SkiaSharp.QrCode 1.0.1

SkiaSharp.QrCode

Migration | Data Capacity

SkiaSharp.QrCode provides high-performance QR code generation/read with SkiaSharp integration.

Benchmark results comparing SkiaSharp.QrCode with other libraries. See src/SkiaSharp.QrCode.Benchmark for details. Above results are generated on .NET 10 with AMD Ryzen 9 7950X3D CPU, with GFNI and AVX2 enabled.

Many existing QR code libraries rely on System.Drawing, which has well-known GDI+ limitations and cross-platform issues. SkiaSharp.QrCode was created to provide high performance, minimum memory allocation, a simpler and more intuitive API while leveraging SkiaSharp's cross-platform capabilities. Generate a QR code in a single line, or customize every detail - the choice is yours.

You can create professional-looking QR codes like this with just a few lines of code:

<p float="left"> <img src="samples/ConsoleApp/samples/pattern15_instagram_frame.png" width="250" alt="Instagram-style"/> <img src="samples/ConsoleApp/samples/pattern6_builder_gradient.png" width="250" alt="Gradient QR"/> <img src="samples/ConsoleApp/samples/pattern7_builder_icon.png" width="250" alt="Icon QR"/> </p>

See samples/ConsoleApp for code examples generating these styles.

Playground

Try SkiaSharp.QrCode in your browser — no install required: SkiaSharp.QrCode Playground

The playground runs the actual library compiled to WebAssembly (GitHub Pages, fully static). Tune gradients, module shapes, finder patterns and logos in realtime, then download the PNG or SVG, or share your settings as a permalink. Every generated code is decoded back in-browser by the library's own decoder as a self-check, and the Decode an image panel reads QR codes from your own image files. Source lives in src/SkiaSharp.QrCode.Playground; it is deployed to GitHub Pages by release.yaml as part of every release.

Overview

SkiaSharp.QrCode is a modern, high-performance QR code generation library built on SkiaSharp. SkiaSharp.QrCode allocates memory only for the actual QR code data, with zero additional allocations during processing.

• Simple API: One-liner QR code generation with sensible defaults
• High Performance: Optimal speed and minimum memory allocation
• Highly Customizable: Gradients, icons, custom shapes, colors, and more
• Raster & Vector Output: PNG, JPEG, WebP, and SVG (scales without quality loss)
• Cross-Platform: Windows, Linux, macOS, iOS, Android, WebAssembly
• Zero Dependencies: QR generation without external libraries (SkiaSharp for rendering only)
• No System.Drawing: Avoids GDI+ issues and Windows dependencies
• NativeAOT Ready: Full support for .NET Native AOT compilation
• Modern .NET: .NET Standard 2.0, 2.1, .NET 8+

Installation

Visit SkiaSharp.QrCode on NuGet.org

dotnet add package SkiaSharp.QrCode

Quick Start

Simplest Example

Single line QR code generation:

using SkiaSharp.QrCode.Image;

// one-liner save to file
File.WriteAllBytes("qrcode.png", QRCodeImageBuilder.GetPngBytes("Hello"));

// Or get bytes
var pngBytes = QRCodeImageBuilder.GetPngBytes("https://example.com");

Common Use Cases

Generate QR Code for URL.

var pngBytes = QRCodeImageBuilder.GetPngBytes("https://example.com");
File.WriteAllBytes("qrcode.png", pngBytes);

WiFi QR Code.

var wifiString = "WIFI:T:WPA;S:MyNetwork;P:MyPassword;;";
File.WriteAllBytes("wifi-qr.png", QRCodeImageBuilder.GetPngBytes(wifiString));

SVG (vector) output.

File.WriteAllText("qrcode.svg", QRCodeImageBuilder.GetSvgString("https://example.com"));

Generate with Custom Settings.

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .WithErrorCorrection(ECCLevel.H)
    .ToByteArray();

Save Directly to Stream

using SkiaSharp.QrCode.Image;

using var stream = File.OpenWrite("qrcode.png");
QRCodeImageBuilder.SavePng("Your content here", stream, ECCLevel.M, size: 512);

Migration

See Migration Guide for details on migrating from older versions of SkiaSharp.QrCode.

