--- a/scripts/ChangeLog	Wed Jun 23 11:44:21 2010 +0200
+++ b/scripts/ChangeLog	Wed Jun 23 12:57:36 2010 +0200
@@ -1,3 +1,10 @@
+2010-06-23  David Bateman  <dbateman@free.fr>
+
+	* whitebg.m: New function.
+	* module.mk (plot_FCN_FILES): Add it here.
+	* __go_draw_figure__.m: Set the border color to the inverse of the
+	background color.
+
 2010-06-17  Brad Froehle <brad.froehle@gmail.com>
 
 	* sparse/spy.m: Fix typo.

--- a/scripts/plot/__go_draw_figure__.m	Wed Jun 23 11:44:21 2010 +0200
+++ b/scripts/plot/__go_draw_figure__.m	Wed Jun 23 12:57:36 2010 +0200
@@ -92,6 +92,9 @@
                 else
                   fg_is_set = false;
                 endif
+                if (bg_is_set)
+                  fprintf (plot_stream, "set border linecolor rgb \"#%02x%02x%02x\"\n", 255 * (1 - bg));
+                endif
                 if (output_to_paper)
                   axes_position_on_page = orig_axes_position .* paper_position([3, 4, 3 ,4]);
                   axes_position_on_page(1:2) = axes_position_on_page(1:2) +  paper_position(1:2);

--- a/scripts/plot/module.mk	Wed Jun 23 11:44:21 2010 +0200
+++ b/scripts/plot/module.mk	Wed Jun 23 12:57:36 2010 +0200
@@ -157,6 +157,7 @@
   plot/title.m \
   plot/view.m \
   plot/waitforbuttonpress.m \
+  plot/whitebg.m \
   plot/xlabel.m \
   plot/xlim.m \
   plot/ylabel.m \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/plot/whitebg.m	Wed Jun 23 12:57:36 2010 +0200
@@ -0,0 +1,143 @@
+## Copyright (C) 2010 David Bateman
+##
+## 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/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} whitebg ()
+## @deftypefnx {Function File} {} whitebg (@var{color})
+## @deftypefnx {Function File} {} whitebg (@var{fig})
+## @deftypefnx {Function File} {} whitebg (@var{fig}, @var{color})
+## Inverts the colors in the current current.  The root properties are
+## also inverted such that all subsequent plot use the new color scheme.
+##
+## If defined, @var{fig} is the handle to the figure to be inverted.  In
+## this case only this figure has its color properties changed
+##
+## The background colors of the figure and its children can be set 
+## specifically if @var{color} is defined.  @var{color} must be a valid
+## color set as a string or an RGB triplet, or  the value "none".
+##
+## @seealso{reset, colordef}
+## @end deftypefn
+
+function whitebg (varargin)
+  h = 0;
+  color = NaN;
+
+  if (nargin > 0 && nargin < 2)
+    if (ishandle (varargin{1}))
+      h = varargin{1};
+      if (nargin == 2)
+        color = varargin{2};
+      endif
+    elseif (nargin == 1)
+      color = varargin{1};
+    else
+      print_usage ();
+    endif
+  elseif (nargin != 0)
+    print_usage ();
+  endif
+
+  typ = get (h, "type");
+
+  if (strcmp (typ, "root"))
+    isroot = true;
+    fig = gcf ();
+  elseif (strcmp (typ, "figure"))
+    isroot = false;
+    fig = h;
+  else
+    error ("expecting a figure handle");
+  endif
+
+  axes = findall (fig, "type", "axes");
+  if (isnan (color))
+    ## Root figure. Set the default axes and figure properties so that
+    ## subsequent plots have the new color scheme
+    if (isroot)
+      fac = get (0, "factory");
+      fields = fieldnames (fac);
+      fieldindex = intersect (find (!cellfun (@isempty, regexp(fields, ".*color.*"))), union (find (!cellfun (@isempty, regexp(fields, "factoryaxes.*"))), find (!cellfun (@isempty, regexp(fields, "factoryfigure.*")))));
+
+      ## Check whether the factory value has been replaced
+      for nf = 1 : numel (fieldindex);
+        defaultfield = strrep (fields {fieldindex (nf)}, "factory", "default");
+        try
+          defaultvalue = 1 - get (0, defaultfield {n});
+        catch
+          field = fields {fieldindex (nf)};
+          defaultvalue = 1 - subsref (fac, struct ("type", ".", "subs", field));
+        end_try_catch
+        set (0, defaultfield, defaultvalue);
+      endfor
+    endif
+
+    ## Load all objects which qualify for being searched.
+    handles = fig;
+    h = fig;
+    while (numel (handles))
+      children = [];
+      for n = 1 : numel (handles)
+        children = union (children, get(handles(n), "children"));
+      endfor 
+      handles = children;
+      h = union (h, children);
+    endwhile
+
+    for nh = 1 : numel(h)
+      p = get (h (nh));
+      fields = fieldnames (p);
+      fieldindex = find (!cellfun (@isempty, regexp(fields, ".*color.*")));
+      if (numel (fieldindex))
+        for nf = 1 : numel (fieldindex);
+          field = fields {fieldindex (nf)};
+          c = subsref (p, struct ("type", ".", "subs", field));
+          if (! ischar(c) && columns(c) == 3)
+            set (h (nh), field, 1 - c);
+          endif
+        endfor
+      endif
+
+      ## If h(nh) is a figure or axes invert default color properties
+      typ = subsref (p, struct ("type", ".", "subs", "type"));
+      if (strcmp (typ, "axes") || strcmp (typ, "figure"))
+        def = get (h (nh), "default");
+        fields = fieldnames (def);
+        if (! isempty (fields))
+          fieldindex = find (!cellfun (@isempty, regexp(fields, ".*color.*")));
+          for nf = 1 : numel (fieldindex)
+            defaultfield = fields {fieldindex (nf)};
+            defaultvalue = 1 - subsref (def, struct ("type", ".", "subs", defaultfield));
+            set (h (nh), defaultfield, defaultvalue);
+          endfor
+        endif
+      endif
+    endfor
+  else
+    ## FIXME
+    ## Is this the right thing to do in this case?
+    set (findall (fig, "type", "axes"), "color", color);
+    if (isroot)
+      defs = get (0, "defaults");
+      if (isfield (defs, "defaultaxescolor") 
+          && strcmp (defs.defaultaxescolor, "none"))
+        set (0, "defaultaxescolor", color);
+      endif
+    endif
+  endif
+endfunction