+ /**
+ * The extended area that the margin widget would like to be sized to.
+ * @remarks This area is the area specified by sizeHint, extended by
+ * the area to overlap the viewport.
+ */
+ virtual QSize extended_size_hint() const = 0;
+
+protected:
+ /**
+ * Gets the items in the margin widget.
+ */
+ virtual std::vector< std::shared_ptr<pv::view::ViewItem> > items() = 0;
+
+ /**
+ * Gets the first view item which has a label that contains @c pt .
+ * @param pt the point to search with.
+ * @return the view item that has been found, or and empty
+ * @c shared_ptr if no item was found.
+ */
+ virtual std::shared_ptr<pv::view::ViewItem> get_mouse_over_item(
+ const QPoint &pt) = 0;
+
+ /**
+ * Shows the popup of a the specified @c ViewItem .
+ * @param item The item to show the popup for.
+ */
+ void show_popup(const std::shared_ptr<ViewItem> &item);
+
+ /**
+ * Handles left mouse button press events.
+ * @param event the mouse event that triggered this handler.
+ */
+ void mouse_left_press_event(QMouseEvent *event);
+
+ /**
+ * Handles left mouse button release events.
+ * @param event the mouse event that triggered this handler.
+ */
+ void mouse_left_release_event(QMouseEvent *event);
+
+protected:
+ void mousePressEvent(QMouseEvent * event);
+ void mouseReleaseEvent(QMouseEvent *event);
+ void mouseMoveEvent(QMouseEvent *event);
+
+ void leaveEvent(QEvent *event);
+
+ virtual void contextMenuEvent(QContextMenuEvent *event);
+
+ virtual void keyPressEvent(QKeyEvent *e);
+