# HG changeset patch
# User jwe
# Date 1173896760 0
# Node ID f7c06f96bd18ccc2cf6726793df92fde67f16055
# Parent  b298a4c12fc3dd13589263fd2b42758e4b591338
[project @ 2007-03-14 18:26:00 by jwe]

diff -r b298a4c12fc3 -r f7c06f96bd18 src/graphics.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/graphics.cc	Wed Mar 14 18:26:00 2007 +0000
@@ -0,0 +1,3425 @@
+/*
+
+Copyright (C) 2007 John W. Eaton
+
+This file is part of Octave.
+
+Octave 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, or (at your option) any
+later version.
+
+Octave 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 Octave; see the file COPYING.  If not, write to the Free
+Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <cctype>
+
+#include <algorithm>
+#include <list>
+#include <map>
+#include <set>
+#include <string>
+
+#include <defun.h>
+#include <ov.h>
+#include <oct-obj.h>
+#include <oct-map.h>
+#include <ov-fcn-handle.h>
+#include <parse.h>
+
+static void
+gripe_set_invalid (const std::string& pname)
+{
+  error ("set: invalid value for %s property", pname.c_str ());
+}
+
+static octave_value
+nan_to_empty (double val)
+{
+  return xisnan (val) ? octave_value (Matrix ()) : octave_value (val);
+}
+
+static octave_value
+empty_to_nan (const octave_value& val)
+{
+  return val.is_empty () ? octave_value (octave_NaN) : val;
+}
+
+// ---------------------------------------------------------------------
+
+class color_property
+{
+public:
+  color_property (double r = 0, double g = 0, double b = 1)
+    : red (r), green (g), blue (b)
+  {
+    validate ();
+  }
+
+  color_property (const octave_value& val)
+    : red (), green (), blue ()
+  {
+    // FIXME -- need some error checking here.
+
+    Matrix m = val.matrix_value ();
+
+    if (! error_state && m.numel () == 3)
+      {
+	red = m(0);
+	green = m(1);
+	blue = m(2);
+
+	validate ();
+      }
+    else
+      error ("invalid RGB color specification");
+  }
+
+  void validate (void) const
+  {
+    if (red < 0 || red > 1 || green < 0 || green > 1 || blue < 0 || blue > 1)
+      error ("invalid RGB color specification");
+  }
+
+  operator octave_value (void) const
+  {
+    Matrix retval (1, 3);
+
+    retval(0) = red;
+    retval(1) = green;
+    retval(2) = blue;
+
+    return retval;
+  }
+
+private:
+  double red;
+  double green;
+  double blue;
+};
+
+class colormap_property
+{
+public:
+  colormap_property (const Matrix& m = Matrix ())
+    : cmap (m)
+  {
+    if (cmap.is_empty ())
+      {
+	cmap = Matrix (64, 3);
+
+	for (octave_idx_type i = 0; i < 64; i++)
+	  cmap(i,0) = cmap(i,1) = cmap(i,2) = i / 64.0;
+      }
+
+    validate ();
+  }
+
+  colormap_property (const octave_value& val)
+  {
+    cmap = val.matrix_value ();
+
+    validate ();
+  }
+
+  void validate (void) const
+  {
+    if (error_state || cmap.columns () != 3)
+      error ("invalid colormap specification");
+  }
+
+  operator octave_value (void) const { return cmap; }
+
+private:
+  Matrix cmap;
+};
+
+// ---------------------------------------------------------------------
+
+class property_name : public std::string
+{
+public:
+  typedef std::string::iterator iterator;
+  typedef std::string::const_iterator const_iterator;
+
+  property_name (void) : std::string () { }
+  property_name (const std::string& s) : std::string (s) { }
+  property_name (const char *s) : std::string (s) { }
+
+  property_name (const property_name& name) : std::string (name) { }
+
+  property_name& operator = (const property_name& pname)
+  {
+    std::string::operator = (pname);
+    return *this;
+  }
+
+  operator std::string (void) const { return *this; }
+
+  // Case-insensitive comparison.
+  bool compare (const std::string& s, size_t limit = NPOS) const
+  {
+    const_iterator p1 = begin ();
+    const_iterator p2 = s.begin ();
+
+    size_t k = 0;
+
+    while (p1 != end () && p2 != s.end () && k++ < limit)
+      {
+	if (std::tolower (*p1) != std::tolower (*p2))
+	  return false;
+
+	*p1++;
+	*p2++;
+      }
+
+    return (limit == NPOS) ? size () == s.size () : k == limit;
+  }
+};
+
+// ---------------------------------------------------------------------
+
+class property_list
+{
+public:
+  typedef std::map<std::string, octave_value> pval_map_type;
+  typedef std::map<std::string, pval_map_type> plist_map_type;
+  
+  typedef pval_map_type::iterator pval_map_iterator;
+  typedef pval_map_type::const_iterator pval_map_const_iterator;
+
+  typedef plist_map_type::iterator plist_map_iterator;
+  typedef plist_map_type::const_iterator plist_map_const_iterator;
+
+  property_list (const plist_map_type& m = plist_map_type ())
+    : plist_map (m) { }
+
+  ~property_list (void) { }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    size_t offset = 0;
+
+    size_t len = name.length ();
+
+    if (len > 4)
+      {
+	property_name pfx = name.substr (0, 4);
+
+	if (pfx.compare ("axes") || pfx.compare ("line")
+	    || pfx.compare ("text"))
+	  offset = 4;
+	else if (len > 5)
+	  {
+	    pfx = name.substr (0, 5);
+
+	    if (pfx.compare ("image"))
+	      offset = 5;
+	    else if (len > 6)
+	      {
+		pfx = name.substr (0, 6);
+
+		if (pfx.compare ("figure"))
+		  offset = 6;
+		else if (len > 7)
+		  {
+		    pfx = name.substr (0, 7);
+
+		    if (pfx.compare ("surface"))
+		      offset = 7;
+		  }
+	      }
+	  }
+
+	if (offset > 0)
+	  {
+	    // FIXME -- should we validate property names and values here?
+
+	    std::string pname = name.substr (offset);
+
+	    std::transform (pfx.begin (), pfx.end (), pfx.begin (), tolower);
+	    std::transform (pname.begin (), pname.end (), pname.begin (), tolower);
+
+	    bool remove = false;
+	    if (val.is_string ())
+	      {
+		property_name tval = val.string_value ();
+
+		remove = tval.compare ("remove");
+	      }
+
+	    pval_map_type& pval_map = plist_map[pfx];
+
+	    if (remove)
+	      {
+		pval_map_iterator p = pval_map.find (pname);
+
+		if (p != pval_map.end ())
+		  pval_map.erase (p);
+	      }
+	    else
+	      pval_map[pname] = val;
+	  }
+      }
+
+    if (offset == 0)
+      error ("invalid default property specification");
+  }
+
+  octave_value lookup (const property_name& name) const
+  {
+    octave_value retval;
+
+    size_t offset = 0;
+
+    size_t len = name.length ();
+
+    if (len > 4)
+      {
+	property_name pfx = name.substr (0, 4);
+
+	if (pfx.compare ("axes") || pfx.compare ("line")
+	    || pfx.compare ("text"))
+	  offset = 4;
+	else if (len > 5)
+	  {
+	    pfx = name.substr (0, 5);
+
+	    if (pfx.compare ("image"))
+	      offset = 5;
+	    else if (len > 6)
+	      {
+		pfx = name.substr (0, 6);
+
+		if (pfx.compare ("figure"))
+		  offset = 6;
+		else if (len > 7)
+		  {
+		    pfx = name.substr (0, 7);
+
+		    if (pfx.compare ("surface"))
+		      offset = 7;
+		  }
+	      }
+	  }
+
+	if (offset > 0)
+	  {
+	    std::string pname = name.substr (offset);
+
+	    std::transform (pfx.begin (), pfx.end (), pfx.begin (), tolower);
+	    std::transform (pname.begin (), pname.end (), pname.begin (), tolower);
+
+	    plist_map_const_iterator p = find (pfx);
+
+	    if (p != end ())
+	      {
+		const pval_map_type& pval_map = p->second;
+
+		pval_map_const_iterator q = pval_map.find (pname);
+
+		if (q != pval_map.end ())
+		  retval = q->second;
+	      }
+	  }
+      }
+
+    return retval;
+  }
+
+  plist_map_iterator begin (void) { return plist_map.begin (); }
+  plist_map_const_iterator begin (void) const { return plist_map.begin (); }
+
+  plist_map_iterator end (void) { return plist_map.end (); }
+  plist_map_const_iterator end (void) const { return plist_map.end (); }
+
+  plist_map_iterator find (const std::string& go_name)
+  {
+    return plist_map.find (go_name);
+  }
+
+  plist_map_const_iterator find (const std::string& go_name) const
+  {
+    return plist_map.find (go_name);
+  }
+
+  Octave_map as_struct (const std::string& prefix_arg) const
+  {
+    Octave_map m;
+
+    for (plist_map_const_iterator p = begin (); p != end (); p++)
+      {
+	std::string prefix = prefix_arg + p->first;
+
+	const pval_map_type pval_map = p->second;
+
+	for (pval_map_const_iterator q = pval_map.begin ();
+	     q != pval_map.end ();
+	     q++)
+	  m.assign (prefix + q->first, q->second);
+      }
+
+    return m;    
+  }
+
+private:
+  plist_map_type plist_map;
+};
+
+// ---------------------------------------------------------------------
+
+typedef double graphics_handle;
+
+// ---------------------------------------------------------------------
+
+class base_graphics_object
+{
+public:
+  friend class graphics_object;
+
+  base_graphics_object (void) : count (1) { }
+
+  base_graphics_object (const base_graphics_object&) { }
+
+  virtual ~base_graphics_object (void) { }
+
+  virtual void override_defaults (base_graphics_object&)
+  {
+    error ("base_graphics_object::override_defaults: invalid graphics object");
+  }
+
+  virtual void set_from_list (property_list&)
+  {
+    error ("base_graphics_object::set_from_list: invalid graphics object");
+  }
+
+  virtual void set (const property_name&, const octave_value&)
+  {
+    error ("base_graphics_object::set: invalid graphics object");
+  }
+
+  virtual void set_defaults (const std::string&)
+  {
+    error ("base_graphics_object::set_defaults: invalid graphics object");
+  }
+
+  virtual octave_value get (void) const
+  {
+    error ("base_graphics_object::get: invalid graphics object");
+    return octave_value ();
+  }
+
+  virtual octave_value get (const property_name&) const
+  {
+    error ("base_graphics_object::get: invalid graphics object");
+    return octave_value ();
+  }
+
+  virtual octave_value get_default (const property_name&) const;
+
+  virtual octave_value get_factory_default (const property_name&) const;
+
+  virtual octave_value get_defaults (void) const
+  {
+    error ("base_graphics_object::get_defaults: invalid graphics object");
+    return octave_value ();
+  }
+
+  virtual octave_value get_factory_defaults (void) const
+  {
+    error ("base_graphics_object::get_factory_defaults: invalid graphics object");
+    return octave_value ();
+  }
+
+  virtual graphics_handle get_parent (void) const
+  {
+    error ("base_graphics_object::get_parent: invalid graphics object");
+    return octave_NaN;
+  }
+
+  virtual void remove_child (const graphics_handle&)
+  {
+    error ("base_graphics_object::remove_child: invalid graphics object");
+  }
+
+  virtual void adopt (const graphics_handle&)
+  {
+    error ("base_graphics_object::adopt: invalid graphics object");
+  }
+
+  virtual void reparent (const graphics_handle&)
+  {
+    error ("base_graphics_object::reparent: invalid graphics object");
+  }
+
+  virtual void defaults (void) const
+  {
+    error ("base_graphics_object::default: invalid graphics object");
+  }
+
+  virtual bool valid_object (void) const { return false; }
+
+  virtual std::string type (void) const { return "unknown"; }
+
+  bool isa (const std::string& go_name) const
+  {
+    return type () == go_name;
+  }
+
+protected:
+  // A reference count.
