add gesture detecting widget

lib/gesture_detecting_filament_view.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/widgets.dart';
+import 'package:mimetic_filament/filament_controller.dart';
+import 'package:mimetic_filament/view/filament_widget.dart';
+
+class GestureDetectingFilamentView extends StatefulWidget {
+  final FilamentController controller;
+
+  const GestureDetectingFilamentView({Key? key, required this.controller})
+      : super(key: key);
+
+  @override
+  State<StatefulWidget> createState() => _GestureDetectingFilamentViewState();
+}
+
+class _GestureDetectingFilamentViewState
+    extends State<GestureDetectingFilamentView> {
+  bool _rotate = false;
+  int _primitiveIndex = 0;
+  double _weight = 0.0;
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+        behavior: HitTestBehavior.opaque,
+        onPanDown: (details) {
+          _rotate
+              ? widget.controller.rotateStart(
+                  details.localPosition.dx, details.localPosition.dy)
+              : widget.controller
+                  .panStart(details.localPosition.dx, details.localPosition.dy);
+        },
+        onPanUpdate: (details) {
+          _rotate
+              ? widget.controller.rotateUpdate(
+                  details.localPosition.dx, details.localPosition.dy)
+              : widget.controller.panUpdate(
+                  details.localPosition.dx, details.localPosition.dy);
+        },
+        onPanEnd: (d) {
+          _rotate ? widget.controller.rotateEnd() : widget.controller.panEnd();
+        },
+        child: FilamentWidget(controller: widget.controller));
+  }
+}