Merge branch 'canvasredesign' into cairocanvas

gtk2_ardour/audio_region_view.cc

@@ -75,7 +75,7 @@ using namespace ArdourCanvas;
 static const int32_t sync_mark_width = 9;
 static double const handle_size = 10; /* height of fade handles */
 
-AudioRegionView::AudioRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &tv, boost::shared_ptr<AudioRegion> r, double spu,
+AudioRegionView::AudioRegionView (ArdourCanvas::Layout *parent, RouteTimeAxisView &tv, boost::shared_ptr<AudioRegion> r, double spu,
 				  uint32_t basic_color)
 	: RegionView (parent, tv, r, spu, basic_color)
 	, sync_mark(0)
@@ -96,7 +96,7 @@ AudioRegionView::AudioRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView
 	Config->ParameterChanged.connect (*this, invalidator (*this), boost::bind (&AudioRegionView::parameter_changed, this, _1), gui_context());
 }
 
-AudioRegionView::AudioRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &tv, boost::shared_ptr<AudioRegion> r, double spu,
+AudioRegionView::AudioRegionView (ArdourCanvas::Layout *parent, RouteTimeAxisView &tv, boost::shared_ptr<AudioRegion> r, double spu,
 				  uint32_t basic_color, bool recording, TimeAxisViewItem::Visibility visibility)
 	: RegionView (parent, tv, r, spu, basic_color, recording, visibility)
 	, sync_mark(0)

gtk2_ardour/audio_region_view.h

@@ -51,13 +51,13 @@ class RouteTimeAxisView;
 class AudioRegionView : public RegionView
 {
   public:
-	AudioRegionView (ArdourCanvas::Group *,
+	AudioRegionView (ArdourCanvas::Layout *,
 			 RouteTimeAxisView&,
 			 boost::shared_ptr<ARDOUR::AudioRegion>,
 			 double initial_samples_per_pixel,
 			 uint32_t base_color);
 
-	AudioRegionView (ArdourCanvas::Group *,
+	AudioRegionView (ArdourCanvas::Layout *,
 			 RouteTimeAxisView&,
 			 boost::shared_ptr<ARDOUR::AudioRegion>,
 			 double samples_per_pixel,

gtk2_ardour/automation_line.cc

@@ -70,7 +70,7 @@ using namespace Editing;
 /** @param converter A TimeConverter whose origin_b is the start time of the AutomationList in session frames.
  *  This will not be deleted by AutomationLine.
  */
-AutomationLine::AutomationLine (const string& name, TimeAxisView& tv, ArdourCanvas::Group& parent,
+AutomationLine::AutomationLine (const string& name, TimeAxisView& tv, ArdourCanvas::Item& parent,
                                 boost::shared_ptr<AutomationList> al,
                                 Evoral::TimeConverter<double, framepos_t>* converter)
 	: trackview (tv)
@@ -99,7 +99,7 @@ AutomationLine::AutomationLine (const string& name, TimeAxisView& tv, ArdourCanv
 	terminal_points_can_slide = true;
 	_height = 0;
 
-	group = new ArdourCanvas::Group (&parent);
+	group = new ArdourCanvas::Layout (&parent);
 	CANVAS_DEBUG_NAME (group, "region gain envelope group");
 
 	line = new ArdourCanvas::PolyLine (group);

gtk2_ardour/automation_line.h

@@ -37,7 +37,7 @@
 #include "ardour/types.h"
 
 #include "canvas/types.h"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/poly_line.h"
 
 class AutomationLine;
@@ -60,7 +60,7 @@ public:
 		SelectedControlPoints = 0x4
 	};
 	
-	AutomationLine (const std::string& name, TimeAxisView&, ArdourCanvas::Group&,
+	AutomationLine (const std::string& name, TimeAxisView&, ArdourCanvas::Item&,
 	                boost::shared_ptr<ARDOUR::AutomationList>,
 	                Evoral::TimeConverter<double, ARDOUR::framepos_t>* converter = 0);
 	virtual ~AutomationLine ();
@@ -105,7 +105,7 @@ public:
 
 	TimeAxisView& trackview;
 
-	ArdourCanvas::Group& canvas_group() const { return *group; }
+	ArdourCanvas::Layout& canvas_group() const { return *group; }
 	ArdourCanvas::Item&  parent_group() const { return _parent_group; }
 	ArdourCanvas::Item&  grab_item() const { return *line; }
 
@@ -173,8 +173,8 @@ protected:
 	/** true if we did a push at any point during the current drag */
 	bool    did_push;
 
-	ArdourCanvas::Group&        _parent_group;
+	ArdourCanvas::Item&        _parent_group;
-	ArdourCanvas::Group*        group;
+	ArdourCanvas::Layout*       group;
 	ArdourCanvas::PolyLine*     line; /* line */
 	ArdourCanvas::Points        line_points; /* coordinates for canvas line */
 	std::vector<ControlPoint*>  control_points; /* visible control points */

gtk2_ardour/automation_region_view.cc

@@ -39,7 +39,7 @@
 
 #include "i18n.h"
 
-AutomationRegionView::AutomationRegionView (ArdourCanvas::Group*                      parent,
+AutomationRegionView::AutomationRegionView (ArdourCanvas::Layout*                      parent,
 					    AutomationTimeAxisView&                   time_axis,
 					    boost::shared_ptr<ARDOUR::Region>         region,
 					    const Evoral::Parameter&                  param,

gtk2_ardour/automation_region_view.h

@@ -37,7 +37,7 @@ class TimeAxisView;
 class AutomationRegionView : public RegionView
 {
 public:
-	AutomationRegionView(ArdourCanvas::Group*,
+	AutomationRegionView(ArdourCanvas::Layout*,
 	                     AutomationTimeAxisView&,
 	                     boost::shared_ptr<ARDOUR::Region>,
 	                     const Evoral::Parameter& parameter,

gtk2_ardour/crossfade_view.h

@@ -36,7 +36,7 @@ namespace ArdourCanvas {
 class CrossfadeView : public TimeAxisViewItem
 {
 public:
-	CrossfadeView (ArdourCanvas::Group*,
+	CrossfadeView (ArdourCanvas::Layout*,
 		       RouteTimeAxisView&,
 		       boost::shared_ptr<ARDOUR::Crossfade>,
 		       double initial_samples_per_pixel,

gtk2_ardour/editor.h

@@ -451,10 +451,10 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 		_stepping_axis_view = v;
 	}
 
- 	ArdourCanvas::Group* get_trackview_group () const { return _trackview_group; }
+ 	ArdourCanvas::Layout* get_trackview_group () const { return _trackview_group; }
-        ArdourCanvas::Group* get_hscroll_group () const { return h_scroll_group; }
+        ArdourCanvas::ScrollGroup* get_hscroll_group () const { return h_scroll_group; }
-        ArdourCanvas::Group* get_vscroll_group () const { return v_scroll_group; }
+        ArdourCanvas::ScrollGroup* get_vscroll_group () const { return v_scroll_group; }
-        ArdourCanvas::Group* get_hvscroll_group () const { return hv_scroll_group; }
+        ArdourCanvas::ScrollGroup* get_hvscroll_group () const { return hv_scroll_group; }
 
         ArdourCanvas::GtkCanvasViewport* get_track_canvas () const;
 
@@ -560,7 +560,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	void refresh_location_display ();
 	void refresh_location_display_internal (ARDOUR::Locations::LocationList&);
 	void add_new_location (ARDOUR::Location *);
-	ArdourCanvas::Group* add_new_location_internal (ARDOUR::Location *);
+	ArdourCanvas::Layout* add_new_location_internal (ARDOUR::Location *);
 	void location_gone (ARDOUR::Location *);
 	void remove_marker (ArdourCanvas::Item&, GdkEvent*);
 	gint really_remove_marker (ARDOUR::Location* loc);
@@ -606,7 +606,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	LocationMarkerMap location_markers;
 
 	void update_marker_labels ();
-	void update_marker_labels (ArdourCanvas::Group *);
+	void update_marker_labels (ArdourCanvas::Layout *);
 	void check_marker_label (Marker *);
 
 	/** A set of lists of Markers that are in each of the canvas groups
@@ -615,7 +615,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	 *  a marker has moved we can decide whether we need to update the labels
 	 *  for all markers or for just a few.
 	 */
-	std::map<ArdourCanvas::Group *, std::list<Marker *> > _sorted_marker_lists;
+	std::map<ArdourCanvas::Layout *, std::list<Marker *> > _sorted_marker_lists;
 	void remove_sorted_marker (Marker *);
 
 	void hide_marker (ArdourCanvas::Item*, GdkEvent*);
@@ -729,42 +729,42 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	ArdourCanvas::Pixbuf     *logo_item;
 #if 0    
     /* these will be needed when we have canvas rulers */
-	ArdourCanvas::Group      *minsec_group;
+	ArdourCanvas::Layout      *minsec_group;
-	ArdourCanvas::Group      *bbt_group;
+	ArdourCanvas::Layout      *bbt_group;
-	ArdourCanvas::Group      *timecode_group;
+	ArdourCanvas::Layout      *timecode_group;
-	ArdourCanvas::Group      *frame_group;
+	ArdourCanvas::Layout      *frame_group;
 #endif
 
-	ArdourCanvas::Group      *tempo_group;
+	ArdourCanvas::Layout      *tempo_group;
-	ArdourCanvas::Group      *meter_group;
+	ArdourCanvas::Layout      *meter_group;
-	ArdourCanvas::Group      *marker_group;
+	ArdourCanvas::Layout      *marker_group;
-	ArdourCanvas::Group      *range_marker_group;
+	ArdourCanvas::Layout      *range_marker_group;
-	ArdourCanvas::Group      *transport_marker_group;
+	ArdourCanvas::Layout      *transport_marker_group;
-	ArdourCanvas::Group*      cd_marker_group;
+	ArdourCanvas::Layout*      cd_marker_group;
 
 	/* parent for groups which themselves contain time markers */
-	ArdourCanvas::Group*     _time_markers_group;
+	ArdourCanvas::Layout*     _time_markers_group;
 
 	/* The group containing all other groups that are scrolled vertically
 	   and horizontally.
 	*/
-        ArdourCanvas::Group* hv_scroll_group;
+        ArdourCanvas::ScrollGroup* hv_scroll_group;
 
 	/* The group containing all other groups that are scrolled vertically ONLY
 	*/
-        ArdourCanvas::Group* v_scroll_group;
+        ArdourCanvas::ScrollGroup* v_scroll_group;
 
 	/* The group containing all other groups that are scrolled horizontally ONLY
 	*/
-        ArdourCanvas::Group* h_scroll_group;
+        ArdourCanvas::ScrollGroup* h_scroll_group;
 
 	/* The group containing all trackviews. */
-	ArdourCanvas::Group* _trackview_group;
+	ArdourCanvas::Layout* _trackview_group;
 
 	/* The group holding things (mostly regions) while dragging so they
 	 * are on top of everything else
 	 */
-	ArdourCanvas::Group* _drag_motion_group;
+	ArdourCanvas::Layout* _drag_motion_group;
 
         /* a rect that sits at the bottom of all tracks to act as a drag-no-drop/clickable
 	 * target area.
@@ -898,7 +898,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 
 	/* videtimline related actions */
 	Gtk::Label                videotl_label;
-	ArdourCanvas::Group*      videotl_group;
+	ArdourCanvas::Layout*      videotl_group;
 	Glib::RefPtr<Gtk::ToggleAction> ruler_video_action;
 	Glib::RefPtr<Gtk::ToggleAction> xjadeo_proc_action;
 	Glib::RefPtr<Gtk::ToggleAction> xjadeo_ontop_action;
@@ -1478,8 +1478,8 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 
 	TempoLines* tempo_lines;
 
-	ArdourCanvas::Group* global_rect_group;
+	ArdourCanvas::Layout* global_rect_group;
-	ArdourCanvas::Group* time_line_group;
+	ArdourCanvas::Layout* time_line_group;
 
 	void hide_measures ();
         void draw_measures (ARDOUR::TempoMap::BBTPointList::const_iterator& begin,

gtk2_ardour/editor_canvas.cc

@@ -101,7 +101,7 @@ Editor::initialize_canvas ()
 	}
 
 	/*a group to hold global rects like punch/loop indicators */
-	global_rect_group = new ArdourCanvas::Group (hv_scroll_group);
+	global_rect_group = new ArdourCanvas::Layout (hv_scroll_group);
 	CANVAS_DEBUG_NAME (global_rect_group, "global rect group");
 
         transport_loop_range_rect = new ArdourCanvas::Rectangle (global_rect_group, ArdourCanvas::Rect (0.0, 0.0, 0.0, ArdourCanvas::COORD_MAX));
@@ -113,10 +113,10 @@ Editor::initialize_canvas ()
 	transport_punch_range_rect->hide();
 
 	/*a group to hold time (measure) lines */
-	time_line_group = new ArdourCanvas::Group (hv_scroll_group);
+	time_line_group = new ArdourCanvas::Layout (hv_scroll_group);
 	CANVAS_DEBUG_NAME (time_line_group, "time line group");
 
-	_trackview_group = new ArdourCanvas::Group (hv_scroll_group);
+	_trackview_group = new ArdourCanvas::Layout (hv_scroll_group);
 	CANVAS_DEBUG_NAME (_trackview_group, "Canvas TrackViews");
 	
 	// used to show zoom mode active zooming
@@ -131,30 +131,30 @@ Editor::initialize_canvas ()
 	/* a group to hold stuff while it gets dragged around. Must be the
 	 * uppermost (last) group with hv_scroll_group as a parent
 	 */
-	_drag_motion_group = new ArdourCanvas::Group (hv_scroll_group);                                                                                                                                     
+	_drag_motion_group = new ArdourCanvas::Layout (hv_scroll_group);                                                                                                                                     
         CANVAS_DEBUG_NAME (_drag_motion_group, "Canvas Drag Motion");
 
