs and web services.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("API Data", QRCodeGenerator.ECCLevel.M);
using var png = new PngByteQRCode(data);

// Default black and white
byte[] pngBytes = png.GetGraphic(5);
File.WriteAllBytes("qrcode.png", pngBytes);

// With custom colors (RGB)
byte[] darkColor = new byte[] { 0, 0, 128 };      // Dark blue
byte[] lightColor = new byte[] { 255, 255, 200 };  // Light yellow
byte[] colorBytes = png.GetGraphic(5, darkColor, lightColor);

// With transparency (RGBA)
byte[] darkAlpha = new byte[] { 0, 0, 0, 255 };
byte[] lightAlpha = new byte[] { 255, 255, 255, 128 };  // Semi-transparent
byte[] alphaBytes = png.GetGraphic(5, darkAlpha, lightAlpha);

SVG

Generates the QR Code as an SVG string — perfect for web and vector documents.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("https://example.com", QRCodeGenerator.ECCLevel.Q);
using var svg = new SvgQRCode(data);

// Default SVG
string svgString = svg.GetGraphic(10);
File.WriteAllText("qrcode.svg", svgString);

// With custom colors
string colorSvg = svg.GetGraphic(10, SKColors.DarkRed, SKColors.White);

// With specific viewBox size
string viewBoxSvg = svg.GetGraphic(new Size(200, 200));

// Without quiet zone
string noBorderSvg = svg.GetGraphic(10, SKColors.Black, SKColors.White, false);

// With embedded SVG logo
string svgLogo = File.ReadAllText("logo.svg");
var logoObj = new SvgQRCode.SvgLogo(svgLogo, 15);
string logoSvg = svg.GetGraphic(10, SKColors.Black, SKColors.White, logo: logoObj);

Base64

Generates the QR Code as Base64-encoded string — useful for embedding in HTML/CSS.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Base64 Data", QRCodeGenerator.ECCLevel.M);
using var b64 = new Base64QRCode(data);

// PNG as Base64
string base64Png = b64.GetGraphic(5);

// JPEG as Base64
string base64Jpeg = b64.GetGraphic(5, SKColors.Black, SKColors.White,
    true, Base64QRCode.ImageType.Jpeg);

// Use in HTML
string htmlImg = $"<img src=\"data:image/png;base64,{base64Png}\" alt=\"QR Code\" />";

PDF

Generates the QR Code as a PDF document in bytes.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("PDF Document", QRCodeGenerator.ECCLevel.M);
using var pdf = new PdfByteQRCode(data);

// Default PDF
byte[] pdfBytes = pdf.GetGraphic(5);
File.WriteAllBytes("qrcode.pdf", pdfBytes);

// With custom colors and DPI
byte[] colorPdf = pdf.GetGraphic(5, "#000080", "#FFFFFF", 300, 95);

ASCII Art

Generates the QR Code as ASCII text — useful for terminal output and logs.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Terminal QR", QRCodeGenerator.ECCLevel.L);
using var ascii = new AsciiQRCode(data);

// Default
string text = ascii.GetGraphic(1);
Console.WriteLine(text);

// Custom symbols
string custom = ascii.GetGraphic(1, "██", "  ", true);

// Get line by line
string[] lines = ascii.GetLineByLineGraphic(1);
foreach (var line in lines)
    Console.WriteLine(line);

// Via helper (one-liner)
string result = AsciiQRCodeHelper.GetQRCode("Quick!", 1, "██", "  ",
    QRCodeGenerator.ECCLevel.M);

Postscript / EPS

Generates the QR Code in Postscript or EPS format.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Print Quality", QRCodeGenerator.ECCLevel.M);
using var ps = new PostscriptQRCode(data);

// Standard Postscript
string postscript = ps.GetGraphic(5);
File.WriteAllText("qrcode.ps", postscript);

// EPS format
string eps = ps.GetGraphic(5, epsFormat: true);
File.WriteAllText("qrcode.eps", eps);

// With colors
string colorPs = ps.GetGraphic(5, "#FF0000", "#FFFFFF");

// With viewBox
string viewBoxPs = ps.GetGraphic(new Size(200, 200));

Artistic QR Code

Generates QR Codes with artistic styling (dots instead of squares).

