remove use of boost::optional to define "undefined" Canvas::Rect, and use Rect::empty instead.

This commit includes Rect::operator bool() which might be a candidate for removal in a future commit, in an attempt
to make the meaning clearer

3 files changed, 11 insertions, 10 deletions

diff --git a/libs/canvas/canvas/canvas.h b/libs/canvas/canvas/canvas.h
index 7731b8533b..7932705483 100644
--- a/libs/canvas/canvas/canvas.h
+++ b/libs/canvas/canvas/canvas.h
@@ -95,11 +95,11 @@ public:
         ArdourCanvas::Color background_color() const { return _bg_color; }
 
 	/** Called when an item is being destroyed */
-	virtual void item_going_away (Item *, boost::optional<Rect>) {}
+	virtual void item_going_away (Item *, Rect) {}
 	void item_shown_or_hidden (Item *);
         void item_visual_property_changed (Item*);
-	void item_changed (Item *, boost::optional<Rect>);
-	void item_moved (Item *, boost::optional<Rect>);
+	void item_changed (Item *, Rect);
+	void item_moved (Item *, Rect);
 
         Duple canvas_to_window (Duple const&, bool rounded = true) const;
         Duple window_to_canvas (Duple const&) const;
@@ -224,7 +224,7 @@ public:
         void pick_current_item (Duple const &, int state);
 
 private:
-	void item_going_away (Item *, boost::optional<Rect>);
+	void item_going_away (Item *, Rect);
 	bool send_leave_event (Item const *, double, double) const;
 
 	Cairo::RefPtr<Cairo::Surface> canvas_image;
diff --git a/libs/canvas/canvas/item.h b/libs/canvas/canvas/item.h
index dacb9d559b..517b4401ba 100644
--- a/libs/canvas/canvas/item.h
+++ b/libs/canvas/canvas/item.h
@@ -136,7 +136,7 @@ public:
 
 	ScrollGroup* scroll_parent() const { return _scroll_parent; }
 
-	boost::optional<Rect> bounding_box () const;
+	Rect bounding_box () const;
         Coord height() const;
         Coord width() const;
 
@@ -275,10 +275,10 @@ protected:
 	/** true if this item is visible (ie to be drawn), otherwise false */
 	bool _visible;
 	/** our bounding box before any change that is currently in progress */
-	boost::optional<Rect> _pre_change_bounding_box;
+	Rect _pre_change_bounding_box;
 
 	/** our bounding box; may be out of date if _bounding_box_dirty is true */
-	mutable boost::optional<Rect> _bounding_box;
+	mutable Rect _bounding_box;
 	/** true if _bounding_box might be out of date, false if its definitely not */
 	mutable bool _bounding_box_dirty;
 
diff --git a/libs/canvas/canvas/types.h b/libs/canvas/canvas/types.h
index d0fecf1fda..a3f1b81ea1 100644
--- a/libs/canvas/canvas/types.h
+++ b/libs/canvas/canvas/types.h
@@ -117,15 +117,15 @@ struct LIBCANVAS_API Rect
 	Coord x1;
 	Coord y1;
 
-	boost::optional<Rect> intersection (Rect const & o) const throw () {
+	Rect intersection (Rect const & o) const throw () {
 		Rect i (std::max (x0, o.x0), std::max (y0, o.y0),
 			std::min (x1, o.x1), std::min (y1, o.y1));
 
 		if (i.x0 > i.x1 || i.y0 > i.y1) {
-			return boost::optional<Rect> ();
+			return Rect();
 		}
 
-		return boost::optional<Rect> (i);
+		return i;
 	}
 
 	Rect extend (Rect const & o) const throw () {
@@ -165,6 +165,7 @@ struct LIBCANVAS_API Rect
 	}
 
 	bool empty() const throw () { return (x0 == x1 && y0 == y1); }
+	operator bool() const throw () { return !empty(); }
 
 	Distance width () const  throw () {
 		return x1 - x0;