+  int count;
+};
+
+class graphics_object
+{
+public:
+  graphics_object (void) : rep (new base_graphics_object ()) { }
+
+  graphics_object (base_graphics_object *new_rep)
+    : rep (new_rep) { }
+
+  graphics_object (const graphics_object& obj)
+  {
+    rep = obj.rep;
+    rep->count++;
+  }
+
+  graphics_object& operator = (const graphics_object& obj)
+  {
+    if (rep != obj.rep)
+      {
+	if (--rep->count == 0)
+	  delete rep;
+
+	rep = obj.rep;
+	rep->count++;
+      }
+
+    return *this;
+  }
+
+  ~graphics_object (void)
+  {
+    if (--rep->count == 0)
+      delete rep;
+  }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    rep->override_defaults (obj);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    rep->set_from_list (plist);
+  }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    rep->set (name, val);
+  }
+
+  void set (const octave_value_list& args)
+  {
+    int nargin = args.length ();
+
+    if (nargin == 0)
+      rep->defaults ();
+    else if (nargin % 2 == 0)
+      {
+	for (int i = 0; i < nargin; i += 2)
+	  {
+	    property_name name = args(i).string_value ();
+
+	    if (! error_state)
+	      {
+		octave_value val = args(i+1);
+
+		if (val.is_string ())
+		  {
+		    property_name tval = val.string_value ();
+
+		    if (tval.compare ("default"))
+		      val = get_default (name);
+		    else if (tval.compare ("factory"))
+		      val = get_factory_default (name);
+		  }
+
+		if (error_state)
+		  break;
+
+		rep->set (name, val);
+	      }
+	    else
+	      error ("set: expecting argument %d to be a property name", i);
+	  }
+      }
+    else
+      error ("set: invalid number of arguments");
+  }
+
+  void set_defaults (const std::string& mode)
+  {
+    rep->set_defaults (mode);
+  }
+
+  octave_value get (void) const
+  {
+    return rep->get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    return name.compare ("default")
+      ? get_defaults ()
+      : (name.compare ("factory")
+	 ? get_factory_defaults () : rep->get (name));
+  }
+
+  octave_value get_default (const property_name& name) const
+  {
+    return rep->get_default (name);
+  }
+
+  octave_value get_factory_default (const property_name& name) const
+  {
+    return rep->get_factory_default (name);
+  }
+
+  octave_value get_defaults (void) const { return rep->get_defaults (); }
+
+  octave_value get_factory_defaults (void) const
+  {
+    return rep->get_factory_defaults ();
+  }
+
+  graphics_handle get_parent (void) const { return rep->get_parent (); }
+
+  void remove_child (const graphics_handle& h) { return rep->remove_child (h); }
+
+  void adopt (const graphics_handle& h) { return rep->adopt (h); }
+
+  void reparent (const graphics_handle& h) { return rep->reparent (h); }
+
+  void defaults (void) const { rep->defaults (); }
+
+  bool isa (const std::string& go_name) const { return rep->isa (go_name); }
+
+  bool valid_object (void) const { return rep->valid_object (); }
+
+  operator bool (void) const { return rep->valid_object (); }
+
+private:
+  base_graphics_object *rep;
+};
+
+// ---------------------------------------------------------------------
+
+class gh_manager
+{
+protected:
+
+  gh_manager (void);
+
+public:
+
+  static bool instance_ok (void)
+  {
+    bool retval = true;
+
+    if (! instance)
+      instance = new gh_manager ();
+
+    if (! instance)
+      {
+	::error ("unable to create gh_manager!");
+
+	retval = false;
+      }
+
+    return retval;
+  }
+
+  static void free (const graphics_handle& h)
+  {
+    if (instance_ok ())
+      instance->do_free (h);
+  }
+
+  static graphics_handle lookup (double val)
+  {
+    return instance_ok () ? instance->do_lookup (val) : graphics_handle ();
+  }
+
+  static graphics_object get_object (const graphics_handle& h)
+  {
+    return instance_ok () ? instance->do_get_object (h) : graphics_object ();
+  }
+
+  static graphics_handle
+  make_graphics_handle (const std::string& go_name,
+			const graphics_handle& parent)
+  {
+    return instance_ok ()
+      ? instance->do_make_graphics_handle (go_name, parent) : octave_NaN;
+  }
+
+  static graphics_handle make_figure_handle (double val)
+  {
+    return instance_ok ()
+      ? instance->do_make_figure_handle (val) : octave_NaN;
+  }
+
+  static void push_figure (const graphics_handle& h)
+  {
+    if (instance_ok ())
+      instance->do_push_figure (h);
+  }
+
+  static void pop_figure (const graphics_handle& h)
+  {
+    if (instance_ok ())
+      instance->do_pop_figure (h);
+  }
+
+  static graphics_handle current_figure (void)
+  {
+    return instance_ok () ? instance->do_current_figure () : octave_NaN;
+  }
+
+  static Matrix list (void)
+  {
+    return instance_ok () ? instance->do_list () : Matrix ();
+  }
+
+private:
+
+  static gh_manager *instance;
+
+  typedef std::map<graphics_handle, graphics_object>::iterator iterator;
+  typedef std::map<graphics_handle, graphics_object>::const_iterator const_iterator;
+
+  typedef std::set<graphics_handle>::iterator free_list_iterator;
+  typedef std::set<graphics_handle>::const_iterator const_free_list_iterator;
+
+  typedef std::list<graphics_handle>::iterator figure_list_iterator;
+  typedef std::list<graphics_handle>::const_iterator const_figure_list_iterator;
+
+  // A map of handles to graphics objects.
+  std::map<graphics_handle, graphics_object> handle_map;
+
+  // The available graphics handles.
+  std::set<graphics_handle> handle_free_list;
+
+  // The next handle available if handle_free_list is empty.
+  graphics_handle next_handle;
+
+  // The allocated figure handles.  Top of the stack is most recently
+  // created.
+  std::list<graphics_handle> figure_list;
+
+  graphics_handle get_handle (const std::string& go_name)
+  {
+    graphics_handle retval;
+
+    if (go_name == "figure")
+      {
+	// We always want the lowest unused figure number.
