--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libinterp/corefcn/graphics-toolkit.h	Fri Jul 14 16:05:59 2017 -0400
@@ -0,0 +1,226 @@
+/*
+
+Copyright (C) 2007-2017 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 3 of the License, 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, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#if ! defined (octave_graphics_toolkit_h)
+#define octave_graphics_toolkit_h 1
+
+#include "octave-config.h"
+
+#include <map>
+#include <string>
+
+#include "dMatrix.h"
+
+#include "Cell.h"
+#include "error.h"
+#include "graphics-handle.h"
+
+class graphics_toolkit;
+class graphics_object;
+
+class base_graphics_toolkit
+{
+public:
+  friend class graphics_toolkit;
+
+public:
+  base_graphics_toolkit (const std::string& nm)
+    : name (nm), count (0) { }
+
+  virtual ~base_graphics_toolkit (void) = default;
+
+  std::string get_name (void) const { return name; }
+
+  virtual bool is_valid (void) const { return false; }
+
+  virtual void redraw_figure (const graphics_object&) const
+  { gripe_if_tkit_invalid ("redraw_figure"); }
+
+  virtual void print_figure (const graphics_object&, const std::string&,
+                             const std::string&,
+                             const std::string& = "") const
+  { gripe_if_tkit_invalid ("print_figure"); }
+
+  virtual uint8NDArray get_pixels (const graphics_object&) const
+  {
+    gripe_if_tkit_invalid ("get_pixels");
+    return uint8NDArray ();
+  }
+
+  virtual Matrix get_canvas_size (const graphics_handle&) const
+  {
+    gripe_if_tkit_invalid ("get_canvas_size");
+    return Matrix (1, 2, 0.0);
+  }
+
+  virtual double get_screen_resolution (void) const
+  {
+    gripe_if_tkit_invalid ("get_screen_resolution");
+    return 72.0;
+  }
+
+  virtual Matrix get_screen_size (void) const
+  {
+    gripe_if_tkit_invalid ("get_screen_size");
+    return Matrix (1, 2, 0.0);
+  }
+
+  // Callback function executed when the given graphics object
+  // changes.  This allows the graphics toolkit to act on property
+  // changes if needed.
+  virtual void update (const graphics_object&, int)
+  { gripe_if_tkit_invalid ("base_graphics_toolkit::update"); }
+
+  void update (const graphics_handle&, int);
+
+  // Callback function executed when the given graphics object is
+  // created.  This allows the graphics toolkit to do toolkit-specific
+  // initializations for a newly created object.
+  virtual bool initialize (const graphics_object&)
+  {
+    gripe_if_tkit_invalid ("base_graphics_toolkit::initialize");
+    return false;
+  }
+
+  bool initialize (const graphics_handle&);
+
+  // Callback function executed just prior to deleting the given
+  // graphics object.  This allows the graphics toolkit to perform
+  // toolkit-specific cleanup operations before an object is deleted.
+  virtual void finalize (const graphics_object&)
+  { gripe_if_tkit_invalid ("base_graphics_toolkit::finalize"); }
+
+  void finalize (const graphics_handle&);
+
+  // Close the graphics toolkit.
+  virtual void close (void)
+  { gripe_if_tkit_invalid ("base_graphics_toolkit::close"); }
+
+private:
+  std::string name;
+  octave::refcount<int> count;
+
+private:
+  void gripe_if_tkit_invalid (const std::string& fname) const
+  {
+    if (! is_valid ())
+      error ("%s: invalid graphics toolkit", fname.c_str ());
+  }
+};
+
+class graphics_toolkit
+{
+public:
+  graphics_toolkit (void)
+    : rep (new base_graphics_toolkit ("unknown"))
+  {
+    rep->count++;
+  }
+
+  graphics_toolkit (base_graphics_toolkit *b)
+    : rep (b)
+  {
+    rep->count++;
+  }
+
+  graphics_toolkit (const graphics_toolkit& b)
+    : rep (b.rep)
+  {
+    rep->count++;
+  }
+
+  ~graphics_toolkit (void)
+  {
+    if (--rep->count == 0)
+      delete rep;
+  }
+
+  graphics_toolkit& operator = (const graphics_toolkit& b)
+  {
+    if (rep != b.rep)
+      {
+        if (--rep->count == 0)
+          delete rep;
+
+        rep = b.rep;
+        rep->count++;
+      }
+
+    return *this;
+  }
+
+  operator bool (void) const { return rep->is_valid (); }
+
+  std::string get_name (void) const { return rep->get_name (); }
+
+  void redraw_figure (const graphics_object& go) const
+  { rep->redraw_figure (go); }
+
+  void print_figure (const graphics_object& go, const std::string& term,
+                     const std::string& file,
+                     const std::string& debug_file = "") const
+  { rep->print_figure (go, term, file, debug_file); }
+
+  uint8NDArray get_pixels (const graphics_object& go) const
+  { return rep->get_pixels (go); }
+
+  Matrix get_canvas_size (const graphics_handle& fh) const
+  { return rep->get_canvas_size (fh); }
+
+  double get_screen_resolution (void) const
+  { return rep->get_screen_resolution (); }
+
+  Matrix get_screen_size (void) const
+  { return rep->get_screen_size (); }
+
+  // Notifies graphics toolkit that object't property has changed.
+  void update (const graphics_object& go, int id)
+  { rep->update (go, id); }
+
+  void update (const graphics_handle& h, int id)
+  { rep->update (h, id); }
+
+  // Notifies graphics toolkit that new object was created.
+  bool initialize (const graphics_object& go)
+  { return rep->initialize (go); }
+
+  bool initialize (const graphics_handle& h)
+  { return rep->initialize (h); }
+
+  // Notifies graphics toolkit that object was destroyed.
+  // This is called only for explicitly deleted object.
+  // Children are deleted implicitly and graphics toolkit isn't notified.
+  void finalize (const graphics_object& go)
+  { rep->finalize (go); }
+
+  void finalize (const graphics_handle& h)
+  { rep->finalize (h); }
+
+  // Close the graphics toolkit.
+  void close (void) { rep->close (); }
+
+private:
+
+  base_graphics_toolkit *rep;
+};
+
+#endif