first commit

lib/services/qr_service_web.dart

@@ -0,0 +1,60 @@
+import 'dart:async';
+import 'dart:html';
+import 'dart:js' as js;
+import 'dart:typed_data';
+
+Future<String?> decodeQRFromBytes(Uint8List bytes) async {
+  final completer = Completer<String?>();
+
+  final blob = Blob([bytes]);
+  final url = Url.createObjectUrlFromBlob(blob);
+
+  final img = ImageElement()..src = url;
+
+  img.onLoad.listen((_) {
+    try {
+      final canvas = CanvasElement(
+        width: img.naturalWidth,
+        height: img.naturalHeight,
+      );
+      final ctx = canvas.context2D;
+      ctx.drawImage(img, 0, 0);
+      final imageData = ctx.getImageData(
+        0,
+        0,
+        img.naturalWidth,
+        img.naturalHeight,
+      );
+
+      if (!js.context.hasProperty('jsQR')) {
+        Url.revokeObjectUrl(url);
+        completer.completeError('jsQR library not loaded');
+        return;
+      }
+
+      final result = js.context.callMethod('jsQR', [
+        imageData.data,
+        imageData.width,
+        imageData.height,
+      ]);
+
+      Url.revokeObjectUrl(url);
+
+      if (result != null) {
+        completer.complete(result['data'] as String?);
+      } else {
+        completer.complete(null);
+      }
+    } catch (e) {
+      Url.revokeObjectUrl(url);
+      completer.completeError(e);
+    }
+  });
+
+  img.onError.listen((_) {
+    Url.revokeObjectUrl(url);
+    completer.complete(null);
+  });
+
+  return completer.future;
+}