improved performance and battery usage on older devices

lib/widget/share_position_origin.dart

@@ -4,7 +4,7 @@ class SharePositionOrigin {
   static Rect get(BuildContext context) => Rect.fromLTWH(
     0,
     0,
-    MediaQuery.of(context).size.width,
-    MediaQuery.of(context).size.height / 2,
+    MediaQuery.sizeOf(context).width,
+    MediaQuery.sizeOf(context).height / 2,
   );
 }