3 files changed, 53 insertions, 13 deletions

diff --git a/libs/canvas/canvas/item.h b/libs/canvas/canvas/item.h
index 429df33894..487efae4d0 100644
--- a/libs/canvas/canvas/item.h
+++ b/libs/canvas/canvas/item.h
@@ -112,22 +112,17 @@ public:
 	void set_y_position (Coord);
 	void move (Duple);
 
-	enum ScrollSensitivity {
-		ScrollsVertically = 0x1,
-		ScrollsHorizontally = 0x2
-	};
-	
-	void set_scroll_sensitivity (ScrollSensitivity s);
-	ScrollSensitivity scroll_sensitivity () const { return _scroll_sensitivity; }
-
-	virtual void scroll_to (Duple const& d);
-	Duple scroll_offset() const { return _scroll_offset; }
+	virtual void scroll_to (Duple const&) {}
 
 	/** @return Position of this item in the parent's coordinates */
 	Duple position () const {
 		return _position;
 	}
 
+	virtual Duple canvas_position () const {
+		return _position;
+	}
+
 	boost::optional<Rect> bounding_box () const;
         Coord height() const;
         Coord width() const;
@@ -248,8 +243,6 @@ private:
 	void init ();
 
 	bool _ignore_events;
-	ScrollSensitivity _scroll_sensitivity;
-	Duple _scroll_offset;
 };
 
 extern LIBCANVAS_API std::ostream& operator<< (std::ostream&, const ArdourCanvas::Item&);
diff --git a/libs/canvas/canvas/scroll_group.h b/libs/canvas/canvas/scroll_group.h
new file mode 100644
index 0000000000..c2b26bf9d9
--- /dev/null
+++ b/libs/canvas/canvas/scroll_group.h
@@ -0,0 +1,47 @@
+/*
+    Copyright (C) 2014 Paul Davis
+
+    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_SCROLL_GROUP_H__
+#define __CANVAS_SCROLL_GROUP_H__
+
+#include "canvas/group.h"
+
+namespace ArdourCanvas {
+
+class LIBCANVAS_API ScrollGroup : public Group
+{
+  public:
+	enum ScrollSensitivity {
+		ScrollsVertically = 0x1,
+		ScrollsHorizontally = 0x2
+	};
+	
+	explicit ScrollGroup (Group *, ScrollSensitivity);
+	explicit ScrollGroup (Group *, Duple, ScrollSensitivity);
+
+	void scroll_to (Duple const& d);
+	Duple canvas_position() const;
+
+  private:
+	ScrollSensitivity _scroll_sensitivity;
+	Duple             _scroll_offset;
+};
+
+}
+
+#endif
diff --git a/libs/canvas/canvas/wave_view.h b/libs/canvas/canvas/wave_view.h
index 307528c685..0ddffca180 100644
--- a/libs/canvas/canvas/wave_view.h
+++ b/libs/canvas/canvas/wave_view.h
@@ -173,7 +173,7 @@ private:
         void handle_clip_level_change ();
 
         void ensure_cache (ARDOUR::framepos_t sample_start, ARDOUR::framepos_t sample_end) const;
-        ArdourCanvas::Coord position (double) const;
+        ArdourCanvas::Coord y_extent (double) const;
         void draw_image (ARDOUR::PeakData*, int npeaks) const;
 };