 	/* TIME BAR CANVAS */
 	
-	_time_markers_group = new ArdourCanvas::Group (h_scroll_group);
+	_time_markers_group = new ArdourCanvas::Layout (h_scroll_group);
 	CANVAS_DEBUG_NAME (_time_markers_group, "time bars");
 
-	cd_marker_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, 0.0));
+	cd_marker_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, 0.0));
 	CANVAS_DEBUG_NAME (cd_marker_group, "cd marker group");
 	/* the vide is temporarily placed a the same location as the
 	   cd_marker_group, but is moved later.
 	*/
-	videotl_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple(0.0, 0.0));
+	videotl_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple(0.0, 0.0));
 	CANVAS_DEBUG_NAME (videotl_group, "videotl group");
-	marker_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, timebar_height + 1.0));
+	marker_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, timebar_height + 1.0));
 	CANVAS_DEBUG_NAME (marker_group, "marker group");
-	transport_marker_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 2.0) + 1.0));
+	transport_marker_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 2.0) + 1.0));
 	CANVAS_DEBUG_NAME (transport_marker_group, "transport marker group");
-	range_marker_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 3.0) + 1.0));
+	range_marker_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 3.0) + 1.0));
 	CANVAS_DEBUG_NAME (range_marker_group, "range marker group");
-	tempo_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 4.0) + 1.0));
+	tempo_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 4.0) + 1.0));
 	CANVAS_DEBUG_NAME (tempo_group, "tempo group");
-	meter_group = new ArdourCanvas::Group (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 5.0) + 1.0));
+	meter_group = new ArdourCanvas::Layout (_time_markers_group, ArdourCanvas::Duple (0.0, (timebar_height * 5.0) + 1.0));
 	CANVAS_DEBUG_NAME (meter_group, "meter group");
 
 	meter_bar = new ArdourCanvas::Rectangle (meter_group, ArdourCanvas::Rect (0.0, 0.0, ArdourCanvas::COORD_MAX, timebar_height));

gtk2_ardour/editor_cursors.cc

@@ -22,6 +22,7 @@
 
 #include "canvas/canvas.h"
 #include "canvas/debug.h"
+#include "canvas/scroll_group.h"
 
 #include "utils.h"
 #include "editor_cursors.h"

gtk2_ardour/editor_drag.cc

@@ -736,8 +736,8 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 			/* reparent the regionview into a group above all
 			 * others
 			 */
-
+			
-			ArdourCanvas::Group* rvg = rv->get_canvas_group();                                                                                                                                     
+			ArdourCanvas::Item* rvg = rv->get_canvas_group();
                         Duple rv_canvas_offset = rvg->parent()->canvas_origin ();
                         Duple dmg_canvas_offset = _editor->_drag_motion_group->canvas_origin ();
                         rv->get_canvas_group()->reparent (_editor->_drag_motion_group);

gtk2_ardour/editor_markers.cc

@@ -64,7 +64,7 @@ Editor::add_new_location (Location *location)
 {
 	ENSURE_GUI_THREAD (*this, &Editor::add_new_location, location);
 
-	ArdourCanvas::Group* group = add_new_location_internal (location);
+	ArdourCanvas::Layout* group = add_new_location_internal (location);
 
 	/* Do a full update of the markers in this group */
 	update_marker_labels (group);
@@ -82,14 +82,14 @@ Editor::add_new_location (Location *location)
  *  the caller must call update_marker_labels () after calling this.
  *  @return canvas group that the location's marker was added to.
  */
-ArdourCanvas::Group*
+ArdourCanvas::Layout*
 Editor::add_new_location_internal (Location* location)
 {
 	LocationMarkers *lam = new LocationMarkers;
 	uint32_t color;
 
 	/* make a note here of which group this marker ends up in */
-	ArdourCanvas::Group* group = 0;
+	ArdourCanvas::Layout* group = 0;
 
 	if (location->is_cd_marker()) {
 		color = location_cd_marker_color;
@@ -311,14 +311,14 @@ struct MarkerComparator {
 void
 Editor::update_marker_labels ()
 {
-	for (std::map<ArdourCanvas::Group *, std::list<Marker *> >::iterator i = _sorted_marker_lists.begin(); i != _sorted_marker_lists.end(); ++i) {
+	for (std::map<ArdourCanvas::Layout *, std::list<Marker *> >::iterator i = _sorted_marker_lists.begin(); i != _sorted_marker_lists.end(); ++i) {
 		update_marker_labels (i->first);
 	}
 }
 
 /** Look at all markers in a group and update label widths */
 void
-Editor::update_marker_labels (ArdourCanvas::Group* group)
+Editor::update_marker_labels (ArdourCanvas::Layout* group)
 {
 	list<Marker*>& sorted = _sorted_marker_lists[group];
 
@@ -1576,7 +1576,7 @@ Editor::toggle_marker_lines ()
 void
 Editor::remove_sorted_marker (Marker* m)
 {
-	for (std::map<ArdourCanvas::Group *, std::list<Marker *> >::iterator i = _sorted_marker_lists.begin(); i != _sorted_marker_lists.end(); ++i) {
+	for (std::map<ArdourCanvas::Layout *, std::list<Marker *> >::iterator i = _sorted_marker_lists.begin(); i != _sorted_marker_lists.end(); ++i) {
 		i->second.remove (m);
 	}
 }

gtk2_ardour/editor_rulers.cc

@@ -29,10 +29,11 @@
 
 #include <gtk/gtkaction.h>
 
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/canvas.h"
 #include "canvas/ruler.h"
 #include "canvas/debug.h"
+#include "canvas/scroll_group.h"
 
 #include "ardour/session.h"
 #include "ardour/tempo.h"

gtk2_ardour/ghostregion.cc

@@ -18,7 +18,7 @@
 */
 
 #include "evoral/Note.hpp"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/rectangle.h"
 #include "canvas/wave_view.h"
 #include "canvas/debug.h"
@@ -38,11 +38,11 @@ using namespace ARDOUR;
 
 PBD::Signal1<void,GhostRegion*> GhostRegion::CatchDeletion;
 
-GhostRegion::GhostRegion (ArdourCanvas::Group* parent, TimeAxisView& tv, TimeAxisView& source_tv, double initial_pos)
+GhostRegion::GhostRegion (ArdourCanvas::Layout* parent, TimeAxisView& tv, TimeAxisView& source_tv, double initial_pos)
 	: trackview (tv)
 	, source_trackview (source_tv)
 {
-	group = new ArdourCanvas::Group (parent);
+	group = new ArdourCanvas::Layout (parent);
 	CANVAS_DEBUG_NAME (group, "ghost region");
 	group->set_position (ArdourCanvas::Duple (initial_pos, 0));
 
@@ -191,7 +191,7 @@ MidiGhostRegion::~MidiGhostRegion()
 	clear_events ();
 }
 
-MidiGhostRegion::GhostEvent::GhostEvent (NoteBase* e, ArdourCanvas::Group* g)
+MidiGhostRegion::GhostEvent::GhostEvent (NoteBase* e, ArdourCanvas::Layout* g)
 	: event (e)
 {
 	rect = new ArdourCanvas::Rectangle (g, ArdourCanvas::Rect (e->x0(), e->y0(), e->x1(), e->y1()));

gtk2_ardour/ghostregion.h

@@ -36,7 +36,7 @@ class TimeAxisView;
 class GhostRegion : public sigc::trackable
 {
 public:
-	GhostRegion(ArdourCanvas::Group* parent, TimeAxisView& tv, TimeAxisView& source_tv, double initial_unit_pos);
+	GhostRegion(ArdourCanvas::Layout* parent, TimeAxisView& tv, TimeAxisView& source_tv, double initial_unit_pos);
 	virtual ~GhostRegion();
 
 	virtual void set_samples_per_pixel (double) = 0;
@@ -52,7 +52,7 @@ public:
 	TimeAxisView& trackview;
 	/** TimeAxisView that we are a ghost for */
 	TimeAxisView& source_trackview;
-	ArdourCanvas::Group* group;
+	ArdourCanvas::Layout* group;
 	ArdourCanvas::Rectangle* base_rect;
 
 	static PBD::Signal1<void,GhostRegion*> CatchDeletion;
@@ -73,7 +73,7 @@ class MidiGhostRegion : public GhostRegion {
 public:
 	class GhostEvent : public sigc::trackable {
 	  public:
-	    GhostEvent(::NoteBase *, ArdourCanvas::Group *);
+	    GhostEvent(::NoteBase *, ArdourCanvas::Layout *);
 	    virtual ~GhostEvent ();
 	    
 	    NoteBase* event;

gtk2_ardour/hit.cc

@@ -30,10 +30,10 @@
 using namespace ARDOUR;
 using namespace ArdourCanvas;
 
-Hit::Hit (MidiRegionView& region, Group* group, double size, const boost::shared_ptr<NoteType> note, bool with_events) 
+Hit::Hit (MidiRegionView& region, Item* parent, double size, const boost::shared_ptr<NoteType> note, bool with_events) 
 	: NoteBase (region, with_events, note)
 {
-	_polygon = new ArdourCanvas::Polygon (group);
+	_polygon = new ArdourCanvas::Polygon (parent);
 	CANVAS_DEBUG_NAME (_polygon, "note");
 	set_item (_polygon);
 	set_height (size);

gtk2_ardour/hit.h

@@ -33,7 +33,7 @@ public:
 	typedef Evoral::Note<double> NoteType;
 
 	Hit (MidiRegionView&                   region,
-	     ArdourCanvas::Group*              group,
+	     ArdourCanvas::Item*               parent,
 	     double                            size,
 	     const boost::shared_ptr<NoteType> note = boost::shared_ptr<NoteType>(),
 	     bool with_events = true);

gtk2_ardour/marker.cc

@@ -21,11 +21,12 @@
 #include "ardour/tempo.h"
 
 #include "canvas/rectangle.h"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/line.h"
 #include "canvas/polygon.h"
 #include "canvas/text.h"
 #include "canvas/canvas.h"
+#include "canvas/scroll_group.h"
 #include "canvas/debug.h"
 
 #include "ardour_ui.h"
@@ -52,7 +53,7 @@ PBD::Signal1<void,Marker*> Marker::CatchDeletion;
 
 static const double marker_height = 13.0;
 
-Marker::Marker (PublicEditor& ed, ArdourCanvas::Group& parent, guint32 rgba, const string& annotation,
+Marker::Marker (PublicEditor& ed, ArdourCanvas::Layout& parent, guint32 rgba, const string& annotation,
 		Type type, framepos_t frame, bool handle_events)
 
 	: editor (ed)
@@ -241,7 +242,7 @@ Marker::Marker (PublicEditor& ed, ArdourCanvas::Group& parent, guint32 rgba, con
 	unit_position = editor.sample_to_pixel (frame);
 	unit_position -= _shift;
 
-	group = new ArdourCanvas::Group (&parent, ArdourCanvas::Duple (unit_position, 0));
+	group = new ArdourCanvas::Layout (&parent, ArdourCanvas::Duple (unit_position, 0));
 #ifdef CANVAS_DEBUG
 	group->name = string_compose ("Marker::group for %1", annotation);
 #endif	
@@ -301,7 +302,7 @@ Marker::~Marker ()
 	delete _track_canvas_line;
 }
 
-void Marker::reparent(ArdourCanvas::Group & parent)
+void Marker::reparent(ArdourCanvas::Layout & parent)
 {
 	group->reparent (&parent);
 	_parent = &parent;
@@ -500,7 +501,7 @@ Marker::set_right_label_limit (double p)
 
 /***********************************************************************/
 
-TempoMarker::TempoMarker (PublicEditor& editor, ArdourCanvas::Group& parent, guint32 rgba, const string& text,
+TempoMarker::TempoMarker (PublicEditor& editor, ArdourCanvas::Layout& parent, guint32 rgba, const string& text,
 			  ARDOUR::TempoSection& temp)
 	: Marker (editor, parent, rgba, text, Tempo, 0, false),
 	  _tempo (temp)
@@ -515,7 +516,7 @@ TempoMarker::~TempoMarker ()
 
 /***********************************************************************/
 
-MeterMarker::MeterMarker (PublicEditor& editor, ArdourCanvas::Group& parent, guint32 rgba, const string& text,
+MeterMarker::MeterMarker (PublicEditor& editor, ArdourCanvas::Layout& parent, guint32 rgba, const string& text,
 			  ARDOUR::MeterSection& m)
 	: Marker (editor, parent, rgba, text, Meter, 0, false),
 	  _meter (m)

gtk2_ardour/marker.h

@@ -56,7 +56,7 @@ class Marker : public sigc::trackable
 	};
 
 
-	Marker (PublicEditor& editor, ArdourCanvas::Group &, guint32 rgba, const std::string& text, Type,
+	Marker (PublicEditor& editor, ArdourCanvas::Layout &, guint32 rgba, const std::string& text, Type,
 		framepos_t frame = 0, bool handle_events = true);
 
 	virtual ~Marker ();
@@ -76,8 +76,8 @@ class Marker : public sigc::trackable
 
 	framepos_t position() const { return frame_position; }
 
-	ArdourCanvas::Group * get_parent() { return _parent; }
+	ArdourCanvas::Layout * get_parent() { return _parent; }
-	void reparent (ArdourCanvas::Group & parent);
+	void reparent (ArdourCanvas::Layout & parent);
 
 	void hide ();
 	void show ();
@@ -98,8 +98,8 @@ class Marker : public sigc::trackable
 
 	Pango::FontDescription name_font;
 
