Bonoscan.Components.Client

In-browser scan engine for Bonoscan.Components (Blazor WebAssembly / .NET MAUI Blazor Hybrid): DocAligner detection on onnxruntime-web + a pure-C# warp, all in the browser. For Blazor Server use Bonoscan.Components.Server.

The model, onnxruntime-web, and the detection Web Worker ship inside this package and are served from the app bundle (_content/Bonoscan.Components.Client/) — no model to host, no CDN, no runtime downloads. Live detection runs off the UI thread inside the worker, so it works fully offline, including in a packaged MAUI app.

Nothing external is pulled in for detection: the contract — RgbImage, DetectionParameters, DetectionResult, IAsyncDocumentDetector — comes from Bonoscan.Components, and BrowserDocAlignerDetector in this package is the binding over the bundled JS module, sharing the one worker the viewfinder already loads.

Install

<!-- nuget.config -->
<add key="bonoscan-local" value="/abs/path/to/scanner/local-feed" />

<PackageReference Include="Bonoscan.Components.Client" Version="0.30.0" />

Use

// Program.cs / MauiProgram.cs
builder.Services.AddBonoscanClient(o =>
{
    o.GuideAspect   = 0.707;
    o.CaptureWidth  = 2480;
    o.CaptureHeight = 3508;
    o.Mime          = "image/jpeg";
    o.Quality       = 0.92;
});

<!-- host index.html -->
<link rel="stylesheet" href="_content/Bonoscan.Components/bonoscan.css" />

<DocumentScanner OnCaptured="r => _bytes = r.Bytes" />

See Bonoscan.Components for the full component / ScannerOptions / theming reference. AddBonoscanClient registers the shared ScannerOptions and an IScannerEngineFactory. Neither the engine nor its BrowserDocAlignerDetector is a container-tracked service: each scanner creates its own pair and disposes both, so mounting the scanner repeatedly can neither accumulate dead engines nor pin a detection worker for the lifetime of the app.

The worker itself is shared by the page and reference-counted inside docaligner-ort.js — created on the first claim, terminated when the last is released. Stopping or resetting a scanner keeps the claim, so a retake does not reload the model; disposing the scanner gives it back.

MAUI camera access

getUserMedia needs the OS permission and the WebView's permission gate:

• Android — <uses-permission android:name="android.permission.CAMERA" />, runtime Permissions.RequestAsync<Permissions.Camera>(), and grant RESOURCE_VIDEO_CAPTURE in the WebView's WebChromeClient.OnPermissionRequest.
• iOS / Mac Catalyst — NSCameraUsageDescription in Info.plist. Verify on a real device: WKWebView getUserMedia from MAUI's custom scheme can need extra config.
• Windows — allow the WebView2 PermissionRequested (camera).

Detection runtime (MAUI)

Live detection runs in a Web Worker inside the WebView — the worker, onnxruntime-web, and the model are all bundled and served from the app (_content/Bonoscan.Components.Client/), so it stays fully offline; nothing is fetched at runtime. Verify on a real device: Android WebView / WKWebView / WebView2 support Web Workers, but worker creation from the BlazorWebView virtual origin should be confirmed per platform. WebGPU is usually unavailable in mobile WebViews, so inference falls back to the bundled WASM EP; multi-threaded WASM needs cross-origin isolation (COOP/COEP) that a BlazorWebView host generally doesn't set, so it runs single-threaded in the worker (still off the UI thread).

Licensing

Library code MIT. Bundled assets: onnxruntime-web (MIT, Microsoft) and the DocAligner weights (Apache-2.0, DocsaidLab/DocAligner).