private void DrawGrid()
        {
            var size = WindowRect.size;

            GridDrawer.Draw(new Rect(Vector2.zero, size));
            Handles.color = Color.gray;
            Handles.DrawLines(new []
            {
                Origin - new Vector3(size.x * .5f, 0, 0), Origin + new Vector3(size.x * .5f, 0, 0),
                Origin - new Vector3(0, size.y * .5f, 0), Origin + new Vector3(0, size.y * .5f, 0)
            });
        }
        public override void OnPreviewGUI(Rect r, GUIStyle background)
        {
            if (Event.current.type != EventType.Repaint)
            {
                return;
            }

            _gesture = (Gesture)target;
            GridDrawer.Draw(r);
            Handles.color = Color.cyan;
            DrawGesture(r);
        }