handle non null corners

@@ -151,7 +151,7 @@ class BarcodeOverlay extends CustomPainter {
 
   @override
   void paint(Canvas canvas, Size size) {
-    if (barcode.corners == null) {
+    if (barcode.corners.isEmpty) {
       return;
     }
 
@@ -183,7 +183,7 @@ class BarcodeOverlay extends CustomPainter {
     }
 
     final List<Offset> adjustedOffset = [];
-    for (final offset in barcode.corners!) {
+    for (final offset in barcode.corners) {
       adjustedOffset.add(
         Offset(
           offset.dx / ratioWidth + horizontalPadding,

@@ -130,8 +130,6 @@ class MobileScannerWebPlugin {
       _barCodeStreamSubscription =
           barCodeReader.detectBarcodeContinuously().listen((code) {
         if (code != null) {
-          final List<Offset>? corners = code.corners;
-
           controller.add({
             'name': 'barcodeWeb',
             'data': {
@@ -140,8 +138,8 @@ class MobileScannerWebPlugin {
               'format': code.format.rawValue,
               'displayValue': code.displayValue,
               'type': code.type.rawValue,
-              if (corners != null && corners.isNotEmpty)
-                'corners': corners
+              if (code.corners.isNotEmpty)
+                'corners': code.corners
                     .map(
                       (Offset c) => <Object?, Object?>{'x': c.dx, 'y': c.dy},
                     )

@@ -444,7 +444,8 @@ class MobileScannerController {
                   corners: toCorners(
                         (barcode['corners'] as List<Object?>? ?? [])
                             .cast<Map<Object?, Object?>>(),
-                  ),
+                      ) ??
+                      const <Offset>[],
                 ),
             ],
           ),