Lyo.QRCode 3.0.0

Lyo.QRCode

Generate and read QR codes: IQRCodeService, QRCodeBuilder, in-box ISO Model 2 encoding (BuiltInQRCodeService), optional QRCoder adapter package Lyo.QRCode.QRCoder, and typed payload helpers (Lyo.QRCode.Payloads) for Wi-Fi, URLs, vCard, mailto:, etc.

Examples

Generate with the built-in encoder

using Lyo.QRCode;
using Lyo.QRCode.Models;
using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();
services.AddQRCodeService(o => {
    o.DefaultSize = 16; // pixels per module, not total width
    o.DefaultFormat = QRCodeFormat.Png;
    o.DefaultErrorCorrectionLevel = QRCodeErrorCorrectionLevel.Medium;
});

var qr = services.BuildServiceProvider().GetRequiredService<IQRCodeService>();
var result = await qr.GenerateAsync("https://example.com");

if (result.IsSuccess && result is QRCodeResult r && r.ImageBytes != null)
    await File.WriteAllBytesAsync("qr.png", r.ImageBytes);

Wi-Fi payload example

using Lyo.QRCode;
using Lyo.QRCode.Payloads;

var payload = new WifiQrPayload("MySSID", "secret", QrWifiSecurityType.Wpa);
var (_, opts) = QRCodeBuilder.New()
    .WithPayload(payload)
    .WithFormat(QRCodeFormat.Png)
    .WithSize(12)
    .Build();

How the pieces fit

Optional QRCoder package

Reference Lyo.QRCode.QRCoder and call AddQRCoderQrCodeService (or AddQRCoderQrCodeServiceFromConfiguration) instead of or alongside AddQRCodeService, depending on how you register IQRCodeService.

Payload helpers (Lyo.QRCode.Payloads)

• Wi-Fi (WifiQrPayload). Drops H: when the SSID is not hidden (better phone compatibility than H:false). Open networks omit P (not P:;).
• SMS (SmsPayload). Defaults to the sms: URI scheme. smsto: is opt-in (some Android SMS apps crash on long smsto: bodies). Very long URIs throw (MaxSmsQrUriLength) to avoid app crashes.

Key options

• QRCodeOptions.Size. Pixels per module (each black/white square), not the image width. Total size ≈ module count per side × Size. Later decoration may grow that further.
• QRCodeOptions.Icon. Encoder hint only. The only field used is IconSizePercent, which raises the effective ECC level so a planned center logo does not break scanning. IconBytes, IconFilePath, and DrawIconBorder are metadata for the consumer's overlay call. The QR encoder never composites the icon. Apply the overlay (and any frame/caption/padding) after generation through Lyo.Images.IImageDecorationService (see the migration note below).

Migration: decoration left the encoder

QRCodeOptions.Frame, QRCodeBuilder.WithFrame(...), and the optional IImageService / IQrFrameLayoutService constructor parameters on BuiltInQRCodeService no longer exist. Compose icons and chrome on the returned bytes with Lyo.Images:

using Lyo.Images;
using Lyo.Images.Builders;
using Lyo.Common.Core.Enums;

var qr = await qrService.GenerateAsync(data, options);
var qrBytes = ((QRCodeResult)qr).ImageBytes!;

var decorated = await decoration.Pipeline(qrBytes)
    .Overlay(logoBytes, b => b.WithOverlaySizePercent(18).WithPadColor("#FFFFFF").WithBorder("#000000"))
    .AddCaption(b => b.WithText("Scan Me").WithNotch())
    .AddOuterPadding(b => b.WithPanelColor("#FFFFFF").WithCornerRadius(16))
    .AddFrame(b => b.WithStrokeColor("#1e293b").WithStrokeWidth(2).WithCornerRadius(16))
    .ToByteArrayAsync(ImageFormat.Png);

OverlayAsync accepts PNG (raster) and SVG (embeds a base64 PNG <image> before </svg>); the other primitives require raster input.

Error correction

QRCodeErrorCorrectionLevel: Low (~7%), Medium (~15%), Quartile (~25%), High (~30%) recovery. Higher levels survive damage and logos better, but they raise the symbol version for the same payload.

Optional Blazor UI

• Lyo.QRCode.Web.Components. QrCodeWorkbench plus related MudBlazor components.

Dependencies

Generated from ProjectReference / PackageReference (same model as docs/Lyo.ProjectGraph.html).

• Lyo.Common.Core (direct, lyo)
• Lyo.Exceptions (direct, lyo)
• Lyo.Metrics (direct, lyo)
• Lyo.Result (direct, lyo)
• Microsoft.Extensions.Configuration.Binder 10.0.5 (direct, microsoft)
• Microsoft.Extensions.DependencyInjection.Abstractions 10.0.5 (direct, microsoft)
• Microsoft.Extensions.Logging.Abstractions 10.0.5 (direct, microsoft)
• SixLabors.ImageSharp 3.1.12 (direct, third-party)
• ZXing.Net 0.16.11 (direct, third-party)
• ZXing.Net.Bindings.ImageSharp.V3 0.16.18 (direct, third-party)
• Microsoft.Bcl.AsyncInterfaces 10.0.5 (transitive, microsoft, netstandard2.0)
• System.Memory 4.6.3 (transitive, microsoft, netstandard2.0)
• System.Text.Json 10.0.5 (transitive, microsoft, netstandard2.0)