--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libinterp/corefcn/cdisplay.c	Thu Jul 17 11:19:21 2014 -0400
@@ -0,0 +1,164 @@
+/*
+
+Copyright (C) 2009-2014 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/>.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#if defined (OCTAVE_USE_WINDOWS_API)
+#include <windows.h>
+#elif defined (HAVE_FRAMEWORK_CARBON)
+#include <Carbon/Carbon.h>
+#elif defined (HAVE_X_WINDOWS)
+#include <X11/Xlib.h>
+#endif
+
+#include "cdisplay.h"
+
+const char *
+octave_get_display_info (int *ht, int *wd, int *dp, double *rx, double *ry,
+                         int *dpy_avail)
+{
+  const char *msg = 0;
+
+  *dpy_avail = 0;
+
+#if defined (OCTAVE_USE_WINDOWS_API)
+
+  HDC hdc = GetDC (0);
+
+  if (hdc)
+    {
+      *dp = GetDeviceCaps (hdc, BITSPIXEL);
+
+      *ht = GetDeviceCaps (hdc, VERTRES);
+      *wd = GetDeviceCaps (hdc, HORZRES);
+
+      double ht_mm = GetDeviceCaps (hdc, VERTSIZE);
+      double wd_mm = GetDeviceCaps (hdc, HORZSIZE);
+
+      *rx = *wd * 25.4 / wd_mm;
+      *ry = *ht * 25.4 / ht_mm;
+
+      *dpy_avail = 1;
+    }
+  else
+    msg = "no graphical display found";
+
+#elif defined (HAVE_FRAMEWORK_CARBON)
+
+  CGDirectDisplayID display = CGMainDisplayID ();
+
+  if (display)
+    {
+#if defined (HAVE_CARBON_CGDISPLAYBITSPERPIXEL)
+
+      *dp = CGDisplayBitsPerPixel (display);
+
+#else
+
+      /* FIXME: This will only work for MacOS > 10.5. For earlier versions
+         this code is not needed (use CGDisplayBitsPerPixel instead).  */
+
+      CGDisplayModeRef mode = CGDisplayCopyDisplayMode (display);
+      CFStringRef pixelEncoding = CGDisplayModeCopyPixelEncoding (mode);
+
+      if (CFStringCompare (pixelEncoding, CFSTR (IO32BitDirectPixels), 0) == 0)
+        *dp = 32;
+      else if (CFStringCompare (pixelEncoding,
+                                CFSTR (IO16BitDirectPixels), 0) == 0)
+        *dp = 16;
+      else
+        *dp = 8;
+
+#endif
+
+      *ht = CGDisplayPixelsHigh (display);
+      *wd = CGDisplayPixelsWide (display);
+
+      CGSize sz_mm = CGDisplayScreenSize (display);
+
+      /* For MacOS >= 10.6, CGSize is a struct keeping 2 CGFloat
+         values, but the CGFloat typedef is not present on older
+         systems, so use double instead.  */
+
+      double ht_mm = sz_mm.height;
+      double wd_mm = sz_mm.width;
+
+      *rx = *wd * 25.4 / wd_mm;
+      *ry = *ht * 25.4 / ht_mm;
+
+      *dpy_avail = 1;
+    }
+  else
+    msg = "no graphical display found";
+
+#elif defined (HAVE_X_WINDOWS)
+
+  const char *display_name = getenv ("DISPLAY");
+
+  if (display_name && *display_name)
+    {
+      Display *display = XOpenDisplay (display_name);
+
+      if (display)
+        {
+          Screen *screen = DefaultScreenOfDisplay (display);
+
+          if (screen)
+            {
+              *dp = DefaultDepthOfScreen (screen);
+
+              *ht = HeightOfScreen (screen);
+              *wd = WidthOfScreen (screen);
+
+              int screen_number = XScreenNumberOfScreen (screen);
+
+              double ht_mm = DisplayHeightMM (display, screen_number);
+              double wd_mm = DisplayWidthMM (display, screen_number);
+
+              *rx = *wd * 25.4 / wd_mm;
+              *ry = *ht * 25.4 / ht_mm;
+            }
+          else
+            msg = "X11 display has no default screen";
+
+          XCloseDisplay (display);
+
+          *dpy_avail = 1;
+        }
+      else
+        msg = "unable to open X11 DISPLAY";
+    }
+  else
+    msg = "X11 DISPLAY environment variable not set";
+
+#else
+
+  msg = "no graphical display found";
+
+#endif
+
+  return msg;
+}