API Overview

SkiaSharp.QrCode provides three main APIs for generation, plus QRCodeDecoder for decoding.

Recommendation: Start with QRCodeImageBuilder for most scenarios. Use QRCodeRenderer when you need canvas control. Use QRCodeGenerator only for custom rendering implementations. Use QRCodeDecoder to read QR codes back (round-trip validation, decoding rendered images).

Feature	QRCodeImageBuilder	QRCodeRenderer	QRCodeGenerator
Ease of use	High	Medium	Low
Flexibility	Medium	High	Highest
Built-in rendering	Yes	Yes	No
Custom canvas control	No	Yes	N/A
Recommended for beginners	Yes	No	No

QRCodeImageBuilder (Recommended)

Best for Most use cases - simple to advanced QR code generation. The high-level, fluent API for generating QR codes with minimal code. Provides a builder pattern with sensible defaults and extensive customization options.

Key Features:

• One-liner generation with GetPngBytes(), SavePng(), SaveSvg()
• Fluent API with WithXxx() methods
• Built-in support for colors, gradients, icons, shapes
• Multiple output formats (PNG, JPEG, WebP, SVG)
• Stream and byte array output

When to use:

• Quick QR code generation
• Standard customization needs
• File or stream output

Example:

var pngBytes = QRCodeImageBuilder.GetPngBytes("content");

QRCodeRenderer (Advanced)

Best for Custom rendering with full control over the canvas. The mid-level API that renders QR data onto an existing SkiaSharp canvas. Useful when you need to integrate QR codes into existing graphics or add custom post-processing.

Key Features:

• Render to existing SKCanvas
• Full control over rendering area (SKRect)
• Combine with other SkiaSharp drawing operations
• Custom effects and post-processing

When to use:

• Integrating QR codes into existing graphics
• Adding custom decorations or effects
• Multiple elements on the same canvas

Example:

var qrData = QRCodeGenerator.CreateQrCode("content", ECCLevel.M);
var canvas = surface.Canvas;
QRCodeRenderer.Render(canvas, area, qrData, SKColors.Black, SKColors.White);

QRCodeGenerator (Low-Level)

Best for QR data generation without rendering. The low-level API that generates raw QR code data (QRCodeData). Use this when you need the QR data structure itself, not the image.

Key Features:

• Generates QRCodeData (boolean module matrix stored as 1D byte array)
• Specify ECC level, ECI mode, quiet zone size
• No rendering logic included
• Smallest API surface

When to use:

• Custom rendering implementations
• Non-image output (e.g., ASCII art, LED displays)
• Maximum control over the rendering process

Example:

var qrData = QRCodeGenerator.CreateQrCode("content", ECCLevel.M, quietZoneSize: 4);
// Use qrData for custom rendering
// Access individual modules: bool isDark = qrData[row, col];

Zero-Allocation Generation (Span destination)

For high-throughput scenarios (e.g., per-request QR generation on a web server), you can generate the module matrix into a caller-provided buffer with zero heap allocation. Calculate the required size with GetRequiredBufferSize, allocate (or rent) the buffer yourself, and pass it as Span<byte>:

// 1. Calculate required buffer size (no allocation)
var calculated = QRCodeGenerator.GetRequiredBufferSize("content", ECCLevel.M, quietZoneSize: 4);

// 2. Allocate the buffer yourself (pool it, reuse it, or stackalloc it)
var buffer = ArrayPool<byte>.Shared.Rent(calculated.BufferSize);
try
{
    // 3. Generate directly into the buffer; returns bytes written (= QrSize * QrSize)
    var written = QRCodeGenerator.CreateQrCode("content", ECCLevel.M, buffer, quietZoneSize: 4);

    // 4. Slice to the written region and consume
    var matrix = buffer.AsSpan(0, written);
    // One byte per module (0 = light, 1 = dark), row-major, quiet zone included:
    var isDark = matrix[row * calculated.QrSize + col] != 0;
}
finally
{
    ArrayPool<byte>.Shared.Return(buffer);
}

Buffer sizes are bounded: version 40 with the standard quiet zone needs 185 × 185 = 34,225 bytes, so a pooled or fixed buffer keeps memory usage constant regardless of request volume. The buffer region is cleared before writing, so dirty pooled buffers are fine; bytes beyond the written region are left untouched.

