Returned standard parameters to example

example/lib/main.dart

@@ -151,13 +151,11 @@ class _QRViewExampleState extends State<QRViewExample> {
       key: qrKey,
       onQRViewCreated: _onQRViewCreated,
       overlay: QrScannerOverlayShape(
-        borderColor: Colors.red,
-        borderRadius: 10,
-        borderLength: 30,
-        borderWidth: 10,
-        cutOutSize: /*scanArea*/100,
-        cutOutBottomOffset: 150,
-      ),
+          borderColor: Colors.red,
+          borderRadius: 10,
+          borderLength: 30,
+          borderWidth: 10,
+          cutOutSize: scanArea),
       onPermissionSet: (ctrl, p) => _onPermissionSet(context, ctrl, p),
     );
   }