+
+	retval = 1;
+
+	while (handle_map.find (retval) != handle_map.end ())
+	  retval++;
+      }
+    else
+      {
+	free_list_iterator p = handle_free_list.begin ();
+
+	if (p != handle_free_list.end ())
+	  {
+	    retval = *p;
+	    handle_free_list.erase (p);
+	  }
+	else
+	  retval = next_handle--;
+      }
+
+    return retval;
+  }
+
+  void do_free (const graphics_handle& h)
+  {
+    if (h != 0)
+      {
+	iterator p = handle_map.find (h);
+
+	if (p != handle_map.end ())
+	  {
+	    handle_map.erase (p);
+
+	    if (h < 0)
+	      handle_free_list.insert (h);
+	  }
+	else
+	  error ("graphics_handle::free: invalid object %g", h);
+      }
+    else
+      error ("graphics_handle::free: can't delete root figure");
+  }
+
+  graphics_handle do_lookup (double val)
+  {
+    iterator p = handle_map.find (val);
+
+    return (p != handle_map.end ()) ? p->first : octave_NaN;
+  }
+
+  graphics_object do_get_object (const graphics_handle& h)
+  {
+    iterator p = handle_map.find (h);
+
+    return (p != handle_map.end ()) ? p->second : graphics_object ();
+  }
+
+  graphics_handle do_make_graphics_handle (const std::string& go_name,
+					   const graphics_handle& p);
+
+  graphics_handle do_make_figure_handle (double val);
+
+  Matrix do_list (void)
+  {
+    Matrix retval (1, handle_map.size ());
+    octave_idx_type i = 0;
+    for (const_iterator p = handle_map.begin (); p != handle_map.end (); p++)
+      retval(i++) = p->first;
+    return retval;
+  }
+
+  void do_push_figure (const graphics_handle& h);
+
+  void do_pop_figure (const graphics_handle& h);
+
+  graphics_handle do_current_figure (void) const
+  {
+    return figure_list.empty () ? octave_NaN : figure_list.front ();
+  }
+};
+
+gh_manager *gh_manager::instance = 0;
+
+// ---------------------------------------------------------------------
+
+static void
+xset (const graphics_handle& h, const property_name& name,
+      const octave_value& val)
+{
+  graphics_object obj = gh_manager::get_object (h);
+  obj.set (name, val);
+}
+
+static void
+xset (const graphics_handle& h, const octave_value_list& args)
+{
+  if (args.length () > 0)
+    {
+      graphics_object obj = gh_manager::get_object (h);
+      obj.set (args);
+    }
+}
+
+
+static octave_value
+xget (const graphics_handle& h, const property_name& name)
+{
+  graphics_object obj = gh_manager::get_object (h);
+  return obj.get (name);
+}
+
+static graphics_handle
+reparent (const octave_value& ov, const std::string& who,
+	  const std::string& property, const graphics_handle& new_parent,
+	  bool adopt = true)
+{
+  graphics_handle h = octave_NaN;
+
+  double val = ov.double_value ();
+
+  if (! error_state)
+    {
+      h = gh_manager::lookup (val);
+
+      if (! xisnan (h))
+	{
+	  graphics_object obj = gh_manager::get_object (h);
+	  
+	  graphics_handle parent_h = obj.get_parent ();
+
+	  graphics_object parent_obj = gh_manager::get_object (parent_h);
+
+	  parent_obj.remove_child (h);
+
+	  if (adopt)
+	    obj.set ("parent", new_parent);
+	  else
+	    obj.reparent (new_parent);
+	}
+      else
+	error ("%s: invalid graphics handle (= %g) for %s",
+	       who.c_str (), val, property.c_str ());
+    }
+  else
+    error ("%s: expecting %s to be a graphics handle",
+	   who.c_str (), property.c_str ());
+
+  return h;
+}
+
+// This function is NOT equivalent to the scripting language function gcf.
+graphics_handle
+gcf (void)
+{
+  octave_value val = xget (0, "currentfigure");
+
+  return val.is_empty () ? octave_NaN : val.double_value ();
+}
+
+// This function is NOT equivalent to the scripting language function gca.
+graphics_handle
+gca (void)
+{
+  octave_value val = xget (gcf (), "currentaxes");
+
+  return val.is_empty () ? octave_NaN : val.double_value ();
+}
+
+static void
+adopt (const graphics_handle& p, const graphics_handle& h)
+{
+  graphics_object parent_obj = gh_manager::get_object (p);
+
+  parent_obj.adopt (h);
+}
+
+static bool
+is_handle (double val)
+{
+  return ! xisnan (gh_manager::lookup (val));
+}
+
+static bool
+is_handle (const octave_value& val)
+{
+  return val.is_real_type () && is_handle (val.double_value ());
+}
+
+static bool
+is_figure (double val)
+{
+  graphics_object obj = gh_manager::get_object (val);
+
+  return obj && obj.isa ("figure");
+}
+
+// ---------------------------------------------------------------------
+
+static int
+compare (const void *a_arg, const void *b_arg)
+{
+  double a = *(static_cast<const double *> (a_arg));
+  double b = *(static_cast<const double *> (b_arg));
+
+  return a > b ? 1 : (a < b) ? -1 : 0;
+}
+
+static Matrix
+maybe_set_children (const Matrix& kids, const octave_value& val)
+{
+  const Matrix new_kids = val.matrix_value ();
+
+  bool ok = true;
+
+  if (! error_state)
+    {
+      if (kids.numel () == new_kids.numel ())
+	{
+	  Matrix t1 = kids;
+	  Matrix t2 = new_kids;
+
+	  t1.qsort (compare);
+	  t2.qsort (compare);
+
+	  if (t1 != t2)
+	    ok = false;
+	}      else
+	ok = false;
+
+      if (! ok)
+	error ("set: new children must be a permutation of existing children");
+    }
+  else
+    {
+      ok = false;
+      error ("set: expecting children to be array of graphics handles");
+    }
+
+  return ok ? new_kids : kids;
+}
+
+class base_properties
+{
+public:
+  base_properties (const std::string& t = "unknown",
+		   const graphics_handle& mh = octave_NaN,
+		   const graphics_handle& p = octave_NaN)
+    : type (t), __myhandle__ (mh), parent (p), children () { }
+
+  virtual ~base_properties (void) { }
+
+  virtual std::string graphics_object_name (void) const = 0;
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    graphics_object parent_obj = gh_manager::get_object (parent);
+    parent_obj.override_defaults (obj);
+  }
+
+  // Look through DEFAULTS for properties with given CLASS_NAME, and
+  // apply them to the current object with set (virtual method).
+
+  void set_from_list (base_graphics_object& obj, property_list& defaults)
+  {
+    std::string go_name = graphics_object_name ();
+
+    property_list::plist_map_const_iterator p = defaults.find (go_name);
+
+    if (p != defaults.end ())
+      {
+	const property_list::pval_map_type pval_map = p->second;
+
+	for (property_list::pval_map_const_iterator q = pval_map.begin ();
+	     q != pval_map.end ();
+	     q++)
+	  {
+	    std::string pname = q->first;
+
+	    obj.set (pname, q->second);
+
+	    if (error_state)
+	      {
+		error ("error setting default property %s", pname.c_str ());
+		break;
+	      }
+	  }
+      }
+  }
+
+  virtual void set (const property_name& name, const octave_value& val) = 0;
+
+  graphics_handle get_parent (void) const { return parent; }
+
+  void remove_child (const graphics_handle& h)
+  {
+    octave_idx_type k = -1;
+    octave_idx_type n = children.numel ();
+    for (octave_idx_type i = 0; i < n; i++)
+      {
+	if (h == children(i))
+	  {
+	    k = i;
+	    break;
+	  }
+      }
+
+    if (k >= 0)
+      {
+	Matrix new_kids (1, n-1);
+	octave_idx_type j = 0;
+	for (octave_idx_type i = 0; i < n; i++)
+	  {
+	    if (i != k)
+	      new_kids(j++) = children(i);
+	  }
+	children = new_kids;
+      }
+  }
+
+  void adopt (const graphics_handle& h)
+  {
+    octave_idx_type n = children.numel ();
+    children.resize (1, n+1);
+    children(n) = h;
+  }
+
+  void set_parent (const octave_value& val)
+  {
+    double tmp = val.double_value ();
+
+    graphics_handle new_parent = octave_NaN;
+
+    if (! error_state)
+      {
+	new_parent = gh_manager::lookup (tmp);
+
+	if (! xisnan (new_parent))
+	  {
+	    graphics_object parent_obj = gh_manager::get_object (parent);
+
+	    parent_obj.remove_child (__myhandle__);
+
+	    parent = new_parent;
+
+	    ::adopt (parent, __myhandle__);
+	  }
+	else
+	  error ("set: invalid graphics handle (= %g) for parent", tmp);
+      }
+    else
+      error ("set: expecting parent to be a graphics handle");
+  }
+
+  void reparent (const graphics_handle& new_parent) { parent = new_parent; }
+
+  virtual void delete_children (void)
+  {
+    octave_idx_type n = children.numel ();
+
+    for (octave_idx_type i = 0; i < n; i++)
+      gh_manager::free (children(i));
+  }
+
+protected:
+  std::string type;
+  graphics_handle __myhandle__;
+  graphics_handle parent;
+  Matrix children;
+};
+
+// ---------------------------------------------------------------------
+
+class root_figure : public base_graphics_object
+{
+public:
+  class root_figure_properties : public base_properties
+  {
+  public:
+    root_figure_properties (void)
+      : base_properties ("root figure", 0, octave_NaN),
+	currentfigure (octave_NaN),
+	visible ("on")
+    { }
+
+    ~root_figure_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("currentfigure"))
+	{
+	  octave_value tval = empty_to_nan (val);
+
+	  if (is_handle (tval))
+	    {
+	      currentfigure = tval.double_value ();
+
+	      gh_manager::push_figure (currentfigure);
+	    }
+	  else
+	    gripe_set_invalid ("currentfigure");
+	}
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("visible"))
+	visible = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("currentfigure", nan_to_empty (currentfigure));
+      m.assign ("children", children);
+      m.assign ("visible", visible);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("currentfigure"))
+	retval = nan_to_empty (currentfigure);
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("visible"))
+	retval = visible;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+  private:
+    graphics_handle currentfigure;
+    octave_value visible;
+
+    static std::string go_name;
+  };
+
+  root_figure_properties properties;
+
+public:
+
+  root_figure (void) : properties (), default_properties () { }
+
+  ~root_figure (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Now override with our defaults.  If the default_properties
+    // list includes the properties for all defaults (line,
+    // surface, etc.) then we don't have to know the type of OBJ
+    // here, we just call its set function and let it decide which
+    // properties from the list to use.
+    obj.set_from_list (default_properties);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& value)
+  {
+    if (name.compare ("default", 7))
+      // strip "default", pass rest to function that will
+      // parse the remainder and add the element to the
+      // default_properties map.