QRCodeDecoder (Decoding)

Decodes QR codes back into text — the inverse of QRCodeGenerator. Works at two levels:

• Matrix level: from QRCodeData or a byte-per-module span (the same format the zero-allocation generator produces). Full Reed-Solomon error correction included.
• Image level: from SKBitmap or a grayscale luminance span. Detects the QR code (arbitrary rotation, mirroring, inverted light-on-dark palettes and mild perspective supported), samples the grid, then decodes.

Scope: image decoding targets clean inputs — screenshots, rendered QR codes, and scans. Real-world photos with strong perspective, uneven lighting, or blur are out of scope; use a computer-vision grade reader such as ZXing.Net for those. See QR Code Decoder for design details.

// From QRCodeData (e.g. round-trip validation)
var qrData = QRCodeGenerator.CreateQrCode("content", ECCLevel.M);
if (QRCodeDecoder.TryDecode(qrData, out var text))
{
    Console.WriteLine(text); // "content"
}

// From an image
using var bitmap = SKBitmap.Decode("qr.png");
if (QRCodeDecoder.TryDecode(bitmap, out var text, out var info))
{
    Console.WriteLine($"{text} (version {info.Version}, ECC {info.EccLevel}, {info.ErrorsCorrected} errors corrected)");
}

// Zero-allocation: span in, span out
Span<char> destination = stackalloc char[QRCodeDecoder.GetMaxDecodedLength(version)];
if (QRCodeDecoder.TryDecode(moduleSpan, size, destination, out var written, out _))
{
    var text = destination.Slice(0, written); // no heap allocation
}

On failure, QRCodeDecodeInfo.Status explains why (NotDetected, FormatInformationInvalid, DataUncorrectable, UnsupportedContent, ...). Supported content: Numeric / Alphanumeric / Byte modes, ISO-8859-1 and UTF-8 (with or without ECI), versions 1-40, all ECC levels. Kanji mode, FNC1 and Structured Append are detected and reported as unsupported rather than misdecoded.

Platform-Specific Considerations

Linux Support

SkiaSharp requires native dependencies on Linux. You have two options:

Option 1: With Font Support (Recommended for text rendering)

Requires libfontconfig1:

sudo apt update && apt install -y libfontconfig1

<PackageReference Include="SkiaSharp.QrCode" Version="0.9.0" />
<PackageReference Include="SkiaSharp.NativeAssets.Linux" Version="3.119.1" />

Option 2: No Dependencies (QR code only)

If you don't need advanced font operations:

<PackageReference Include="SkiaSharp.QrCode" Version="0.9.0" />
<PackageReference Include="SkiaSharp.NativeAssets.Linux.NoDependencies" Version="3.119.1" />

Note: NoDependencies can still draw text but cannot search fonts based on characters or use system fonts.

See: SkiaSharp Issue #964

NativeAOT Support

SkiaSharp.QrCode fully supports .NET NativeAOT. You need to include platform-specific native assets:

<PropertyGroup>
  <PublishAot>true</PublishAot>
  <PublishTrimmed>true</PublishTrimmed>
  <InvariantGlobalization>true</InvariantGlobalization>
</PropertyGroup>

Windows

<PackageReference Include="SkiaSharp.QrCode" Version="0.9.0" />
<PackageReference Include="SkiaSharp.NativeAssets.Win32" Version="3.119.1" />

Linux

<PackageReference Include="SkiaSharp.QrCode" Version="0.9.0" />
<PackageReference Include="SkiaSharp.NativeAssets.Linux.NoDependencies" Version="3.119.1" />

macOS

<PackageReference Include="SkiaSharp.QrCode" Version="0.9.0" />
<PackageReference Include="SkiaSharp.NativeAssets.macOS" Version="3.119.1" />

Performance

SkiaSharp.QrCode is designed with performance as a top priority. The library minimizes memory allocations and maximizes throughput for QR code generation.