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Artistic QR", QRCodeGenerator.ECCLevel.H);
using var art = new ArtQRCode(data);

// Default (rounded dots)
using var bmp = art.GetGraphic(10);

// With custom pixel size (0.0 to 1.0)
using var smallBmp = art.GetGraphic(10, SKColors.Black, SKColors.White,
    SKColors.Transparent, pixelSizeFactor: 0.5);

// With background image
using var background = SKBitmap.Decode("background.png");
using var bgBmp = art.GetGraphic(background);

// With custom finder pattern
using var finder = SKBitmap.Decode("finder.png");
using var customBmp = art.GetGraphic(10, SKColors.Black, SKColors.White,
    SKColors.Transparent, finderPatternImage: finder);

BMP Bytes

Generates the QR Code as a Windows Bitmap byte array.

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("BMP test", QRCodeGenerator.ECCLevel.M);
using var bmp = new SKBitmapByteQRCode(data);

// Default
byte[] bmpBytes = bmp.GetGraphic(5);

// With hex colors
byte[] colorBytes = bmp.GetGraphic(5, "#FF0000", "#00FF00");

// Via helper
byte[] helperBytes = SKBitmapByteQRCodeHelper.GetQRCode("Quick!", 5,
    "#000000", "#FFFFFF", QRCodeGenerator.ECCLevel.M);

Payloads (Content Types)

The PayloadGenerator creates structured content for various QR Code types:

WiFi

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var wifi = new PayloadGenerator.WiFi("MyNetwork", "MyPassword123",
    PayloadGenerator.WiFi.Authentication.WPA);
string content = wifi.ToString();

// Hidden network
var hiddenWifi = new PayloadGenerator.WiFi("HiddenNet", "Password",
    PayloadGenerator.WiFi.Authentication.WPA, isHiddenSSID: true);

URL

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var url = new PayloadGenerator.Url("https://github.com/afonsoft/QRCoder.Core");
string content = url.ToString();

Email

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var email = new PayloadGenerator.Mail("contact@example.com",
    "Email Subject", "Message body");
string content = email.ToString();

SMS

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var sms = new PayloadGenerator.SMS("+1234567890", "Hello via QR Code!");
string content = sms.ToString();

Phone Number

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var phone = new PayloadGenerator.PhoneNumber("+1234567890");
string content = phone.ToString();
// Result: tel:+1234567890

Geolocation

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var geo = new PayloadGenerator.Geolocation("40.7128", "-74.0060");
string content = geo.ToString();
// Result: geo:40.7128,-74.0060

Bitcoin

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var btc = new PayloadGenerator.BitcoinAddress(
    "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa",
    amount: 0.001,
    label: "Donation",
    message: "Thank you for your support!");
string content = btc.ToString();

vCard (Contact)

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var contact = new PayloadGenerator.ContactData(
    PayloadGenerator.ContactData.ContactOutputType.VCard3,
    firstname: "John",
    lastname: "Doe",
    org: "Example Corp",
    email: "john@example.com",
    phone: "+1234567890",
    street: "123 Main Street",
    city: "New York",
    stateRegion: "NY",
    country: "United States");
string content = contact.ToString();

Calendar Event

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

var calEvent = new PayloadGenerator.CalendarEvent(
    "Team Meeting",
    "Event description",
    "Room 101",
    new DateTime(2026, 06, 15, 14, 0, 0),
    new DateTime(2026, 06, 15, 15, 0, 0),
    true);
string content = calEvent.ToString();

Advanced Settings

Error Correction Levels (ECC)

Level	Recovery Capacity	Recommended For
L	~7%	Simple data, short URLs
M	~15%	General use (default)
Q	~25%	QR Codes with logos
H	~30%	High-wear environments