+      default_properties.set (name.substr (7), value);
+    else
+      properties.set (name, value);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    octave_value retval;
+
+    if (name.compare ("default", 7))
+      return get_default (name.substr (7));
+    else if (name.compare ("factory", 7))
+      return get_factory_default (name.substr (7));
+    else
+      retval = properties.get (name);
+
+    return retval;
+  }
+
+  octave_value get_default (const property_name& name) const
+  {
+    octave_value retval = default_properties.lookup (name);
+
+    if (retval.is_undefined ())
+      error ("get: invalid default property `%s'", name.c_str ());
+
+    return retval;
+  }
+
+  octave_value get_factory_default (const property_name& name) const
+  {
+    octave_value retval = factory_properties.lookup (name);
+
+    if (retval.is_undefined ())
+      error ("get: invalid factory default property `%s'", name.c_str ());
+
+    return retval;
+  }
+
+  octave_value get_defaults (void) const
+  {
+    return default_properties.as_struct ("default");
+  }
+
+  octave_value get_factory_defaults (void) const
+  {
+    return factory_properties.as_struct ("factory");
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& np) { properties.reparent (np); }
+
+  bool valid_object (void) const { return true; }
+
+private:
+  property_list default_properties;
+
+  static property_list factory_properties;
+
+  static property_list::plist_map_type init_factory_properties (void);
+};
+
+property_list
+root_figure::factory_properties = root_figure::init_factory_properties ();
+
+std::string root_figure::root_figure_properties::go_name ("root figure");
+
+// ---------------------------------------------------------------------
+
+class figure : public base_graphics_object
+{
+public:
+  class figure_properties : public base_properties
+  {
+  public:
+    figure_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	__plot_stream__ (Matrix ()),
+	nextplot ("replace"),
+	closerequestfcn (make_fcn_handle ("closereq")),
+	currentaxes (octave_NaN),
+	colormap (),
+	visible ("on"),
+	paperorientation ("portrait")
+    { }
+
+    ~figure_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("__plot_stream__"))
+	__plot_stream__ = val;
+      else if (name.compare ("nextplot"))
+	nextplot = val;
+      else if (name.compare ("closerequestfcn"))
+	closerequestfcn = val;
+      else if (name.compare ("currentaxes"))
+	{
+	  octave_value tval = empty_to_nan (val);
+	    
+	  if (is_handle (tval))
+	    currentaxes = tval.double_value ();
+	  else
+	    gripe_set_invalid ("currentaxes");
+	}
+      else if (name.compare ("colormap"))
+	colormap = colormap_property (val);
+      else if (name.compare ("visible"))
+	visible = val;
+      else if (name.compare ("paperorientation"))
+	paperorientation = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("__plot_stream__", __plot_stream__);
+      m.assign ("nextplot", nextplot);
+      m.assign ("closerequestfcn", closerequestfcn);
+      m.assign ("currentaxes", nan_to_empty (currentaxes));
+      m.assign ("colormap", colormap);
+      m.assign ("visible", visible);
+      m.assign ("paperorientation", paperorientation);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("__plot_stream__"))
+	retval = __plot_stream__;
+      else if (name.compare ("nextplot"))
+	retval = nextplot;
+      else if (name.compare ("closerequestfcn"))
+	retval = closerequestfcn;
+      else if (name.compare ("currentaxes"))
+	retval = nan_to_empty (currentaxes);
+      else if (name.compare ("colormap"))
+	retval = colormap;
+      else if (name.compare ("visible"))
+	retval = visible;
+      else if (name.compare ("paperorientation"))
+	retval = paperorientation;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    void close (void)
+    {
+      if (! __plot_stream__.is_empty ())
+	{
+	  octave_value_list args;
+	  args(1) = "\nquit;\n";
+	  args(0) = __plot_stream__;
+	  feval ("fputs", args);
+	  args.resize (1);
+	  feval ("fflush", args);
+	  feval ("pclose", args);
+	}
+
+      gh_manager::pop_figure (__myhandle__);
+
+      xset (0, "currentfigure", gh_manager::current_figure ());
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["nextplot"] = "replace";
+      //      m["closerequestfcn"] = make_fcn_handle ("closereq");
+      m["colormap"] = colormap_property ();
+      m["visible"] = "on";
+      m["paperorientation"] = "portrait";
+
+      return m;
+    }
+
+  private:
+    octave_value __plot_stream__;
+    octave_value nextplot;
+    octave_value closerequestfcn;
+    graphics_handle currentaxes;
+    colormap_property colormap;
+    octave_value visible;
+    octave_value paperorientation;
+
+    static std::string go_name;
+  };
+
+  figure_properties properties;
+
+public:
+  figure (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p), default_properties ()
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~figure (void)
+  {
+    properties.delete_children ();
+    properties.close ();
+  }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (root figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+
+    // Now override with our defaults.  If the default_properties
+    // list includes the properties for all defaults (line,
+    // surface, etc.) then we don't have to know the type of OBJ
+    // here, we just call its set function and let it decide which
+    // properties from the list to use.
+    obj.set_from_list (default_properties);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& value)
+  {
+    if (name.compare ("default", 7))
+      // strip "default", pass rest to function that will
+      // parse the remainder and add the element to the
+      // default_properties map.
+      default_properties.set (name.substr (7), value);
+    else
+      properties.set (name, value);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    octave_value retval;
+
+    if (name.compare ("default", 7))
+      retval = get_default (name.substr (7));
+    else
+      retval = properties.get (name);
+
+    return retval;
+  }
+
+  octave_value get_default (const property_name& name) const
+  {
+    octave_value retval = default_properties.lookup (name);
+
+    if (retval.is_undefined ())
+      {
+	graphics_handle parent = get_parent ();
+	graphics_object parent_obj = gh_manager::get_object (parent);
+
+	retval = parent_obj.get_default (name);
+      }
+
+    return retval;
+  }
+
+  octave_value get_defaults (void) const
+  {
+    return default_properties.as_struct ("default");
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& np) { properties.reparent (np); }
+
+  bool valid_object (void) const { return true; }
+
+private:
+  property_list default_properties;
+};
+
+std::string figure::figure_properties::go_name ("figure");
+
+// ---------------------------------------------------------------------
+
+class axes : public base_graphics_object
+{
+public:
+  class axes_properties : public base_properties
+  {
+  public:
+    axes_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	position (Matrix ()),
+	title (octave_NaN),
+	box ("on"),
+	key ("off"),
+	keybox ("off"),
+	keypos (1),
+	dataaspectratio (Matrix (1, 3, 1.0)),
+	dataaspectratiomode ("auto"),
+	xlim (),
+	ylim (),
+	zlim (),
+	xlimmode ("auto"),
+	ylimmode ("auto"),
+	zlimmode ("auto"),
+	xlabel (octave_NaN),
+	ylabel (octave_NaN),
+	zlabel (octave_NaN),
+	xgrid ("off"),
+	ygrid ("off"),
+	zgrid ("off"),
+	xminorgrid ("off"),
+	yminorgrid ("off"),
+	zminorgrid ("off"),
+	xtick (Matrix ()),
+	ytick (Matrix ()),
+	ztick (Matrix ()),
+	xtickmode ("auto"),
+	ytickmode ("auto"),
+	ztickmode ("auto"),
+	xticklabel (""),
+	yticklabel (""),
+	zticklabel (""),
+	xticklabelmode ("auto"),
+	yticklabelmode ("auto"),
+	zticklabelmode ("auto"),
+	xscale ("linear"),
+	yscale ("linear"),
+	zscale ("linear"),
+	xdir ("normal"),
+	ydir ("normal"),
+	zdir ("normal"),
+	view (),
+	nextplot ("replace"),
+	outerposition ()
+    {
+      Matrix tlim (1, 2, 0.0);
+      tlim(1) = 1;
+      xlim = tlim;
+      ylim = tlim;
+      zlim = tlim;
+
+      Matrix tview (1, 2, 0.0);
+      tview(1) = 90;
+      view = tview;
+
+      Matrix touterposition (1, 4, 0.0);
+      touterposition(2) = 1;
+      touterposition(3) = 1;
+      outerposition = touterposition;
+    }
+
+    ~axes_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("parent"))
+	set_parent (val);
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("position"))
+	position = val;
+      else if (name.compare ("title"))
+	{
+	  graphics_handle h = ::reparent (val, "set", "title",
+					  __myhandle__, false);
+	  if (! error_state)
+	    {
+	      if (! xisnan (title))
+		gh_manager::free (title);
+
+	      title = h;
+	    }
+	}
+      else if (name.compare ("box"))
+	box = val;
+      else if (name.compare ("key"))
+	key = val;
+      else if (name.compare ("keybox"))
+	keybox = val;
+      else if (name.compare ("keypos"))
+	keypos = val;
+      else if (name.compare ("dataaspectratio"))
+	{
+	  dataaspectratio = val;
+	  dataaspectratiomode = "manual";
+	}