Key Performance Characteristics

• Minimal Memory Allocation: Memory is only allocated for the final QR code data structure. The generation algorithm avoids intermediate allocations, resulting in minimal GC pressure.
• Zero-Copy Rendering: Direct rendering to SkiaSharp canvas without unnecessary buffer copies.
• Optimized Encoding: Efficient encoding mode selection and bit packing minimize QR code size and generation time.
• Native Performance: Leverages SkiaSharp's native rendering engine for maximum speed.

Benchmark Results

Benchmark results show SkiaSharp.QrCode outperforming other popular .NET QR code libraries in both speed and memory usage.

• Fastest Generation: Outperforms other .NET QR code libraries in most scenarios
• Lowest Memory Usage: Minimal allocations reduce GC overhead
• Consistent Performance: Predictable performance across different QR code sizes and complexity

For detailed benchmark code and results, see the samples/Benchmark directory.

FAQ

Why choose SkiaSharp.QrCode?

SkiaSharp offers several advantages for QR code generation:

• Performance: Native-level performance with hardware acceleration support
• Cross-Platform: Runs on Windows, Linux, macOS, iOS, Android, and WebAssembly
• Modern .NET Support: First-class support for .NET 6+ and .NET Core
• No GDI+ Dependencies: Avoids System.Drawing's Windows-specific issues
• Rich Graphics API: Advanced rendering capabilities (gradients, shapes, effects)
• Active Development: Well-maintained with regular updates

Can I use this in ASP.NET Core?

Yes, SkiaSharp.QrCode works great in ASP.NET Core. SkiaSharp.QrCode also supports IBufferWriter for efficient memory usage.

app.MapGet("/qr", (string url) =>
{
    var pngBytes = QRCodeImageBuilder.GetPngBytes(url);
    return Results.File(pngBytes, "image/png");
});

app.MapGet("/qr.svg", (string url) =>
{
    var svgBytes = QRCodeImageBuilder.GetSvgBytes(url);
    return Results.File(svgBytes, "image/svg+xml");
});

Does it support Blazor WebAssembly?

Yes, SkiaSharp.QrCode works in Blazor WebAssembly & Pure WebAssembly.

• See the samples/BlazorWasm folder for a Blazor WebAssembly example.
• See src/SkiaSharp.QrCode.Playground for Pure WebAssembly usage.

What about NativeAOT and trimming?

Yes, fully supported. See the Platform-Specific Considerations section for details on required native assets.

ISO-8859-2 and other encodings supports

Currently, SkiaSharp.QrCode supports ISO-8859-1 and UTF-8. Other encodings (e.g., ISO-8859-2, Shift JIS) are not supported at this time. This is mainly due to almost all QR code use cases being UTF-8 compatible nowadays. ISO-8859-2 and other legacy encodings are rarely used in practice.

Supported	Encoding Mode	Encoding
Supported	Numeric	ISO-8859-1
Supported	Alphanumeric	ISO-8859-1
Supported	Byte	UTF-8
Not Supported	Kanji	Shift-JIS

Does SVG output require SkiaSharp.Svg or other packages?

No. SVG output uses SKSvgCanvas from the core SkiaSharp package — no additional dependencies. Note that SkiaSharp.QrCode outputs SVG only; it does not read or render existing SVG files.

Any plan to support QR code scanning?

Yes. QRCodeDecoder decodes QR codes from module matrices and from images (see API Overview). Image decoding intentionally targets clean inputs: screenshots, rendered QR codes, and scans, including rotated and mirrored ones. Robust decoding of real-world photos (perspective distortion, uneven lighting, blur) is a computer-vision problem outside this library's scope — use a dedicated reader such as ZXing.Net for camera captures.

What QR code style provides the best scan reliability?