-	ArdourCanvas::Group* _parent;
+	ArdourCanvas::Layout* _parent;
-	ArdourCanvas::Group *group;
+	ArdourCanvas::Layout *group;
 	ArdourCanvas::Polygon *mark;
         ArdourCanvas::Text *_name_item;
 	ArdourCanvas::Points *points;
@@ -134,7 +134,7 @@ private:
 class TempoMarker : public Marker
 {
   public:
-        TempoMarker (PublicEditor& editor, ArdourCanvas::Group &, guint32 rgba, const std::string& text, ARDOUR::TempoSection&);
+        TempoMarker (PublicEditor& editor, ArdourCanvas::Layout &, guint32 rgba, const std::string& text, ARDOUR::TempoSection&);
 	~TempoMarker ();
 
 	ARDOUR::TempoSection& tempo() const { return _tempo; }
@@ -146,7 +146,7 @@ class TempoMarker : public Marker
 class MeterMarker : public Marker
 {
   public:
-        MeterMarker (PublicEditor& editor, ArdourCanvas::Group &, guint32 rgba, const std::string& text, ARDOUR::MeterSection&);
+        MeterMarker (PublicEditor& editor, ArdourCanvas::Layout &, guint32 rgba, const std::string& text, ARDOUR::MeterSection&);
 	~MeterMarker ();
 
 	ARDOUR::MeterSection& meter() const { return _meter; }

gtk2_ardour/midi_automation_line.cc

@@ -29,12 +29,12 @@ using namespace std;
 MidiAutomationLine::MidiAutomationLine (
 	const std::string&                                      name,
 	TimeAxisView&                                           tav,
-	ArdourCanvas::Group&                                    group,
+	ArdourCanvas::Item&                                     parent,
 	boost::shared_ptr<ARDOUR::AutomationList>               list,
 	boost::shared_ptr<ARDOUR::MidiRegion>                   region,
 	Evoral::Parameter                                       parameter,
 	Evoral::TimeConverter<double, ARDOUR::framepos_t>*      converter)
-	: AutomationLine (name, tav, group, list, converter)
+	: AutomationLine (name, tav, parent, list, converter)
 	, _region (region)
 	, _parameter (parameter)
 {

gtk2_ardour/midi_automation_line.h

@@ -26,7 +26,7 @@
 class MidiAutomationLine : public AutomationLine
 {
 public:
-	MidiAutomationLine (const std::string&, TimeAxisView&, ArdourCanvas::Group&,
+	MidiAutomationLine (const std::string&, TimeAxisView&, ArdourCanvas::Item&,
 	                    boost::shared_ptr<ARDOUR::AutomationList>,
 	                    boost::shared_ptr<ARDOUR::MidiRegion>,
 	                    Evoral::Parameter,

gtk2_ardour/midi_region_view.cc

@@ -88,13 +88,13 @@ PBD::Signal1<void, MidiRegionView *> MidiRegionView::SelectionCleared;
 
 #define MIDI_BP_ZERO ((Config->get_first_midi_bank_is_zero())?0:1)
 
-MidiRegionView::MidiRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &tv,
+MidiRegionView::MidiRegionView (ArdourCanvas::Layout *parent, RouteTimeAxisView &tv,
                                 boost::shared_ptr<MidiRegion> r, double spu, uint32_t basic_color)
 	: RegionView (parent, tv, r, spu, basic_color)
 	, _current_range_min(0)
 	, _current_range_max(0)
 	, _active_notes(0)
-	, _note_group (new ArdourCanvas::Group (group))
+	, _note_group (new ArdourCanvas::Layout (group))
 	, _note_diff_command (0)
 	, _ghost_note(0)
 	, _step_edit_cursor (0)
@@ -124,14 +124,14 @@ MidiRegionView::MidiRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &
 	SelectionCleared.connect (_selection_cleared_connection, invalidator (*this), boost::bind (&MidiRegionView::selection_cleared, this, _1), gui_context ());
 }
 
-MidiRegionView::MidiRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &tv,
+MidiRegionView::MidiRegionView (ArdourCanvas::Layout *parent, RouteTimeAxisView &tv,
                                 boost::shared_ptr<MidiRegion> r, double spu, uint32_t basic_color,
                                 TimeAxisViewItem::Visibility visibility)
 	: RegionView (parent, tv, r, spu, basic_color, false, visibility)
 	, _current_range_min(0)
 	, _current_range_max(0)
 	, _active_notes(0)
-	, _note_group (new ArdourCanvas::Group (parent))
+	, _note_group (new ArdourCanvas::Layout (parent))
 	, _note_diff_command (0)
 	, _ghost_note(0)
 	, _step_edit_cursor (0)
@@ -177,7 +177,7 @@ MidiRegionView::MidiRegionView (const MidiRegionView& other)
 	, _current_range_min(0)
 	, _current_range_max(0)
 	, _active_notes(0)
-	, _note_group (new ArdourCanvas::Group (get_canvas_group()))
+	, _note_group (new ArdourCanvas::Layout (get_canvas_group()))
 	, _note_diff_command (0)
 	, _ghost_note(0)
 	, _step_edit_cursor (0)
@@ -205,7 +205,7 @@ MidiRegionView::MidiRegionView (const MidiRegionView& other, boost::shared_ptr<M
 	, _current_range_min(0)
 	, _current_range_max(0)
 	, _active_notes(0)
-	, _note_group (new ArdourCanvas::Group (get_canvas_group()))
+	, _note_group (new ArdourCanvas::Layout (get_canvas_group()))
 	, _note_diff_command (0)
 	, _ghost_note(0)
 	, _step_edit_cursor (0)
@@ -3610,7 +3610,7 @@ void
 MidiRegionView::show_step_edit_cursor (Evoral::MusicalTime pos)
 {
 	if (_step_edit_cursor == 0) {
-		ArdourCanvas::Group* const group = (ArdourCanvas::Group*)get_canvas_group();
+		ArdourCanvas::Layout* const group = (ArdourCanvas::Layout*)get_canvas_group();
 
 		_step_edit_cursor = new ArdourCanvas::Rectangle (group);
 		_step_edit_cursor->set_y0 (0);
@@ -3725,7 +3725,7 @@ MidiRegionView::trim_front_starting ()
 	/* Reparent the note group to the region view's parent, so that it doesn't change
 	   when the region view is trimmed.
 	*/
-	_temporary_note_group = new ArdourCanvas::Group (group->parent ());
+	_temporary_note_group = new ArdourCanvas::Layout (group->parent ());
 	_temporary_note_group->move (group->position ());
 	_note_group->reparent (_temporary_note_group);
 }

gtk2_ardour/midi_region_view.h

@@ -67,7 +67,7 @@ public:
 	typedef Evoral::Note<Evoral::MusicalTime> NoteType;
 	typedef Evoral::Sequence<Evoral::MusicalTime>::Notes Notes;
 
-	MidiRegionView (ArdourCanvas::Group *,
+	MidiRegionView (ArdourCanvas::Layout *,
 	                RouteTimeAxisView&,
 	                boost::shared_ptr<ARDOUR::MidiRegion>,
 	                double initial_samples_per_pixel,
@@ -309,7 +309,7 @@ protected:
 	/** Allows derived types to specify their visibility requirements
 	 * to the TimeAxisViewItem parent class.
 	 */
-	MidiRegionView (ArdourCanvas::Group *,
+	MidiRegionView (ArdourCanvas::Layout *,
 	                RouteTimeAxisView&,
 	                boost::shared_ptr<ARDOUR::MidiRegion>,
 	                double samples_per_pixel,
@@ -387,7 +387,7 @@ private:
 	PatchChanges                         _patch_changes;
 	SysExes                              _sys_exes;
 	Note**                               _active_notes;
-	ArdourCanvas::Group*                 _note_group;
+	ArdourCanvas::Layout*                 _note_group;
 	ARDOUR::MidiModel::NoteDiffCommand*  _note_diff_command;
 	Note*                                _ghost_note;
 	double                               _last_ghost_x;
@@ -401,7 +401,7 @@ private:
 	/** A group used to temporarily reparent _note_group to during start trims, so
 	 *  that the notes don't move with the parent region view.
 	 */
-	ArdourCanvas::Group*                 _temporary_note_group;
+	ArdourCanvas::Layout*                 _temporary_note_group;
 
 	MouseState _mouse_state;
 	int _pressed_button;

gtk2_ardour/midi_streamview.cc

@@ -68,7 +68,7 @@ MidiStreamView::MidiStreamView (MidiTimeAxisView& tv)
 	, _updates_suspended (false)
 {
 	/* use a group dedicated to MIDI underlays. Audio underlays are not in this group. */
-	midi_underlay_group = new ArdourCanvas::Group (_canvas_group);
+	midi_underlay_group = new ArdourCanvas::Layout (_canvas_group);
 	midi_underlay_group->lower_to_bottom();
 
 	/* put the note lines in the timeaxisview's group, so it

gtk2_ardour/midi_streamview.h

@@ -68,7 +68,7 @@ class MidiStreamView : public StreamView
 	};
 
 	Gtk::Adjustment note_range_adjustment;
-	ArdourCanvas::Group* midi_underlay_group;
+	ArdourCanvas::Layout* midi_underlay_group;
 
 	void set_note_range(VisibleNoteRange r);
 

gtk2_ardour/note.cc

@@ -31,9 +31,9 @@ using namespace ARDOUR;
 using namespace ArdourCanvas;
 
 Note::Note (
-	MidiRegionView& region, Group* group, const boost::shared_ptr<NoteType> note, bool with_events)
+	MidiRegionView& region, Item* parent, const boost::shared_ptr<NoteType> note, bool with_events)
 	: NoteBase (region, with_events, note)
-	, _rectangle (new ArdourCanvas::Rectangle (group))
+	, _rectangle (new ArdourCanvas::Rectangle (parent))
 {
 	CANVAS_DEBUG_NAME (_rectangle, "note");
 	set_item (_rectangle);

gtk2_ardour/note.h

@@ -26,7 +26,7 @@
 #include "midi_util.h"
 
 namespace ArdourCanvas {
-	class Group;
+	class Layout;
 }
 
 class Note : public NoteBase
@@ -35,7 +35,7 @@ public:
 	typedef Evoral::Note<Evoral::MusicalTime> NoteType;
 
 	Note (MidiRegionView&                   region,
-	      ArdourCanvas::Group*              group,
+	      ArdourCanvas::Item*               parent,
 	      const boost::shared_ptr<NoteType> note = boost::shared_ptr<NoteType>(),
 	      bool with_events = true);
 

gtk2_ardour/patch_change.cc

@@ -43,7 +43,7 @@ using namespace std;
  */
 PatchChange::PatchChange(
 		MidiRegionView& region,
-		ArdourCanvas::Group* parent,
+		ArdourCanvas::Layout* parent,
 		const string&   text,
 		double          height,
 		double          x,

gtk2_ardour/patch_change.h

@@ -35,7 +35,7 @@ class PatchChange
 public:
 	PatchChange(
 		MidiRegionView& region,
-		ArdourCanvas::Group* parent,
+		ArdourCanvas::Layout* parent,
 		const string&   text,
 		double          height,
 		double          x,

gtk2_ardour/public_editor.h

@@ -365,10 +365,10 @@ class PublicEditor : public Gtk::Window, public PBD::StatefulDestructible, publi
 	virtual Gtk::HBox& get_status_bar_packer() = 0;
 #endif
 
-	virtual ArdourCanvas::Group* get_trackview_group () const = 0;
+	virtual ArdourCanvas::Layout* get_trackview_group () const = 0;
-	virtual ArdourCanvas::Group* get_hscroll_group () const = 0;
+	virtual ArdourCanvas::ScrollGroup* get_hscroll_group () const = 0;
-	virtual ArdourCanvas::Group* get_vscroll_group () const = 0;
+	virtual ArdourCanvas::ScrollGroup* get_vscroll_group () const = 0;
-	virtual ArdourCanvas::Group* get_hvscroll_group () const = 0;
+	virtual ArdourCanvas::ScrollGroup* get_hvscroll_group () const = 0;
 
         virtual ArdourCanvas::GtkCanvasViewport* get_track_canvas() const = 0;
 

gtk2_ardour/region_gain_line.cc

@@ -38,7 +38,7 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
-AudioRegionGainLine::AudioRegionGainLine (const string & name, AudioRegionView& r, ArdourCanvas::Group& parent, boost::shared_ptr<AutomationList> l)
+AudioRegionGainLine::AudioRegionGainLine (const string & name, AudioRegionView& r, ArdourCanvas::Layout& parent, boost::shared_ptr<AutomationList> l)
 	: AutomationLine (name, r.get_time_axis_view(), parent, l)
 	, rv (r)
 {

gtk2_ardour/region_gain_line.h

@@ -35,7 +35,7 @@ class AudioRegionView;
 class AudioRegionGainLine : public AutomationLine
 {
   public:
-	AudioRegionGainLine (const std::string & name, AudioRegionView&, ArdourCanvas::Group& parent, boost::shared_ptr<ARDOUR::AutomationList>);
+	AudioRegionGainLine (const std::string & name, AudioRegionView&, ArdourCanvas::Layout& parent, boost::shared_ptr<ARDOUR::AutomationList>);
 
         void start_drag_single (ControlPoint*, double, float);
         void end_drag (bool with_push, uint32_t final_index);

gtk2_ardour/region_view.cc

@@ -63,7 +63,7 @@ static const int32_t sync_mark_width = 9;
 
 PBD::Signal1<void,RegionView*> RegionView::RegionViewGoingAway;
 
-RegionView::RegionView (ArdourCanvas::Group*              parent,
+RegionView::RegionView (ArdourCanvas::Layout*              parent,
                         TimeAxisView&                     tv,
                         boost::shared_ptr<ARDOUR::Region> r,
                         double                            spu,
@@ -128,7 +128,7 @@ RegionView::RegionView (const RegionView& other, boost::shared_ptr<Region> other
 	GhostRegion::CatchDeletion.connect (*this, invalidator (*this), boost::bind (&RegionView::remove_ghost, this, _1), gui_context());
 }
 