Data Serialization

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Serializable data", QRCodeGenerator.ECCLevel.M);

// Save to file
data.SaveRawData("data.qrr", QRCodeData.Compression.GZip);

// Load from file
using var loadedData = new QRCodeData("data.qrr", QRCodeData.Compression.GZip);

// Serialize to bytes
byte[] rawBytes = data.GetRawData(QRCodeData.Compression.Deflate);

// Deserialize from bytes
using var fromBytes = new QRCodeData(rawBytes, QRCodeData.Compression.Deflate);

Force UTF-8

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
// Force UTF-8 encoding with BOM
using var data = generator.CreateQrCode("Text with special characters",
    QRCodeGenerator.ECCLevel.M,
    forceUtf8: true,
    utf8BOM: true);

Fixed QR Code Version

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
// Force QR Code version 10 (57x57 modules)
using var data = generator.CreateQrCode("Text",
    QRCodeGenerator.ECCLevel.M,
    requestedVersion: 10);

Supported Platforms

Framework	Version	Status
.NET Standard	2.1	Supported
.NET	8.0	Supported
.NET	10.0	Supported
.NET Framework	4.8	Supported
Xamarin.Android	-	Via SkiaSharp
Xamarin.iOS	-	Via SkiaSharp
.NET MAUI	-	Via SkiaSharp

ASP.NET Core API Example

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

[HttpGet("qrcode")]
public IActionResult GenerateQRCode([FromQuery] string text)
{
    using var generator = new QRCodeGenerator();
    using var data = generator.CreateQrCode(text, QRCodeGenerator.ECCLevel.M);
    using var png = new PngByteQRCode(data);

    byte[] bytes = png.GetGraphic(5);
    return File(bytes, "image/png");
}

.NET MAUI / Xamarin Example

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

public ImageSource GenerateQRCodeImage(string text)
{
    using var generator = new QRCodeGenerator();
    using var data = generator.CreateQrCode(text, QRCodeGenerator.ECCLevel.M);
    using var png = new PngByteQRCode(data);

    byte[] bytes = png.GetGraphic(5);
    return ImageSource.FromStream(() => new MemoryStream(bytes));
}

Console Example

using System;
using System.IO;
using QRCoder.Core.Generators;
using QRCoder.Core.Models;
using QRCoder.Core.Renderers;
using SkiaSharp;

using var generator = new QRCodeGenerator();
using var data = generator.CreateQrCode("Terminal!", QRCodeGenerator.ECCLevel.L);
using var ascii = new AsciiQRCode(data);

Console.WriteLine(ascii.GetGraphic(1));

Navigation Menu

QRCoder.Core — Usage Guide (en-US)

Table of Contents

Installation

Platform-Specific Dependencies

Quick Start

Output Formats

QRCode (SKBitmap)

PNG Bytes

SVG

Base64

PDF

ASCII Art

Postscript / EPS

Artistic QR Code

BMP Bytes

Payloads (Content Types)

WiFi

URL

Email

SMS

Phone Number

Geolocation

Bitcoin

vCard (Contact)

Calendar Event

Advanced Settings

Error Correction Levels (ECC)

Data Serialization

Force UTF-8

Fixed QR Code Version

Supported Platforms

ASP.NET Core API Example

.NET MAUI / Xamarin Example

Console Example

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QRCoder.Core — Usage Guide (en-US)

Table of Contents

Installation

Platform-Specific Dependencies

Quick Start

Output Formats

QRCode (SKBitmap)

PNG Bytes

SVG

Base64

PDF

ASCII Art

Postscript / EPS

Artistic QR Code

BMP Bytes

Payloads (Content Types)

WiFi

URL

Email

SMS

Phone Number

Geolocation

Bitcoin

vCard (Contact)

Calendar Event

Advanced Settings

Error Correction Levels (ECC)

Data Serialization

Force UTF-8

Fixed QR Code Version

Supported Platforms

ASP.NET Core API Example

.NET MAUI / Xamarin Example

Console Example