For optimal scan reliability, we recommend:

• Use rectangular modules (default): Rectangle-shaped modules (RectangleModuleShape) provide the lowest error rate when scanning QR codes.
• Avoid gaps between modules: Using smaller module sizes or shapes like Circle or RoundRect creates gaps between modules, which increases scan error rates.
• Use ECCLevel.H for non-standard styles: If you need to use Circle, RoundRect, or other custom module shapes, we strongly recommend setting the error correction level to ECCLevel.H (High - 30% recovery capacity) to compensate for the reduced readability.
• Always use ECCLevel.H with icons/logos: When embedding icons or logos using IconData, ECCLevel.H is required to ensure the QR code remains scannable even when the center is partially obscured.

Example:

// Best reliability - default settings with rectangular modules
var pngBytes = QRCodeImageBuilder.GetPngBytes("https://example.com");

// If using Circle or RoundRect - use High error correction
var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithErrorCorrection(ECCLevel.H) // Required for custom shapes
    .WithModuleShape(CircleModuleShape.Default);

// When using icons/logos - always use High error correction
using var logo = SKBitmap.Decode(File.ReadAllBytes("logo.png"));
var icon = IconData.FromImage(logo, iconSizePercent: 15);

var qrCodeWithIcon = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithErrorCorrection(ECCLevel.H) // Required for icons
    .WithIcon(icon);

How can I display QR codes in LINQPad?

Following shows how to display a QRCode inside a LINQPad Results pane.

Bitmap.FromStream(new MemoryStream(QRCodeImageBuilder.GetPngBytes("WIFI:T:WPA;S:mynetwork;P:mypass;;"))).Dump();

QR code Specifications

ECC Level (Error Correction Levels)

QR codes support four levels of error correction, which allow the code to remain readable even when partially damaged or obscured:

ECC Level	Error Correction Capability	Use Case
L (Low)	~7% recovery	Clean environments, maximum data capacity
M (Medium)	~15% recovery	General purpose (default recommended)
Q (Quartile)	~25% recovery	Outdoor use, moderate damage expected
H (High)	~30% recovery	Required when adding logos/icons, harsh environments

Tip: Use ECC Level H when embedding icons in QR codes to ensure readability even when the center is obscured.

Encoding Modes

QR codes support different encoding modes optimized for specific character types:

Mode	Character Set	Bits per Character	Example
Numeric	0-9	~3.3 bits	Phone numbers, postal codes
Alphanumeric	0-9, A-Z, space, $ % * + - . / :	~5.5 bits	URLs (uppercase), product codes
Byte	ISO-8859-1, UTF-8	8 bits	Text, URLs (mixed case), binary data
Kanji	Shift JIS characters	13 bits	Japanese text

Note: The library automatically selects the most efficient encoding mode for your content.

Version and Size

QR codes come in 40 versions (sizes), from Version 1 (21×21 modules) to Version 40 (177×177 modules). Each version adds 4 modules per side.

• Version 1: 21×21 modules
• Version 2: 25×25 modules
• ...
• Version 40: 177×177 modules

The library automatically selects the minimum version that can fit your content based on the selected ECC level.

See Data Capacity Reference for practical capacities and full tables by version and ECC level.

Usage Examples

Basic Usage

Using Builder Pattern

using SkiaSharp.QrCode.Image;

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithErrorCorrection(ECCLevel.H)
    .WithQuietZone(4);

var pngBytes = qrCode.ToByteArray();
File.WriteAllBytes("qrcode.png", pngBytes);

Direct File Output

using SkiaSharp.QrCode.Image;
using var stream = File.OpenWrite("qrcode.png");

new QRCodeImageBuilder("https://example.com")
    .WithSize(1024, 1024)
    .WithErrorCorrection(ECCLevel.H)
    .SaveTo(stream);

Raster Output (PNG / JPEG / WebP)

Default format is PNG. Switch with WithFormat() — quality (0–100) applies to lossy formats (JPEG, WebP).

using SkiaSharp;
using SkiaSharp.QrCode.Image;

// PNG (default)
var pngBytes = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .ToByteArray();

// JPEG
var jpegBytes = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .WithFormat(SKEncodedImageFormat.Jpeg, quality: 90)
    .ToByteArray();

// WebP
var webpBytes = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .WithFormat(SKEncodedImageFormat.Webp, quality: 80)
    .ToByteArray();