-RegionView::RegionView (ArdourCanvas::Group*         parent,
+RegionView::RegionView (ArdourCanvas::Layout*         parent,
                         TimeAxisView&                tv,
                         boost::shared_ptr<ARDOUR::Region> r,
                         double                       spu,

gtk2_ardour/region_view.h

@@ -49,7 +49,7 @@ namespace ArdourCanvas {
 class RegionView : public TimeAxisViewItem
 {
   public:
-	RegionView (ArdourCanvas::Group* parent,
+	RegionView (ArdourCanvas::Layout* parent,
 	            TimeAxisView&        time_view,
 	            boost::shared_ptr<ARDOUR::Region> region,
 	            double               samples_per_pixel,
@@ -128,7 +128,7 @@ class RegionView : public TimeAxisViewItem
 	/** Allows derived types to specify their visibility requirements
 	 * to the TimeAxisViewItem parent class
 	 */
-	RegionView (ArdourCanvas::Group *,
+	RegionView (ArdourCanvas::Layout *,
 		    TimeAxisView&,
 		    boost::shared_ptr<ARDOUR::Region>,
 		    double samples_per_pixel,

gtk2_ardour/streamview.cc

@@ -52,9 +52,9 @@ using namespace ARDOUR;
 using namespace PBD;
 using namespace Editing;
 
-StreamView::StreamView (RouteTimeAxisView& tv, ArdourCanvas::Group* canvas_group)
+StreamView::StreamView (RouteTimeAxisView& tv, ArdourCanvas::Layout* canvas_group)
 	: _trackview (tv)
-	, _canvas_group (canvas_group ? canvas_group : new ArdourCanvas::Group (_trackview.canvas_display()))
+	, _canvas_group (canvas_group ? canvas_group : new ArdourCanvas::Layout (_trackview.canvas_display()))
 	, _samples_per_pixel (_trackview.editor().get_current_zoom ())
 	, rec_updating(false)
 	, rec_active(false)

gtk2_ardour/streamview.h

@@ -42,7 +42,7 @@ namespace ARDOUR {
 
 namespace ArdourCanvas {
 	class Rectangle;
-	class Group;
+	class Layout;
 }
 
 struct RecBoxInfo {
@@ -82,7 +82,7 @@ public:
  	void set_layer_display (LayerDisplay);
 	LayerDisplay layer_display () const { return _layer_display; }
 
-	ArdourCanvas::Group* canvas_item() { return _canvas_group; }
+	ArdourCanvas::Layout* canvas_item() { return _canvas_group; }
 
 	enum ColorTarget {
 		RegionColor,
@@ -128,7 +128,7 @@ public:
 	sigc::signal<void> ContentsHeightChanged;
 
 protected:
-       StreamView (RouteTimeAxisView&, ArdourCanvas::Group* canvas_group = 0);
+       StreamView (RouteTimeAxisView&, ArdourCanvas::Layout* canvas_group = 0);
 
 	void         transport_changed();
 	void         transport_looped();
@@ -151,7 +151,7 @@ protected:
 	virtual void color_handler () = 0;
 
 	RouteTimeAxisView&        _trackview;
-	ArdourCanvas::Group*      _canvas_group;
+	ArdourCanvas::Layout*      _canvas_group;
 	ArdourCanvas::Rectangle*   canvas_rect; /* frame around the whole thing */
 
 	typedef std::list<RegionView* > RegionViewList;

gtk2_ardour/sys_ex.cc

@@ -26,7 +26,7 @@ using namespace std;
 
 SysEx::SysEx (
 	MidiRegionView& region,
-	ArdourCanvas::Group* parent,
+	ArdourCanvas::Layout* parent,
 	string&         text,
 	double          height,
 	double          x,

gtk2_ardour/sys_ex.h

@@ -31,7 +31,7 @@ class SysEx
 public:
 	SysEx (
 			MidiRegionView& region,
-			ArdourCanvas::Group* parent,
+			ArdourCanvas::Layout* parent,
 			std::string&    text,
 			double          height,
 			double          x,

gtk2_ardour/tape_region_view.cc

@@ -46,7 +46,7 @@ const TimeAxisViewItem::Visibility TapeAudioRegionView::default_tape_visibility
 		TimeAxisViewItem::HideFrameRight |
 		TimeAxisViewItem::FullWidthNameHighlight);
 
-TapeAudioRegionView::TapeAudioRegionView (ArdourCanvas::Group *parent, RouteTimeAxisView &tv,
+TapeAudioRegionView::TapeAudioRegionView (ArdourCanvas::Layout *parent, RouteTimeAxisView &tv,
 					  boost::shared_ptr<AudioRegion> r,
 					  double spu,
 					  uint32_t basic_color)

gtk2_ardour/tape_region_view.h

@@ -27,7 +27,7 @@
 class TapeAudioRegionView : public AudioRegionView
 {
   public:
-	TapeAudioRegionView (ArdourCanvas::Group *,
+	TapeAudioRegionView (ArdourCanvas::Layout *,
 			     RouteTimeAxisView&,
 			     boost::shared_ptr<ARDOUR::AudioRegion>,
 			     double initial_samples_per_pixel,

gtk2_ardour/tempo_lines.cc

@@ -28,7 +28,7 @@
 
 using namespace std;
 
-TempoLines::TempoLines (ArdourCanvas::Group* group, double)
+TempoLines::TempoLines (ArdourCanvas::Layout* group, double)
 	: lines (group, ArdourCanvas::LineSet::Vertical)
 {
 	lines.set_extent (ArdourCanvas::COORD_MAX);

gtk2_ardour/tempo_lines.h

@@ -25,7 +25,7 @@
 
 class TempoLines {
 public:
-	TempoLines (ArdourCanvas::Group* group, double screen_height);
+	TempoLines (ArdourCanvas::Layout* group, double screen_height);
 
 	void tempo_map_changed();
 

gtk2_ardour/time_axis_view.cc

@@ -97,16 +97,16 @@ TimeAxisView::TimeAxisView (ARDOUR::Session* sess, PublicEditor& ed, TimeAxisVie
 		compute_heights ();
 	}
 
-	_canvas_display = new Group (ed.get_trackview_group (), ArdourCanvas::Duple (0.0, 0.0));
+	_canvas_display = new ArdourCanvas::Layout (ed.get_trackview_group (), ArdourCanvas::Duple (0.0, 0.0));
 	CANVAS_DEBUG_NAME (_canvas_display, "main for TAV");
 	_canvas_display->hide(); // reveal as needed
 
-	selection_group = new Group (_canvas_display);
+	selection_group = new ArdourCanvas::Layout (_canvas_display);
 	CANVAS_DEBUG_NAME (selection_group, "selection for TAV");
 	selection_group->set_data (X_("timeselection"), (void *) 1);
 	selection_group->hide();
 	
-	_ghost_group = new Group (_canvas_display);
+	_ghost_group = new ArdourCanvas::Layout (_canvas_display);
 	CANVAS_DEBUG_NAME (_ghost_group, "ghost for TAV");
 	_ghost_group->lower_to_bottom();
 	_ghost_group->show();

gtk2_ardour/time_axis_view.h

@@ -59,7 +59,7 @@ namespace Gtk {
 
 namespace ArdourCanvas {
 	class Canvas;
-	class Group;
+	class Layout;
 	class Item;
 }
 
@@ -104,8 +104,8 @@ class TimeAxisView : public virtual AxisView
         virtual void enter_internal_edit_mode () {}
         virtual void leave_internal_edit_mode () {}
 
-	ArdourCanvas::Group* canvas_display () { return _canvas_display; }
+	ArdourCanvas::Layout* canvas_display () { return _canvas_display; }
-	ArdourCanvas::Group* ghost_group () { return _ghost_group; }
+	ArdourCanvas::Layout* ghost_group () { return _ghost_group; }
 
 	/** @return effective height (taking children into account) in canvas units, or
 	    0 if this TimeAxisView has not yet been shown */
@@ -212,15 +212,15 @@ class TimeAxisView : public virtual AxisView
 	std::string            controls_base_selected_name;
 	Gtk::Menu*             display_menu; /* The standard LHS Track control popup-menus */
 	TimeAxisView*          parent;
-	ArdourCanvas::Group*   selection_group;
+	ArdourCanvas::Layout*   selection_group;
-	ArdourCanvas::Group*  _ghost_group;
+	ArdourCanvas::Layout*  _ghost_group;
 	std::list<GhostRegion*> ghosts;
 	std::list<SelectionRect*> free_selection_rects;
 	std::list<SelectionRect*> used_selection_rects;
 	bool                  _hidden;
 	bool                   in_destructor;
 	Gtk::Menu*            _size_menu;
-	ArdourCanvas::Group*  _canvas_display;
+	ArdourCanvas::Layout*  _canvas_display;
 	double                _y_position;
 	PublicEditor&         _editor;
 

gtk2_ardour/time_axis_view_item.cc

@@ -28,7 +28,7 @@
 #include "gtkmm2ext/utils.h"
 #include "gtkmm2ext/gui_thread.h"
 
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/rectangle.h"
 #include "canvas/debug.h"
 #include "canvas/text.h"
@@ -119,7 +119,7 @@ TimeAxisViewItem::set_constant_heights ()
  * @param automation true if this is an automation region view
  */
 TimeAxisViewItem::TimeAxisViewItem(
-	const string & it_name, ArdourCanvas::Group& parent, TimeAxisView& tv, double spu, uint32_t base_color,
+	const string & it_name, ArdourCanvas::Item& parent, TimeAxisView& tv, double spu, uint32_t base_color,
 	framepos_t start, framecnt_t duration, bool recording, bool automation, Visibility vis
 	)
 	: trackview (tv)
@@ -149,7 +149,7 @@ TimeAxisViewItem::TimeAxisViewItem (const TimeAxisViewItem& other)
 {
 	/* share the other's parent, but still create a new group */
 
-	ArdourCanvas::Group* parent = other.group->parent();
+	ArdourCanvas::Item* parent = other.group->parent();
 	
 	_selected = other._selected;
 	
@@ -158,11 +158,11 @@ TimeAxisViewItem::TimeAxisViewItem (const TimeAxisViewItem& other)
 }
 
 void
-TimeAxisViewItem::init (ArdourCanvas::Group* parent, double fpp, uint32_t base_color, 
+TimeAxisViewItem::init (ArdourCanvas::Item* parent, double fpp, uint32_t base_color, 
 			framepos_t start, framepos_t duration, Visibility vis, 
 			bool wide, bool high)
 {
-	group = new ArdourCanvas::Group (parent);
+	group = new ArdourCanvas::Layout (parent);
 	CANVAS_DEBUG_NAME (group, string_compose ("TAVI group for %1", get_item_name()));
 	group->Event.connect (sigc::mem_fun (*this, &TimeAxisViewItem::canvas_group_event));
 
@@ -646,7 +646,7 @@ TimeAxisViewItem::get_canvas_frame()
 	return frame;
 }
 
-ArdourCanvas::Group*
+ArdourCanvas::Item*
 TimeAxisViewItem::get_canvas_group()
 {
 	return group;

gtk2_ardour/time_axis_view_item.h

@@ -33,8 +33,8 @@ namespace ArdourCanvas {
 	class Pixbuf;
 	class Rectangle;
 	class Item;
-	class Group;
+        class Layout;
-	class Text;
+ 	class Text;
 }
 
 using ARDOUR::framepos_t;
@@ -79,7 +79,7 @@ class TimeAxisViewItem : public Selectable, public PBD::ScopedConnectionList
         uint32_t get_fill_color () const;
 
 	ArdourCanvas::Item* get_canvas_frame();
-	ArdourCanvas::Group* get_canvas_group();
+	ArdourCanvas::Item* get_canvas_group();
 	ArdourCanvas::Item* get_name_highlight();
 
 	virtual void set_samples_per_pixel (double);
@@ -170,12 +170,12 @@ class TimeAxisViewItem : public Selectable, public PBD::ScopedConnectionList
 	};
 
   protected:
-	TimeAxisViewItem (const std::string &, ArdourCanvas::Group&, TimeAxisView&, double, uint32_t fill_color,
+	TimeAxisViewItem (const std::string &, ArdourCanvas::Item&, TimeAxisView&, double, uint32_t fill_color,
 			  framepos_t, framecnt_t, bool recording = false, bool automation = false, Visibility v = Visibility (0));
 
 	TimeAxisViewItem (const TimeAxisViewItem&);
 
-        void init (ArdourCanvas::Group*, double, uint32_t, framepos_t, framepos_t, Visibility, bool, bool);
+        void init (ArdourCanvas::Item*, double, uint32_t, framepos_t, framepos_t, Visibility, bool, bool);
 
         virtual bool canvas_group_event (GdkEvent*);
 
@@ -240,7 +240,7 @@ class TimeAxisViewItem : public Selectable, public PBD::ScopedConnectionList
 	bool high_enough_for_name;
         bool rect_visible;
 
-	ArdourCanvas::Group*      group;
+	ArdourCanvas::Layout*      group;
 	ArdourCanvas::Rectangle* vestigial_frame;
 	ArdourCanvas::Rectangle* frame;
 	ArdourCanvas::Text*      name_text;

gtk2_ardour/verbose_cursor.cc

@@ -23,6 +23,7 @@
 #include "ardour/profile.h"
 
 #include "canvas/debug.h"
+#include "canvas/scroll_group.h"
 
 #include "ardour_ui.h"
 #include "audio_clock.h"

gtk2_ardour/video_image_frame.cc

@@ -24,7 +24,7 @@
 #include "video_image_frame.h"
 #include "public_editor.h"
 #include "utils.h"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "utils_videotl.h"
 
