c2pa_view 0.2.1

`c2pa_view` is a Flutter plugin for viewing C2PA manifests in files. It provides an interactive interface to extract and display C2PA metadata using the official C2PA Rust library and the Flutter Rust Bridge.

c2pa_view

A Flutter plugin for reading and displaying C2PA (Coalition for Content Provenance and Authenticity) content credentials. It extracts embedded C2PA manifests from media files using the official c2pa-rs Rust library and renders provenance data as interactive Flutter widgets.

• 🗃️ Read C2PA manifests from files or raw bytes.
• 🌳 Display an interactive provenance tree with a detail panel
• 📜 Show manifest details as a popup overlay from any button
• 🔍 Access structured provenance data: actions, ingredients, signatures, EXIF, AI generation info, and more
• ✅ Full validation with trust-list checking

Setup

Version compatibility note

This package intentionally pins flutter_rust_bridge to a specific tested version (2.12.0) instead of a broad range.

If you need a different FRB version, update it together with regenerated bindings and verify all target platforms before publishing.

Initialization

Before any C2PA operations, initialize the Rust library once at app startup:

import 'package:c2pa_view/c2pa_view.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await RustLib.init();
  runApp(const MyApp());
}

Loading a ManifestStore

A ManifestStore is the root object containing all C2PA manifests found in a file. Create one from any source:

// From a local file path
final store = ManifestStore.fromLocalPath('/path/to/image.jpg');

// From raw bytes and MIME type
final store = ManifestStore.fromBytes(imageBytes, 'image/jpeg');

// From a URL (async)
final store = await ManifestStore.fromUrl('https://example.com/image.jpg');

All methods return null if no C2PA manifest is found.

Usage: Full Viewer

C2paManifestViewer shows an interactive provenance tree on the left and a detail panel on the right. Clicking a tree node updates the detail panel.

import 'package:c2pa_view/c2pa_view.dart';

// 1. Load the manifest store
final store = ManifestStore.fromBytes(imageBytes, 'image/jpeg');
if (store == null) return const Text('No manifest found');

// 2. Build the provenance graph (DAG of all manifests)
final graph = ProvenanceMapper.mapToGraph(store);

// 3. Display the full viewer wrapped in a theme
C2paViewerTheme(
  data: const C2paViewerThemeData(),
  child: C2paManifestViewer(
    graph: graph,
    mimeType: 'image/jpeg',
    mediaImage: MemoryImage(imageBytes), // fallback when no embedded thumbnail
  ),
);

See testfiles_app/lib/main.dart — the ManifestViewerPage class demonstrates this pattern with network-loaded images.

Usage: Popup from an Icon Button

showManifestDetailPopup opens a positioned overlay anchored to any widget. This is useful for adding a "content credentials" button to image thumbnails.

import 'package:c2pa_view/c2pa_view.dart';

// 1. Load the manifest store
final store = ManifestStore.fromBytes(imageBytes, 'image/jpeg');
if (store == null) return;

// 2. Get the active manifest and map it to a view model
final manifest = store.manifests[store.activeManifest]!;
final viewData = ManifestViewDataMapper.map(manifest);

// 3. Use a Builder to get a BuildContext anchored to the button
Builder(
  builder: (buttonContext) {
    return IconButton(
      icon: const Icon(Icons.verified_user),
      onPressed: () {
        showManifestDetailPopup(
          buttonContext,
          data: viewData,
          mimeType: 'image/jpeg',
          mediaImage: MemoryImage(imageBytes),
        );
      },
    );
  },
);

See testfiles_app/lib/main.dart — the _PopupDemoCard class demonstrates this pattern with a thumbnail and icon button.

Theming

Wrap your widget tree with C2paViewerTheme to customize the appearance. All c2pa_view widgets read from this theme, falling back to defaults when absent.

C2paViewerTheme(
  data: const C2paViewerThemeData(
    validColor: Color(0xFF1B8D3E),
    invalidColor: Color(0xFFD93025),
    sidebarWidth: 400,
  ),
  child: C2paManifestViewer(graph: graph),
);

// Dark mode
C2paViewerTheme(
  data: C2paViewerThemeData.dark(),
  child: C2paManifestViewer(graph: graph),
);

C2paViewerThemeData controls: validation status colors, surface/border/text colors, six text style tiers, layout dimensions (sidebar width, thumbnail size, node spacing), and border radii.

Data-Only Usage

You can use the package purely for data extraction without any widgets:

final store = ManifestStore.fromLocalPath('/path/to/image.jpg');
if (store == null) return;

final manifest = store.manifests[store.activeManifest]!;

// Access structured data
print(manifest.title);
print(manifest.signatureInfo?.issuer);
print(manifest.ingredients.length);
print(manifest.actions?.map((a) => a.action));

// Or get the raw JSON string
final json = C2paBridgeService.getManifestJsonFromFile('/path/to/image.jpg');

Platforms

This is an FFI plugin with native Rust code compiled for all platforms:

Platform	Status
Android	Supported
iOS	Supported
Linux	Supported
macOS	Supported
Windows	Supported