+      else if (name.compare ("dataaspectratiomode"))
+	dataaspectratiomode = val;
+      else if (name.compare ("xlim"))
+	{
+	  xlim = val;
+	  xlimmode = "manual";
+	}
+      else if (name.compare ("ylim"))
+	{
+	  ylim = val;
+	  ylimmode = "manual";
+	}
+      else if (name.compare ("zlim"))
+	{
+	  zlim = val;
+	  zlimmode = "manual";
+	}
+      else if (name.compare ("xlimmode"))
+	xlimmode = val;
+      else if (name.compare ("ylimmode"))
+	ylimmode = val;
+      else if (name.compare ("zlimmode"))
+	zlimmode = val;
+      else if (name.compare ("xlabel"))
+	{
+	  graphics_handle h = ::reparent (val, "set", "xlabel",
+					  __myhandle__, false);
+	  if (! error_state)
+	    {
+	      if (! xisnan (xlabel))
+		gh_manager::free (xlabel);
+
+	      xlabel = h;
+	    }
+	}
+      else if (name.compare ("ylabel"))
+	{
+	  graphics_handle h = ::reparent (val, "set", "ylabel",
+					  __myhandle__, false);
+	  if (! error_state)
+	    {
+	      if (! xisnan (ylabel))
+		gh_manager::free (ylabel);
+
+	      ylabel = h;
+	    }
+	}
+      else if (name.compare ("zlabel"))
+	{
+	  graphics_handle h = ::reparent (val, "set", "zlabel",
+					  __myhandle__, false);
+	  if (! error_state)
+	    {
+	      if (! xisnan (zlabel))
+		gh_manager::free (zlabel);
+
+	      zlabel = h;
+	    }
+	}
+      else if (name.compare ("xgrid"))
+	xgrid = val;
+      else if (name.compare ("ygrid"))
+	ygrid = val;
+      else if (name.compare ("zgrid"))
+	zgrid = val;
+      else if (name.compare ("xminorgrid"))
+	xminorgrid = val;
+      else if (name.compare ("yminorgrid"))
+	yminorgrid = val;
+      else if (name.compare ("zminorgrid"))
+	zminorgrid = val;
+      else if (name.compare ("xtick"))
+	{
+	  xtick = val;
+	  xtickmode = "manual";
+	}
+      else if (name.compare ("ytick"))
+	{
+	  ytick = val;
+	  ytickmode = "manual";
+	}
+      else if (name.compare ("ztick"))
+	{
+	  ztick = val;
+	  ztickmode = "manual";
+	}
+      else if (name.compare ("xtickmode"))
+	xtickmode = val;
+      else if (name.compare ("ytickmode"))
+	ytickmode = val;
+      else if (name.compare ("ztickmode"))
+	ztickmode = val;
+      else if (name.compare ("xticklabel"))
+	{
+	  xticklabel = val;
+	  xticklabelmode = "manual";
+	}
+      else if (name.compare ("yticklabel"))
+	{
+	  yticklabel = val;
+	  yticklabelmode = "manual";
+	}
+      else if (name.compare ("zticklabel"))
+	{
+	  zticklabel = val;
+	  zticklabelmode = "manual";
+	}
+      else if (name.compare ("xticklabelmode"))
+	xticklabelmode = val;
+      else if (name.compare ("yticklabelmode"))
+	yticklabelmode = val;
+      else if (name.compare ("zticklabelmode"))
+	zticklabelmode = val;
+      else if (name.compare ("xscale"))
+	xscale = val;
+      else if (name.compare ("yscale"))
+	yscale = val;
+      else if (name.compare ("zscale"))
+	zscale = val;
+      else if (name.compare ("xdir"))
+	xdir = val;
+      else if (name.compare ("ydir"))
+	ydir = val;
+      else if (name.compare ("zdir"))
+	zdir = val;
+      else if (name.compare ("view"))
+	view = val;
+      else if (name.compare ("nextplot"))
+	nextplot = val;
+      else if (name.compare ("outerposition"))
+	outerposition = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    void set_defaults (base_graphics_object& obj, const std::string& mode)
+    {
+      position = Matrix ();
+      title = octave_NaN;
+      box = "on";
+      key = "off";
+      keybox = "off";
+      keypos = 1;
+      dataaspectratio = Matrix (1, 3, 1.0);
+      dataaspectratiomode = "auto";
+
+      Matrix tlim (1, 2, 0.0);
+      tlim(1) = 1;
+      xlim = tlim;
+      ylim = tlim;
+      zlim = tlim;
+
+      xlimmode = "auto";
+      ylimmode = "auto";
+      zlimmode = "auto";
+      xlabel = octave_NaN;
+      ylabel = octave_NaN;
+      zlabel = octave_NaN;
+      xgrid = "off";
+      ygrid = "off";
+      zgrid = "off";
+      xminorgrid = "off";
+      yminorgrid = "off";
+      zminorgrid = "off";
+      xtick = Matrix ();
+      ytick = Matrix ();
+      ztick = Matrix ();
+      xtickmode = "auto";
+      ytickmode = "auto";
+      ztickmode = "auto";
+      xticklabel = "";
+      yticklabel = "";
+      zticklabel = "";
+      xticklabelmode = "auto";
+      yticklabelmode = "auto";
+      zticklabelmode = "auto";
+      xscale = "linear";
+      yscale = "linear";
+      zscale = "linear";
+      xdir = "normal";
+      ydir = "normal";
+      zdir = "normal";
+
+      Matrix tview (1, 2, 0.0);
+      tview(1) = 90;
+      view = tview;
+
+      nextplot = "replace";
+
+      // FIXME -- this is not quite right; we should preserve
+      // "position" and "units".
+
+      if (mode == "replace")
+	{
+	  Matrix touterposition (1, 4, 0.0);
+	  touterposition(2) = 1;
+	  touterposition(3) = 1;
+	  outerposition = touterposition;
+	}
+
+      delete_children ();
+
+      children = Matrix ();
+
+      override_defaults (obj);
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+      
+      if (xisnan (title))
+	title = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+      if (xisnan (xlabel))
+	xlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+      if (xisnan (ylabel))
+	ylabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+      if (xisnan (zlabel))
+	zlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("position", position);
+      m.assign ("title", title);
+      m.assign ("box", box);
+      m.assign ("key", key);
+      m.assign ("keybox", keybox);
+      m.assign ("keypos", keypos);
+      m.assign ("dataaspectratio", dataaspectratio);
+      m.assign ("dataaspectratiomode", dataaspectratiomode);
+      m.assign ("xlim", xlim);
+      m.assign ("ylim", ylim);
+      m.assign ("zlim", zlim);
+      m.assign ("xlimmode", xlimmode);
+      m.assign ("ylimmode", ylimmode);
+      m.assign ("zlimmode", zlimmode);
+      m.assign ("xlabel", xlabel);
+      m.assign ("ylabel", ylabel);
+      m.assign ("zlabel", zlabel);
+      m.assign ("xgrid", xgrid);
+      m.assign ("ygrid", ygrid);
+      m.assign ("zgrid", zgrid);
+      m.assign ("xminorgrid", xminorgrid);
+      m.assign ("yminorgrid", yminorgrid);
+      m.assign ("zminorgrid", zminorgrid);
+      m.assign ("xtick", xtick);
+      m.assign ("ytick", ytick);
+      m.assign ("ztick", ztick);
+      m.assign ("xtickmode", xtickmode);
+      m.assign ("ytickmode", ytickmode);
+      m.assign ("ztickmode", ztickmode);
+      m.assign ("xticklabel", xticklabel);
+      m.assign ("yticklabel", yticklabel);
+      m.assign ("zticklabel", zticklabel);
+      m.assign ("xticklabelmode", xticklabelmode);
+      m.assign ("yticklabelmode", yticklabelmode);
+      m.assign ("zticklabelmode", zticklabelmode);
+      m.assign ("xscale", xscale);
+      m.assign ("yscale", yscale);
+      m.assign ("zscale", zscale);
+      m.assign ("xdir", xdir);
+      m.assign ("ydir", ydir);
+      m.assign ("zdir", zdir);
+      m.assign ("view", view);
+      m.assign ("nextplot", nextplot);
+      m.assign ("outerposition", outerposition);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("position"))
+	retval = position;
+      else if (name.compare ("title"))
+	{
+	  if (xisnan (title))
+	    title = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+	  retval = title;
+	}
+      else if (name.compare ("box"))
+	retval = box;
+      else if (name.compare ("key"))
+	retval = key;
+      else if (name.compare ("keybox"))
+	retval = keybox;
+      else if (name.compare ("keypos"))
+	retval = keypos;
+      else if (name.compare ("dataaspectratio"))
+	retval = dataaspectratio;
+      else if (name.compare ("dataaspectratiomode"))
+	retval = dataaspectratiomode;
+      else if (name.compare ("xlim"))
+	retval = xlim;
+      else if (name.compare ("ylim"))
+	retval = ylim;
+      else if (name.compare ("zlim"))
+	retval = zlim;
+      else if (name.compare ("xlimmode"))
+	retval = xlimmode;
+      else if (name.compare ("ylimmode"))
+	retval = ylimmode;
+      else if (name.compare ("zlimmode"))
+	retval = zlimmode;
+      else if (name.compare ("xlabel"))
+	{
+	  if (xisnan (xlabel))
+	    xlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+	  retval = xlabel;
+	}
+      else if (name.compare ("ylabel"))
+	{
+	  if (xisnan (ylabel))
+	    ylabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+	  retval = ylabel;
+	}
+      else if (name.compare ("zlabel"))
+	{
+	  if (xisnan (zlabel))
+	    zlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+
+	  retval = zlabel;
+	}
+      else if (name.compare ("xgrid"))
+	retval = xgrid;
+      else if (name.compare ("ygrid"))
+	retval = ygrid;
+      else if (name.compare ("zgrid"))
+	retval = zgrid;
+      else if (name.compare ("xminorgrid"))
+	retval = xminorgrid;
+      else if (name.compare ("yminorgrid"))
+	retval = yminorgrid;
+      else if (name.compare ("zminorgrid"))
+	retval = zminorgrid;
+      else if (name.compare ("xtick"))
+	retval = xtick;
+      else if (name.compare ("ytick"))
+	retval = ytick;
+      else if (name.compare ("ztick"))
+	retval = ztick;
+      else if (name.compare ("xtickmode"))
+	retval = xtickmode;
+      else if (name.compare ("ytickmode"))