 #include <gtkmm2ext/utils.h>
@@ -43,7 +43,7 @@ static void freedata_cb (uint8_t *d, void* /*arg*/) {
 	free (d);
 }
 
-VideoImageFrame::VideoImageFrame (PublicEditor& ed, ArdourCanvas::Group& parent, int w, int h, std::string vsurl, std::string vfn)
+VideoImageFrame::VideoImageFrame (PublicEditor& ed, ArdourCanvas::Layout& parent, int w, int h, std::string vsurl, std::string vfn)
 	: editor (ed)
 	, _parent(&parent)
 	, clip_width(w)

gtk2_ardour/video_image_frame.h

@@ -32,7 +32,7 @@
 #include "ardour/ardour.h"
 #include "pbd/signals.h"
 
-#include "canvas/group.h"
+#include "canvas/layout.h"
 #include "canvas/pixbuf.h"
 #include "canvas/image.h"
 
@@ -49,7 +49,7 @@ class PublicEditor;
 class VideoImageFrame : public sigc::trackable
 {
 	public:
-	VideoImageFrame (PublicEditor&, ArdourCanvas::Group&, int, int, std::string, std::string);
+	VideoImageFrame (PublicEditor&, ArdourCanvas::Layout&, int, int, std::string, std::string);
 	virtual ~VideoImageFrame ();
 
 	void set_position (framepos_t);
@@ -69,7 +69,7 @@ class VideoImageFrame : public sigc::trackable
 	protected:
 
 	PublicEditor& editor;
-	ArdourCanvas::Group *_parent;
+	ArdourCanvas::Layout *_parent;
 	ArdourCanvas::Image *image;
 	boost::shared_ptr<ArdourCanvas::Image::Data> img;
 

gtk2_ardour/video_timeline.cc

@@ -51,7 +51,7 @@ using namespace PBD;
 using namespace Timecode;
 using namespace VideoUtils;
 
-VideoTimeLine::VideoTimeLine (PublicEditor *ed, ArdourCanvas::Group *vbg, int initial_height)
+VideoTimeLine::VideoTimeLine (PublicEditor *ed, ArdourCanvas::Layout *vbg, int initial_height)
 	: editor (ed)
 		, videotl_group(vbg)
 		, bar_height(initial_height)

gtk2_ardour/video_timeline.h

@@ -29,7 +29,7 @@
 #include "video_image_frame.h"
 #include "video_monitor.h"
 #include "pbd/signals.h"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 
 namespace ARDOUR {
 	class Session;
@@ -55,7 +55,7 @@ class PublicEditor;
 class VideoTimeLine : public sigc::trackable, public ARDOUR::SessionHandlePtr, public PBD::ScopedConnectionList, public PBD::StatefulDestructible
 {
 	public:
-	VideoTimeLine (PublicEditor*, ArdourCanvas::Group*, int);
+	VideoTimeLine (PublicEditor*, ArdourCanvas::Layout*, int);
 	virtual ~VideoTimeLine ();
 
 	void set_session (ARDOUR::Session *s);
@@ -102,7 +102,7 @@ class VideoTimeLine : public sigc::trackable, public ARDOUR::SessionHandlePtr, p
 	protected:
 
 	PublicEditor *editor;
-	ArdourCanvas::Group *videotl_group;
+	ArdourCanvas::Layout *videotl_group;
 	int bar_height;
 
 	std::string _xjadeo_bin;

libs/canvas/arc.cc

@@ -39,8 +39,8 @@ Arc::Arc (Canvas* c)
 {
 }
 
-Arc::Arc (Group* g)
+Arc::Arc (Item* parent)
-	: Item (g)
+	: Item (parent)
 	, _radius (0.0)
 	, _arc_degrees (0.0)
 	, _start_degrees (0.0)

libs/canvas/arrow.cc

@@ -35,13 +35,13 @@ using namespace ArdourCanvas;
  *  @param parent Parent canvas group.
  */
 Arrow::Arrow (Canvas* c)
-	: Group (c)
+	: Layout (c)
 {
 	setup ();
 }
 
-Arrow::Arrow (Group* g)
+Arrow::Arrow (Item* parent)
-	: Group (g)
+	: Layout (parent)
 {
 	setup ();
 }

libs/canvas/canvas.cc

@@ -392,15 +392,14 @@ GtkCanvas::pick_current_item (Duple const & point, int state)
 
 	for (i = items.begin(); i != items.end(); ++i) {
 
-		Item const * new_item = *i;
+		Item const * possible_item = *i;
 
-		/* We ignore invisible items, groups and items that ignore events */
+		/* We ignore invisible items, containers and items that ignore events */
 
-		if (!new_item->visible() || new_item->ignore_events() || dynamic_cast<Group const *>(new_item) != 0) {
+		if (!possible_item->visible() || possible_item->ignore_events() || dynamic_cast<ArdourCanvas::Container const *>(possible_item) != 0) {
 			continue;
 		}
-		
+		within_items.push_front (possible_item);
-		within_items.push_front (new_item);
 	}
 
 	if (within_items.empty()) {

libs/canvas/canvas/arc.h

@@ -32,7 +32,7 @@ class LIBCANVAS_API Arc : public Item
 {
 public:
 	Arc (Canvas*);
-	Arc (Group*);
+	Arc (Item*);
 
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
 	void compute_bounding_box () const;

libs/canvas/canvas/arrow.h

@@ -26,8 +26,7 @@
 #define __CANVAS_ARROW_H__
 
 #include "canvas/visibility.h"
-
+#include "canvas/layout.h"
-#include "canvas/group.h"
 
 namespace ArdourCanvas {
 
@@ -46,11 +45,11 @@ class Polygon;
  *  to draw lines at any angle.
  */
 	
-class LIBCANVAS_API Arrow : public Group
+class LIBCANVAS_API Arrow : public Layout
 {
 public:
 	Arrow (Canvas*);
-	Arrow (Group*);
+	Arrow (Item*);
 
 	void set_show_head (int, bool);
 	void set_head_outward (int, bool);

libs/canvas/canvas/canvas.h

@@ -42,7 +42,7 @@ namespace ArdourCanvas
 {
 
 class Rect;
-class Group;	
+class Item;
 class ScrollGroup;
 
 /** The base class for our different types of canvas.
@@ -78,7 +78,7 @@ public:
 	void render (Rect const &, Cairo::RefPtr<Cairo::Context> const &) const;
 
 	/** @return root group */
-	Group* root () {
+	Item* root () {
 		return &_root;
 	}
 
@@ -122,8 +122,8 @@ public:
 protected:
 	void queue_draw_item_area (Item *, Rect);
 	
-	/** our root group */
+	/** our root item */
-	RootGroup _root;
+	Root _root;
 
         virtual void pick_current_item (int state) = 0;
         virtual void pick_current_item (Duple const &, int state) = 0;

libs/canvas/canvas/circle.h

@@ -29,7 +29,7 @@ class LIBCANVAS_API Circle : public Arc
 {
   public:
 	Circle (Canvas*);
-	Circle (Group*);
+	Circle (Item*);
 };
 	
 }

libs/canvas/canvas/curve.h

@@ -33,7 +33,7 @@ class LIBCANVAS_API Curve : public PolyItem, public InterpolatedCurve
 {
   public:
     Curve (Canvas*);
-    Curve (Group*);
+    Curve (Item*);
 
     enum CurveFill {
 	    None,

libs/canvas/canvas/flag.h

@@ -18,8 +18,8 @@
 */
 
 #include "canvas/visibility.h"
-#include "canvas/group.h"
 #include "canvas/types.h"
+#include "canvas/layout.h"
 
 namespace ArdourCanvas {
 
@@ -27,11 +27,11 @@ class Text;
 class Line;
 class Rectangle;
 
-class LIBCANVAS_API Flag : public Group
+class LIBCANVAS_API Flag : public Layout
 {
 public:
 	Flag (Canvas *, Distance, Color, Color, Duple);
-	Flag (Group*, Distance, Color, Color, Duple);
+	Flag (Item*, Distance, Color, Color, Duple);
 
 	void set_text (std::string const &);
 	void set_height (Distance);

libs/canvas/canvas/fwd.h

@@ -33,6 +33,7 @@ namespace ArdourCanvas {
 	class GtkCanvasViewport;
 	class Text;
 	class Curve;
+        class ScrollGroup;
 }
 
 #endif /* __canvas_canvas_fwd_h__ */

libs/canvas/canvas/group.h

@@ -1,79 +0,0 @@
-/*
-    Copyright (C) 2011-2013 Paul Davis
-    Author: Carl Hetherington <cth@carlh.net>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-#ifndef __CANVAS_GROUP_H__
-#define __CANVAS_GROUP_H__
-
-#include <list>
-#include <vector>
-
-#include "canvas/visibility.h"
-#include "canvas/item.h"
-#include "canvas/types.h"
-#include "canvas/lookup_table.h"
-
-namespace ArdourCanvas {
-
-class LIBCANVAS_API Group : public Item
-{
-public:
-	Group (Canvas*);
-	Group (Group*);
-	Group (Group*, Duple const& positon);
-	virtual ~Group ();
-
-	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
-	virtual void compute_bounding_box () const;
-
-	void add (Item *);
-	void remove (Item *);
-         void clear (bool with_delete = false);
-	std::list<Item*> const & items () const {
-		return _items;
-	}
-
-	void raise_child_to_top (Item *);
-	void raise_child (Item *, int);
-	void lower_child_to_bottom (Item *);
-	void child_changed ();
-	
-	void scroll_to (Duple const& d);
-	
-	void add_items_at_point (Duple, std::vector<Item const *> &) const;
-
-        void dump (std::ostream&) const;
-
-	static int default_items_per_cell;
-
-private:
-	friend class ::OptimizingLookupTableTest;
-	
-	void ensure_lut () const;
-	void invalidate_lut () const;
-	void clear_items (bool with_delete);
-
-	/* our items, from lowest to highest in the stack */
-	std::list<Item*> _items;
-
-	mutable LookupTable* _lut;
-};
-
-}
-
-#endif

libs/canvas/canvas/image.h

@@ -35,7 +35,7 @@ class LIBCANVAS_API Image : public Item
 {
 public:
     Image (Canvas *, Cairo::Format, int width, int height);
-    Image (Group*, Cairo::Format, int width, int height);
+    Image (Item*, Cairo::Format, int width, int height);
     
     struct Data {
 	Data (uint8_t *d, int w, int h, int s, Cairo::Format fmt)

libs/canvas/canvas/item.h

@@ -32,12 +32,12 @@
 #include "canvas/types.h"
 #include "canvas/fill.h"
 #include "canvas/outline.h"
+#include "canvas/lookup_table.h"
 
 namespace ArdourCanvas
 {
 
 class Canvas;
-class Group;
 class Rect;	
 class ScrollGroup;
 
@@ -56,8 +56,8 @@ class LIBCANVAS_API Item : public Fill, public Outline
 {
 public:
 	Item (Canvas *);
-	Item (Group *);
+	Item (Item *);
-	Item (Group *, Duple const& p);
+	Item (Item *, Duple const& p);
 	virtual ~Item ();
 
         void redraw () const;
@@ -80,13 +80,11 @@ public:
 	 *
 	 * Note that Item::add_items_at_window_point() is only intended to be 
 	 * called on items already looked up in a LookupTable (i.e. by a
-	 * parent group) and thus known to cover @param point already.
+	 * parent) and thus known to cover @param point already.
 	 *
-	 * Derived classes may add more items than themselves (e.g. Group).
+	 * Derived classes may add more items than themselves (e.g. containers).
 	 */
-	virtual void add_items_at_point (Duple /*point*/, std::vector<Item const *>& items) const {
+	virtual void add_items_at_point (Duple /*point*/, std::vector<Item const *>& items) const;
-		items.push_back (this);
-	}
 
         virtual bool covers (Duple const &) const;
 
@@ -97,10 +95,10 @@ public:
 	void ungrab ();
 	
 	void unparent ();
-	void reparent (Group *);
+	void reparent (Item *);
 
 	/** @return Parent group, or 0 if this is the root group */
-	Group* parent () const {
+	Item* parent () const {
 		return _parent;
 	}
     
@@ -124,8 +122,6 @@ public:
 	void set_y_position (Coord);
 	void move (Duple);
 
-	virtual void scroll_to (Duple const&) {}
-
 	/** @return Position of this item in the parent's coordinates */
 	Duple position () const {
 		return _position;
@@ -187,6 +183,21 @@ public:
 
 	void set_data (std::string const &, void *);
 	void* get_data (std::string const &) const;
+
+	/* nested item ("grouping") API */
+	void add (Item *);
+	void remove (Item *);
+        void clear (bool with_delete = false);
+	std::list<Item*> const & items () const {
+		return _items;
+	}
+	void raise_child_to_top (Item *);
+	void raise_child (Item *, int);
+	void lower_child_to_bottom (Item *);
+	void child_changed ();
+
+	static int default_items_per_cell;
+
 	
 	/* This is a sigc++ signal because it is solely
 	   concerned with GUI stuff and is thus single-threaded
@@ -243,7 +254,7 @@ protected:
 
 	Canvas* _canvas;
 	/** parent group; may be 0 if we are the root group or if we have been unparent()ed */
-	Group* _parent;
+	Item* _parent;
 	/** scroll parent group; may be 0 if we are the root group or if we have been unparent()ed */
 	ScrollGroup* _scroll_parent;
 	/** position of this item in parent coordinates */
@@ -261,6 +272,18 @@ protected:
 	/* XXX: this is a bit grubby */
 	std::map<std::string, void *> _data;
 