// Or one-liner helpers
var bytes = QRCodeImageBuilder.GetImageBytes(
    "https://example.com", SKEncodedImageFormat.Jpeg, ECCLevel.M, size: 512, quality: 90);

SVG Output (Vector)

SVG output draws the QR code as vector shapes, so it scales to any size without quality loss — ideal for print and web embedding. All builder options (colors, module shapes, gradients, finder patterns, icons) apply to SVG as well.

using SkiaSharp;
using SkiaSharp.QrCode.Image;

// One-liner: save to stream
using var stream = File.Create("qrcode.svg");
QRCodeImageBuilder.SaveSvg("https://example.com", stream);

// One-liner: SVG document string, e.g. for inline HTML embedding
var svg = QRCodeImageBuilder.GetSvgString("https://example.com");

// Builder: full styling support
var svgString = new QRCodeImageBuilder("https://example.com")
    .WithModulePixelSize(10)
    .WithErrorCorrection(ECCLevel.H)
    .WithColors(codeColor: SKColor.Parse("1B9CFC"))
    .ToSvgString(); // or SaveToSvg(stream) / SaveToSvg(bufferWriter) / GetSvgBytes(...)

Size options define the SVG viewport (in SVG units instead of pixels); WithFormat() does not apply to SVG output.

The root element always carries a viewBox, so the QR code scales its content when displayed at any size (<img>, CSS, or attribute-based sizing). Plain rectangular modules also get shape-rendering="crispEdges" to prevent antialiasing seams between modules; custom shapes (circles, rounded rects) keep antialiasing for smooth curves.

Choosing Image Size

Goal	API	Notes
Keep module edges sharp / logo aligned	WithModulePixelSize(n)	Output side = QR matrix size * n. Best default when using logos.
Also fit a fixed UI frame	WithModulePixelSize(n) + WithSize(w, h)	Canvas must be >= content size. Extra space is centered padding (clearColor). Too-small canvas throws.
Only need a fixed pixel box	WithSize(w, h)	Simple, but module size may become fractional when QR version changes.

Recommended (module-aligned):

using SkiaSharp.QrCode.Image;

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithModulePixelSize(10) // content = (QR matrix size in modules) * 10
    .WithErrorCorrection(ECCLevel.H)
    .WithQuietZone(4);

var pngBytes = qrCode.ToByteArray();

Recommended (module-aligned + fixed canvas):

using SkiaSharp;
using SkiaSharp.QrCode.Image;

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithModulePixelSize(10)
    .WithSize(512, 512) // must be >= content size
    .WithColors(clearColor: SKColors.Transparent)
    .WithErrorCorrection(ECCLevel.H);

var pngBytes = qrCode.ToByteArray();

Fixed box only (may use fractional module pixels):

using SkiaSharp.QrCode.Image;

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .WithErrorCorrection(ECCLevel.H);

var pngBytes = qrCode.ToByteArray();

Advanced Usage

Request Veresion

"abc" can fit in Version 1, but we request Version 10 to show more dots. This can be useful for adding logo with short content.

using SkiaSharp;
using SkiaSharp.QrCode.Image;

new QRCodeImageBuilder("abc")
    .WithSize(512, 512)
    .WithVersion(10)
    .ToByteArray();

Custom Colors

using SkiaSharp;
using SkiaSharp.QrCode.Image;

new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithColors(
        codeColor: SKColor.Parse("#000080"),      // Navy
        backgroundColor: SKColor.Parse("#FFE4B5"), // Moccasin
        clearColor: SKColors.Transparent)
    .ToByteArray();

Gradient QR code

using SkiaSharp;
using SkiaSharp.QrCode.Image;

var gradient = new GradientOptions(
    [SKColors.Blue, SKColors.Purple, SKColors.Pink],
    GradientDirection.TopLeftToBottomRight,
    [0f, 0.5f, 1f]);

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithErrorCorrection(ECCLevel.H)
    .WithGradient(gradient)
    .WithModuleShape(RoundedRectangleModuleShape.Default, sizePercent: 0.9f);

var pngBytes = qrCode.ToByteArray();