+	retval = ytickmode;
+      else if (name.compare ("ztickmode"))
+	retval = ztickmode;
+      else if (name.compare ("xticklabel"))
+	retval = xticklabel;
+      else if (name.compare ("yticklabel"))
+	retval = yticklabel;
+      else if (name.compare ("zticklabel"))
+	retval = zticklabel;
+      else if (name.compare ("xticklabelmode"))
+	retval = xticklabelmode;
+      else if (name.compare ("yticklabelmode"))
+	retval = yticklabelmode;
+      else if (name.compare ("zticklabelmode"))
+	retval = zticklabelmode;
+      else if (name.compare ("xscale"))
+	retval = xscale;
+      else if (name.compare ("yscale"))
+	retval = yscale;
+      else if (name.compare ("zscale"))
+	retval = zscale;
+      else if (name.compare ("xdir"))
+	retval = xdir;
+      else if (name.compare ("ydir"))
+	retval = ydir;
+      else if (name.compare ("zdir"))
+	retval = zdir;
+      else if (name.compare ("view"))
+	retval = view;
+      else if (name.compare ("nextplot"))
+	retval = nextplot;
+      else if (name.compare ("outerposition"))
+	retval = outerposition;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    void remove_child (const graphics_handle& h)
+    {
+      if (! xisnan (title) && h == title)
+	title = gh_manager::make_graphics_handle ("text", __myhandle__);
+      else if (! xisnan (xlabel) && h == xlabel)
+	xlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+      else if (! xisnan (ylabel) && h == ylabel)
+	ylabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+      else if (! xisnan (zlabel) && h == zlabel)
+	zlabel = gh_manager::make_graphics_handle ("text", __myhandle__);
+      else
+	base_properties::remove_child (h);
+    }
+
+    void delete_children (void)
+    {
+      base_properties::delete_children ();
+
+      if (! xisnan (title))
+	gh_manager::free (title);
+
+      if (! xisnan (xlabel))
+	gh_manager::free (xlabel);
+
+      if (! xisnan (ylabel))
+	gh_manager::free (ylabel);
+
+      if (! xisnan (zlabel))
+	gh_manager::free (zlabel);
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["position"] = Matrix ();
+      m["title"] = octave_NaN;
+      m["box"] = "on";
+      m["key"] = "off";
+      m["keybox"] = "off";
+      m["keypos"] = 1;
+      m["dataaspectratio"] = Matrix (1, 3, 1.0);
+      m["dataaspectratiomode"] = "auto";
+
+      Matrix tlim (1, 2, 0.0);
+      tlim(1) = 1;
+
+      m["xlim"] = tlim;
+      m["ylim"] = tlim;
+      m["zlim"] = tlim;
+
+      m["xlimmode"] = "auto";
+      m["ylimmode"] = "auto";
+      m["zlimmode"] = "auto";
+      m["xlabel"] = octave_NaN;
+      m["ylabel"] = octave_NaN;
+      m["zlabel"] = octave_NaN;
+      m["xgrid"] = "off";
+      m["ygrid"] = "off";
+      m["zgrid"] = "off";
+      m["xminorgrid"] = "off";
+      m["yminorgrid"] = "off";
+      m["zminorgrid"] = "off";
+      m["xtick"] = Matrix ();
+      m["ytick"] = Matrix ();
+      m["ztick"] = Matrix ();
+      m["xtickmode"] = "auto";
+      m["ytickmode"] = "auto";
+      m["ztickmode"] = "auto";
+      m["xticklabel"] = "";
+      m["yticklabel"] = "";
+      m["zticklabel"] = "";
+      m["xticklabelmode"] = "auto";
+      m["yticklabelmode"] = "auto";
+      m["zticklabelmode"] = "auto";
+      m["xscale"] = "linear";
+      m["yscale"] = "linear";
+      m["zscale"] = "linear";
+      m["xdir"] = "normal";
+      m["ydir"] = "normal";
+      m["zdir"] = "normal";
+
+      Matrix tview (1, 2, 0.0);
+      tview(1) = 90;
+
+      m["view"] = tview;
+
+      m["nextplot"] = "replace";
+
+      Matrix touterposition (1, 4, 0.0);
+      touterposition(2) = 1;
+      touterposition(3) = 1;
+
+      m["outerposition"] = touterposition;
+
+      return m;
+    }
+
+  private:
+    octave_value position;
+    mutable graphics_handle title;
+    octave_value box;
+    octave_value key;
+    octave_value keybox;
+    octave_value keypos;
+    octave_value dataaspectratio;
+    octave_value dataaspectratiomode;
+    octave_value xlim;
+    octave_value ylim;
+    octave_value zlim;
+    octave_value xlimmode;
+    octave_value ylimmode;
+    octave_value zlimmode;
+    mutable graphics_handle xlabel;
+    mutable graphics_handle ylabel;
+    mutable graphics_handle zlabel;
+    octave_value xgrid;
+    octave_value ygrid;
+    octave_value zgrid;
+    octave_value xminorgrid;
+    octave_value yminorgrid;
+    octave_value zminorgrid;
+    octave_value xtick;
+    octave_value ytick;
+    octave_value ztick;
+    octave_value xtickmode;
+    octave_value ytickmode;
+    octave_value ztickmode;
+    octave_value xticklabel;
+    octave_value yticklabel;
+    octave_value zticklabel;
+    octave_value xticklabelmode;
+    octave_value yticklabelmode;
+    octave_value zticklabelmode;
+    octave_value xscale;
+    octave_value yscale;
+    octave_value zscale;
+    octave_value xdir;
+    octave_value ydir;
+    octave_value zdir;
+    octave_value view;
+    octave_value nextplot;
+    octave_value outerposition;
+
+    static std::string go_name;
+  };
+
+  axes_properties properties;
+
+public:
+  axes (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p), default_properties ()
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~axes (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+
+    // Now override with our defaults.  If the default_properties
+    // list includes the properties for all defaults (line,
+    // surface, etc.) then we don't have to know the type of OBJ
+    // here, we just call its set function and let it decide which
+    // properties from the list to use.
+    obj.set_from_list (default_properties);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& value)
+  {
+    if (name.compare ("default", 7))
+      // strip "default", pass rest to function that will
+      // parse the remainder and add the element to the
+      // default_properties map.
+      default_properties.set (name.substr (7), value);
+    else
+      properties.set (name, value);
+  }
+
+  void set_defaults (const std::string& mode)
+  {
+    properties.set_defaults (*this, mode);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    octave_value retval;
+
+    // FIXME -- finish this.
+    if (name.compare ("default", 7))
+      retval = get_default (name.substr (7));
+    else
+      retval = properties.get (name);
+
+    return retval;
+  }
+
+  octave_value get_default (const property_name& name) const
+  {
+    octave_value retval = default_properties.lookup (name);
+
+    if (retval.is_undefined ())
+      {
+	graphics_handle parent = get_parent ();
+	graphics_object parent_obj = gh_manager::get_object (parent);
+
+	retval = parent_obj.get_default (name);
+      }
+
+    return retval;
+  }
+
+  octave_value get_defaults (void) const
+  {
+    return default_properties.as_struct ("default");
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& np) { properties.reparent (np); }
+
+  bool valid_object (void) const { return true; }
+
+private:
+  property_list default_properties;
+};
+
+std::string axes::axes_properties::go_name ("axes");
+
+// ---------------------------------------------------------------------
+
+static Matrix
+default_data (void)
+{
+  Matrix retval (1, 2);
+
+  retval(0) = 0;
+  retval(1) = 1;
+
+  return retval;
+}
+
+class line : public base_graphics_object
+{
+public:
+  class line_properties : public base_properties
+  {
+  public:
+    line_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	xdata (default_data ()),
+	ydata (default_data ()),
+	zdata (Matrix ()),
+	ldata (Matrix ()),
+	udata (Matrix ()),
+	xldata (Matrix ()),
+	xudata (Matrix ()),
+	color (),
+	linestyle ("-"),
+	linewidth (0.5),
+	marker ("none"),
+	markersize (1),
+	keylabel ("") { }
+
+    ~line_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("parent"))
+	set_parent (val);
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("xdata"))
+	xdata = val;
+      else if (name.compare ("ydata"))
+	ydata = val;
+      else if (name.compare ("zdata"))
+	zdata = val;
+      else if (name.compare ("ldata"))
+	ldata = val;
+      else if (name.compare ("udata"))
+	udata = val;
+      else if (name.compare ("xldata"))
+	xldata = val;
+      else if (name.compare ("xudata"))
+	xudata = val;
+      else if (name.compare ("color"))
+	color = color_property (val);
+      else if (name.compare ("linestyle"))
+	linestyle = val;
+      else if (name.compare ("linewidth"))
+	linewidth = val;
+      else if (name.compare ("marker"))
+	marker = val;
+      else if (name.compare ("markersize"))
+	markersize = val;
+      else if (name.compare ("keylabel"))
+	keylabel = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("xdata", xdata);
+      m.assign ("ydata", ydata);
+      m.assign ("zdata", zdata);
+      m.assign ("ldata", ldata);
+      m.assign ("udata", udata);
+      m.assign ("xldata", xldata);
+      m.assign ("xudata", xudata);
+      m.assign ("color", color);
+      m.assign ("linestyle", linestyle);
+      m.assign ("linewidth", linewidth);
+      m.assign ("marker", marker);
+      m.assign ("markersize", markersize);
+      m.assign ("keylabel", keylabel);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("xdata"))