+	/* nesting ("grouping") API */
+
+	void invalidate_lut () const;
+	void clear_items (bool with_delete);
+
+	void ensure_lut () const;
+	mutable LookupTable* _lut;
+	/* our items, from lowest to highest in the stack */
+	std::list<Item*> _items;
+
+	void add_child_bounding_boxes() const;
+
 private:
 	void init ();
 

libs/canvas/canvas/line.h

@@ -31,7 +31,7 @@ class LIBCANVAS_API Line : public Item
 {
   public:
 	Line (Canvas*);
-	Line (Group*);
+	Line (Item*);
 
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
 	void compute_bounding_box () const;

libs/canvas/canvas/line_set.h

@@ -36,7 +36,7 @@ public:
 	};
 
 	LineSet (Canvas*, Orientation o = Vertical);
-	LineSet (Group*, Orientation o = Vertical);
+	LineSet (Item*, Orientation o = Vertical);
 
 	void compute_bounding_box () const;
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;

libs/canvas/canvas/lookup_table.h

@@ -31,12 +31,11 @@ class OptimizingLookupTableTest;
 namespace ArdourCanvas {
 
 class Item;
-class Group;
 
 class LIBCANVAS_API LookupTable
 {
 public:
-    LookupTable (Group const &);
+    LookupTable (Item const &);
     virtual ~LookupTable ();
     
     virtual std::vector<Item*> get (Rect const &) = 0;
@@ -45,13 +44,13 @@ public:
 
 protected:
 	
-    Group const & _group;
+    Item const & _item;
 };
 
 class LIBCANVAS_API DumbLookupTable : public LookupTable
 {
 public:
-    DumbLookupTable (Group const &);
+	DumbLookupTable (Item const &);
     
     std::vector<Item*> get (Rect const &);
     std::vector<Item*> items_at_point (Duple const &) const;
@@ -61,7 +60,7 @@ public:
 class LIBCANVAS_API OptimizingLookupTable : public LookupTable
 {
 public:
-    OptimizingLookupTable (Group const &, int);
+    OptimizingLookupTable (Item const &, int);
     ~OptimizingLookupTable ();
     std::vector<Item*> get (Rect const &);
     std::vector<Item*> items_at_point (Duple const &) const;

libs/canvas/canvas/pixbuf.h

@@ -35,7 +35,7 @@ class LIBCANVAS_API Pixbuf : public Item
 {
 public:
 	Pixbuf (Canvas*);
-	Pixbuf (Group*);
+	Pixbuf (Item*);
 
 	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
 	void compute_bounding_box () const;

libs/canvas/canvas/poly_item.h

@@ -30,7 +30,7 @@ class LIBCANVAS_API PolyItem : public Item
 {
 public:
 	PolyItem (Canvas*);
-	PolyItem (Group*);
+	PolyItem (Item*);
 
 	void compute_bounding_box () const;
 

libs/canvas/canvas/poly_line.h

@@ -30,7 +30,7 @@ class LIBCANVAS_API PolyLine : public PolyItem
 {
   public:
 	PolyLine (Canvas*);
-	PolyLine (Group*);
+	PolyLine (Item*);
 	
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;
 	

libs/canvas/canvas/polygon.h

@@ -31,7 +31,7 @@ class LIBCANVAS_API Polygon : public PolyItem
 {
 public:
 	Polygon (Canvas*);
-	Polygon (Group*);
+	Polygon (Item*);
         virtual ~Polygon();
 
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;

libs/canvas/canvas/rectangle.h

@@ -34,8 +34,8 @@ class LIBCANVAS_API Rectangle : public Item
 public:
 	Rectangle (Canvas*);
 	Rectangle (Canvas*, Rect const &);
-	Rectangle (Group*);
+	Rectangle (Item*);
-	Rectangle (Group*, Rect const &);
+	Rectangle (Item*, Rect const &);
 	
 	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
 	void compute_bounding_box () const;

libs/canvas/canvas/root_group.h

@@ -21,19 +21,18 @@
 #define __CANVAS_ROOT_GROUP_H__
 
 #include "canvas/visibility.h"
-#include "canvas/group.h"
+#include "canvas/layout.h"
 
 namespace ArdourCanvas {
 
-class LIBCANVAS_API RootGroup : public Group
+class LIBCANVAS_API Root : public Layout
 {
 private:
 	friend class Canvas;
 	
-	RootGroup (Canvas *);
+	Root (Canvas *);
 
 	void compute_bounding_box () const;
-	void child_changed ();
 };
 
 }

libs/canvas/canvas/ruler.h

@@ -57,8 +57,8 @@ public:
 	
 	Ruler (Canvas*, const Metric& m);
 	Ruler (Canvas*, const Metric& m, Rect const&);
-	Ruler (Group*, const Metric& m);
+	Ruler (Item*, const Metric& m);
-	Ruler (Group*, const Metric& m, Rect const&);
+	Ruler (Item*, const Metric& m, Rect const&);
 	
 	void set_range (double lower, double upper);
 	void set_font_description (Pango::FontDescription);

libs/canvas/canvas/scroll_group.h

@@ -19,11 +19,15 @@
 #ifndef __CANVAS_SCROLL_GROUP_H__
 #define __CANVAS_SCROLL_GROUP_H__
 
-#include "canvas/group.h"
+#include "canvas/layout.h"
 
 namespace ArdourCanvas {
 
-class LIBCANVAS_API ScrollGroup : public Group
+/** A ScrollGroup has no contents of its own, but renders
+ *  its children in a way that reflects the most recent
+ *  call to its scroll_to() method.
+ */
+class LIBCANVAS_API ScrollGroup : public Layout
 {
   public:
 	enum ScrollSensitivity {
@@ -32,7 +36,7 @@ class LIBCANVAS_API ScrollGroup : public Group
 	};
 	
 	ScrollGroup (Canvas*, ScrollSensitivity);
-	ScrollGroup (Group*, ScrollSensitivity);
+	ScrollGroup (Item*, ScrollSensitivity);
 
 	void scroll_to (Duple const& d);
 	Duple scroll_offset() const { return _scroll_offset; }

libs/canvas/canvas/stateful_image.h

@@ -50,7 +50,7 @@ class StatefulImage : public Item
   public:
 
     StatefulImage (Canvas*, const XMLNode&);
-    StatefulImage (Group*, const XMLNode&);
+    StatefulImage (Item*, const XMLNode&);
     ~StatefulImage ();
 
     bool set_state (States::size_type);

libs/canvas/canvas/text.h

@@ -32,7 +32,7 @@ class LIBCANVAS_API Text : public Item
 {
 public:
 	Text (Canvas*);
-	Text (Group*);
+	Text (Item*);
        ~Text();
 
 	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;

libs/canvas/canvas/wave_view.h

@@ -92,7 +92,7 @@ public:
 
 
 	WaveView (Canvas *, boost::shared_ptr<ARDOUR::AudioRegion>);
-	WaveView (Group*, boost::shared_ptr<ARDOUR::AudioRegion>);
+	WaveView (Item*, boost::shared_ptr<ARDOUR::AudioRegion>);
        ~WaveView ();
 
 	void render (Rect const & area, Cairo::RefPtr<Cairo::Context>) const;

libs/canvas/canvas/widget.h

@@ -32,7 +32,7 @@ class LIBCANVAS_API Widget : public Item
 {
 public:
 	Widget (Canvas*, CairoWidget&);
-	Widget (Group*, CairoWidget&);
+	Widget (Item*, CairoWidget&);
 	
 	void render (Rect const &, Cairo::RefPtr<Cairo::Context>) const;
 	void compute_bounding_box () const;

libs/canvas/canvas/xfade_curve.h

@@ -36,8 +36,8 @@ public:
 
 	XFadeCurve (Canvas *);
 	XFadeCurve (Canvas *, XFadePosition);
-	XFadeCurve (Group*);
+	XFadeCurve (Item*);
-	XFadeCurve (Group*, XFadePosition);
+	XFadeCurve (Item*, XFadePosition);
 
 	void set_fade_position (XFadePosition xfp) { _xfadeposition = xfp; }
 	

libs/canvas/circle.cc

@@ -26,8 +26,8 @@ Circle::Circle (Canvas* c)
 	set_arc (360.0);
 }
 
-Circle::Circle (Group* g)
+Circle::Circle (Item * parent)
-	: Arc (g)
+	: Arc (parent)
 {
 	set_arc (360.0);
 }

libs/canvas/curve.cc

@@ -36,8 +36,8 @@ Curve::Curve (Canvas* c)
 {
 }
 
-Curve::Curve (Group* g)
+Curve::Curve (Item* parent)
-	: PolyItem (g)
+	: PolyItem (parent)
 	, n_samples (0)
 	, points_per_segment (16)
 	, curve_type (CatmullRomCentripetal)

libs/canvas/flag.cc

@@ -26,15 +26,15 @@ using namespace std;
 using namespace ArdourCanvas;
 
 Flag::Flag (Canvas* canvas, Distance height, Color outline_color, Color fill_color, Duple position)
-	: Group (canvas)
+	: Layout (canvas)
 	, _outline_color (outline_color)
 	, _fill_color (fill_color)
 {
 	setup (height, position);
 }
 
-Flag::Flag (Group* group, Distance height, Color outline_color, Color fill_color, Duple position)
+Flag::Flag (Item* parent, Distance height, Color outline_color, Color fill_color, Duple position)
-	: Group (group)
+	: Layout (parent)
 	, _outline_color (outline_color)
 	, _fill_color (fill_color)
 {

libs/canvas/group.cc

@@ -1,395 +0,0 @@
-/*
-    Copyright (C) 2011-2013 Paul Davis
-    Author: Carl Hetherington <cth@carlh.net>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-#include <iostream>
-#include <cairomm/context.h>
-
-#include "pbd/stacktrace.h"
-#include "pbd/compose.h"
-
-#include "canvas/group.h"
-#include "canvas/types.h"
-#include "canvas/debug.h"
-#include "canvas/item.h"
-#include "canvas/canvas.h"
-
-using namespace std;
-using namespace ArdourCanvas;
-
-int Group::default_items_per_cell = 64;
-
-
-Group::Group (Canvas* canvas)
-	: Item (canvas)
-	, _lut (0)
-{
-}
-
-Group::Group (Group* group)
-	: Item (group)
-	, _lut (0)
-{
-}
-
-Group::Group (Group* group, Duple const& p)
-	: Item (group, p)
-	, _lut (0)
-{
-}
-
-Group::~Group ()
-{
-	clear_items (true);
-}
-
-/** @param area Area to draw in window coordinates.
- *  @param context Context, set up with its origin at this group's position.
- */
-void
-Group::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
-{
-	ensure_lut ();
-	vector<Item*> items = _lut->get (area);
-
-#ifdef CANVAS_DEBUG
-	if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-		cerr << string_compose ("%1GROUP %2 @ %7 render %5 @ %6 %3 items out of %4\n", 
-					_canvas->render_indent(), (name.empty() ? string ("[unnamed]") : name), items.size(), _items.size(), area, _position, this);
-	}
-#endif
-
-	++render_depth;
-		
-	for (vector<Item*>::const_iterator i = items.begin(); i != items.end(); ++i) {
-
-		if (!(*i)->visible ()) {
-#ifdef CANVAS_DEBUG
-			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] invisible - skipped\n";
-			}
-#endif
-			continue;
-		}
-		
-		boost::optional<Rect> item_bbox = (*i)->bounding_box ();
-
-		if (!item_bbox) {
-#ifdef CANVAS_DEBUG
-			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] empty - skipped\n";
-			}
-#endif
-			continue;
-		}
-		
-		Rect item = (*i)->item_to_window (item_bbox.get());
-		boost::optional<Rect> d = item.intersection (area);
-		
-		if (d) {
-			Rect draw = d.get();
-			if (draw.width() && draw.height()) {
-#ifdef CANVAS_DEBUG
-				if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-					if (dynamic_cast<Group*>(*i) == 0) {
-						cerr << _canvas->render_indent() << "render "
-						     << ' ' 
-						     << (*i)
-						     << ' '
-						     << (*i)->whatami()
-						     << ' '
-						     << (*i)->name
-						     << " item "
-						     << item_bbox.get()
-						     << " window = " 
-						     << item
-						     << " intersect = "
-						     << draw
-						     << " @ " 
-						     << _position
-						     << endl;
-					}
-				}
-#endif
-
-				(*i)->render (area, context);
-				++render_count;
-			}
-
-		} else {
-
-#ifdef CANVAS_DEBUG
-			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << string_compose ("%1skip render of %2 %3, no intersection between %4 and %5\n", _canvas->render_indent(), (*i)->whatami(),
-							(*i)->name, item, area);
-			}
-#endif
-
-		}
-	}
-
-	--render_depth;
-}
-
-void
-Group::scroll_to (Duple const& d)
-{
-	Item::scroll_to (d);
-	
-	for (list<Item*>::iterator i = _items.begin(); i != _items.end(); ++i) {
-		(*i)->scroll_to (d);
-	}
-}
-
-void
-Group::compute_bounding_box () const
-{
-	Rect bbox;
-	bool have_one = false;
-
-	for (list<Item*>::const_iterator i = _items.begin(); i != _items.end(); ++i) {
-
-		boost::optional<Rect> item_bbox = (*i)->bounding_box ();
-
-		if (!item_bbox) {
-			continue;
-		}
-
-		Rect group_bbox = (*i)->item_to_parent (item_bbox.get ());
-		if (have_one) {
-			bbox = bbox.extend (group_bbox);
-		} else {
-			bbox = group_bbox;
-			have_one = true;
-		}
-	}
-
-	if (!have_one) {
-		_bounding_box = boost::optional<Rect> ();
-	} else {
-		_bounding_box = bbox;
-	}
-
-	_bounding_box_dirty = false;
-}
-
-void
-Group::add (Item* i)
-{
-	/* XXX should really notify canvas about this */
-
-	_items.push_back (i);
-	i->reparent (this);
-	invalidate_lut ();
-	_bounding_box_dirty = true;
-}
-
-void
-Group::remove (Item* i)
-{
-
-	if (i->parent() != this) {
-		return;
-	}
-
-	/* we cannot call bounding_box() here because that will iterate over
-	   _items, one of which (the argument, i) may be in the middle of
-	   deletion, making it impossible to call compute_bounding_box()
-	   on it.
-	*/
-
-	if (_bounding_box) {
-		_pre_change_bounding_box = _bounding_box;
-	} else {
-		_pre_change_bounding_box = Rect();
-	}
-
-	i->unparent ();
-	_items.remove (i);
-	invalidate_lut ();
-	_bounding_box_dirty = true;
-	
-	end_change ();
-}
-
-void
-Group::clear (bool with_delete)
-{
-	begin_change ();
-
-	clear_items (with_delete);
-
-	invalidate_lut ();
-	_bounding_box_dirty = true;
-
-	end_change ();
-}
-
-void
-Group::clear_items (bool with_delete)
-{
-	for (list<Item*>::iterator i = _items.begin(); i != _items.end(); ) {
-
-		list<Item*>::iterator tmp = i;
-		Item *item = *i;
-
-		++tmp;
-
-		/* remove from list before doing anything else, because we
-		 * don't want to find the item in _items during any activity
-		 * driven by unparent-ing or deletion.
-		 */
-
-		_items.erase (i);
-		item->unparent ();
-		
-		if (with_delete) {
-			delete item;
-		}
-
-		i = tmp;
-	}
-}
-
-void
-Group::raise_child_to_top (Item* i)
-{
-	if (!_items.empty()) {
-		if (_items.back() == i) {
-			return;
-		}
-	}
-
-	_items.remove (i);
-	_items.push_back (i);
-	invalidate_lut ();
-}
-
-void
-Group::raise_child (Item* i, int levels)
-{
-	list<Item*>::iterator j = find (_items.begin(), _items.end(), i);
-	assert (j != _items.end ());
-
-	++j;
-	_items.remove (i);
-
-	while (levels > 0 && j != _items.end ()) {
-		++j;
-		--levels;
-	}
-
-	_items.insert (j, i);
-	invalidate_lut ();
-}
-
-void
-Group::lower_child_to_bottom (Item* i)
-{
-	if (!_items.empty()) {
-		if (_items.front() == i) {
-			return;
-		}
-	}
-	_items.remove (i);
-	_items.push_front (i);
-	invalidate_lut ();
-}
-
-void
-Group::ensure_lut () const
-{
-	if (!_lut) {
-		_lut = new DumbLookupTable (*this);
-	}
-}
-
-void
-Group::invalidate_lut () const
-{
-	delete _lut;
-	_lut = 0;
-}
-
-void
-Group::child_changed ()
-{
-	invalidate_lut ();
-	_bounding_box_dirty = true;
-
-	if (_parent) {
-		_parent->child_changed ();
-	}
-}
-
-void
-Group::add_items_at_point (Duple const point, vector<Item const *>& items) const
-{
-	boost::optional<Rect> const bbox = bounding_box ();
-
-	/* Point is in window coordinate system */
-
-	if (!bbox || !item_to_window (bbox.get()).contains (point)) {
-		return;
-	}
-
-	/* now recurse and add any items within our group that contain point */
-
-	ensure_lut ();
-	vector<Item*> our_items = _lut->items_at_point (point);
-
-	if (!our_items.empty()) {
-		/* this adds this group itself to the list of items at point */
-		Item::add_items_at_point (point, items);
-	}
-
-	for (vector<Item*>::iterator i = our_items.begin(); i != our_items.end(); ++i) {
-		(*i)->add_items_at_point (point, items);
-	}
-}
-
-void
-Group::dump (ostream& o) const
-{
-#ifdef CANVAS_DEBUG
-	o << _canvas->indent();
-	o << "Group " << this << " [" << name << ']';
-	o << " @ " << position();
-	o << " Items: " << _items.size();
-	o << " Visible ? " << _visible;
-
-	boost::optional<Rect> bb = bounding_box();
-
-	if (bb) {
-		o << endl << _canvas->indent() << "  bbox: " << bb.get();
-		o << endl << _canvas->indent() << "  CANVAS bbox: " << item_to_canvas (bb.get());
-	} else {
-		o << "  bbox unset";
-	}
-
-	o << endl;
-#endif
-
-	ArdourCanvas::dump_depth++;
-
-	for (list<Item*>::const_iterator i = _items.begin(); i != _items.end(); ++i) {
-		o << **i;
-	}
-
-	ArdourCanvas::dump_depth--;
-}

