Tidy up a bit in the case where the port matrix has nothing to display.

git-svn-id: svn://localhost/ardour2/branches/3.0@6089 d708f5d6-7413-0410-9779-e7cbd77b26cf

3 files changed, 47 insertions, 2 deletions

diff --git a/gtk2_ardour/port_group.cc b/gtk2_ardour/port_group.cc
index 8d10be23c8..938e82af0b 100644
--- a/gtk2_ardour/port_group.cc
+++ b/gtk2_ardour/port_group.cc
@@ -565,6 +565,17 @@ PortGroupList::io_from_bundle (boost::shared_ptr<ARDOUR::Bundle> b) const
 	return boost::shared_ptr<IO> ();
 }
 
+bool
+PortGroupList::empty () const
+{
+	List::const_iterator i = _groups.begin ();
+	while (i != _groups.end() && (*i)->total_channels() == 0) {
+		++i;
+	}
+
+	return (i == _groups.end());
+}
+
 
 RouteBundle::RouteBundle (boost::shared_ptr<Bundle> r)
 	: _route (r)
diff --git a/gtk2_ardour/port_group.h b/gtk2_ardour/port_group.h
index 27698ddbb0..e367adec9b 100644
--- a/gtk2_ardour/port_group.h
+++ b/gtk2_ardour/port_group.h
@@ -122,13 +122,15 @@ class PortGroupList : public sigc::trackable
 	void resume_signals ();
 
 	List::const_iterator begin () const {
-		return _groups.begin();
+		return _groups.begin ();
 	}
 
 	List::const_iterator end () const {
-		return _groups.end();
+		return _groups.end ();
 	}
 
+	bool empty () const;
+
 	sigc::signal<void> Changed;
 	sigc::signal<void, ARDOUR::Bundle::Change> BundleChanged;
 
diff --git a/gtk2_ardour/port_matrix_body.cc b/gtk2_ardour/port_matrix_body.cc
index 6fcc773253..6696a67204 100644
--- a/gtk2_ardour/port_matrix_body.cc
+++ b/gtk2_ardour/port_matrix_body.cc
@@ -55,6 +55,31 @@ PortMatrixBody::~PortMatrixBody ()
 bool
 PortMatrixBody::on_expose_event (GdkEventExpose* event)
 {
+	if (_matrix->columns()->empty() || _matrix->rows()->empty()) {
+
+		/* nothing to connect */
+
+		cairo_t* cr = gdk_cairo_create (get_window()->gobj());
+
+		cairo_set_source_rgb (cr, 0, 0, 0);
+		cairo_rectangle (cr, 0, 0, _alloc_width, _alloc_height);
+		cairo_fill (cr);
+
+		stringstream t;
+		t << _("There are no ") << (_matrix->type() == ARDOUR::DataType::AUDIO ? _("audio") : _("MIDI")) << _(" ports to connect.");
+
+		cairo_text_extents_t ext;
+		cairo_text_extents (cr, t.str().c_str(), &ext);
+
+		cairo_set_source_rgb (cr, 1, 1, 1);
+		cairo_move_to (cr, (_alloc_width - ext.width) / 2, (_alloc_height + ext.height) / 2);
+		cairo_show_text (cr, t.str().c_str ());
+
+		cairo_destroy (cr);
+
+		return true;
+	}
+
 	Gdk::Rectangle const exposure (
 		event->area.x, event->area.y, event->area.width, event->area.height
 		);
@@ -147,6 +172,13 @@ PortMatrixBody::on_size_request (Gtk::Requisition *req)
 	pair<int, int> const row = _row_labels->dimensions ();
 	pair<int, int> const grid = _grid->dimensions ();
 
+	if (grid.first == 0 && grid.second == 0) {
+		/* nothing to display */
+		req->width = 256;
+		req->height = 64;
+		return;
+	}
+
 	/* don't ask for the maximum size of our contents, otherwise GTK won't
 	   let the containing window shrink below this size */