+	retval = xdata;
+      else if (name.compare ("ydata"))
+	retval = ydata;
+      else if (name.compare ("zdata"))
+	retval = zdata;
+      else if (name.compare ("ldata"))
+	retval = ldata;
+      else if (name.compare ("udata"))
+	retval = udata;
+      else if (name.compare ("xldata"))
+	retval = xldata;
+      else if (name.compare ("xudata"))
+	retval = xudata;
+      else if (name.compare ("color"))
+	retval = color;
+      else if (name.compare ("linestyle"))
+	retval = linestyle;
+      else if (name.compare ("linewidth"))
+	retval = linewidth;
+      else if (name.compare ("marker"))
+	retval = marker;
+      else if (name.compare ("markersize"))
+	retval = markersize;
+      else if (name.compare ("keylabel"))
+	retval = keylabel;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["xdata"] = default_data ();
+      m["ydata"] = default_data ();
+      m["zdata"] = Matrix ();
+      m["ldata"] = Matrix ();
+      m["udata"] = Matrix ();
+      m["xldata"] = Matrix ();
+      m["xudata"] = Matrix ();
+      m["color"] = color_property ();
+      m["linestyle"] = "-";
+      m["linewidth"] = 0.5;
+      m["marker"] = "none";
+      m["markersize"] = 1;
+      m["keylabel"] = "";
+
+      return m;
+    }
+
+  private:
+    octave_value xdata;
+    octave_value ydata;
+    octave_value zdata;
+    octave_value ldata;
+    octave_value udata;
+    octave_value xldata;
+    octave_value xudata;
+    color_property color;
+    octave_value linestyle;
+    octave_value linewidth;
+    octave_value marker;
+    octave_value markersize;
+    octave_value keylabel;
+
+    static std::string go_name;
+  };
+
+  line_properties properties;
+
+public:
+  line (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p)
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~line (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    properties.set (name, val);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    return properties.get (name);
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& h) { properties.reparent (h); }
+
+  bool valid_object (void) const { return true; }
+};
+
+std::string line::line_properties::go_name ("line");
+
+// ---------------------------------------------------------------------
+
+class text : public base_graphics_object
+{
+public:
+  class text_properties : public base_properties
+  {
+  public:
+    text_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	string (""),
+	units ("data"),
+	position (Matrix (1, 3, 0.0)),
+	horizontalalignment ("left")
+    { }
+
+    ~text_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("parent"))
+	set_parent (val);
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("string"))
+	string = val;
+      else if (name.compare ("units"))
+	units = val;
+      else if (name.compare ("position"))
+	position = val;
+      else if (name.compare ("horizontalalignment"))
+	horizontalalignment = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("string", string);
+      m.assign ("units", units);
+      m.assign ("position", position);
+      m.assign ("horizontalalignment", horizontalalignment);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("string"))
+	retval = string;
+      else if (name.compare ("units"))
+	retval = units;
+      else if (name.compare ("position"))
+	retval = position;
+      else if (name.compare ("horizontalalignment"))
+	retval = horizontalalignment;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["string"] = "";
+      m["units"] = "data";
+      m["position"] = Matrix (1, 3, 0.0);
+      m["horizontalalignment"] = "left";
+
+      return m;
+    }
+
+  private:
+    octave_value string;
+    octave_value units;
+    octave_value position;
+    octave_value horizontalalignment;
+
+    static std::string go_name;
+  };
+
+  text_properties properties;
+
+public:
+  text (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p)
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~text (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    properties.set (name, val);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    return properties.get (name);
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& h) { properties.reparent (h); }
+
+  bool valid_object (void) const { return true; }
+};
+
+std::string text::text_properties::go_name ("text");
+
+// ---------------------------------------------------------------------
+
+class image : public base_graphics_object
+{
+public:
+  class image_properties : public base_properties
+  {
+  public:
+    image_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	cdata (Matrix ()),
+	xdata (Matrix ()),
+	ydata (Matrix ())
+    { }
+
+    ~image_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("parent"))
+	set_parent (val);
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("cdata"))
+	cdata = val;
+      else if (name.compare ("xdata"))
+	xdata = val;
+      else if (name.compare ("ydata"))
+	ydata = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("cdata", cdata);
+      m.assign ("xdata", xdata);
+      m.assign ("ydata", ydata);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("cdata"))
+	retval = cdata;
+      else if (name.compare ("xdata"))
+	retval = xdata;
+      else if (name.compare ("ydata"))
+	retval = ydata;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["cdata"] = Matrix ();
+      m["xdata"] = Matrix ();
+      m["ydata"] = Matrix ();
+
+      return m;
+    }
+
+  private:
+    octave_value cdata;
+    octave_value xdata;
+    octave_value ydata;
+
+    static std::string go_name;
+  };
+
+  image_properties properties;
+
+public:
+  image (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p)
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~image (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    properties.set (name, val);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    return properties.get (name);
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& h) { properties.reparent (h); }
+
+  bool valid_object (void) const { return true; }
+};
+
+std::string image::image_properties::go_name ("image");
+
+// ---------------------------------------------------------------------
+
+class surface : public base_graphics_object
+{
+public:
+  class surface_properties : public base_properties
+  {
+  public:
+    surface_properties (const graphics_handle& mh, const graphics_handle& p)
+      : base_properties (go_name, mh, p),
+	xdata (Matrix ()),
+	ydata (Matrix ()),
+	zdata (Matrix ()),
+	keylabel ("")
+    { }
+
+    ~surface_properties (void) { }
+
+    void set (const property_name& name, const octave_value& val)
+    {
+      if (name.compare ("parent"))
+	set_parent (val);
+      else if (name.compare ("children"))
+	children = maybe_set_children (children, val);
+      else if (name.compare ("xdata"))
+	xdata = val;
+      else if (name.compare ("ydata"))
+	ydata = val;
+      else if (name.compare ("zdata"))
+	zdata = val;
+      else if (name.compare ("keylabel"))
+	keylabel = val;
+      else
+	warning ("set: invalid property `%s'", name.c_str ());
+    }
+
+    octave_value get (void) const
+    {
+      Octave_map m;
+
+      m.assign ("type", type);
+      m.assign ("parent", parent);
+      m.assign ("children", children);
+      m.assign ("xdata", xdata);
+      m.assign ("ydata", ydata);
+      m.assign ("zdata", zdata);
+      m.assign ("keylabel", keylabel);
+
+      return m;
+    }
+
+    octave_value get (const property_name& name) const
+    {
+      octave_value retval;
+
+      if (name.compare ("type"))
+	retval = type;
+      else if (name.compare ("parent"))
+	retval = parent;
+      else if (name.compare ("children"))
+	retval = children;
+      else if (name.compare ("xdata"))
+	retval = xdata;
+      else if (name.compare ("ydata"))
+	retval = ydata;
+      else if (name.compare ("zdata"))
+	retval = zdata;
+      else if (name.compare ("keylabel"))
+	retval = keylabel;
+      else
+	warning ("get: invalid property `%s'", name.c_str ());
+
+      return retval;
+    }
+
+    std::string graphics_object_name (void) const { return go_name; }
+
+    static property_list::pval_map_type factory_defaults (void)
+    {
+      property_list::pval_map_type m;
+
+      m["xdata"] = Matrix ();
+      m["ydata"] = Matrix ();
+      m["zdata"] = Matrix ();
+      m["keylabel"] = "";
+
+      return m;
+    }
+
+  private:
+    octave_value xdata;
+    octave_value ydata;
+    octave_value zdata;
+    octave_value keylabel;
+
+    static std::string go_name;
+  };
+
+  surface_properties properties;
+
+public:
+  surface (const graphics_handle& mh, const graphics_handle& p)
+    : base_graphics_object (), properties (mh, p)
+  {
+    properties.override_defaults (*this);
+  }
+
+  ~surface (void) { properties.delete_children (); }
+
+  std::string type (void) const { return properties.graphics_object_name (); }
+
+  void override_defaults (base_graphics_object& obj)
+  {
+    // Allow parent (figure) to override first (properties knows how
+    // to find the parent object).