libs/canvas/image.cc

@@ -32,8 +32,8 @@ Image::Image (Canvas* canvas, Cairo::Format fmt, int width, int height)
 	DataReady.connect (data_connections, MISSING_INVALIDATOR, boost::bind (&Image::accept_data, this), gui_context());
 }
 
-Image::Image (Group* group, Cairo::Format fmt, int width, int height)
+Image::Image (Item* parent, Cairo::Format fmt, int width, int height)
-	: Item (group)
+	: Item (parent)
 	, _format (fmt)
 	, _width (width)
 	, _height (height)

libs/canvas/item.cc

@@ -25,7 +25,6 @@
 
 #include "canvas/canvas.h"
 #include "canvas/debug.h"
-#include "canvas/group.h"
 #include "canvas/item.h"
 #include "canvas/scroll_group.h"
 
@@ -33,6 +32,8 @@ using namespace std;
 using namespace PBD;
 using namespace ArdourCanvas;
 
+int Item::default_items_per_cell = 64;
+
 Item::Item (Canvas* canvas)
 	: Fill (*this)
 	, Outline (*this)
@@ -41,12 +42,13 @@ Item::Item (Canvas* canvas)
 	, _scroll_parent (0)
 	, _visible (true)
 	, _bounding_box_dirty (true)
+	, _lut (0)
 	, _ignore_events (false)
 {
 	DEBUG_TRACE (DEBUG::CanvasItems, string_compose ("new canvas item %1\n", this));
 }	
 
-Item::Item (Group* parent)
+Item::Item (Item* parent)
 	: Fill (*this)
 	, Outline (*this)
 	,  _canvas (parent->canvas())
@@ -54,6 +56,7 @@ Item::Item (Group* parent)
 	, _scroll_parent (0)
 	, _visible (true)
 	, _bounding_box_dirty (true)
+	, _lut (0)
 	, _ignore_events (false)
 {
 	DEBUG_TRACE (DEBUG::CanvasItems, string_compose ("new canvas item %1\n", this));
@@ -65,7 +68,7 @@ Item::Item (Group* parent)
 	find_scroll_parent ();
 }	
 
-Item::Item (Group* parent, Duple const& p)
+Item::Item (Item* parent, Duple const& p)
 	: Fill (*this)
 	, Outline (*this)
 	,  _canvas (parent->canvas())
@@ -74,6 +77,7 @@ Item::Item (Group* parent, Duple const& p)
 	, _position (p)
 	, _visible (true)
 	, _bounding_box_dirty (true)
+	, _lut (0)
 	, _ignore_events (false)
 {
 	DEBUG_TRACE (DEBUG::CanvasItems, string_compose ("new canvas item %1\n", this));
@@ -95,6 +99,9 @@ Item::~Item ()
 	if (_canvas) {
 		_canvas->item_going_away (this, _bounding_box);
 	}
+
+	clear_items (true);
+	delete _lut;
 }
 
 Duple
@@ -350,7 +357,7 @@ Item::unparent ()
 }
 
 void
-Item::reparent (Group* new_parent)
+Item::reparent (Item* new_parent)
 {
 	if (new_parent == _parent) {
 		return;
@@ -516,6 +523,7 @@ Item::bounding_box () const
 	if (_bounding_box_dirty) {
 		compute_bounding_box ();
 		assert (!_bounding_box_dirty);
+		add_child_bounding_boxes ();
 	}
 
 	return _bounding_box;
@@ -626,30 +634,6 @@ Item::set_ignore_events (bool ignore)
 	_ignore_events = ignore;
 }
 
-void
-Item::dump (ostream& o) const
-{
-	boost::optional<ArdourCanvas::Rect> bb = bounding_box();
-
-	o << _canvas->indent() << whatami() << ' ' << this << " Visible ? " << _visible;
-	o << " @ " << position();
-	
-#ifdef CANVAS_DEBUG
-	if (!name.empty()) {
-		o << ' ' << name;
-	}
-#endif
-
-	if (bb) {
-		o << endl << _canvas->indent() << "\tbbox: " << bb.get();
-		o << endl << _canvas->indent() << "\tCANVAS bbox: " << item_to_canvas (bb.get());
-	} else {
-		o << " bbox unset";
-	}
-
-	o << endl;
-}
-
 std::string
 Item::whatami () const 
 {
@@ -687,6 +671,276 @@ Item::covers (Duple const & point) const
 	return r.get().contains (p);
 }
 
+/* nesting/grouping API */
+
+void
+Item::add_child_bounding_boxes() const
+{
+	boost::optional<Rect> self;
+	Rect bbox;
+	bool have_one = false;
+
+	if (_bounding_box) {
+		bbox = _bounding_box.get();
+		have_one = true;
+	}
+
+	for (list<Item*>::const_iterator i = _items.begin(); i != _items.end(); ++i) {
+
+		boost::optional<Rect> item_bbox = (*i)->bounding_box ();
+
+		if (!item_bbox) {
+			continue;
+		}
+
+		Rect group_bbox = (*i)->item_to_parent (item_bbox.get ());
+		if (have_one) {
+			bbox = bbox.extend (group_bbox);
+		} else {
+			bbox = group_bbox;
+			have_one = true;
+		}
+	}
+
+	if (!have_one) {
+		_bounding_box = boost::optional<Rect> ();
+	} else {
+		_bounding_box = bbox;
+	}
+}
+
+void
+Item::add (Item* i)
+{
+	/* XXX should really notify canvas about this */
+
+	_items.push_back (i);
+	i->reparent (this);
+	invalidate_lut ();
+	_bounding_box_dirty = true;
+}
+
+void
+Item::remove (Item* i)
+{
+
+	if (i->parent() != this) {
+		return;
+	}
+
+	/* we cannot call bounding_box() here because that will iterate over
+	   _items, one of which (the argument, i) may be in the middle of
+	   deletion, making it impossible to call compute_bounding_box()
+	   on it.
+	*/
+
+	if (_bounding_box) {
+		_pre_change_bounding_box = _bounding_box;
+	} else {
+		_pre_change_bounding_box = Rect();
+	}
+
+	i->unparent ();
+	_items.remove (i);
+	invalidate_lut ();
+	_bounding_box_dirty = true;
+	
+	end_change ();
+}
+
+void
+Item::clear (bool with_delete)
+{
+	begin_change ();
+
+	clear_items (with_delete);
+
+	invalidate_lut ();
+	_bounding_box_dirty = true;
+
+	end_change ();
+}
+
+void
+Item::clear_items (bool with_delete)
+{
+	for (list<Item*>::iterator i = _items.begin(); i != _items.end(); ) {
+
+		list<Item*>::iterator tmp = i;
+		Item *item = *i;
+
+		++tmp;
+
+		/* remove from list before doing anything else, because we
+		 * don't want to find the item in _items during any activity
+		 * driven by unparent-ing or deletion.
+		 */
+
+		_items.erase (i);
+		item->unparent ();
+		
+		if (with_delete) {
+			delete item;
+		}
+
+		i = tmp;
+	}
+}
+
+void
+Item::raise_child_to_top (Item* i)
+{
+	if (!_items.empty()) {
+		if (_items.back() == i) {
+			return;
+		}
+	}
+
+	_items.remove (i);
+	_items.push_back (i);
+	invalidate_lut ();
+}
+
+void
+Item::raise_child (Item* i, int levels)
+{
+	list<Item*>::iterator j = find (_items.begin(), _items.end(), i);
+	assert (j != _items.end ());
+
+	++j;
+	_items.remove (i);
+
+	while (levels > 0 && j != _items.end ()) {
+		++j;
+		--levels;
+	}
+
+	_items.insert (j, i);
+	invalidate_lut ();
+}
+
+void
+Item::lower_child_to_bottom (Item* i)
+{
+	if (!_items.empty()) {
+		if (_items.front() == i) {
+			return;
+		}
+	}
+	_items.remove (i);
+	_items.push_front (i);
+	invalidate_lut ();
+}
+
+void
+Item::ensure_lut () const
+{
+	if (!_lut) {
+		_lut = new DumbLookupTable (*this);
+	}
+}
+
+void
+Item::invalidate_lut () const
+{
+	delete _lut;
+	_lut = 0;
+}
+
+void
+Item::child_changed ()
+{
+	invalidate_lut ();
+	_bounding_box_dirty = true;
+
+	if (_parent) {
+		_parent->child_changed ();
+	}
+}
+
+void
+Item::add_items_at_point (Duple const point, vector<Item const *>& items) const
+{
+	boost::optional<Rect> const bbox = bounding_box ();
+
+	/* Point is in window coordinate system */
+
+	if (!bbox || !item_to_window (bbox.get()).contains (point)) {
+		return;
+	}
+
+	/* recurse and add any items within our group that contain point */
+
+	vector<Item*> our_items;
+
+	if (!_items.empty()) {
+		ensure_lut ();
+		our_items = _lut->items_at_point (point);
+	}
+
+	if (!our_items.empty() || covers (point)) {
+		/* this adds this item itself to the list of items at point */
+		items.push_back (this);
+	}
+
+	for (vector<Item*>::iterator i = our_items.begin(); i != our_items.end(); ++i) {
+		(*i)->add_items_at_point (point, items);
+	}
+}
+
+void
+Item::dump (ostream& o) const
+{
+	boost::optional<ArdourCanvas::Rect> bb = bounding_box();
+
+	o << _canvas->indent() << whatami() << ' ' << this << " Visible ? " << _visible;
+	o << " @ " << position();
+	
+#ifdef CANVAS_DEBUG
+	if (!name.empty()) {
+		o << ' ' << name;
+	}
+#endif
+
+	if (bb) {
+		o << endl << _canvas->indent() << "\tbbox: " << bb.get();
+		o << endl << _canvas->indent() << "\tCANVAS bbox: " << item_to_canvas (bb.get());
+	} else {
+		o << " bbox unset";
+	}
+
+	o << endl;
+
+	if (!_items.empty()) {
+
+#ifdef CANVAS_DEBUG
+		o << _canvas->indent();
+		o << " @ " << position();
+		o << " Items: " << _items.size();
+		o << " Visible ? " << _visible;
+		
+		boost::optional<Rect> bb = bounding_box();
+		
+		if (bb) {
+			o << endl << _canvas->indent() << "  bbox: " << bb.get();
+			o << endl << _canvas->indent() << "  CANVAS bbox: " << item_to_canvas (bb.get());
+		} else {
+			o << "  bbox unset";
+		}
+		
+		o << endl;
+#endif
+		
+		ArdourCanvas::dump_depth++;
+		
+		for (list<Item*>::const_iterator i = _items.begin(); i != _items.end(); ++i) {
+			o << **i;
+		}
+		
+		ArdourCanvas::dump_depth--;
+	}
+}
+
 ostream&
 ArdourCanvas::operator<< (ostream& o, const Item& i)
 {

libs/canvas/line.cc

@@ -34,8 +34,8 @@ Line::Line (Canvas* c)
 {
 }
 
-Line::Line (Group* group)
+Line::Line (Item* parent)
-	: Item (group)
+	: Item (parent)
 {
 }
 

libs/canvas/line_set.cc

@@ -38,8 +38,8 @@ LineSet::LineSet (Canvas* c, Orientation o)
 