QR code with Logo (icon only)

Prefer module-based sizing so the logo sits on the QR grid. See Choosing Image Size.

using SkiaSharp;
using SkiaSharp.QrCode.Image;

using var logo = SKBitmap.Decode(File.ReadAllBytes("logo.png"));

// Percent/pixel sizing (existing)
var iconByPercent = IconData.FromImage(logo, iconSizePercent: 15, iconBorderWidth: 10);

// Module-based sizing (recommended with WithModulePixelSize)
var iconByModules = IconData.FromImageByModules(logo, iconSizeModules: 7, iconBorderModules: 1);

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithModulePixelSize(12)
    // .WithSize(512, 512) // optional: larger canvas with centered padding
    .WithErrorCorrection(ECCLevel.H) // High ECC recommended for icons
    .WithIcon(iconByModules);

var pngBytes = qrCode.ToByteArray();

QR code with Logo (icon and text)

using SkiaSharp;
using SkiaSharp.QrCode.Image;

using var logo = SKBitmap.Decode(File.ReadAllBytes("logo.png"));
using var font = new SKFont
{
    Size = 18,
    Typeface = SKTypeface.FromFamilyName("sans-serif", SKFontStyle.Bold)
};
var icon = new IconData
{
    // Default text is placed below the icon image, centered
    Icon = new ImageTextIconShape(logo, "FooBar", SKColors.Black, font, textPadding: 2),
    IconSizePercent = 13,
    IconBorderWidth = 18,
};
var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithErrorCorrection(ECCLevel.H) // High ECC recommended for icons
    .WithIcon(icon);

var pngBytes = qrCode.ToByteArray();

Custom Module Shapes

using SkiaSharp;
using SkiaSharp.QrCode.Image;

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(800, 800)
    .WithModuleShape(CircleModuleShape.Default, sizePercent: 0.95f)
    .WithColors(codeColor: SKColors.DarkBlue);

var pngBytes = qrCode.ToByteArray();

Custom Finder Pattern

var qrCode = new QRCodeImageBuilder("https://example.com")
    .WithSize(512, 512)
    .WithFinderPatternShape(RoundedRectangleFinderPatternShape.Default)
    .WithColors(codeColor: SKColors.DarkBlue);

var pngBytes = qrCode.ToByteArray();

Gradient QR Code

var instagramGradient = new GradientOptions([
        SKColor.Parse("FCAF45"),  // Orange
        SKColor.Parse("F77737"),  // Orange-Red
        SKColor.Parse("E1306C"),  // Pink
        SKColor.Parse("C13584"),  // Purple
        SKColor.Parse("833AB4")   // Deep Purple
    ],
    GradientDirection.TopLeftToBottomRight,
    [0f, 0.25f, 0.5f, 0.75f, 1f]);

var qrCode = new QRCodeImageBuilder(content)
    .WithSize(512, 512)
    .WithColors(backgroundColor: SKColors.White, clearColor: SKColors.White)
    .WithModuleShape(CircleModuleShape.Default, sizePercent: 0.95f)
    .WithFinderPatternShape(RoundedRectangleCircleFinderPatternShape.Default)
    .WithGradient(instagramGradient);

var pngBytes = qrCode.ToByteArray();

Low-Level Canvas Rendering

For maximum control over rendering:

using SkiaSharp;
using SkiaSharp.QrCode;

// Generate QR data
var qrData = QRCodeGenerator.CreateQrCode("https://example.com", ECCLevel.M, quietZoneSize: 4);

// Create canvas
var info = new SKImageInfo(800, 800);
using var surface = SKSurface.Create(info);
var canvas = surface.Canvas;

// Render QR code
canvas.Render(qrData, info.Width, info.Height);

// Save
using var image = surface.Snapshot();
using var data = image.Encode(SKEncodedImageFormat.Png, 100);
using var stream = File.OpenWrite("qrcode.png");
data.SaveTo(stream);

License

MIT

Acknowledgments

• aloisdeniel/Xam.Forms.QRCode : Qr Sample with Skia
• codebude/QRCoder : QRCode generation algorithms