add a transparent rect that is always located at the bottom of the track canvas

This gives us an event/drag-n-drop/click target for things "at the bottom"

3 files changed, 34 insertions, 1 deletions

diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 47021c552b..f3f6bfeee7 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -737,6 +737,12 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	/* The group used for region motion.  Sits on top of _trackview_group */
 	ArdourCanvas::Group* _region_motion_group;
 
+        /* a rect that sits at the bottom of all tracks to act as a drag-no-drop/clickable
+	 * target area.
+	 */
+        ArdourCanvas::Rectangle* _canvas_bottom_rect;
+        bool canvas_bottom_rect_event (GdkEvent* event);
+
 	enum RulerType {
 		ruler_metric_timecode = 0,
 		ruler_metric_bbt = 1,
diff --git a/gtk2_ardour/editor_canvas.cc b/gtk2_ardour/editor_canvas.cc
index 98feae94c8..3b9c5dea37 100644
--- a/gtk2_ardour/editor_canvas.cc
+++ b/gtk2_ardour/editor_canvas.cc
@@ -212,6 +212,13 @@ Editor::initialize_canvas ()
 		logo_item->lower_to_bottom ();
 	}
 
+
+	_canvas_bottom_rect = new ArdourCanvas::Rectangle (_track_canvas->root(), ArdourCanvas::Rect (0.0, 0.0, max_canvas_coordinate, 20));
+	/* this thing is transparent */
+	_canvas_bottom_rect->set_fill (false);
+	_canvas_bottom_rect->set_outline (false);
+	_canvas_bottom_rect->Event.connect (sigc::mem_fun (*this, &Editor::canvas_bottom_rect_event));
+
 	/* these signals will initially be delivered to the canvas itself, but if they end up remaining unhandled, they are passed to Editor-level
 	   handlers.
 	*/
@@ -316,12 +323,24 @@ Editor::reset_controls_layout_width ()
 void
 Editor::reset_controls_layout_height (int32_t h)
 {
+	/* ensure that the rect that represents the "bottom" of the canvas
+	 * (the drag-n-drop zone) is, in fact, at the bottom.
+	 */
+
+	_canvas_bottom_rect->set_position (ArdourCanvas::Duple (0, h));
+
+	/* track controls layout must span the full height of "h" (all tracks)
+	 * plus the bottom rect.
+	 */
+
+	h += _canvas_bottom_rect->height ();
+
         /* set the height of the scrollable area (i.e. the sum of all contained widgets)
+	 * for the controls layout. The size request is set elsewhere.
          */
 
         controls_layout.property_height() = h;
 
-        /* size request is set elsewhere, see ::track_canvas_allocate() */
 }
 
 bool
diff --git a/gtk2_ardour/editor_canvas_events.cc b/gtk2_ardour/editor_canvas_events.cc
index c74c6b6e19..864624a690 100644
--- a/gtk2_ardour/editor_canvas_events.cc
+++ b/gtk2_ardour/editor_canvas_events.cc
@@ -1010,6 +1010,13 @@ Editor::canvas_note_event (GdkEvent *event, ArdourCanvas::Item* item)
 }
 
 bool
+Editor::canvas_bottom_rect_event (GdkEvent* event)
+{
+	cerr << "CBR event, type " << event << endl;
+	return true;
+}
+
+bool
 Editor::track_canvas_drag_motion (Glib::RefPtr<Gdk::DragContext> const& context, int x, int y, guint time)
 {
 	boost::shared_ptr<Region> region;
@@ -1191,3 +1198,4 @@ Editor::key_release_handler (ArdourCanvas::Item* item, GdkEvent* event, ItemType
 
 	return handled;
 }
+