 }
 
-LineSet::LineSet (Group* group, Orientation o)
+LineSet::LineSet (Item* parent, Orientation o)
-	: Item (group)
+	: Item (parent)
 	, _extent (0)
 	, _orientation (o)
 {

libs/canvas/lookup_table.cc

@@ -17,14 +17,14 @@
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
+#include "canvas/item.h"
 #include "canvas/lookup_table.h"
-#include "canvas/group.h"
 
 using namespace std;
 using namespace ArdourCanvas;
 
-LookupTable::LookupTable (Group const & group)
+LookupTable::LookupTable (Item const & item)
-	: _group (group)
+	: _item (item)
 {
 
 }
@@ -34,8 +34,8 @@ LookupTable::~LookupTable ()
 
 }
 
-DumbLookupTable::DumbLookupTable (Group const & group)
+DumbLookupTable::DumbLookupTable (Item const & item)
-	: LookupTable (group)
+	: LookupTable (item)
 {
 
 }
@@ -43,7 +43,7 @@ DumbLookupTable::DumbLookupTable (Group const & group)
 vector<Item *>
 DumbLookupTable::get (Rect const &)
 {
-	list<Item *> const & items = _group.items ();
+	list<Item *> const & items = _item.items ();
 	vector<Item *> vitems;
 	copy (items.begin(), items.end(), back_inserter (vitems));
 	return vitems;
@@ -54,7 +54,7 @@ DumbLookupTable::items_at_point (Duple const & point) const
 {
 	/* Point is in window coordinate system */
 
-	list<Item *> const & items (_group.items ());
+	list<Item *> const & items (_item.items ());
 	vector<Item *> vitems;
 
 	for (list<Item *>::const_iterator i = items.begin(); i != items.end(); ++i) {
@@ -73,7 +73,7 @@ DumbLookupTable::has_item_at_point (Duple const & point) const
 {
 	/* Point is in window coordinate system */
 
-	list<Item *> const & items (_group.items ());
+	list<Item *> const & items (_item.items ());
 	vector<Item *> vitems;
 
 	for (list<Item *>::const_iterator i = items.begin(); i != items.end(); ++i) {
@@ -92,12 +92,12 @@ DumbLookupTable::has_item_at_point (Duple const & point) const
 	return false;
 }
 
-OptimizingLookupTable::OptimizingLookupTable (Group const & group, int items_per_cell)
+OptimizingLookupTable::OptimizingLookupTable (Item const & item, int items_per_cell)
-	: LookupTable (group)
+	: LookupTable (item)
 	, _items_per_cell (items_per_cell)
 	, _added (false)
 {
-	list<Item*> const & items = _group.items ();
+	list<Item*> const & items = _item.items ();
 
 	/* number of cells */
 	int const cells = items.size() / _items_per_cell;
@@ -109,8 +109,8 @@ OptimizingLookupTable::OptimizingLookupTable (Group const & group, int items_per
 		_cells[i] = new Cell[_dimension];
 	}
 
-	/* our group's bounding box in its coordinates */
+	/* our item's bounding box in its coordinates */
-	boost::optional<Rect> bbox = _group.bounding_box ();
+	boost::optional<Rect> bbox = _item.bounding_box ();
 	if (!bbox) {
 		return;
 	}
@@ -130,11 +130,11 @@ OptimizingLookupTable::OptimizingLookupTable (Group const & group, int items_per
 			continue;
 		}
 
-		/* and in the group's coordinates */
+		/* and in the item's coordinates */
-		Rect const item_bbox_in_group = (*i)->item_to_parent (item_bbox.get ());
+		Rect const item_bbox_in_item = (*i)->item_to_parent (item_bbox.get ());
 
 		int x0, y0, x1, y1;
-		area_to_indices (item_bbox_in_group, x0, y0, x1, y1);
+		area_to_indices (item_bbox_in_item, x0, y0, x1, y1);
 
 		/* XXX */
 		assert (x0 >= 0);
@@ -147,19 +147,19 @@ OptimizingLookupTable::OptimizingLookupTable (Group const & group, int items_per
 		//assert (y1 <= _dimension);
 
 		if (x0 > _dimension) {
-			cout << "WARNING: item outside bbox by " << (item_bbox_in_group.x0 - bbox.get().x0) << "\n";
+			cout << "WARNING: item outside bbox by " << (item_bbox_in_item.x0 - bbox.get().x0) << "\n";
 			x0 = _dimension;
 		}
 		if (x1 > _dimension) {
-			cout << "WARNING: item outside bbox by " << (item_bbox_in_group.x1 - bbox.get().x1) << "\n";
+			cout << "WARNING: item outside bbox by " << (item_bbox_in_item.x1 - bbox.get().x1) << "\n";
 			x1 = _dimension;
 		}
 		if (y0 > _dimension) {
-			cout << "WARNING: item outside bbox by " << (item_bbox_in_group.y0 - bbox.get().y0) << "\n";
+			cout << "WARNING: item outside bbox by " << (item_bbox_in_item.y0 - bbox.get().y0) << "\n";
 			y0 = _dimension;
 		}
 		if (y1 > _dimension) {
-			cout << "WARNING: item outside bbox by " << (item_bbox_in_group.y1 - bbox.get().y1) << "\n";
+			cout << "WARNING: item outside bbox by " << (item_bbox_in_item.y1 - bbox.get().y1) << "\n";
 			y1 = _dimension;
 		}
 
@@ -284,7 +284,7 @@ OptimizingLookupTable::has_item_at_point (Duple const & point) const
 	return false;
 }
 	
-/** @param area Area in our owning group's coordinates */
+/** @param area Area in our owning item's coordinates */
 vector<Item*>
 OptimizingLookupTable::get (Rect const & area)
 {

libs/canvas/pixbuf.cc

@@ -30,8 +30,8 @@ Pixbuf::Pixbuf (Canvas* c)
 {
 }
 
-Pixbuf::Pixbuf (Group* g)
+Pixbuf::Pixbuf (Item* parent)
-	: Item (g)
+	: Item (parent)
 {
 }
 

libs/canvas/poly_item.cc

@@ -32,8 +32,8 @@ PolyItem::PolyItem (Canvas* c)
 {
 }
 
-PolyItem::PolyItem (Group* g)
+PolyItem::PolyItem (Item* parent)
-	: Item (g)
+	: Item (parent)
 {
 }
 

libs/canvas/poly_line.cc

@@ -31,8 +31,8 @@ PolyLine::PolyLine (Canvas* c)
 {
 }
 
-PolyLine::PolyLine (Group* g)
+PolyLine::PolyLine (Item* parent)
-	: PolyItem (g)
+	: PolyItem (parent)
 	, _threshold (1.0)
 {
 }

libs/canvas/polygon.cc

@@ -29,8 +29,8 @@ Polygon::Polygon (Canvas* c)
 {
 }
 
-Polygon::Polygon (Group* g)
+Polygon::Polygon (Item* parent)
-	: PolyItem (g)
+	: PolyItem (parent)
 	, multiple (0)
 	, constant (0)
 	, cached_size (0)

libs/canvas/rectangle.cc

@@ -43,14 +43,14 @@ Rectangle::Rectangle (Canvas* c, Rect const & rect)
 {
 }
 
-Rectangle::Rectangle (Group* g)
+Rectangle::Rectangle (Item* parent)
-	: Item (g)
+	: Item (parent)
 	, _outline_what ((What) (LEFT | RIGHT | TOP | BOTTOM))
 {
 }
 
-Rectangle::Rectangle (Group* g, Rect const & rect)
+Rectangle::Rectangle (Item* parent, Rect const & rect)
-	: Item (g)
+	: Item (parent)
 	, _rect (rect)
 	, _outline_what ((What) (LEFT | RIGHT | TOP | BOTTOM))
 {

libs/canvas/root_group.cc

@@ -23,8 +23,8 @@
 using namespace std;
 using namespace ArdourCanvas;
 
-RootGroup::RootGroup (Canvas* canvas)
+Root::Root (Canvas* canvas)
-	: Group (canvas)
+	: Layout (canvas)
 {
 #ifdef CANVAS_DEBUG
 	name = "ROOT";
@@ -32,11 +32,12 @@ RootGroup::RootGroup (Canvas* canvas)
 }
 
 void
-RootGroup::compute_bounding_box () const
+Root::compute_bounding_box () const
 {
-	Group::compute_bounding_box ();
+	Layout::compute_bounding_box ();
 
 	if (_bounding_box) {
-		_canvas->request_size (Duple (_bounding_box.get().width (), _bounding_box.get().height ()));
+		Rect r (_bounding_box.get());
+		_canvas->request_size (Duple (r.width (), r.height ()));
 	}
 }

libs/canvas/ruler.cc

@@ -49,8 +49,8 @@ Ruler::Ruler (Canvas* c, const Metric& m, Rect const& r)
 {
 }
 
-Ruler::Ruler (Group* g, const Metric& m)
+Ruler::Ruler (Item* parent, const Metric& m)
-	: Rectangle (g)
+	: Rectangle (parent)
 	, _metric (m)
 	, _lower (0)
 	, _upper (0)
@@ -58,8 +58,8 @@ Ruler::Ruler (Group* g, const Metric& m)
 {
 }
 
-Ruler::Ruler (Group* g, const Metric& m, Rect const& r)
+Ruler::Ruler (Item* parent, const Metric& m, Rect const& r)
-	: Rectangle (g, r)
+	: Rectangle (parent, r)
 	, _metric (m)
 	, _lower (0)
 	, _upper (0)

libs/canvas/scroll_group.cc

@@ -28,13 +28,13 @@ using namespace std;
 using namespace ArdourCanvas;
 
 ScrollGroup::ScrollGroup (Canvas* c, ScrollSensitivity s)
-	: Group (c)
+	: Layout (c)
 	, _scroll_sensitivity (s)	
 {
 }
 
-ScrollGroup::ScrollGroup (Group* g, ScrollSensitivity s)
+ScrollGroup::ScrollGroup (Item* parent, ScrollSensitivity s)
-	: Group (g)
+	: Layout (parent)
 	, _scroll_sensitivity (s)	
 {
 }
@@ -60,12 +60,10 @@ ScrollGroup::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) c
 	context->save ();
 	context->rectangle (self.x0, self.y0, self.width(), self.height());
 	context->clip ();
-
+	
-	Group::render (area, context);
+	Layout::render (area, context);
 
 	context->restore ();
-
-
 }
 
 void

libs/canvas/text.cc

@@ -43,8 +43,8 @@ Text::Text (Canvas* c)
 {
 }
 
-Text::Text (Group* g)
+Text::Text (Item* parent)
-	: Item (g)
+	: Item (parent)
 	, _color (0x000000ff)
 	, _font_description (0)
 	, _alignment (Pango::ALIGN_LEFT)

libs/canvas/wave_view.cc

@@ -76,8 +76,8 @@ WaveView::WaveView (Canvas* c, boost::shared_ptr<ARDOUR::AudioRegion> region)
 	ClipLevelChanged.connect_same_thread (invalidation_connection, boost::bind (&WaveView::handle_clip_level_change, this));
 }
 
-WaveView::WaveView (Group* g, boost::shared_ptr<ARDOUR::AudioRegion> region)
+WaveView::WaveView (Item* parent, boost::shared_ptr<ARDOUR::AudioRegion> region)
-	: Item (g)
+	: Item (parent)
 	, _region (region)
 	, _channel (0)
 	, _samples_per_pixel (0)

libs/canvas/widget.cc

@@ -36,8 +36,8 @@ Widget::Widget (Canvas* c, CairoWidget& w)
 	Event.connect (sigc::mem_fun (*this, &Widget::event_proxy));
 }
 
-Widget::Widget (Group* g, CairoWidget& w)
+Widget::Widget (Item* parent, CairoWidget& w)
-	: Item (g)
+	: Item (parent)
 	, _widget (w)
 {
 	Event.connect (sigc::mem_fun (*this, &Widget::event_proxy));