+    properties.override_defaults (obj);
+  }
+
+  void set_from_list (property_list& plist)
+  {
+    properties.set_from_list (*this, plist);
+  }
+
+  void set (const property_name& name, const octave_value& val)
+  {
+    properties.set (name, val);
+  }
+
+  octave_value get (void) const
+  {
+    return properties.get ();
+  }
+
+  octave_value get (const property_name& name) const
+  {
+    return properties.get (name);
+  }
+
+  graphics_handle get_parent (void) const { return properties.get_parent (); }
+
+  void remove_child (const graphics_handle& h) { properties.remove_child (h); }
+
+  void adopt (const graphics_handle& h) { properties.adopt (h); }
+
+  void reparent (const graphics_handle& h) { properties.reparent (h); }
+
+  bool valid_object (void) const { return true; }
+};
+
+std::string surface::surface_properties::go_name ("surface");
+
+// ---------------------------------------------------------------------
+
+octave_value
+base_graphics_object::get_default (const property_name& name) const
+{
+  graphics_handle parent = get_parent ();
+  graphics_object parent_obj = gh_manager::get_object (parent);
+
+  return parent_obj.get_default (type () + name);
+}
+
+octave_value
+base_graphics_object::get_factory_default (const property_name& name) const
+{
+  graphics_object parent_obj = gh_manager::get_object (0);
+
+  return parent_obj.get_factory_default (type () + name);
+}
+
+gh_manager::gh_manager (void)
+  : handle_map (), handle_free_list (), next_handle (-1)
+{
+  handle_map[0] = graphics_object (new root_figure ());
+}
+
+graphics_handle
+gh_manager::do_make_graphics_handle (const std::string& go_name,
+				     const graphics_handle& p)
+{
+  graphics_handle h = get_handle (go_name);
+
+  base_graphics_object *go = 0;
+
+  if (go_name == "figure")
+    go = new figure (h, p);
+  else if (go_name == "axes")
+    go = new axes (h, p);
+  else if (go_name == "line")
+    go = new line (h, p);
+  else if (go_name == "text")
+    go = new text (h, p);
+  else if (go_name == "image")
+    go = new image (h, p);
+  else if (go_name == "surface")
+    go = new surface (h, p);
+
+  if (go)
+    handle_map[h] = graphics_object (go);
+  else
+    error ("gh_manager::do_make_graphics_handle: invalid object type `%s'",
+	   go_name.c_str ());
+
+  return h;
+}
+
+graphics_handle
+gh_manager::do_make_figure_handle (double val)
+{
+  graphics_handle h = val;
+
+  handle_map[h] = graphics_object (new figure (h, 0));
+
+  return h;
+}
+
+void
+gh_manager::do_push_figure (const graphics_handle& h)
+{
+  do_pop_figure (h);
+
+  figure_list.push_front (h);
+}
+
+void
+gh_manager::do_pop_figure (const graphics_handle& h)
+{
+  for (figure_list_iterator p = figure_list.begin ();
+       p != figure_list.end ();
+       p++)
+    {
+      if (*p == h)
+	{
+	  figure_list.erase (p);
+	  break;
+	}
+    }
+}
+
+property_list::plist_map_type
+root_figure::init_factory_properties (void)
+{
+  property_list::plist_map_type plist_map;
+
+  plist_map["figure"] = figure::figure_properties::factory_defaults ();
+  plist_map["axes"] = axes::axes_properties::factory_defaults ();
+  plist_map["line"] = line::line_properties::factory_defaults ();
+  plist_map["text"] = text::text_properties::factory_defaults ();
+  plist_map["image"] = image::image_properties::factory_defaults ();
+  plist_map["surface"] = surface::surface_properties::factory_defaults ();
+
+  return plist_map;
+}
+
+// ---------------------------------------------------------------------
+
+DEFUN (ishandle, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Function File} {} ishandle (@var{h})\n\
+Return true if @var{h} is a graphics handle and false otherwise.\n\
+@end deftypefn")
+{
+  octave_value retval;
+
+  if (args.length () == 1)
+    retval = is_handle (args(0));
+  else
+    print_usage ();
+
+  return retval;
+}
+
+DEFUN (set, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Function File} {} set (@var{h}, @var{p}, @var{v}, @dots{})\n\
+Set the named property @var{p} to the value @var{v} in the graphics\n\
+handle @var{h}.\n\
+@end deftypefn")
+{
+  octave_value retval;
+
+  int nargin = args.length ();
+
+  if (nargin > 0)
+    {
+      double handle = args(0).double_value ();
+
+      if (! error_state)
+	{
+	  graphics_object obj = gh_manager::get_object (handle);
+
+	  if (obj)
+	    {
+	      obj.set (args.splice (0, 1));
+
+	      feval ("__request_drawnow__");
+	    }
+	  else
+	    error ("set: invalid handle (= %g)", handle);
+	}
+      else
+	error ("set: expecting graphics handle as first argument");
+    }
+  else
+    print_usage ();
+
+  return retval;
+}
+
+DEFUN (get, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Function File} {} get (@var{h}, @var{p})\n\
+Return the named property @var{p} from the graphics handle @var{h}.\n\
+If @var{p} is omitted, return the complete property list for @var{h}.\n\
+@end deftypefn")
+{
+  octave_value retval;
+
+  int nargin = args.length ();
+
+  if (nargin == 1 || nargin == 2)
+    {
+      double handle = args(0).double_value ();
+
+      if (! error_state)
+	{
+	  graphics_object obj = gh_manager::get_object (handle);
+
+	  if (obj)
+	    {
+	      if (nargin == 1)
+		retval = obj.get ();
+	      else
+		{
+		  property_name property = args(1).string_value ();
+
+		  if (! error_state)
+		    retval = obj.get (property);
+		  else
+		    error ("get: expecting property name as second argument");
+		}
+	    }
+	  else
+	    error ("get: invalid handle (= %g)", handle);
+	}
+      else
+	error ("get: expecting graphics handle as first argument");
+    }
+  else
+    print_usage ();
+
+  return retval;
+}
+
+static octave_value
+make_graphics_object (const std::string& go_name,
+		      const octave_value_list& args)
+{
+  octave_value retval;
+
+  double val = args(0).double_value ();
+
+  if (! error_state)
+    {
+      graphics_handle parent = gh_manager::lookup (val);
+
+      if (! xisnan (parent))
+	{
+	  graphics_handle h
+	    = gh_manager::make_graphics_handle (go_name, parent);
+
+	  if (! error_state)
+	    {
+	      adopt (parent, h);
+
+	      xset (h, args.splice (0, 1));
+
+	      retval = h;
+	    }
+	  else
+	    error ("__go%s__: unable to create graphics handle",
+		   go_name.c_str ());
+	}
+      else
+	error ("__go_%s__: invalid parent", go_name.c_str ());
+    }
+  else
+    error ("__go_%s__: invalid parent", go_name.c_str ());
+
+  return retval;
+}
+
+DEFUN (__go_figure__, args, ,
+   "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_figure__ (@var{fignum})\n\
+Create a figure graphics object.\n\
+@end deftypefn")
+{
+  octave_value retval;
+
+  if (args.length () > 0)
+    {
+      double val = args(0).double_value ();
+
+      if (! error_state)
+	{
+	  if (is_figure (val))
+	    {
+	      graphics_handle h = gh_manager::lookup (val);
+
+	      xset (h, args.splice (0, 1));
+
+	      retval = h;
+	    }
+	  else
+	    {
+	      graphics_handle h = octave_NaN;
+
+	      if (xisnan (val))
+		h = gh_manager::make_graphics_handle ("figure", 0);
+	      else if (val > 0 && D_NINT (val) == val)
+		h = gh_manager::make_figure_handle (val);
+	      else
+		error ("__go_figure__: invalid figure number");
+
+	      if (! (error_state || xisnan (h)))
+		{
+		  adopt (0, h);
+
+		  xset (h, args.splice (0, 1));
+
+		  retval = h;
+		}
+	      else
+		error ("__go_figure__: failed to create figure handle");
+	    }
+	}
+      else
+	error ("__go_figure__: expecting figure number to be double value");
+    }
+  else
+    print_usage ();
+
+  return retval;
+}
+
+#define GO_BODY(TYPE) \
+  octave_value retval; \
+ \
+  if (args.length () > 0) \
+    retval = make_graphics_object (#TYPE, args); \
+  else \
+    print_usage (); \
+ \
+  return retval
+
+DEFUN (__go_axes__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_axes__ (@var{parent})\n\
+Create an axes graphics object.\n\
+@end deftypefn")
+{
+  GO_BODY (axes);
+}
+
+DEFUN (__go_line__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_line__ (@var{parent})\n\
+Create a line graphics object.\n\
+@end deftypefn")
+{
+  GO_BODY (line);
+}
+
+DEFUN (__go_text__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_text__ (@var{parent})\n\
+Create a text graphics object.\n\
+@end deftypefn")
+{
+  GO_BODY (text);
+}
+
+DEFUN (__go_image__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_image__ (@var{parent})\n\
+Create an image graphics object.\n\
+@end deftypefn")
+{
+  GO_BODY (image);
+}
+
+DEFUN (__go_surface__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_surface__ (@var{parent})\n\
+Create a surface graphics object.\n\
+@end deftypefn")
+{
+  GO_BODY (surface);
+}
+
+DEFUN (__go_delete__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_delete__ (@var{h})\n\
+@end deftypefn")
+{
+  octave_value_list retval;
+
+  if (args.length () == 1)
+    {
+      graphics_handle h = octave_NaN;
+
+      double val = args(0).double_value ();
+
+      if (! error_state)
+	{
+	  h = gh_manager::lookup (val);
+
+	  if (! xisnan (h))
+	    {
+	      graphics_object obj = gh_manager::get_object (h);
+
+	      graphics_handle parent_h = obj.get_parent ();
+
+	      graphics_object parent_obj = gh_manager::get_object (parent_h);
+
+	      parent_obj.remove_child (h);
+
+	      gh_manager::free (h);
+	    }
+	  else
+	    error ("delete: invalid graphics object (= %g)", val);
+	}
+      else
+	error ("delete: invalid graphics object");
+    }
+  else
+    print_usage ();
+
+  return retval;
+}
+
+DEFUN (__go_axes_init__, args, ,
+  "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_axes_init__ (@var{h}, @var{mode})\n\
+Initialize axes object.\n\
+@end deftypefn")
+{
+  octave_value retval;
+
+  int nargin = args.length ();
+
+  std::string mode = "";
+
+  if (nargin == 2)
+    {
+      mode = args(1).string_value ();
+
+      if (error_state)
+	return retval;
+    }
+
+  if (nargin == 1 || nargin == 2)
+    {
+      graphics_handle h = octave_NaN;
+
+      double val = args(0).double_value ();
+
+      if (! error_state)
+	{
+	  h = gh_manager::lookup (val);
+
+	  if (! xisnan (h))
+	    {
+	      graphics_object obj = gh_manager::get_object (h);
+
+	      obj.set_defaults (mode);
+	    }
+	  else
+	    error ("__go_axes_init__: invalid graphics object (= %g)", val);
+	}
+      else
+	error ("__go_axes_init__: invalid graphics object");
+    }
+  else
+    print_usage ();
+
+  return retval;
+}
+
+DEFUN (__go_handles__, , ,
+   "-*- texinfo -*-\n\
+@deftypefn {Built-in Function} {} __go_handles__ ()\n\
+Return current list of function handles.\n\
+@end deftypefn")
+{
+  return octave_value (gh_manager::list ());
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/